Post on 13-Jul-2015
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
IN WHAT LOBE DOES THE LATERAL (SYLVIAN)
FISSURE TERMINATE?
The Parietal Lobe
THE CAUDAL BORDER OF THE PARIETAL LOBE IS
BEST SEEN IN WHAT VIEW
Medial : the parieto-occipital sulcus is apparent in this view.
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
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
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
ANTERIOR CHOROIDAL ARTERIES
Branch off INTERNAL CAROTID
Supplies the optic tracts and the posterior limb of the internal capsule.
OPTIC CHIASM
The point of intersection between the optic nerve CN II and the optic tracts
WHAT LIES BETWEEN THE TWO CEREBRAL
PEDUNCLES?
Interpeduncular fossa: exit of oculomotor nerve
Mamillary bodies
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.
THE INTRAPARIETAL SULCUS DIVIDES THESE
TWO STRUCTURES
Superior and Inferior Parietal Lobules
A PATIENT WHO HAS DIFFICULTY RECOGNIZING
ONE SIDE OF THEIR BODY MAY HAVE DAMAGE
TO THIS REGION
Inferior parietal lobule
THE PRECENTRAL AND POSTCENTRAL GYRI
COME TOGETHER TO FORM THE…
Paracentral lobule
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
THE INSULAR CORTEX IS INVOLVED IN…
Taste
Visceral physiological function
Nicotine addiction
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
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
Fourth ventricle – medulla and pons
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
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.
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
IDENTIFY THE BONES OF THE SKULL
ethmoid
frontal
mandible
maxillary
occipital
nasal
palatine
parietal
sphenoid
temporal
vomer
zygomatic
Note: the two frontal bones
fuse (usually) by 6 years of age.
Until then they are separated by
the metopic suture.
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
THE INTERNAL CAROTID ARTERY PASSES OVER
WHICH FORAMEN BEFORING ENTERING
CANAL?
Foramen lacerum
MIDDLE EAR IS LOCATED LATERAL OR MEDIAL
TO THE SEMICIRCULAR CANALS?
Lateral
THE FACIAL NERVE EXITS THE SKULL THROUGH
THE ________?
Stylomastoid foramen
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 and some
other smaller ones
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
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.
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 , Vagus and Hypoglossal nerves
Anterolateral – sphenoid
Posterolateral - mastoid
WHICH THREE CRANIAL NERVES ARE MIXED
NERVES?
Facial
Glossopharyngeal
Vagus
Also Trigeminal?
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…
Superior 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
Note the drainage is asymmetric in that the superior sagittal sinus drains into one of the transverse sinuses
and the straight sinus goes into the other.
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
Note the cavernous sinus drains into both the superior and inferior petrosal sinuses (both of which eventually
end at the jugular vein)
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?
C4
THE OPTHALMIC ARTERY TRAVELS WITH THE
________ AND IS A BRANCH OF THE _________
Optic nerve
Internal carotid artery
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
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. DESCRIBE HOW THE
MOTOR PORTION OF CN VII IS ASSESSED IN A
NEUROLOGICAL EXAM. Bell Palsy is defined as an idiopathic injury of the facial nerve affecting all or some of its branches.
Facial paralysis resulting from a dysfunction of CN VII. 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 viral inflammatory/immune mechanism is the most common cause of Bell’s Palsy, followed by Herpes zoster.
Symptoms include:
Sudden onset of unilateral facial paralysis
Sagging Eyebrows
Inability to close eyes
Disappearance of nasolabial fold
Mouth drawn on non-affected side
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
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
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
Comprised of the loose connective tissue layer—so named because pus or
blood spreads easily within this 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, and this is the route blood would take to reach the cavernous sinuses from the
pterygoid plexus.
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 (connection not shown in
above diagram). As previously discussed, the pterygoid plexus subsequently
communicates with the cavernous sinus.
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)—according to Wikipedia, the 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
(and thus separate functions).
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.
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 (class PP)
external carotid artery
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 (CARTILAGE AND BONE)
DERIVED FROM ARCHES 2-6.
IDENTIFY THE STRUCTURES DERIVED FROM
PHARYNGEAL POUCHES 2-4.
DESCRIBE THE DEVELOPMENTAL BASIS OF A
PYRAMIDAL LOBE OF THE THYROID GLAND AND
ACCESSORY GLANDULAR TISSUE.
Background on development:
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 ultimobranchial body
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 thyroglossal duct 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.
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 symptoms often 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 = Sterno + cl
+ (random “eido”) + mastoid
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.”
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.
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
- 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
*Note: injection actually made above stellate ganglion, enough anesthetic injected to spread up and down
Needle insertion:
Medially – trachea
Laterally – sternocleidomastoid muscle, common carotid artery
Landmarks – cricoid cartilage (medial) and transverse process of C6 (lateral)
If successful, the following occurs:
Vasodilation – blood vessels of head, neck, upper limb
Horner syndrome (includes these):
Miosis – constriction of pupil
Ptosis – drooping of eyelid
Hemianhydrosis – loss of sweating on one side
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 C4
Surface landmark: thyroid cartilage*
*Note: HYA and Lab instructions say thyroid cartilage at C5 level, so it’s
technically it’s a little below the full bifurcation. See atlas.
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).
From lab guide:
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.
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
FASCIA
IDENTIFY THE LAYERS OF THE DEEP CERVICAL
FASCIA THAT BOUND THE RETROPHARYNGEAL
SPACE. DESCRIBE THE CLINICAL SIGNIFICANCE
OF THIS SPACE.
Retropharyngeal space
deep cervical fascia layers
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
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
round or square opening is made in the anterior wall of the trachea in order
to insert a tube
structures at potential risk of injury
large blood vessels
thyroid gland
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