TERMINOLOGY

Cranial cavity: This compartment houses the brain, its associated meninges and blood supply and the twelve pairs of cranial nerves.

Orbits: Pyramidal-shaped cavities in the facial skeleton, the orbits contain and protect the eyes and their muscles, nerves and vessels, and most of the lacrimal apparatus.

Ear: Each ear is divided into external, middle and inner portions; the middle and inner ears are located entirely within the “petrous portion” of the temporal bone, the external ear is located in the temporal bone and in the face.

Nose: This superior-most portion of the respiratory system is divided into right and left nasal cavities by the midline nasal septum.

Oral cavity: This compartment houses the teeth, tongue, two of the three pairs of major salivary glands and their associated nerves and vessels.

WHAT ARE THE COMPARTMENTS OF THE NECK

Deep muscular compartment: Enclosed within the prevertebral layer of the deep cervical fascia; this compartment contains the cervical vertebral column and its associated muscles.

Visceral compartment: Enclosed by the pretracheal layer of the deep cervical fascia; this compartment contains the cervical viscera (pharynx/esophagus, larynx/trachea, thyroid gland) and their associated nerves and vessels.

Carotid sheath: Enclosed by contributions from all three layers of the deep cervical fascia; this compartment contains the common carotid and internal carotid arteries, the internal jugular vein and the vagus nerve (CN X).

The investing (superficial) layer of the deep cervical fascia encloses all three deep compartments and surrounds the neck like a cervical collar; on each side it splits to “invest” two muscles (trapezius and sternocleidomastoid) and two salivary glands (parotid and submandibular).

NAME 3 SYNOVIAL JOINTS IN THE HEAD

Temporomandibular joint (TMJ): this singular joint occurs between the right and left condyles of the mandible and the right and left mandibular fossae of the temporal bones, respectively

Each articulation is divided in two by an intervening fibrocartilaginous disc

Movements allowed include protrusion and retrusion, and rotation (elevation and depression) of the mandible.

Atlanto-occipital joints: between the lateral masses of the C1 vertebra and the occipital condyles of the skull

primary movements permitted at these joints are flexion and extension

Interossicular joints: between the maleus and incus and between the incus and the stapes of the middle ear

the mobile chain of auditory ossicles transmits vibrations from the tympanic membrane (eardrum) to the sensory organs of the inner ear.

INTERNAL CAROTID ARTERY

From the carotid bifurcation, the internal carotid artery ascends vertically within

the neck without branching and enters the carotid canal of the temporal bone.

Upon exiting the carotid canal the internal carotid artery passes through the

cavernous sinus. Posterior to the optic canal the internal carotid artery pierces

the dural roof of the cavernous sinus and gives off the ophthalmic artery. It then

enters the subarachnoid space at the base of the brain where it terminates as

the middle and anterior cerebral arteries.

EXTERNAL CAROTID ARTERY

From the carotid bifurcation the external carotid artery exits the carotid sheath and ascends, slightly anterior to the internal carotid artery, to enter the substance of the parotid gland. Within the gland the external carotid artery gives rise to its two terminal branches: the superficial temporal artery and the maxillary artery.

Within the neck the external carotid artery gives rise to the following clinically important branches:

Superior thyroid artery. This artery descends to supply the thyroid gland.

Lingual artery. This artery supplies structures in the floor of the oral cavity (i.e., Tongue, mucosa, sublingual gland).

Facial artery. This artery supplies the muscles of facial expression, the lacrimal sac and the anterior aspect of the nasal septum.

Posterior auricular. This artery supplies the scalp posterior to the ear (auricle).

Occipital artery. This artery supplies the posterior aspect of the scalp.

WHICH ARTERIES SUPPLY THE HEAD AND NECK

AND WHAT ARE THEIR ORIGINS

Common carotid Internal carotid

Subclavian Vertebral-Basilar

On the right side from the Brachiocephalic trunk

On the left side direct from the aortic arch

HOW DOES THE VERTEBRAL ARTERY ENTER

THE CRANIAL CAVITY

The vertebral artery is the FIRST branch of the subclavian

It branches between the subclavian outlet and the interscalene triangle

Ascends through the transverse foramina starting at C6

Passes along superior surface of posterior arch of C1

Enters through the foramen magnum

DESCRIBE THE DRAINAGE OF THE CRANIAL

CAVITY

The dural venous sinuses empty into the Internal jugular veins

Dural venous sinuses are the endothelial- lined channels between the layers

of the dura mater

NO VALVES OR SMOOTH MUSCLE

Extracranial veins empty into internal jugular vein or subclavian

The internal jugular and subclavian brachiocephalic superior vena cava

Intra and extra-cranial veins communicate via EMISSARY VEINS

IMPORTANT ROUTE OF INFECTIONS

DESCRIBE THE LOCATION OF THE DEEP

CERVICAL CHAIN

The deep cervical chain consists of 15-30 nodes that lie along the carotid

sheath, deep to the sternocleidomastoid muscle.

Deep cervical nodes are subdivided into two groups based upon their location

relative to the superior belly of the omohyoid muscle: Superior and Inferior

THE SKULL

SUTURES

Sutures are tension-adapted growth centers of the skull; new bone tissue is

deposited at sutures (along the margins of both bones) in direct response to the

tension generated within them as the brain, eyes, nasal septum, nasal mucosa,

and tongue expand, and as the teeth develop and erupt into occlusion.

Sutures normally fuse after growth has ceased. Some sutures, especially

those of the calvaria fuse long after the growth has ceased. For example,

fusion of the sagittal and coronal sutures typically begins sometime between

the ages of 30 and 40 years.

OSSIFICATION

The bone of the skull is produced through both endochondral and

intramembranous ossification.

Most of the bone of the basicranium (ethmoid and portions of frontal, sphenoid,

temporals and occipital) is preformed in cartilage

Bone of the calvaria (parietal and portions of frontal, sphenoid, temporals and

occipital) and most of the bones of the face are preformed in membrane.

DESCRIBE THE FUNCTION OF CRANIAL

FONTANELLES DURING PARTURITION.

The softness of the cranial bones of the neonate and their loose connections at

sutures enable the skull to change shape (mold) as it passes through the birth

canal.

Anterior, anterolateral (sphenoid) and posterolateral (mastoid)

PALATINE, VOMER, ZYGOMATIC BONES

Mandible

IDENTIFY THE CLINICAL SIGNIFICANCE OF THE

ANTERIOR FONTANELLE IN NEONATES.

Palpation of the fontanelles is a part of the physical examination of an infant

A bulging or tense fontanelle indicates raised intracranial pressure

A sunken fontanelle indicates dehydration

Cerebral arteries cause pulsation and blood samples can be obtained here

IDENTIFY THE BONE IN THE SKULL THAT

HOUSES THE CAROTID CANAL

Petrous Temporal Bone

Also inner and middle ear and facial canal

Structures of the inner ear = cochlea, semicircular canals

Structures of middle ear = Auditory Ossicles = malleus, incus, and stapes

The internal carotid artery exits the petrous bone, enters the cavernous

sinus, does a big wiggle and then branches into the ACA and MCA

LIST THE FOUR BONES INVADED BY

PARANASAL AIR SINUSES DURING BIRTH

Frontal

Ethmoid

Sphenoid

Maxillary

THE SKULL

The neurocranium is further divided

into the cranial base (basicranium)

and the calvaria. The calvaria

consists of the flat bones that form

the walls and roof of the

neurocranium.

Viscerocranium: frontal, maxilla,

nasal, zygomatic, palatine,

mandible

WHAT IS THE CAUSE OF CRANIOSYNOSTOSIS?

Premature fusion of sutures

WHAT ARE THE COMPONENTS OF THE NASAL

SEPTUM

Vomer

Perpendicular plate

of ethmoid

Nasal septum

cartilage

NAME TWO IMPORTANT GROWTH CARTILAGES

OF THE SKULL

Spheno-occipital synchondrosis

Nasal septum cartilage

Can be affected by achondroplasia!

Pterion

(“P” is silent)

Styloid process

Mastoid process

Ramus of mandible

Angle of mandibleBody of mandible

PTERYGOPALATINE FOSSA

Pterygopalatine fossa

(“P” is silent)

THE INTERNAL CAROTID ARTERY PASSES OVER

WHICH FORAMEN BEFORING ENTERING

CANAL?

Foramen lacerum

NAME THE SEGMENTS OF THE INTERNAL

CAROTID

Certical cervical segment in the neck, followed by a sharp horizontal bend as

the internal carotid enters the temporal bone as the petrous segment.

Cavernous segment as the internal carotid begins an S-shaped turn, also

known as the carotid siphon, within the cavernous sinus.

Passes the anterior clinoid process to pierce the dura and bends posteriorly to

enter the subarachnoid space as the supraclinoid, or intracranial segment.

Main branches of the supraclinoid internal carotid artery can be remembered by

the mnemonic OPAAM: Ophthalmic, Posterior communicating, Anterior

choroidal, Anterior cerebral, and Middle cerebral arteries.

The ophthalmic artery usually arises from the bend in the internal carotid just

after it enters the dura. The ophthalmic artery enters the optic foramen with the

optic nerve and provides the main blood supply to the retina.

MIDDLE EAR IS LOCATED LATERAL OR MEDIAL

TO THE SEMICIRCULAR CANALS?

Lateral

IN WHAT LOBE DOES THE LATERAL (SYLVIAN)

FISSURE TERMINATE?

The Parietal Lobe

NAME FOUR FUNCTIONS OF THE TEMPORAL LOBE

Speech

Memory

Olfaction

Audition

NAME THE TWO BLOOD SUPPLIES OF THE BRAIN

Vertebral-Basilar

Temporal

Occipital

Brain stem

Cerebellum

Internal Carotid

Diencephalon

Frontal

Parietal

Basal Ganglia

Internal Capsule

VERY LITTLE MIXING

NAME TWO KEY SYMPTOMS OF A BLOCKAGE OF THE

VERTEBRAL-BASILAR CIRCULATION

Vision problems (occipital)

Dizziness (cerebellum)

NAME THE BRANCHES OF THE VERTEBRAL

ARTERIES

PICA

Anterior Spinal

Posterior Spinal

Basilar

PICA

PICA runs circumferentially around the medulla

Gives off penetrating branches that supply the dorsolateral medulla and the

choroid plexus of the fourth ventricle.

PICA then continues superiorly to supply posterior and inferior parts of the

cerebellum and cerebellar peduncles.

ANTERIOR SPINAL

Supplies median and paramedian aspects of the medulla oblongata and

anterior 2/3 of spinal cord

NAME THE BRANCHES OF THE BASILAR ARTERY

AICA

Pontine

Superior Cerebellar

Posterior Cerebral Artery

AICA

Travels along the caudal end of the middle cerebellar peduncle

Supplies the upper medulla and lower pons, and the anterior inferior surface of

the cerebellum.

SUPERIOR CEREBELLAR

Travels along the pons and middle cerebellar peduncle

Supplies the superior cerebellum

POSTERIOR CEREBRAL ARTERIES

The basilar artery branches at the level of the midbrain and each posterior

cerebral artery supplies:

• MEDIAL and INFERIOR surface of the temporal and occipital lobes,

Thalamus

Internal structures

Hippocampus*

Occlusion of PCA may lead to visual field deficits. Patients may be unable to

drive or read, resulting in major limitations in their quality of life, despite normal

motor function.

