Skull, Neck and Muscles

By : Hermizan HalihanafiahBsc Biomedical Sc (Hons), UKMhermizanhalihanafiah@yahoo.com

http://www.slideshare.net/hermizan84

SkullContains 22 bones

Rest superior to the

vertebral column

Consists 2 sets of bones,

facial and cranial bones

Cranial bones forms the

cranial cavity, which

encloses and protect the

brain

Facial bones form the face.

Cranial Bones (8 bones)

1 Frontal bone

2 parietal bones

2 temporal bones

1 Occipital bone

1 Sphenoid bone

1 Ethmoid bone

Facial bones (14 bones)

2 nasal bones

2 maxillas

2 zygomatic bones

Mandible

2 lacrimal bones

2 palatines bone

2 inferior nasal

conchae

Vomer

Figure 8.4a

Figure 8.4b

Function of the skull

Protect the brain

Inner surface attach to the membranes (meninges)

that stabilize the position of the brain, blood

vessels and nerves.

Outer surface of cranial bones provide large areas

for muscle attachment that move various part of

the head.

The bones also provide muscle attachment for

some muscles that produce facial expressions.

Facial bones – forms framework of the face

Facial bones – provide support for entrance to the

digestive and respiratory system

Together cranial and facial bones protect and

support the delicate special sense organs for vision,

taste, smell, hearing and equibilirium.

Function of the skull

Frontal Bones

Forms the forehead, the roof of the orbits and most of the anterior part of the cranial floor

Soon after birth, the left and right side of the frontal bone united together by the metopic suture, usually disappear by age of six to eight.

Frontal BonesFrontal Bone that forms the forehead – Frontal squama

Superior to the orbits the frontal bone thickens, forming the supraorbital margin.

From this margin, the frontal bone extends posteriorly to form the roof of the orbits, which is part of the floor of the cranial cavity.

Within the supraorbital margin, slightly medial to its midpoint, is a hole called supraorbital foramen where supraorbital nerve and artery pass through it.

Frontal Bones

Frontal sinuses lie deep to the frontal

squama.

Sinuses, or called parasinuses, are

mucous membrane – lined cavities in

certain skull bones.

Figure 8.8

Parietal Bones

2 parietal bones

Form the greater portion of the side and roof of the cranial cavity

Internal surface of parietal bones contain many protrusion and depression that accommodate the blood vessels supplying the dura mater (superficial connective tissue that lining the brain.

No foramina in the parietal bones.

Temporal Bones

2 temporal bones

Form the inferior lateral aspects of the cranium and part of the cranial floor

Lateral view of the temporal bones, called temporal squama, the thin, flat part that form the anterior and superior part of the temple.

Projecting from the inferior portion of the temporal squama is the zygomatic process.

Zygomatic archMandibular Fossa

Articular Tubercle

Figure 8.4b

Temporal Bone

Zygomatic process of temporal bones articulate with temporal process of zygomatic (cheek) bone form the zygomatic arch

A socket called the mandibular fossa is located on the inferior posterior surface of the zygomatic process of the temporal bones.

Anterior to the mandibular fossa is a rounded elevation called articular tubercle.

The mandibular fossa and articular tubercle

articulate with the mandible (lower jawbone)

to form the temporomandibular joint (TMJ).

Located posteriorly on the temporal bone is

the mastoid portion.

It is located posterior and inferior to the

external auditory meatus or ear canal.

Temporal Bone

The mastoid process is a rounded projection of the mastoid portion of the temporal bone posterior to the external auditory meatus.

It is the point for several neck muscles attachment.

The internal auditory meatus is the opening through which facial nerve (cranial nerve VII) and vestibulocochlear nerve (cranial nerve VIII) passes.

Temporal Bone

The styloid process projects inferiorly from

the inferior surface of the temporal bones

and serve as a point of attachment for

muscles and ligaments of the tongue a neck.

Between the styloid process and mastoid

process is the stylomastoid foramen.

Temporal Bone

Figure 8.4a

Zygomatic arch

At the floor of the cranial cavity is the petrous

portion of the temporal bone.