Thalamic involvement can produce sensory loss or thalamic pain syndrome, a

hypersensitivity to pain.

NAME THE BRANCHES OF THE INTERNAL

CAROTID SYSTEM

Opthalmic artery

Middle cerebral artery

Anterior cerebral artery

Anterior choroidal artery

Lenticulostriate arteries

OPTHALMIC

Supplies orbit, eye and scalp

Shade going down over one eye

RISK OF FUTURE STROKE

MIDDLE CEREBRAL ARTERIES

Runs laterally between the temporal lobe and the frontal lobe to emerge from

the LATERAL sulcus (sylvian fissure).

Each MCA divides into several branches to supply the LATERAL surface of the

hemisphere, including the primary motor and primary sensory areas of cortex,

located in the pre-central and post-central gyri.

ANTERIOR CEREBRAL ARTERIES

Runs along the medial surface of each cerebral hemisphere and curves

dorsally and caudally to lie superior to the corpus callosum – wraps around

corpus callosum

The ACAs supply the MEDIAL portions of the frontal and parietal lobes as well

as the corpus callosum.

Distal branches of the ACAs supply the MEDIAL surface of the parietal lobe,

including the paracentral lobule.

LENTICULOSTRIATE ARTERIES

Small arteries arising from the middle and anterior cerebral arteries that

penetrate the brain in the anterior perforated substance

Supply deep structures: basal ganglia and internal capsule

These small vessels arise from the initial portions of the middle cerebral artery

before it enters the Sylvian fissure and they penetrate the anterior perforated

substance to supply large regions of the basal ganglia and internal capsule.

Lacunar infarct

ANTERIOR CHOROIDAL ARTERIES

Branch off INTERNAL CAROTID

Supplies the optic tracts and the posterior limb of the internal capsule.

Its territory includes portions of the globus pallidus, putamen, thalamus

(sometimes involving part of the lateral geniculate nucleus), and the posterior

limb of the internal capsule extending up to the lateral ventricle

Recall that the posterior limb of the internal capsule contains important motor

pathways through the corticobulbar and corticospinal tracts. Thus, lacunar

infarction in either the lenticulostriate or anterior choroidal territories often

causes contralateral hemiparesis

OPTIC CHIASM

The point of intersection between the optic nerve CN II and the optic tracts

DAMAGE TO THE FRONTAL LOBE IMPAIRS…

the ability to make decisions, including anticipating the future consequences of

an action and responding appropriately in social situations.

THE CINGULATE GYRUS IS INVOLVED IN…

The cingulate gyrus is a prominent part of the limbic system, which plays a role

in emotion, behavior, long-term memory and olfaction.

A PATIENT WHO HAS DIFFICULTY RECOGNIZING

ONE SIDE OF THEIR BODY MAY HAVE DAMAGE

TO THIS REGION

Inferior parietal lobule

THE INSULAR CORTEX IS INVOLVED IN…

Taste

Visceral physiological function

Nicotine addiction

Blood vessel Deficit

Left MCA Right hemiplegia,

hemianesthesia, homonymous

hemianopia and global aphasia.

Left gaze preference.

Right MCA Left hemiplegia,

hemianesthesia, homonymous

hemianopia and profound left

hemineglect. Right gaze

preference.

ACA Contralateral leg weakness and

sensory loss, grasp reflex,

frontal lobe behavioral

abnormalities

PCA Right homonymous

hemianopia. Infarcts extending

to thalamus and internal

capsule may cause

hemiparesis or hemianesthesia

LACUNAR SYNDROMES

GIVEN HORIZONTAL, CORONAL OR

MIDSAGITTAL SECTIONS OF THE BRAIN,

IDENTIFY THE VASCULAR TERRITORIES OF MCA,

ACA, PCA, PICA, SCA, AICA, AND THE ANTERIOR

CHOROIDAL AND LENTICULOSTRIATE ARTERIES.

NAME THE ARTERIES THAT SUPPLY MEDIAL

BRAINSTEM STRUCTURES. NAME THE ARTERIES

THAT SUPPLY DORSOLATERAL BRAINSTEM

STRUCTURES.

Medial: Basilar, Anterior Spinal Artery

Dorsolateral: PICA, SCA, PCA

NAME THE BLOOD VESSELS THAT SUPPLY THE

SPINAL CORD.

The Spinal Cord is supplied by the vertebral

arteries and the anterior and posterior spinal

arteries.

Paramedian branches penetrate along the

ventro-medial fissure.

Circumferential branches penetrate white

matter on the lateral aspect of the cord to

supply ventral and lateral portions of the cord”

DEFINE A BERRY ANEURYSM. DISCUSS THE

SIGNIFICANCE OF BERRY ANEURYSMS IN

SUBARACHNOID HEMORRHAGE.

A berry or saccular aneurysm is an aneurism that arises in the small branching points of arteries near the circle of Willis

Abnormal widening due to weakness of vessel

Although a cerebral aneurysm may be present without symptoms, the most common initial symptom of a cerebral saccular aneurysm is a sudden headache from a subarachnoid hemorrhage (SAH).

85% in anterior circulation

Subhyaloid hemorrhages are pathognomonic for subarachnoid hemorrhage

LIST THE THREE DIVISIONS OF CN V

(TRIGEMINAL) AND IDENTIFY THE NERVE

COMPONENTS CARRIED BY EACH.

V1 - Opthalmic

sensory only

V2 - Maxillary

sensory only

V3 - Mandibular

sensory + motor root

innervations muscles of

mastication (masseter,

temporalis, medial and

lateral pterygoids and

some other smaller ones

THE FACIAL NERVE EXITS THE SKULL THROUGH

THE ________?

Stylomastoid foramen

LIST THE THREE PRIMARY BRANCHES OF CN VII

(FACIAL) AND DESCRIBE THEIR FUNCTIONS.

“Motor”

Motor to muscles of facial expression; motor to stapedius muscle of middle

ear

Greater petrosal

Delivers preganglionic parasympathetic fibers to pterygopalatine ganglion

Chorda tympani

Delivers preganglionic parasympathetic fibers to submandibular ganglion;

taste sensation from anterior 2/3 of tongue

IDENTIFY THE SENSORY AND AUTONOMIC

FUNCTIONS OF CN IX (GLOSSOPHARYNGEAL).

Somatic Sensory from posterior 1/3 of tongue, nasopharynx, oropharynx,

tympanic cavity & internal surface of tympanic membrane, posterior soft palate

Taste sensation from posterior 1/3 of tongue

Visceral sensation from carotid body and carotid sinus

Autonomic preganglionic parasympathetic innervation to otic ganglion (parotid

gland)

IDENTIFY THE SENSORY, MOTOR AND

AUTONOMIC FUNCTIONS OF CN X (VAGUS).

Superior laryngeal nerve

Sensory from larynx superior to the vocal folds (internal branch); motor to cricothyroid and cricopharyngeus muscles (external branch)

Inferior (recurrent) laryngeal nerve

Sensory from vocal folds and inferior larynx

Motor to all intrinsic laryngeal muscles except cricothyroid

Additional branches

Sensory from dura, auricle, external auditory meatus, laryngopharynx

Visceral sensory from carotid body and carotid sinus, thoracic and abdominal viscera

Motor to pharynx, uvula and elevator of soft palate

Autonomic preganglionic parasympathetic innervation to terminal ganglia in walls of thoracic and abdominal viscera

LIST THE THREE CRANIAL NERVES THAT CARRY

SPECIAL SENSORY FIBERS AND IDENTIFY THE

MODALITY TO WHICH EACH IS DEDICATED.

CN I - Olfactory - Smell

CN II - Optic - Vision

CN VIII - Vestibulocochlear – Hearing and balance

LIST THE TWELVE CRANIAL NERVES AND

IDENTIFY THE FORAMINA OF THE CRANIAL

BASE THAT TRANSMIT THEM FROM THE

CRANIAL CAVITY. CN I – Olfactory - Cribriform plate of ethmoid bone to nasal cavity CN II – Optic - Optic canal of sphenoid bone to orbit CN III – Oculomotor - Superior orbital fissure to orbit CN IV – Trochlear - Superior orbital fissure to orbit CN V – Trigeminal

Opthalmic – Superior orbital fissure Maxillary – Foramen rotundum Mandibular – foramen ovale

CN VI – Abducens - Superior orbital fissure to orbit CN VII – Facial – Internal acoustic meatus and out stylomastoid foramen CN VIII – Vestibulocochlear – Internal acoustic meatus CN IX – Glossopharyngeal – Jugular foramen CN X – Vagus – Jugular foramen CN XI – Spinal Accessory – Enters foramen magnum, exits jugular foramen CN XII – Hypoglossal – Hypoglossal canal

LIST THE NERVES THAT PROVIDE SENSORY

INNERVATION TO THE DURA AND DESCRIBE

THEIR GENERAL DISTRIBUTION.

Anterior fossa: trigeminal nerve – V1. V2. V3

Posterior fossa: C1-3 and, Vagus nerves

WHICH THREE CRANIAL NERVES ARE MIXED

NERVES?

Facial

Glossopharyngeal

Vagus

Also Trigeminal…

LAYERS OF HEAD/NECK

Skin

Connective tissue (Dense) – External blood vessels are here

Aponeurosis of the epicranium

Loose connective tissue

Pericranium – Diploe

Emissary veins

Periosteal Dura mater

Meningeal Dura mater – meningeal arteries, dural venous sinuses

Bridging veins, Arachnoid granulations

Arachnoid mater

Subarachnoid Space – Cerebral/cerebellar arteries/veins

Pia Mater

Brain

THE CAUDAL BORDER OF THE PARIETAL LOBE IS

BEST SEEN IN WHAT VIEW

Medial : the parieto-occipital sulcus is apparent in this view.

WHAT LIES BETWEEN THE TWO CEREBRAL

PEDUNCLES?

Interpeduncular fossa: exit of oculomotor nerve

Mamillary bodies

THE PRECENTRAL AND POSTCENTRAL GYRI

COME TOGETHER TO FORM THE…

Paracentral lobule

THE INTRAPARIETAL SULCUS DIVIDES THESE

TWO STRUCTURES

Superior and Inferior Parietal Lobules

IN THE OCCIPATAL LOBE, THE _____ FISSURE

DIVIDES THE ______ AND _______

Calcarine

Cuneus : upper retina – lower visual field

Lingual gyrus: lower retina – upper visual field

THE CAUDAL PORTION OF THE SUPERIOR

TEMPORAL GYRUS HAS SMALL OBLIQUE GYRI

Transverse temporal gyri (of Heschl)

Primary auditory cortex

THESE GYRI CAN BE VIEWED ON THE INFERIOR

SURFACE OF THE BRAIN

Parahippocampal gyrus (medial)

Uncus

Occipito-temporal

NAME THE FOUR PARTS OF THE CORPUS

CALLOSUM FROM ROSTRAL TO CAUDAL

Rostrum

Genu

Body

Splenium

NAME THE 5 COMMISSURES

Corpus callosum

Anterior commissure

Posterior commissure

Fornix

Optic chiasm

WHAT IS THE RELATION OF THE

HYPOTHALAMUS TO THE THALAMUS

The hypothalamus is the rostral and inferior border of the thalami.

The hypothalamus is a smaller brain structure that comprises the inferolateral

borders of the third ventricle.

The third ventricle forms the medial border of the hypothalamus.

The anterior border of the hypothalamus is the lamina terminalis, a thin sheet

of neural tissue that marks the rostral boundary of the original neural tube

from which the brain and spinal cord developed.

The optic chiasm (mentioned above) is the rostral border of the

hypothalamus.

The mammillary bodies form the caudal border of the hypothalamus

The hypothalamus also includes the infundibulum, which is the pituitary stalk

connecting the pituitary to the hypothalamus. The hypothalamus has

homeostatic and reproductive functions.

NAME THE IMPORTANT CISTERNS IN THE

CRANIAL CAVITY

Cerebellomedullary cistern

Superior cistern

Interpeduncular cistern

Pontine cistern

Chiasmatic cistern

Cistern of lateral fossa

Lumbar cistern

THE CSF ESCAPES TO THE SUBARACHNOID

SPACE THROUGH…

Lateral foramina of Luschka

Midline median aperture of Magendie

CHOROID PLEXUS

Choroid Plexus = highly specialized tissue with elaborate folds and many villi

projecting into the four large ventricles of the brain

Found on the roofs of the third/fourth ventricles and in parts of the two lateral

ventricular walls = regions where the ependymal lining directly contacts pia

mater

FUNCTION = remove water from blood and release it as CSF

CSF = clear, containing Na, K, and Cl ions but little protein

Produced continuously and provides the ions required for CNS neuronal activity

and also serves as a shock absorber

NAME THE THIN MEMBRANE THAT SEPARATES

THE LATERAL VENTRICLES

Septum Pallucidum

WHAT IS THE RESULT OF A BUILDUP OF CSF

Hydrocephalus

EACH VENTRICLE IS ASSOCIATED WITH A

PRINCIPLE BRAIN REGION..

Lateral ventricle – telencephalon

Third Ventricle – diencephalon

Cerebral aqueduct – midbrain - MESENCEPHALON

Fourth ventricle – medulla and pons –

METENCEPHALON/MYELENCEPHALON

WHAT NERVE EXITS THE BRAIN AT THE SULCUS

THAT DIVIDES THE OLIVES FROM THE

MEDULLARY PYRAMIDS

Hypoglossal nerve

THE SUPERIOR COLLICULI ARE INVOLVED IN…

Coordinating eye movements – SEEING

Inferior - auditory

A THIN SHEET OF NEURAL TISSUE THAT MARKS

THE ROSTRAL BOUNDARY OF THE ORIGINAL

NEURAL TUBE FROM WHICH THE BRAIN AND

SPINAL CORD DEVELOPED

Lamina Terminalis – anterior border of hypothalamus

IDENTIFY THE ARTERY OF ORIGIN OF THE

MIDDLE MENINGEAL ARTERY

External carotid artery → Maxillary artery → Middle meningeal artery

Middle meningeal through foramen spinosum

DISCUSS THE SIGNIFICANCE OF THE MIDDLE

MENINGEAL ARTERY WITH RESPECT TO

CALVARIAL FRACTURES AND EPIDURAL

(EXTRADURAL) HEMORRHAGE.

The middle meningeal artery lies under the thin pterion bone. A strong blow to

the side of the head can cause this bone to fracture. A fracture in the pterion is

called a calvarial fracture and commonly causes tears in the middle meningeal

arteries below. These tears lead to bleeding into the epidural space called

epidural (extradural) hemorrhage.

DISTINGUISH A DURAL VENOUS SINUS FROM A

PARANASAL SINUS.

Dural Venous Sinus

Between dural layers

Contains blood and CSF

Paranasal sinus

Between cranial bones around nose

Contains air

VENOUS DRAINAGE OF THE BRAIN…

Cerebral veins→ Superior sagittal sinus→ confluence of sinuses→ transverse sinus (usually

right)→ becomes sigmoid sinuses → Internal jugular vein

Inferior sagittal sinus→ straight sinus→ confluence of sinuses→ transverse sinus (usually left)

→ becomes sigmoid sinuses→ Internal jugular vein

Drainage is asymmetric in that the superior sagittal sinus drains into right transverse

Ophthalmic veins, middle cerebral veins, sphenoparietal sinus → cavernous sinus Superior

petrosal sinus→ transverse sinuses→ becomes sigmoid sinuses→ Internal jugular vein

Inferior petrosal sinus→ Internal jugular vein

Carvernous sinus drains into both the superior and inferior petrosal sinuses

DOES THE SUPERIOR SAGITTAL SINUS USUALLY

DRAIN INTO THE RIGHT OR LEFT TRANSVERSE?

Right

Straight Sinus goes to left

DISCUSS THE SIGNIFICANCE OF THE BASILAR

PLEXUS AND OCCIPITAL SINUSES IN THE

METASTASIS OF CANCER TO THE VERTEBRAE

AND BRAIN.

The occipital sinus, along with the basilar plexus (a.k.a transverse sinuses) of

veins located on the basioccipital clivus communicate with the internal vertebral

venous plexus through the foramen magnum.

Because these venous channels are valveless, compression of the thorax,

abdomen and pelvis (during coughing or heavy straining) may force venous

blood from these regions into the internal vertebral venous system and

subsequently into the dural venous sinuses.

As a result, pus in abscesses and tumor cells in these regions may spread to

the vertebrae and brain.

DEFINE “BRIDGING” VEINS. DISCUSS THE

SIGNIFICANCE OF BRIDGING VEINS TO DURAL

BORDER (SUBDURAL) HEMATOMAS.

“Cerebral and cerebellar veins - veins which drain brain tissue – drain to the

dural venous sinuses. These veins are often referred to as “bridging veins”

because they must “bridge” the subarachnoid space in order to gain access to

and open into the dural venous sinuses.

In light of this, extravasated blood from a torn bridging vein collects between

the dura and the arachnoid and results in a subdural (dural border) hemorrhage

LIST THE SEVEN (7) STRUCTURES CONTAINED

WITHIN THE CAVERNOUS SINUS OR ITS WALL.

Embedded

Oculomotor

Trochlear

Opthalmic CN V1

Maxillary CN V2

Pass through

Abducens

Internal Carotid

CSF IS RECYCLED INTO THE VENOUS SYSTEM

THROUGH THESE STRUCTURES

Arachnoid granulations superior sagittal sinus

DURAL VENOUS SINUSES LIE AT THE

SEPARATION OF THESE TWO STRUCTURES

The periosteal and meningeal dural layers

THE STRAIGHT SINUS IS FORMED BY THE …

Inferior sagittal sinus and the great cerebral vein (of Galen)

THE SICKLE-SHAPED FOLD OF DURA THAT

EXTENDS INTO THE LONGITUDINAL CEREBRAL

FISSURE OF THE BRAIN,

Cerebral Falx

Attachment: Crista Galli

TRANSVERSELY-ORIENTED FOLD OF DURA

WITHIN THE TRANSVERSE CEREBRAL FISSURE.

Cerebellar Tentorium

Attachment: Petrosal arch

LATERAL TO THE CEREBRAL FALX WHICH

ARTERY CAN BE IDENTIFIED WITHIN THE DURA?

Middle meningeal artery

THE SIGMOID SINUS BEGINS WHERE…

By definition the sigmoid sinus begins where the superior petrosal sinus joins

the transverse sinus

internal jugular vein begins where the inferior petrosal sinus joins the sigmoid

sinus

WHAT THREE STRUCTURES COMPOSE THE

SELLA TURCICA

Hypophyseal fossa

Anterior clinoid process

Dorsum sellae

HOUSES PITUITARY GLAND

THE OLFACTORY BULB SITS WITHIN THIS

STRUCTURE

Cribiform plate

AT WHAT LEVEL DOES THE CAROTID

BIFURCATIONS OCCUR?

C5

THE OPTHALMIC ARTERY TRAVELS WITH THE

________ AND IS A BRANCH OF THE _________

Optic nerve

Internal carotid artery

DESCRIBE THE FUNCTIONS OF THE FOLLOWING

MUSCLES OF FACIAL EXPRESSION:

ORBICULARIS OCULI (ORBITAL AND PALPEBRAL

PARTS), ORBICULARIS ORIS, BUCCINATOR.

Orbicularis oculi - Blinking. Keeps your cornea and sclera wet by spreading

“lacrimal fluid” over it.

Palpebral part - involuntary, closes eye gently (blinking)

Orbital part - voluntary, more forceful as in photophobia

Orbicularis oris - seals lips and prevents drooling

Buccinator - keeps food out of the oral vestibule

IDENTIFY WHERE THE MOTOR PORTION OF CN

VII IS VULNERABLE TO INJURY.

The motor portion of CN VII is vulnerable to injury in neonatal skulls during

forceps delivery due to the absence of the mastoid and styloid processes.

Otherwise, they can be damaged from any superficial lacerations due to their

superficial location on the face. The facial nerve (motor portion) emerges from

the stylomastoid foramen and enters the parotid gland then branches.

Also, these facial nerves can be affected in cold weather.

DEFINE BELL (BELL’S) PALSY AND LIST ITS

COMMON SYMPTOMS.

Bell Palsy is an idiopathic injury of the facial nerve resulting in facial paralysis.

It is thought that inflammation of the facial nerve where it exits the facial canal

causes pressure that impinges on that nerve, damaging the nerve and blocking

conduction.

Herpes simplex-mediated inflammation is the most common cause of Bell’s

Palsy

Symptoms include:

Sudden onset of unilateral facial paralysis

Sagging Eyebrows

Inability to close eyes

Disappearance of nasolabial fold

Mouth drawn on non-affected side

DESCRIBE HOW THE MOTOR PORTION OF CN VII

IS ASSESSED IN A NEUROLOGICAL EXAM.

Neurological Exam of Motor portion CN VII include:

Testing Corneal Reflex (involuntary blinking in response of a foreign body

touching the eye)

Ability to smile, squint and raise eyebrow

Sound Sensitivity

From handout: functional testing of the occipitofrontalis muscle (frontal belly) is

used to assess deficits in the facial nerve.

DISCUSS TRIGEMINAL NEURALGIA AND

IDENTIFY THE DIVISION OF CN V MOST OFTEN

AFFECTED.

Trigeminal neuralgia - intense nerve pain (“lightning-like”) that lasts for 15

minutes or more

There’s often a patch of skin called the “trigger zone” that is hypersensitive to

touch and precipitates the neuralgia

Maxillary nerve most often affected.

LIST THE FIVE LAYERS OF THE SCALP. IDENTIFY

THE LAYER IN WHICH THE ARTERIES AND VEINS

OF THE SCALP ARE LOCATED.

Skin

Connective tissue (Dense) - Blood vessels are here.

Aponeurosis of the epicranium

Loose connective tissue

Pericranium

DESCRIBE THE FUNCTION OF THE FRONTALIS

PORTION OF THE EPICRANIUS MUSCLE.

Also known as the epicranius muscle, the two bellies of the occipitofrontalis

muscle are joined by the epicranial aponeurosis.

Raises the eyebrows and wrinkles the forehead.

Test for facial nerve function.

LIST THE ARTERIES THAT SUPPLY THE SCALP.