This part is the triangular and it is located at

the base of the skull between the sphenoid

and occipital bones.

The petrous portion houses the internal and

middle ear, structure involve hearing and

equibilirium.

Temporal Bone

It also contain the carotid foramen,

through which the carotid artery passes.

Posterior to the carotid foramen and

anterior to the occipital bone is the jugular

foramen, passageway for the jugular vein.

Temporal Bone

Occipital Bone

Forms the posterior part and most of the base of the cranium

The foramen magnum is in the inferior part of the bone.

Within this foramen, the medulla oblongata connect with the spinal cord.

The vertebral and spinal arteries also pass through this foramen.

The occipital condyles are oval processes with convex surface, one on either side of the foramen magnum.

They articulates with depression on the 1st cervical vertebra (atlas) to form the atlanto-occipital joint.

Superior to each occipital condyle on the inferior surface of the skull is the hypoglossal foramen.

Occipital Bone

The external occipital protuberance is a

prominent midline projection on the posterior

surface of the bone just above the foramen

magnum.

A large fibrous, elastic ligament, the

ligamentum nuchae, which help support the

head, extend from the external occipital

protuberance to the 7th cervical vertebra.

Occipital Bone

Extending laterally from the protuberance

are two curved ridges, the superior nuchal

lines, and below these are two inferior

nuchal lines, which is areas for the

muscles attachment.

Occipital Bone

Sphenoid Bone

Lies at the middle part of the base of the skull.

Keystone of the cranial floor because it articulates with all the other cranial bones, holding them together

Sphenoid articulation – joins anteriorly with the frontal bone, laterally with the temporal bones and posteriorly with the occipital bones.

Sphenoid

Lie posterior and slightly superior to the nasal

cavity and forms part of the floor, side walls,

and rear wall of the orbit.

The shape of the sphenoid resembles a bat

with outstretched wings.

The body of the sphenoid is the cube-like

medial portion between the ethmoid and

occipital bones.

Sphenoid Bone

Figure 16.11 The sphenoid bone viewed from above.

It contains the sphenoidal sinuses, which

drain into the nasal cavity.

The sella turcica, ia bony saddle-shaped

structure on the superior surface of the body

of the sphenoid.

Anterior part of the sella turcica, which form

the horn of the saddle, is a ridge called the

tuberculum sellae.

Sphenoid Bone

The seat of the saddle is a depression, called hypophyseal fossa, which contain pituitary gland.

The posterior part of the sella turcica, which forms the back of the saddle, is another ridge called the dorsum sellae.

The greater wings of the sphenoid project laterally from the body and form the anterolateral floor of the cranium.

Sphenoid Bone

The greater wings also form part of the

lateral wall of the skull just anterior to the

temporal bone.

The lesser wings, which are smaller, form a

ridge of bone anterior and superior to the

greater wings.

They form part of the floor of the cranium and

the posterior part of the orbit of the eye.

Sphenoid Bone

Between the body and lesser wing, just anterior to the sella turcica is the optic foramen.

Lateral to the body between the greater and lesser wings is a triangular slit called the superior orbital fissure.

Pterygoid process – structures project inferiorly from the point where the body and wings unite and form the lateral posterior region of the nasal cavity.

Some of the muscles that move the mandible attach to the pterygoid process.

Sphenoid Bone

At the base of the pterygoid process in the

greater wings is the foramen ovale.

The foramen lacerum is bounded anteriorly

by the sphenoid bone and medially by

sphenoid and occipital bones

Foramen rotundum – located at the junction

of the anterior and medial parts of the

sphenoid bone.

Sphenoid Bone

Ethmoid Bone

Light, spongylike bone, located on the

midline in the anterior part of the cranial

floor medial to the orbits.

Anterior to the sphenoid and posterior to

the nasal bones

Ethmoid

Ethmoid bone forms:

Part of the anterior portion of the cranial

floor

Medial wall of the orbit

Superior portion of the nasal septum

Most of the superior sidewalls of the

nasal cavity.

Ethmoid Bone

The lateral masses of the ethmoid bone

compose most of the wall between the nasal

cavity and orbits.