IDENTIFY WHICH OF THESE ARTERIES ARE

BRANCHES OF THE EXTERNAL CAROTID

ARTERY AND WHICH ARE BRANCHES OF THE

INTERNAL CAROTID ARTERY.

Internal carotid artery:

ophthalmic artery → supratrochlear and supraorbital arteries

External carotid artery:

superficial temporal artery

posterior auricular artery

occipital artery

THE SCALP CONTAINS NUMEROUS VESSELS

AND NERVES.

Branches of ophthalmic

artery (a direct branch of

internal carotid artery)

Direct branches of

external carotid artery

IDENTIFY THE DANGER SPACE OF THE SCALP

AND DISCUSS ITS SIGNIFICANCE WITH

RESPECT TO THE SPREAD OF SCALP

INFECTIONS. Danger space of the scalp: Loose Connective tissue layer

Infections in the loose connective tissue layer can also spread to the cranial

cavity via emissary veins. Because the occipital belly of the occipitofrontalis

muscle attaches firmly to the occipital bone, and the epicranial aponeurosis

attaches firmly to the zygomatic arches, infections or blood in the “danger

space” cannot spread into the neck.

However, because the frontal belly of the occipitofrontalis muscle inserts into

skin, infections and blood in the “danger space” can and do spread to the

eyelids and bridge of the nose

DESCRIBE EMISSARY VEINS. DISCUSS THE

SIGNIFICANCE OF EMISSARY VEINS TO THE

SPREAD OF FACE & SCALP INFECTIONS TO THE

CRANIAL CAVITY.

Emissary veins are a connection between the dural venous sinuses and the

veins of the scalp. Emissary veins travel through small foramina in the calvaria.

Infections in the loose connective tissue layer of the scalp can spread through

these valveless veins and reach the cranial cavity.

IDENTIFY THE TWO PRINCIPAL ROUTES

THROUGH WHICH VENOUS BLOOD FROM THE

FACE AND SCALP CAN FLOW TO THE

CAVERNOUS SINUS.

The pterygoid plexus is located on the surfaces of the pterygoid muscles.

These structures are located in the infratemporal fossa. The pterygoid plexus

connects to the cavernous sinus.

Venous blood from the face drains via the facial vein. The pterygoid plexus

communicates with the facial vein via the deep facial vein and ophthalmic vein.

Venous blood from the anterior scalp reaches the cavernous sinus via branches

of the ophthalmic vein on the scalp. These are presumably named the

supratrochlear and supraorbital veins.

LIST THE STRUCTURES POTENTIALLY AFFECTED

IN CAVERNOUS SINUS THROMBOPHLEBITIS

Abducens nerve (CN VI)—most commonly affected

Internal carotid artery

Oculomotor nerve (CN III)

Trochlear nerve (CN IV)

Opthalmic branch of the trigeminal nerve (CN V1)

Maxillary branch of the trigeminal nerve (CN V2)

(Pituitary gland)

CAVERNOUS SINUS

IDENTIFY THE BONY ARTICULATIONS OF THE

TEMPOROMANDIBULAR JOINT. LIST THE

MOVEMENTS ALLOWED AT THIS JOINT.

The temporomandibular joint (TMJ) occurs between the mandibular fossa of the

temporal bone and the condyle of the mandible.

Four movements are allowed at this joint:

Protrusion

Retraction

Elevation

Depression

RELATE THE MOVEMENTS AT THE TMJ TO THE

ARTICULAR DISC INCLUDED WITHIN

The articular disk within the TMJ divides it into two separate synovial capsules

Superior capsule—allows for gliding movements within the mandibular fossa

(protrusion/retraction)

Inferior capsule—allows for rotation of the mandibular condyle against the

articular disk (elevation/depression)

The coordination of these two “joints” allow the mouth to open widely.

LIST THE FOUR MUSCLES OF MASTICATION AND

IDENTIFY THEIR ACTION(S) AT THE

TEMPOROMANDIBULAR JOINT

Masseter: elevation, retraction (deep fibers)

Temporalis: elevation, retraction (posterior fibers)

Lateral pterygoid: protrusion

Medial pterygoid: protrusion, elevation

Innervated by V3

IDENTIFY THE SENSORY DOMAINS OF THE

FOLLOWING SENSORY BRANCHES OF V3:

AURICULOTEMPORAL, BUCCAL, LINGUAL,

INFERIOR ALVEOLAR, MENTAL

Buccal: skin and mucosa of cheek (Maxillary)

Inferior alveolar: gingivae and teeth of lower jaw (Maxillary)

Auriculotemporal: outer surface of tympanic membrane (Mandibular)

Lingual: tongue (Mandibular)

Mental: anterior aspects of the chin and lower lip as well as the buccal gingivae

of the mandibular anterior teeth and the premolars

Inferior auricular mandibular

IDENTIFY THE FASCIAL LAYER OF ORIGIN OF

THE PAROTID SHEATH. DISCUSS THE

SIGNIFICANCE OF THE PAROTID SHEATH WITH

RESPECT TO THE PAIN ASSOCIATED WITH

PAROTID INFECTIONS.

Origin of parotid sheath: the investing (superficial) layer of the deep cervical

fascia (head and neck handout)

Role of sheath in pain associated with parotid infections: Infection causes

inflammation and swelling of the parotid gland. Severe pain occurs because the

parotid sheath limits swelling.

IDENTIFY THE STRUCTURES AT RISK OF INJURY

IN A PAROTIDECTOMY AND IN FACIAL

LACERATIONS.

Branches of facial nerve along with the parotid duct

External carotid artery

Surgery on the parotid gland may damage the auriculotemporal nerve of CN V

and cause loss of sensation in the auriculotemporal area. The nerve also

carries postganglionic sympathetic nerve fibers to the sweat glands of the head

and postganglionic parasympathetic nerve fibers to the parotid gland for

salivation. If this nerve is severed, aberrant regeneration may cause sweating

whenever the person eats (Frey syndrome) –

LIST THE FOUR CLINICALLY IMPORTANT

GROUPS OF LYMPH NODES OF THE

PERICERVICAL COLLAR AND DESCRIBE, IN

GENERAL TERMS, THE ANATOMICAL LOCATIONS

OF EACH.

Parotid nodes - attached to the superficial surface of the parotid gland and

embedded within it (lowest members are sometimes referred to as “superficial

cervical nodes”)

Submandibular nodes - attached to superficial surface of submandibular gland

and embedded within it

Submental nodes - located inferior to the chin in anterior neck

Mastoid nodes – superior to sternocleidomastoid muscle

IDENTIFY THE STRUCTURES OF THE HEAD AND

NECK INNERVATED BY THE SYMPATHETIC

NERVOUS SYSTEM.

Body wall viscera

Sweat glands

Arrector pili muscles

Smooth muscle in the walls of blood vessels

Dilator pupillae – “muscle” of the iris formed by myoepithelium

Superior tarsal muscle – muscle of the upper eyelid

Salivary glands

IDENTIFY THE PARAVERTEBRAL (CHAIN)

GANGLIA THAT CONTAIN THE POSTGANGLIONIC

SYMPATHETIC NEURONS THAT INNERVATE

THESE STRUCTURES.

The paravertebral (chain) ganglia involved are located in the cervical region

and have fused into three cervical ganglia: superior, middle, and inferior:

Superior cervical ganglion – C1-C4

Middle cervical ganglion – C5-C6

Inferior cervical ganglion – C7-C8 & usually one or more thoracic ganglia

creating the cervicothoracic or “stellate” ganglia

IDENTIFY THE SPINAL CORD SEGMENTS THAT

CONTAIN THE PREGANGLIONIC SYMPATHETIC

NEURONS INVOLVED IN THE INNERVATION OF

HEAD & NECK STRUCTURES.

T1-T4

LIST THE SYMPTOMS OF HORNER’S SYNDROME

AND IDENTIFY ITS ETIOLOGY.

Horner’s syndrome results from the interruption of a cervical sympathetic trunk and is manifested by the absence of sympathetically stimulated functions on the ipsilateral side of the head. This disruption of the sympathetic supply to the head and neck can be a consequence of many pathological conditions and is often a product of compression of the sympathetic chain, especially seen in lung tumors.

Symptoms:

Ptosis – drooping of superior eyelid – due to loss of function of superior tarsal muscle

Miosis – constriction of the pupil – due to unopposed action of constrictor pupillae muscle

Anhidrosis – absence of sweating – due to loss of sympathetic innervation to sweat glands

Vasodilation – redness and increased temperature of the skin

IDENTIFY THE CRANIAL NERVE ASSOCIATED

WITH EACH PHARYNGEAL ARCH. IDENTIFY THE

SKELETAL ELEMENTS DERIVED FROM ARCHES

Arch Nerve Cartilage

1 V2 Maxillary

V3 Mandibular

Malleus, incus, sphenomandibular

ligament

2 Facial CNVII Stapes, styloid process, stylohyoid

ligament and lesser horns of hyoid bone

3 Glossopharyngeal CNIX Greater horns of hyoid bone

4 Superior laryngeal CNX Thyroid cartilage

6 Recurrent laryngeal CNX Cricoid cartilage

IDENTIFY THE STRUCTURES DERIVED FROM

PHARYNGEAL POUCHES 2-4.

Pharyngeal

pouch

Structure Derived

1 Tympanic cavity, auditory tube, tympanic membrane

2 Primordium of palatine tonsil

3 Inferior parathyroid gland, thymus

4 Superior parathyroid gland, ultimobranchial body

parafollicular C cells

DESCRIBE THE DEVELOPMENTAL BASIS OF A

PYRAMIDAL LOBE OF THE THYROID GLAND AND

ACCESSORY GLANDULAR TISSUE.

Thyroid gland initially appears as a median epithelial thickening in the floor of the primitive pharynx

It then descends in the neck anterior to the developing hyoid bone and laryngeal cartilages to its final position anterior to the trachea

During the descent, it receives follicular cells derived from the ultimobranchialbody as well as the superior and inferior parathyroid glands

It also remains connected to the tongue during the descent by a narrow thyroglossal duct; however, once it gets into its final position the thyroglossalduct should degenerate

The pyramidal lobe of the thyroid occurs in individuals when the distal portion of the thyroglossal duct persists instead of degenerating.

DISTINGUISH A THYROGLOSSAL DUCT CYST FROM A

LATERAL CERVICAL CYST.

Thyroglossal duct cyst Lateral cervical cyst

Cause Remnants of thyroglossal

duct persis and give rise to

cyst.

Failed degeneration of cervical sinus.

Location Tongue or midline neck, just

inferior to hyoid bone.

Anterior to anterior border of

sternocleidomastoid muscle.

Presentation Duct moves superiorly with

protrusion of tongue.

Presents in late childhood,

accumulation of fluid painless

swelling in neck, may form fistula

DESCRIBE THE DEVELOPMENTAL BASIS OF

ECTOPIC PARATHYROID GLANDS

Because of their extensive migrations during early embryogenesis, parathyroid

glands and components of the thymus gland are often found in abnormal sites.

Ectopic thymic tissue is typically found in the neck; ectopic inferior parathyroid

glands are often found either at the carotid bifurcation or in the superior

mediastinum.

LIST THE PRIMARY CHARACTERISTICS OF

CATCH-22 SYNDROMES AND RELATE THESE TO

PHARYNGEAL ARCH DEVELOPMENT &

DIFFERENTIATION.

CATCH is the acronym for the sx seen in syndromes involving Chromosome 22 deletions. These symptoms are associated with malformation of Neural Crest Cell derived tissues of the 3rd and 4th pharyngeal arches C: cardiac defects A: abnormal facies T: thymic aplasia causes immune problems C: cleft palate H: hypocalcemia secondary to parathyroid aplasia

Chromosome 22q11 (small arm of 22) deletion syndromes: DiGeorge Syndrome Velocardiofacial Syndrome Conotruncal Anomaly Face Syndrome

IDENTIFY THE SPINAL NERVES THAT FORM THE

CERVICAL PLEXUS AND THEIR CUTANEOUS

BRANCHES. Cervical Plexus is formed by: Ventral Primary Rami of C1 - C4 Spinal Nerves

C1: Lesser Occipital Nerve

C2: Great Auricular Nerve

C3: Transverse Cervical Nerve

C4: Supraclavicular Nerve

“Sometimes considered part of the cervical plexus”: C5: Phrenic Nerve

Innervation:

neck muscles derived from ventral dermomyotomes of cervical somites

skin of anterior and lateral neck

portion of the face and shoulder

DESCRIBE THE ACTION OF THE

STERNOCLEIDOMASTOID MUSCLE (WHEN

ACTING BOTH UNILATERALLY AND

BILATERALLY) AND IDENTIFY ITS INNERVATION.

Sternocleidomastoid:

Origin: sternum + medial ⅓ of clavical; Inserts: mastoid process

Action: to see it: http://www.youtube.com/watch?v=4ueRbHZh4js

Unilaterally: tilts the head to the same side while rotating the face in the

opposite direction

Bilaterally: flex cervical spine to bring the chin towards the manubrium

Innervation: Cranial Nerve XI: Spinal Accessory Nerve

DEFINE TORTICOLLIS AND DESCRIBE ITS

TYPICAL PRESENTATION.

Torticollis (“twisted neck”):

Contraction or shortening of the cervical muscles, often congenital

Produces a twisting of the head and slanting of the head

Typical presentation: at birth due to fibrous tissue tumor in the SCM m.

“The most common type of congenital torticollis results from a fibrous tissue

tumor that develops in the sternocleidomastoid muscle before or shortly after

birth. When torticollis occurs prenatally, the abnormal position of the infant’s

head usually necessitates a breech delivery.”

Head tilted laterally towards muscle and rotated to opposite side.

IDENTIFY WHERE IN THE NECK THE SPINAL

ACCESSORY NERVE CAN BE INJURED AND THE

FUNCTIONAL DEFICITS EXPECTED WITH THIS

INJURY.

The Spinal Accessory Nerve crosses through the Posterior (Occipital) Triangle

of the neck

Expected deficits due to CN XI injury:

Paralysis of trapezius

impossible to abduct arm past 90 degrees

can’t shrug shoulders

Also innervates sternocleidomastoid

so.. can’t/weaker flexion of cervical spine or lateral bending of cervical

spine.

POSTERIOR TRIANGLE OF NECK

Borders:

Anterior: Posterior border of the SCM

Posterior: Anterior border of the trapezius muscle

Inferior: Middle 1/3 of the clavicle

Posterior triangle is further divided into “occipital” and “supraclavicular” triangles by the inferior belly of the omohyoid muscle

Contents

Spinal accessory nerve

Phrenic nerve

Cervical plexus cutaneous branches

External jugular vein

Subclavian artery

ANTERIOR TRIANGLE OF NECK

Anterior border of the sternocleidomastoid muscle

Anterior midline of the neck

Inferior border of mandible.

Anterior triangle is further divided into:

“Muscular” (containing the “infrahyoid” muscles),

“Submandibular” (between the anterior and posterior digastric muscles and

the inferior border of the mandible and containing the submandibular gland)

“Submental” (between the right and left anterior digastric muscles, inferior to

the chin)

“Carotid” triangles.

INFRAHYOID MUSCLES

Sternohyoid

Sternothyroid

Thyrohyoid

Omohyoid

Note that the omohyoid muscle consists of superior and inferior bellies.

SUPRAHYOID MUSCLES

Anterior belly of digastric muscle

Mylohyoid muscle

The mylohyoid muscle marks the boundary between the oral cavity and

neck. Structures located superior to the mylohyoid muscle are located in the

oral cavity; structures located inferior to the mylohyoid are located in the

neck.

Deep to submandibular gland

Posterior digastric

Stylohyoid

THE CAROTID SHEATH

Internal jugular

Common carotid

Vagus nerve

Sympathetic chain is located posterior to carotid sheath

IDENTIFY THE VERTEBRAL LEVELS OF THE

FOLLOWING PALPABLE STRUCTURES OF THE

NECK: SUPERIOR BORDER OF THE THYROID

CARTILAGE, CRICOID CARTILAGE.

Superior border of thyroid cartilage – lies opposite the C5 vertebra

Cricoid cartilage – located at level of C6 vertebra

- Marks transition between larynx/trachea (respiratory) and pharynx/esophagus

(digestive)

STELLATE GANGLION BLOCK

Stellate Ganglion Nerve Block – injection of anesthetic into sympathetic tissue

Done above stellate ganglion with enough anesthetic to spread up and down sympathetic trunk

- relieve vasoconstriction after frostbite or microsurgery of hand

- Treat Reynaud phenomenon (reduced blood to toes and fingers because of cold temperatures or emotional stress) and hyperhydrosis (excessive sweating) of the hand

Needle insertion between trachea medially and sternocleiomastoid and common carotid laterally using cricoid cartilage as a landmark.

If successful, the following occurs:

Vasodilation – blood vessels of head, neck, upper limb

Horner syndrome: Miosis, Ptosis, Hemianhydrosis

CERVICAL PLEXUS BLOCK

Cervical plexus nerve block – needle inserted at vertebral level C3

USE: superficial surgery on neck or thyroid gland, pain management

Landmark: line connecting mastoid process to transverse process of C6

*Note: enough anesthetic injected to spread up and down here too

IDENTIFY THE TRANSVERSE LEVEL OF THE

CAROTID BIFURCATION IN THE NECK AND THE

SURFACE LANDMARK USED TO LOCATE IT.

Bifurcation of the common carotid artery

Common carotid --> internal and external carotid

Occurs in anterior triangle of the neck at level of C5

Superior border of thyroid cartilage

Surface landmark: thyroid cartilage*

DISTINGUISH THE FUNCTIONS OF THE CAROTID

SINUS AND CAROTID BODY.

Carotid sinus – pressure receptor, sensory information carried by CN IX and

CN X

Carotid body – oxygen chemoreceptor, info also carried by CN IX and CN X

IDENTIFY WHERE IN THE NECK THE CAROTID

PULSE CAN BE PALPATED AND DISCUSS

POTENTIAL COMPLICATIONS OF THIS

PROCEDURE.

Carotid pulse – palpated at superior border of thyroid cartilage (C5)

Complication: Pressure on carotid sinus can cause reflex drop in blood

pressure and HR Palpation should be somewhere inferior to superior border of

thyroid cartilage

Most clinicians prefer to use cricoid cartilage (C6).

When taking the carotid pulse in the neck, the common carotid artery is

compressed against the enlarged anterior tubercle of the C6 vertebra. For this

reason, this tubercle is referred to as the carotid tubercle.

VERTEBRATE PROMINENS

When the neck is fully flexed, the long spinous process of the C7 vertebra

projects more than that of nearby vertebra and can therefore be easily

recognized. For this reason the C7 vertebra is known clinically as the vertebra

prominens.

LIST THE THREE LAYERS OF THE DEEP

CERVICAL FASCIA AND THE FOUR CERVICAL

COMPARTMENTS THEY DEFINE. DEFINE THE

"BUCCOPHARYNGEAL FASCIA" AND DESCRIBE

ITS LOCATION.

Prevertebral – surrounding cervical spine and muscles associated with it

Pretracheal – surrounding viscera of neck (larynx/trachea, pharynx/esophagus)

and thyroid gland

Buccopharyngeal fascia – portion of pretracheal fascia located posterior to

wall of pharynx

Investing – outermost layer of deep cervical fascia (invests parotid gland,

submandibular gland, sternocleidomastoid, and trapezius)

FASCIA

IDENTIFY THE LAYERS OF THE DEEP CERVICAL

FASCIA THAT BOUND THE RETROPHARYNGEAL

SPACE. DESCRIBE THE CLINICAL SIGNIFICANCE

OF THIS SPACE.

Retropharyngeal space

buccopharyngeal fascia anteriorly

paravertebral fascia posteriorly

Clinical significance

Chief avenue for spread of infection from the mouth, the nose, and the throat

to the medastinum of the thorax

Difficulties in breathng, compression of esophagus, can spread to heart!

LIST THE STRUCTURES ENCLOSED WITHIN THE

CAROTID SHEATH

Carotid artery

Internal jugular vein

Vagus Nerve

DISTINGUISH A CRICOTHYROIDOTOMY FROM A

TRACHEOSTOMY. IDENTIFY THE STRUCTURES AT

POTENTIAL RISK OF INJURY IN TRACHEOSTOMY.

Cricothyroidotomy

incision made in the median cricothyroid ligament

used to quickly establish a temporary airway due to the absence of major

vessels in this location

only used in emergencies because you may accidentally injure the vocal

folds

Tracheostomy

Tube insterted between 2nd and 3rd rings of tracheal cartilage.

Structures at potential risk of injury:

Inferior thyroid veins

Thyroid ima artery

Thmus gland in infants

DESCRIBE THE TYPICAL LOCATIONS OF THE

SUPERIOR AND INFERIOR PARATHYROID

GLANDS.

Superior and inferior parathyroid glands

internal to the connective tissue sheath of the thyroid gland, on the posterior

surface of each lobe

Arterial supply: inferior thyroid artery

ARTERIAL SUPPLY OF THYROID GLAND

External carotid superior thyroid artery

Subclavian thyrocervical trunk inferior thryoid artery

Ima artery

Venous drainage to superior, middle, inferior thyroid veins IJV

Recurrent laryngeal nerves run along posterior surface

IDENTIFY THE BRAIN STRUCTURES IMPORTANT

FOR LANGUAGE

Transverse gyri of heschl: primary auditory cortex

Supramarginal and angular gyrii of inferior parietal lobe: Wernicke’s area

Pars triangularis and pars opercularis of inferior frontal gyrus: Broca’s area

All supplied by MCA

SUBSTANTIA NIGRA

Midbrain structure where dopaminergic neurons are localized

The substantia nigra is visible, just dorsal to the cerebral.

The substantia nigra has a ventral portion called the substantia nigra pars

reticulata, which contains cells very similar to those of the internal segment

of the globus pallidus. The internal segment of the globus pallidus and the

substantia nigra pars reticulata are separated from each other by the internal

capsule, in much the same way that it separates the caudate and putamen.

The more dorsal substantia nigra pars compacta contains the darkly

pigmented dopaminergic neurons that give this nucleus its name.

Degeneration of these dopaminergic neurons is an important pathogenetic

mechanism in Parkinson’s disease.

STRIATUM

The caudate and putamen are histologically and embryologically closely related

and can be thought of as a single large nucleus called the striatum.