Contain 3 to 18 air spaces, or “cells”.

The ethmoidal cells together to form ethmoidal

sinuses.

The perpendicular plate forms the superior

portion of the nasal septum

Ethmoid Bone

The cribriform plate lies in the anterior floor of the cranium and forms the roof of the nasal cavity.

The cribriform plate contain olfactory foramina through which axons of the olfactory nerve pass.

Projecting upward from the cribriform plate is a triangular process called the crista galli.

This structure is serve as a point of attachment for the membrane that cover the brain.

Ethmoid Bone

Figure 16.12 The right ethmoid bone and its related structures.

The lateral masses of the ethmoid bone

contain 2 thin, scroll shaped projection

lateral to the nasal septum.

These are the superior nasal conchae and

middle nasal conchae.

A third pair of conchae, the inferior nasal

conchae, are separated bones.

Ethmoid Bone

The conchae cause turbulance in inhaled air, which result in many inhaled particles striking and becoming trapped in the mucus that lines the nasal passageways.

This turbulence thus cleanses the inhaled air before it passes into the rest of the respiratory tract.

Turbulence airflow around the superior nasal conchae also aids in the distribution of olfactory stimulants for the sensation of smell.

Air striking and mucous lining of the conhae is also warmed and moisted.

Ethmoid Bone

Nasal Bones

Paired of the nasal bones meet at the

midline

Form part of the bridge of the nose

The rest of the supporting tissue of the

nose consists of cartilage

Maxillae

A paired maxillae unite together to form

the upper jawbone

Articulate with every bone of the face

except the mandible (lower jawbone)

Forms part of the floor of the orbits, part of

the lateral walls and floor of the nasal

cavity, and most of the hard palate.

The hard palate is a bony partition formed by palatine process of the maxillae and horizontal plates of the palatine bones that forms roof of the mouth.

Each maxillae contains a large maxillary sinus that empties into the nasal cavity.

The alveolar process of the maxillae is an arch that contain the alveoli (sockets) for the maxillary (upper) teeth.

Maxillae

The palatine process is a horizontal projection of the maxillae that forms the anterior three quarters of the hard palate.

The union and diffusion of the maxillary bones normally is completed before birth.

The infraorbital foramen is an opening in the maxillae below the orbit.

Inferior orbital fissure, located between the greater wing of the sphenoid and the maxilla.

Maxillae

Maxillae

Zygomatic Bones

2 zygomatic bones

Called cheekbones

Form the prominence of the cheek and part of the lateral wall and floor of each orbit

Articulate with the maxillae and the frontal, sphenoid and temporal bones.

Lacrimal Bones

In pairSmallest bones of the faceThin, resemble a fingernail in size and shapePosterior and lateral to nasal bones and form

a part of medial wall of each orbitContain lacrimal fossa, vertical tunnel formed

with maxilla, that houses for the lacrimal sac.Lacrimal fossa – gathers tears and passes

them into the nasal cavity.

Palatine Bones

In pairL-shapedForm the posterior portion of the hard palate,

part of the floor and lateral wall of the nasal cavity, and smallest portion of the floors of the orbits.

The horizontal palate of the palatine bones form the posterior portion of the hard palate, which separate the nasal cavity and oral cavity

Inferior Nasal Conchae

In pair

Inferior to the middle nasal conchae of the ethmoid

bone

Scroll like bones that form a part of the inferior

lateral wall of the nasal cavity and project into the

nasal cavity.

The inferior nasal conchae is a separate bones, they

are not part of the ethmoid bone

All three pairs of the nasal conchae help

swirl and filter air before it passes into the

lungs.

Only superior nasal conchae involve in the

sense of smell

Inferior Nasal Conchae

VomerTriangular bone

Located in the floor of the nasal

cavity

Articulates superiorly with

perpendicular plate of the

ethmoid bone and inferiorly with

both the maxilla and palatine

along the midline

It is apart of the nasal septum,

partition that divides the nasal

cavity into right and left sides.

Mandible

Lower jawbone

Largest, strongest facial bone

Movable skull bone

Consist of a curved , horizontal portion, the

body, and two perpendicular portions, the rami.