The striatum receives virtually all inputs to the basal ganglia.

The caudate and putamen are separated by penetrating fibers of the internal

capsule but remain joined in some places by cellular bridges. The cellular

bridges appear as stripes, or striations, connecting the caudate and putamen in

histological sections, giving rise to the name “striatum.”

LENTIFORM NUCLEUS

Medial to the putamen lies the globus pallidus (or pallidum), meaning “pale

globe,” so named because of the many myelinated fibers traversing this region.

The globus pallidus has an internal segment and an external. The putamen and

globus pallidus together are called the lenticularorlentiform (meaning “lentil- or

lens-shaped”) nucleus.

THE CAUDATE AND THALAMUS ARE ALWAYS

MEDIAL TO THE INTERNAL CAPSULE, WHILE

THE LENTIFORM NUCLEUS (PUTAMEN AND

GLOBUS PALLIDUS) IS ALWAYS LATERAL TO THE

INTERNAL CAPSULE

The fornix is an axon tract which carries fibers

from the hippocampus to the hypothalamus.

The hippocampal commissure carries axons

connecting the left and right hippocampal

formations.

Bilateral internal cerebral veins join

with basal veins to form the great

cerebral vein (of Galen) posterior to

the pineal gland. These veins are all

part of the brain’s deep venous

drainage. The pineal gland is a

melatonin-producing endocrine gland

which regulates circadian rhythm.

STATE THE STRUCTURES THAT FORM THE

LATERAL WALLS AND THE FLOOR OF THE THIRD

VENTRICLE.

Lateral walls of the third ventricle are formed by the thalamus and

hypothalamus

The floor is formed by the optic chiasm, the mammillary bodies, the

infundibulum and the tuber cinereum

The tuber cinereum is a hollow eminence of gray matter situated between the

mammillary bodies and the optic chiasm. The tuber cinereum is part of the

hypothalamus. Infundibulum and infundibular stalk (of the brain) are alternative

names for the pituitary stalk, the connection between the hypothalamus and the

pars nervosa hypophyseos

IDENTIFY THE AMYGDALOID BODY AND STATE

ITS FUNCTIONAL SIGNIFICANCE.

Large rounded mass of gray matter in the anterior part of the temporal horn. It

is continuous with the medial cortex of the temporal lobe in the region of the

uncus. Although it is sometimes included with basal ganglia, the amygdaloid

body is functionally a key structure in the limbic system, which include functions

such as emotional reactions, decision making, and memory.

DISTINGUISH BETWEEN THE FIBER TRACTS

THAT TRAVEL IN THE ANTERIOR LIMB AND THE

POSTERIOR LIMB OF THE INTERNAL CAPSULE.

NAME THE FIBER TRACTS THAT TRAVEL IN THE

GENU OF THE INTERNAL CAPSULE.

Anterior Limb: Part of the internal capsule located between the lentiform nucleus

laterally and the head of the caudate medially. Contains the frontal corticopontine as

well as the fibers connecting the thalamus and frontal cortex (anterior thalamic

radiation)

Posterior Limb: Separates the thalamus on the medial side of the lentiform nucleus

on the lateral side. Contains the corticospinal tract (pyramidal tract), sensory

radiation, the corticopontine and the corticoreticular systems as well as thalamic

radiation.

Genu: Located between anterior and posterior limb. Contains corticobulbar fibers

SYLVIUS STRUCTURES

Corpus callosum

Anterior horn of the lateral ventricle

Posterior horn of the lateral ventricle

Temporal (inferior) horn of the lateral ventricle

Hippocampus

Fornix

Hippocampal commissure

Pineal body

Superior and inferior colliculi

Thalamus (internal medullary lamina and pulvinar) Caudate nucleus (head and tail)

Lentiform nucleus (external capsule, claustrum, extreme capsule, patamen, globuspallidus)

Striatum (putamen and head of caudate) Amygdaloid body

Internal capsule (anterior and posterior limb)

IDENTIFY THE BONES THAT FORM THE ROOF,

LATERAL WALL, MEDIAL WALL AND FLOOR OF

THE BONY ORBIT.

roof = frontal bone and lesser wing of sphenoid bone

lateral wall = zygomatic bone and greater wing of sphenoid bone

medial wall = ethmoid bone and lacrimal bone

floor = maxillary bone and palatine bone

WHAT STRUCTURES PASS THROUGH THE

SUPERIOR ORBITAL FISSURE AND SUPERIOR

ORBITAL FORAMEN

Superior Orbital Fissure:

oculomotor nerve (cranial nerve [CN] III),

trochlear nerve (CN IV),

ophthalmic nerves (branches of the ophthalmic division of the trigeminal

nerve [CN V1),

abducens nerve (CN VI), and

superior ophthalmic vein

Superior orbital foramen

supraorbital branch of opthalmic nerve,

supraorbital artery, and

superior ophthalmic vein

WHAT STRUCTURES PASS THROUGH THE

INFERIOR ORBITAL FISSURE AND INFERIOR

ORBITAL FORAMEN

Inferior Orbital Fissure:

infraorbital nerve and zygomatic nerve (branches of the maxillary n. = CN

V2),

infraorbital artery

Inferior Orbital Canal/Foramen (Infraorbital Foramen and Groove):

infraorbital nerve,

infraorbital artery

Inferior opthalmic vein

IDENTIFY THE STRUCTURES THAT PASS

THROUGH THE OPTIC CANAL AND

NASOLACRIMAL CANAL

Optic Canal:

optic nerve (CN II) and

ophthalmic artery (a branch of the internal carotid artery).

Nasolacrimal Canal:

nasolacrimal duct from the lacrimal sac to the inferior nasal meatus.

THE INFERIOR ORBITAL FISSURE IS

CONTINUOUS WITH…

Pterygopalatine fossa

This space is also continuous with the foramen rotundum

The infraorbital and zygomatic branches of the maxillary nerve enter the

posterior aspect of the orbit from the pterygopalatine fossa.

IN WHAT AREAS IS THE ORBITAL WEAK?

The medial and inferior walls of the orbit are thin due to the adjacent ethmoidal

air cells and maxillary sinus, respectively

Because the margins of the orbit are significantly stronger than its walls, blows

to the orbit may result in either a separation and displacement of bones at

sutures, or a fracture of one or more of its walls (“blowout” fracture). Fractures

of the medial wall may involve the ethmoid or sphenoid sinuses; fractures of the

inferior wall may affect the maxillary sinus and infraorbital nerve. Extra-ocular

muscles can also get trapped within the broken orbital walls.

ORBITAL SEPTUM

The orbital septum is a

fibrous membrane that

passes from the tarsal plates

to the margins of the orbit

Can limit spread of infection

or confine infection to orbit

DEFINE PAPILLEDEMA & IDENTIFY ITS

ANATOMICAL BASIS.

A noninflammatory edema of the optic disc (papilla) due to increased

intracranial pressure usually caused by brain tumors, subdural hematoma, or

hydrocephalus. It usually does not alter visual acuity, but may cause bilateral

enlarged blind spots.

EXTRAOCULAR MUSCLES

Levator palpebrae superioris: CN III, Elevates upper eyelid

Superior Oblique: CN IV Depresses, abducts, intorts

Inferior Oblique: CN III Elevates, abducts, extorts

Superior Rectus: CN III Elevates, adducts, intorts

Medial Rectus: CN III Adducts

Inferior Rectus: CN III Depresses, adducts, extorts

Lateral Rectus: CN VI Abducts

IDENTIFY WHERE THESE NERVES ARE

VULNERABLE AND DESCRIBE THE FUNCTIONAL

DEFICITS ASSOCIATED: CN III, CN IV AND CN VI.

CN III (down and out)

Aneurysm of the posterior cerebral or superior cerebellar arteries

Cavernous sinus infections

Rapidly increasing intracranial pressure often compresses CN III against petrous temporal

Functional deficit: interruption of motor to EOM and levator palpebrae superioris; interruption of preganglionic parasympathetic nerve fibers to ciliary ganglion

CN IV (vertical diplopia, head turned due to extorsion)

Rarely paralyzed alone

Cavernous sinus infections

Functional deficit: interruption of motor to superior oblique

CN VI (affected eye is deviated medially)

Stretched when intracranial pressure rises

Space occupying lesion within the cranial cavity (tumor) may compress nerve

Often first nerve affected in cavernous sinus infections

Functional deficit: interruption of motor to lateral rectus

LIST THE THREE LAYERS (COATS, TUNICS) OF

THE EYEBALL. IDENTIFY THE COMPONENTS OF

THE CORNEOSCLERAL (OUTER) AND UVEAL

(MIDDLE) TUNICS

Corneoscleral Tunic (tunica fibrosa)

Cornea : avascular structure highly innervated by branches of CN V1

Sclera: white, opaque structure that provides attachments for the extraocular eye muscles

Corneoscleral Junction (limbus) : junction of the transparent cornea and the opaque sclera

contains a trabecular network and the canal of schlemm, which are involved in the flow of aqueous humor

Uveal Tunic (tunica vasculosa)

Choroid : pigmented vascular bed that lies immediately deep to the corneoscleral tunic

Stroma of the ciliary body: ciliary muscle is circularly arranged around the entire circumference of the ciliary body and is innervated by the parasympathetic nervous system

Stroma of the iris: contains the dilator pupillae muscle and sphincter pupillae muscle

Retinal Tunic (neural coat)

THE VESSELS OBSERVED ON THE ANTERIOR OF

ASPECT OF THE SCLERA LIE WITHIN WHAT

LAYER?

The conjunctiva

LEVATOR PALPEBRA SUPERIORIS

Insertion: superior tarsal plate

Action: elevates upper eyelid and opens palpebral fissure

Innervation: CN III

Third nerve palsy*

SUPERIOR TARSAL MUSCLE

Stretches between the levator palbebrae superioris tendon and the superior

tarsal plate. This small slip of smooth muscle assists the levator palpebrae

superioris in elevating the upper eyelid.

Loss of function of the superior tarsal muscle (via loss of sympathetic input)

results in a partial ptosis of the upper eyelid. Loss of sympathetic output will

further result in a pin-point pupil due to loss of function of the dilator pupillae

WHAT ARE THE TWO THIN MUCOUS

MEMBRANES THAT COVER THE INSIDE OF THE

EYELIDS AND THE SURFACE OF THE EYE?

Palpebral conjunctiva

Bulbar conjunctiva

Contains small visible blood vessels

Form conjunctival sac

Conjunctivitis is inflammation of the conjunctiva

Can be dangerous w/ N. gonorrhea or C. trachomatis

CORNEA IS AVASCULAR

LIST THE STRUCTURES OF THE EYE THAT CAN

BE OBSERVED WITH AN OPHTHALMOSCOPE.

Fundus of the eye (retina, optic disc, macula, fovea, posterior pole).

Optic disc will be on medial/nasal side, allowing you to distinguish which eye is

being viewed

IS THE MACULA NASAL OR TEMPORAL TO THE

OPTIC DISC?

Temporal

LIST THE TWO MUSCLES OF THE IRIDIAL

STROMA AND IDENTIFY THEIR FUNCTIONS.

IDENTIFY THE DIVISION OF THE AUTONOMIC

NERVOUS SYSTEM RESPONSIBLE FOR

INNERVATING EACH.

Dilator pupillae muscle = pupil dilation; sympathetic innervation

Sphincter pupillae muscle = pupil constriction (miosis); parasympathetic

innervation

ACCOMMODATION

• Close vision: ciliary

muscle contracts,

zonulus fibers relax,

lens becomes

rounder.

• Distant vision: ciliary

muscle relaxes, more

tension on zonulus

fibers, lens becomes

flatter.

DESCRIBE THE DEVELOPMENTAL BASIS OF

CYCLOPIA AND COLOBOMA.

Coloboma:

Normally, choroid fissure allows passage of hyaloid artery to eye and then fuses during 7th week of development

Failure of choroid fissure to fuse completely (can occur at the level of the iris, retina, or optic nerve) causes coloboma

Correlates strongly with congenital heart defects

Cyclopia

Prechordal mesoderm is essential for division of a single primordial eye field into two separate eye fields

Expression of Pax6 (“eye selector”) gene gives rise to development of eye field

Prechordal mesoderm signaling suppresses Pax6 signaling in midline of single primordial eye field, dividing it into two

Disruption signaling causes incorrect spacing of eyes or birth with a single eye = hypotelorism/holoprosencephaly/cyclopia

Also prevents descent of nose between the eyes, causing a superiorly displaced proboscis

DESCRIBE THE DEVELOPMENTAL FATES OF THE

LENS PLACODE, INNER AND OUTER LAYERS OF

THE OPTIC CUP AND THE HYALOID ARTERY.

Fate of the Optic Cup

Outer layer → pigmented layer of the retina

Inner layer → neural layer of the retina

Hyaloid artery → central artery of the retinas

Lens placode → lens vesicle

DESCRIBE THE FUNCTIONS OF THE FOLLOWING

TARSAL GLANDS, CONJUNCTIVAL SAC,

EYELASHES, CILIARY GLANDS.

Tarsal glands (aka meibomian glands) = The lipid secretions of the tarsal glands

reduce surface tension, which has the effect of preventing the spilling of lacrimal fluid

out of the eyelids.

Conjunctival sac = the space formed between the palpebral and the bulbar

conjunctiva

specialized form of mucosal bursa that enables the eyelids to move freely

(frictionless) over the surface of the eye as they open and close

Eyelashes = hairs on the edge of the eyelid that prevent debris from contacting the

eye and provide sensitive mechanoreceptive feedback to protect the eye.

Ciliary glands = modified apocrine sweat glands found on the margin of the eyelid;

empty into adjacent lashes, adding lipid content to tear film, thus reducing

evaporation.

DESCRIBE THE CORNEAL REFLEX AND IDENTIFY

ITS AFFERENT (SENSORY) AND EFFERENT

(MOTOR) LIMBS.

Corneal reflex = involuntary blinking of the eyelids when the cornea is

stimulated/touched OR when there’s noise greater than 40-60 dB (protective)

Afferent/sensory limb: CN V1 (ophthalmic branch of trigeminal)

Efferent/motor limb: CN VII (Facial nerve – temporal and zygomatic

branches)

DESCRIBE THE FUNCTION OF THE FOLLOWING

STRUCTURES: LACRIMAL GLANDS, LACRIMAL

CANALICULI, LACRIMAL SAC, NASOLACRIMAL

DUCT

Lacrimal glands: located in the superior lateral aspect of each orbit and secrete

lacrimal fluid

Lacrimal canaliculi: drains the tears from the surface of the eye

Lacrimal sac: connects the lacrimal canaliculi to the nasolacrimal duct

Nasolacrimal Duct: conveys lacrimal fluid into the nasal cavity; it is transmitted

via the nasolacrimal canal and it goes from the lacrimal sac to the inferior nasal

meatus.

GREATER PETROSAL NERVE AND

PTERYGOPALATINE GANGLION.

Greater Petrosal Nerve: (branch of CN VII) innervates the lacrimal glands;

carries preganglionic parasympathetic fibers to the pterygopalatine ganglion

which then sends fibers to the lacrimal gland via the maxillary and opthalmic

nerves.

Pterygopalatine ganglion: area where the preganglionic axons from the superior

salivary nucleus and the lacrimal nucleus (which run with CN VII) enter and

then synapse with the postganglionic parasympathetic neurons. These

postganglionic parasympathetic neurons then leave the pterygopalatine

ganglion and run with the zygomaticofacial branch of CN V2 and the lacrimal

branch of CNV1 to innervate the lacrimal gland.

DESCRIBE THE FLOW OF LACRIMAL FLUID AND

THE ROLE OF BLINKING IN THIS PROCESS. LIST

THE POTENTIAL COMPLICATIONS OF DRY EYE.

Lacrimal glands make lacrimal fluid → flows through excretory ducts into

conjunctival sac → fluid gathers in the lacrimal lake → gets drawn into puncta

by capillary action → flows through lacrimal canaliculi at inner corner of eyelids

→ enters lacrimal sac → nasolacrimal duct → nasal cavity (inferior nasal

meatus)

Blinking helps spread lacrimal fluid over the surface of the eye.

Complications of dry eye: Ulcers, risk of eye infections; eye inflammation →

scarring and vision problems; makes it hard to do regular activities.

LIST THE THREE SUBDIVISIONS OF THE

PHARYNX AND IDENTIFY THEIR ANATOMICAL

BOUNDARIES Nasopharynx, oropharynx, laryngopharynx (hypopharynx)

When elevated against the posterior pharyngeal wall during swallowing, the soft

palate and uvula distinguish the nasopharynx above from the oropharynx

below.

The paired palatoglossal folds mark the transition from oral cavity to

oropharynx.

The larynx is located between the laryngeal inlet and the inferior border of the

sectioned cricoid cartilage.

The laryngopharynx (hypopharynx) is that portion of the pharynx located

posterior to the laryngeal inlet and larynx

IDENTIFY THE MUSCLES THAT FORM THE

ANTERIOR AND POSTERIOR PILLARS OF THE

TONSILLAR FOSSA

Palatoglossal

Palatopharyngeus

DESCRIBE HOW TO ELICIT THE GAG REFLEX

AND IDENTIFY ITS AFFERENT AND EFFERENT

LIMBS

Stimulation of the glossopharyngeal nerve in the oropharyngeal isthmus elicits

the gag reflex, which is a reflex contraction of the palatoglossus and

palatopharyngeus muscles. Both of these muscles receive their motor input

from the vagus nerve.

COMPARE THE FLOW OF LYMPH FROM THE TIP

OF THE TONGUE WITH THAT OF MORE

POSTERIOR REGIONS OF THE TONGUE.

Lymph from the lateral margins of the tongue, as well as the lateral aspects of

the lower lip, drain principally to the submandibular lymph nodes located inferior

to the body of the mandible.

Lymph from the apex of the tongue, frenulum, and central portion of the lower

lip drains to the submental lymph nodes located inferior to the chin.

Lymph from the central and posterior aspects of the dorsum of the tongue

drain principally to the jugulodigastric node – the largest member of the

superior group of the deep cervical chain.

LIST THE THREE PAIRS OF SALIVARY GLANDS

AND INDICATE WHERE IN THE ORAL CAVITY

EACH DRAINS

Sublingual - drains into the sublingual fold in the floor of the mouth

Submandibular - drains on the frenulum of the tongue

Parotid - drains into the roof of the oral vestibule lateral to the 2nd maxillary

molar

IDENTIFY THE PARASYMPATHETIC GANGLION

THAT PROVIDES SECRETOMOTOR INNERVATION

TO THE PAROTID GLAND. IDENTIFY THE CN THAT

SUPPLIES THE PRESYNAPTIC FIBERS.

Otic Parasympathetic Ganglion provides secretomotor innervation to the

parotid gland

Glossopharyngeal nerve (CN IX) provides presynaptic fibers to the otic

parasympathetic ganglia.

IDENTIFY THE PARASYMPATHETIC GANGLION

THAT INNERVATES THE SUBMANDIBULAR AND

SUBLINGUAL GLANDS. IDENTIFY THE BRANCH

OF THE FACIAL NERVE THAT SUPPLIES THE

PRESYNAPTIC FIBERS

The Submandibular parasympathetic ganglia provide secretomotor innervation

to the submandibular and sublingual glands

The Chorda Tympani branch of the Facial Nerve supplies the presynaptic fibers

to the submandibular parasympathetic ganglia.

TRIGEMINAL NERVE

The trigeminal nerve exits the brainstem from the ventrolateral pons.

The ophthalmic division (V1) travels through the inferior part of the cavernous sinus to exit the skull via the superior orbital fissure. The maxillary division (V2) exits via the foramen rotundum and the mandibular division (V3) via the foramen ovale.

Sensory: Sensation for the face, mouth, anterior two-thirds of the tongue, nasal sinuses, and supratentorial dura.

Motor (V3): Muscles of mastication: masseter, temporalis, med./lat. Pterygoidm.

Zygomatic n (V2): postganglionic parasympathetic fibers from pterygopalatineganglion to lacrimal gland

Auricolutemporal n (V3): postganglionic fibers to parotid gland

FACIAL NERVE

Facial nucleus is located more caudally than the trigeminal nucleus in the pons.

Nerve exits at the pontomedullary junction, and enters the internal auditory

meatus to travel in the petrous temporal bone with CN VIII.

Geniculate ganglion: taste sensation in the anterior 2/3 of the tongue, and

general somatic sensation near the external auditory meatus.

Motor: exits the skull at the stylomastoid foramen, passes through the parotid

gland and divides into five major branchial motor branches: temporal,

zygomatic, buccal, mandibular, and cervical.

Other smaller branchial motor branches innervate the stapedius, occipitalis,

posterior belly of the digastric, and stylohyoid muscles.

Greater petrosal: preganglionic fibers to pterygopalatine ganglion

Chorda tympani: preganglionic fibers with lingual n. (V3) to submandibular

ganglion

GLOSSOPHARYNGEAL NERVE

Exits the brainstem as several rootlets along the upper ventrolateral medulla,

just below the pontomedullary junction and just below CN VIII, between the

inferior olive and the inferior cerebellar peduncle

Exits skull via jugular foramen

Sensory: sensation of touch, pain, and temperature from the posterior one-third

of the tongue, pharynx, middle ear, and a region near the external auditory

meatus

Taste: posterior 1/3 of tongue

Motor: stylopharyngeus m. Gag reflex

Lesser petrosal n.: Parasympathetic preganglionic fibers to otic ganglion

(parotid)

DISTINGUISH THE EXTERNAL NOSE FROM THE

INTERNAL NOSE. DISTINGUISH THE ANTERIOR

NARES FROM THE POSTERIOR CHOANAE.

The external nose projects from the face.

The internal nose is contained within the bones of the skull.

The anterior nares are the external portion of the nostrils; they open into the

nasal cavity and allow the inhalation and exhalation of air (wiki)

The posterior choanae are the openings into the nasopharynx from the nasal

cavities

LIST THE THREE COMPONENTS OF THE NASAL

SEPTUM.