The angle of the mandible is the area where

each ramus meets the body

Each ramus has a posterior condylar process.On each condylar process has a articulating surface

called mandibular condyle that articulates with the mandibular fossa and articular tubercle of the temporal bones.

This articulation called temporomandibular joint (TMJ)

Has anterior coronoid process to which temporalis muscles attaches.

The depression between coronoid and condylar process called the mandibular notch

Mandible

The alveolar process is an arch containing the alveoli (sockets) for the mandibular (lower) teeth.

The mental foramen is located below the mandibular second premolar tooth.

The mandibular foramen on the medial surface of each ramus.

The mandibular foramen, beginning of the mandibular canal, which run obliquely in the ramus and anteriorly to the body deep to the roots of the teeth

Mandible

The inferior alveolar nerves and blood

vessels, which are distributed to the

mandibular teeth, pass through this canal.

Mandible

Figure 8.15

Hyoid Bone

Single

Unique, does not articulate with any bones

Suspended from the styloid processes of the temporal bones by ligaments and muscles.

Located in the anterior neck between the mandible and larynx

Support the tongue, providing attachment sites for some tongue muscles and for muscles of the neck and pharynx.

Consists horizontal body and paired

projection called the lesser horns and the

greater horns.

Muscles and ligaments attach to these

paired projection.

Hyoid Bone

Hyoid Bone

The Important of Hyoid Bone

It helps to support the tongue and serves as an attachment

point for several muscles that help to elevate the larynx during

swallowing and speech.

The hyoid bone is unique in that it is the only bone of the body

that does not articulate with any other bone.

Instead, it is suspended above the larynx where it is anchored

by ligaments to the styloid processes of the temporal bones of

the skull.

When depressed it also assists in locating vocal chords when

intubating a patient

Sutures

Immovable jointHolds skull bone

together5 prominent

suture:CoronalSagittalLambdoidSquamousmetopic

Paranasal Sinuses

Cavities within certain cranial and facial bones and connecting with nasal cavity

Lined with mucous membrane.

Frontal, sphenoid, ethmoid and maxillary sinus.

Fontanels

Soft spot – areas of unossified mesenchyme.

Soon after birth it gradually become suture (intramembranous ossification)

Anterior fontanelPosterior fontanelAnterolateralPosterolateral

•The largest – diamond shape

•Closes – 18 – 24 months

•Smaller than anterior

•Closes – 2 months

•Small, irregular shape

•Closes – 3 months•Small, irregular shape

•Closes – 1-2 months

Muscles of Facial Expression

Scalp muscles

Mouth muscles

Neck muscles

Orbit and eyebrow muscles

Scalp Muscles

Frontalis (anteriorly)

Occipitalis

(posteriorly)

Mouth musclesOrbicularis oris

Zygomaticus major

Zygomaticus minor

Levator labii superioris

Depressor labii inferioris

Depressor anguli oris

Levator anguli oris

Buccinator

Risorius

Mentalis

Orbit and Eyebrow Muscles

Oribicularis oculi

Corrugator supercilli

Levator palpebrae superioris

Muscles Of Mastication

Muscles move the mandibleMuscles move the tongue (extrinsic

tongue muscles)

Muscles Move the Mandible

Masseter

Temporalis

Medial pterygoid

Lateral pterygoid

Muscles Move The Tongue

Genioglossus

Styloglossus

Platoglossus

hyoglossus

Muscles of the Anterior Neck

Located superior to the hyoid bone

(suprahyoid muscles)

1. Digastric

2. Stylohyoid

3. Mylohyoid

4. geniohyoid

Located superior to the hyoid bone

(Infrahyoid muscles)

1. Omohyoid

2. Sternohyoid

3. Sternothyroid

4. Thyrohyoid

Muscles of the Anterior Neck

Muscles that Move the Eyeball(Extrinsic Eye Muscles)

Superior rectus

Inferior rectus

Lateral rectus

Superior oblique

Inferior oblique

Levator palpebrae superioris

Muscles that Moves the Head

Sternocleidomastoid

Semispinalis capitis

Splenius capitis

Longissimus capitis

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