Perpendicular plate of ethmoid bone

Vomer

Septal nasal cartilage

IDENTIFY WHERE THESE STRUCTURES OPEN

INTO THE NASAL CAVITY: FRONTAL SINUS,

ANTERIOR, MIDDLE AND POSTERIOR ETHMOID

AIR CELLS, SPHENOID SINUS, MAXILLARY

SINUS, NASOLACRIMAL DUCT

Posterior ethmoid air cells → superior meatus

Sphenoid sinus → sphenoethmoidal recess

Anterior ethmoid air cells → semilunar hiatus in the middle meatus

Frontal sinus → semilunar hiatus in the middle meatus

Maxillary sinus → semilunar hiatus in the middle meatus

Middle ethmoid air cells → ethmoidal bulla in middle meatus

Nasolacrimal duct from the eye → inferior meatus

IDENTIFY THE BRANCH OF THE TRIGEMINAL

NERVE THAT PROVIDES SENSORY INNERVATION

TO THE FOLLOWING STRUCTURES: FRONTAL

SINUS, MAXILLARY SINUS, ETHMOIDAL AIR

CELLS, SPHENOID SINUS.

Frontal sinus: Ophthalmic branch of trigeminal (CN V1)

Ethmoidal air cells: Ophthalmic branch of trigeminal (CN V1)

Sphenoid sinus: Ophthalmic branch of trigeminal (CN V1)

Maxillary sinus: Maxillary branch of trigeminal (CN V2)

DESCRIBE THE LOCATION OF THE OLFACTORY

EPITHELIUM IN THE NOSE. REVIEW THE

RELATIONSHIP OF THE OLFACTORY NERVE (CNI)

TO THE CRIBRIFORM PLATE.

Olfactory epithelium is present in the superior region of the lateral nasal wall

The cribriform plate supports the olfactory bulb of CN I and has numerous

perforations (foramina) that allow for individual filaments of the olfactory nerve

to pass through to the nasal cavity.

DISTINGUISH THE AREAS OF THE LATERAL AND

MEDIAL NASAL WALLS INNERVATED BY

BRANCHES OF THE OPHTHALMIC, MAXILLARY

AND OLFACTORY NERVES.

The opthalmic artery branches

into anterior and posterior

ethmoidal arteries. These supply

the anterior/superior portion of

the medial and lateral nasal

walls

The maxillary artery branches

into the sphenopalatine artery,

which supplies the

posterior/inferior portion of the

medial and lateral nasal walls

DEFINE EPISTAXIS. DESCRIBE THE LOCATION OF

KIESSELBACH’S AREA IN THE NASAL CAVITY

AND IDENTIFY THE BRANCHES OF THE

EXTERNAL CAROTID ARTERY THAT CONTRIBUTE

Epistaxis: bleeding from the nose (nosebleed)

Kiesselbach’s area:

Located along the anterior aspect of the nasal septum

Area of extensive anastomosis between branches of the ophthalmic, maxillary,

and facial arteries

DEFINE RHINITIS AND LIST THE FIVE LOCATIONS

TO WHICH INFECTIONS OF THE NASAL CAVITIES

CAN SPREAD

Rhinitis: swelling and inflammation of the nasal mucosa

5 locations of spread:

Anterior cranial fossa via the cribriform foramina

Nasopharynx via the posterior choanae

Middle ear via the auditory tube

Paranasal sinuses (resulting in sinusitis)

Lacrimal apparatus and conjunctiva via the nasolacrimal duct

IDENTIFY THE STRUCTURES POTENTIALLY

AFFECTED IN INFECTIONS OF THE ETHMOID

SINUSES.

Dural sheath of optic nerve → optic neuritis

Optic nerve in the optic canal → potential blindness

Infections of the ethmoid sinuses (ethmoidal air cells) may break through the

fragile medial wall of the orbit. Spread of infection from these cells could affect

the dural sheath of the optic nerve, causing optic neuritis. If severe, infections

of the ethmoid sinuses can also cause blindness by spreading to the optic

nerve in the optic canal.

DESCRIBE THE ANATOMICAL BASIS FOR

MAXILLARY SINUS INFECTIONS.

Clinicians usually refer to the maxillary sinus as the antrum (cavity or chamber).

Due to the high position of their drainage ostia (openings), drainage of the

maxillary air sinuses (antra) is impeded, which likely accounts for the high

incidence of maxillary sinus infections.

LIST THE FIVE (5) LYMPHATIC TISSUES THAT

FORM “WALDEYER’S RING” AND DESCRIBE

THEIR LOCATIONS.

Both the nasopharynx and oropharynx are richly endowed with mucosa-

associated lymphoid tissue (MALT)

Waldeyer’s Ring: aggregation of lymphoid tissues guarding the openings of the

digestive and respiratory tracts.

Consists of palatine, lingual, pharyngeal, and tubal tonsillar tissues, MALT

tissue between tonsils

IDENTIFY THE STRUCTURES AT RISK OF INJURY

IN TONSILLECTOMY AND DESCRIBE THE

FUNCTIONAL DEFICITS THAT RESULT. DEFINE

ADENOIDITIS.

A tonsillectomy risks injury to the Glossopharyngeal Nerve (CN IX)

This nerve is the afferent nerve for the Gag Reflex, which receives motor

activation from the Vagus Nerve (CN X). Damage to CN IX would result in a

loss of the gag reflex.

Adenoiditis: Inflammation of the Pharyngeal Tonsil.

DESCRIBE THE CLINICAL SIGNIFICANCE OF THE

“TONSILLAR” NODE OF THE DEEP CERVICAL

CHAIN.

The “Tonsillar” node, officially known as the Jugulo-Digastric node is frequently

enlarged when the palatine tonsil is inflamed, and therefore signifies the

presence of tonsillitis.

DISTINGUISH THE TRUE VOCAL FOLDS FROM

THE FALSE VOCAL (VESTIBULAR) FOLDS

ANATOMICALLY.

SUPERIOR LARYNGEAL NERVE (CN X)

Superior Laryngeal Nerve: Internal Branch: Sensory nerve Innervates the mucosa between the root of the tongue and the vocal cords.

External Branch: Motor nerve Provides motor innervation to the cricopharyngeus and cricothyroid muscles. Cricothyroid muscle: only intrinsic muscle of the larynx innervated by the superior

laryngeal nerve.

Cause of Injury: Puncture of the piriform recess by a sharp object lodged in the throat Damage to the superior laryngeal nerve can result when ligating the superior thyroid

artery during thyroidectomy

Consequence: Weak voice with loss of projection, and the vocal cord on the affected side appears

flaccid Difficulty swallowing

RECURRENT LARYNGEAL NERVE (CN X)

Sensory: larynx mucosa inferior to the vocal cords

Motor: intrinsic laryngeal muscles (Except cricopharyngeus and cricothyroid)

Cause of Injury:

Thyroidectomy

Consequence of injury:

Unilateral damage to the recurrent laryngeal nerve can result from dissection

around the ligament of Berry or ligation of the inferior thyroid artery during

thyroidectomy. Results in hoarse voice, inability to speak for long periods,

and movement of the vocal fold on the affected side toward midline

Bilateral damage to the recurrent laryngeal nerve results from same

processes during thyroidectomy but results in acute breathlessness

(dyspnea) since both vocal folds move toward the midline and close off the

air passage

DEFINE THE FOLLOWING TERMS RELATING TO

THE ANATOMY OF THE LARYNX: VESTIBULE,

VENTRICLE, GLOTTIS, RIMA GLOTTIDIS.

Vestibule – the upper portion of the laryngeal cavity, just inferior to laryngeal

inlet, formed by the paired vestibular membranes

Ventricle – space created between vestibular fold and vocal fold

Glottis – space / plane that extends between the vocal ligaments.

Widens/closes with breathing, speech, etc.

Rima glottidis – the rim around the vocal ligaments

During swallowing/movement of vocal ligaments, you’re changing width of

rima glottidis

DESCRIBE THE FEATURES OF TREACHER

COLLINS SYNDROME AND FIRST ARCH

SYNDROMES. RELATE THESE TO MIGRATION

AND DEVELOPMENT.

Treacher-Collins Syndrome

A “first-arch syndrome” (or mandibulofacial dysostosis) - failure of neural

crest cells to properly migrate to first pharyngeal arch.

Causes:

Some forms are genetically-based (Treacher-Collins and Pierre Robin

Syndrome)

Similar abnormalities also seen with retinoid administration in first month of

pregnancy

Consequences: Congenital malformations of eyes, ears, mandible, and face

DESCRIBE THE EMBRYOLOGICAL BASIS OF

CLEFT LIP, CLEFT PALATE AND OBLIQUE FACIAL

CLEFTS.

Caused by underdevelopment of the first pharyngeal arch mesenchyme:

Mesenchyme is a type of undifferentiated loose connective tissue derived

mostly from mesoderm. In first arch syndrome, issue is with neural crest

cells, whereas with facial clefts, the issue lies in mesenchymal tissue.

Lateral (oblique facial) clefts)

incomplete fusion of the maxillary prominence with the lateral nasal process

in the cheek region = NASOLACRIMAL DUCT!!!!

Cleft lip

failure of the maxillary prominence to fuse with the intermaxillary segment

Cleft palate

failure of the two palantine shelves to fuse with each other along the midline.

DISCUSS THE SIGNIFICANCE OF DEGENERATION

OF THE ORONASAL MEMBRANE IN

DEVELOPMENT OF THE NASAL CAVITY.

As the upper jaw and face take shape, the nasal pits continue to deepen.

Initially, the nasal pits are completely separated from the developing oral cavity

by the oronasal membrane.

Degeneration of this membrane establishes communication of the oral and

nasal cavities through the large primitive choanae.

The primitive choanae are transformed into the definitive choanae upon

completion of secondary palate development.

EMBRYOLOGICAL ORIGIN OF THE PINNA,

MIDDLE EAR, TYMPANIC MEMBRANE, INNER

EAR, EXTERNAL AUDITORY CANAL AND

PHARYNGOTYMPANIC CANAL. First Pharyngeal arch

Tympanic membrane External acoustic meatus Auditory tube Tympanic cavity

Otic vesicle (otocyst) Inner ear (Membranous labyrinth including the utricle, saccule, semicircular ducts, cochlear duct,

sensory hair cells and ganglion cells. The bony labyrinth is formed by neural crest cells that surround the otocyst)

Auricular hillocks (6 swellings) that surround pharyngeal groove 1 External ear (pinna). (3 of these hillocks are components of pharyngeal arch 1, the remaining three are

components of pharyngeal arch 2)

DESCRIBE THE DEVELOPMENTAL BASIS OF

BRANCHIAL CLEFT ABNORMALITIES TYPES I, II,

III AND IV Also known as lateral cervical cysts. When the cervical sinuses derived from the

pharyngeal grooves do not obliterate, they can fill with fluid and form cysts in the neck. ALWAYS ANTERIOR TO STERNOCLEIDOMASTOID MUSCLE. In PRL, the cysts labeled I, II, and III are actually derived from grooves 2,3, and 4. Maldevelopment of the first groove will be seen around ear region as a preauricularfistula or cyst.

First cleft gives rise to external auditory canal. Abnormalities recurrent ear infections

Second cleft forms epidermis of the dorsal half of the auricle and the upper neck. Abnormalities are usually cervical recurrent tonsillitis

Third cleft abnormalities abnormal thymic stalks/cysts (remember DiGeorge is abnormal 3rd and 4th pouches and can cause thymic aplasia)

Fourth cleft forms vagus nerve. Abnormalities cough