Head and neck rs

HEAD HEAD AND NECK AND NECK

Anatomy of the Head and Neck

FontanelsFontanels

• Fontanels are mesenchyme-filled spaces between cranial bones that are present at birth.

• The unpaired anterior fontanel

• The unpaired posterior fontanel

• The paired anterolateral fontanels

• The paired posterolateral fontanels


FontanelsFontanels

• The unpaired anterior fontanel, the largest fontanel, is located at the midline between the two parietal bones and the frontal bone, and is roughly diamond-shaped. • The unpaired posterior fontanel is located at the midline between the two parietal bones and the occipital bone.

• The paired anterolateral fontanels, located laterally between the frontal, parietal, temporal, and sphenoid bones, are small and irregular in shape. • The paired posterolateral fontanels, located laterally between the parietal, occipital, and temporal bones, are irregularly shaped.

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The SkullThe Skull

• The skull consists of the cranium and the facial skeleton.

• The cranium is the bony container for the brain, and the foundation for the facial skeleton.

• The cranium is made up of a number of originally separate bones.

• These lines of fusion are known as sutures.


The SkullThe Skull

• Formed by cranial and facial bones


The CraniumThe Cranium

• The cranium serves to:

• Enclose brain

• Provide attachment sites for some head and neck muscles


The FaceThe Face

• Facial bones serve to:

• Form framework of the face

• Form cavities for the sense organs of sight, taste, and smell

• Provide openings for the passage of air and food

• Hold the teeth

• Anchor muscles of the face


Overview of Skull GeographyOverview of Skull Geography

• Facial bones form anterior aspect

• Cranium is divided into cranial vault (chamber) and the base

• Internally, prominent bony ridges divide skull into distinct fossae



• The skull contains smaller cavities

• Middle and inner ear cavities – in lateral aspect of cranial base

• Nasal cavity – lies in and posterior to the nose

• Orbits – house the eyeballs

• Air-filled sinuses – occur in several bones around the nasal cavity



• The skull contains approximately 85 named openings

• Foramina, canals, and fissures

• Provide openings for important structures

•Spinal cord

•Blood vessels serving the brain

•12 pairs of cranial nerves


Cranial BonesCranial Bones

• Formed from eight large bones

• Paired bones include

• Temporal bones

• Parietal bones

• Unpaired bones include

• Frontal bone

• Occipital bone

• Sphenoid bone

• Ethmoid bone


Frontal BonesFrontal Bones

• Forms the forehead and roofs of the orbits

• Forms superciliary arches

• Internally, it contributes to the anterior cranial fossa

• Contains frontal sinuses

• Soon after birth, the left and right sides of the frontal bone are united by the metopic suture, which usually disappears between the ages of six and eight.


Parietal Bones and SuturesParietal Bones and Sutures

• Parietal bones form superior and lateral parts of skull


Parietal Bones and SuturesParietal Bones and Sutures

• A suture is an immovable joint in mostcases in an adult skull that holds most skull bones together.

1. The coronal suture unites thefrontal bone and both parietal bones.2. The sagittal suture unitesthe two parietal bones on the superior midline of the skull 3. The lambdoid suture unites the two parietal bones to the occipital bone. 4. The squamous sutures unitethe parietal and temporal bones on the lateral aspects of the skull.


The Skull – Posterior ViewThe Skull – Posterior View


Occipital Bone Occipital Bone

• Forms the posterior portion of the cranium and cranial base

• Articulates with the temporal bones and parietal bones

• Forms the posterior cranial fossa

• The most striking feature of the occipital bone is this large opening, the foramen magnum, located at its base, through which the spinal cord and its accompanying structures pass.



• The part of the occipital bone in front of the foramen magnum is called the basilar part, often referred to as the base of the occiput.

• The two temporal bones converge on it from each side.

• The occipital bone that's behind the foramen magnum, the squamous part.



• Features and structures

• Occipital condyles

• Hypoglossal foramen

• External occipital protuberance

• Superior nuchal lines

• Inferior nuchal lines



• Features and structures

• Occipital condyles:The occipital condyles are the joint surfaces which articulate with the atlas vertebra to form the atlanto-occipital joints.

• Hypoglossal foramen

• External occipital protuberance: Thelump in the middle is the external occipital protuberance.

• Superior nuchal lines

• Inferior nuchal lines

• (faint ridge, leading out toward the mastoid process)


Inferior Aspect of the SkullInferior Aspect of the Skull


Temporal Bones Temporal Bones

• Lie inferior to parietal bones

• Form the inferolateral portion of the skull

• Specific regions of temporal bone

• Squamous, temporal, petrous, and mastoid regions

• It's easy to feel the mastoid process behind and below the ear.


Lateral Aspect of the SkullLateral Aspect of the Skull


The Temporal BoneThe Temporal Bone



• The zygomatic arch is formed largely by the temporal bone, and partly by the adjoining zygomatic bone.

• At the underside of the root of the zygomatic arch, there is a complex curved surface that articulates with the condyle of the mandible to form the temporomandibularjoint.



• Also note the external auditory meatus, leading to the middle ear, the sharp projection, the styloid process.

• At the base of the styloid is the little stylomastoid foramen, through which the facial nerve passes.

• Medial to the styloid process are two major openings for blood vessels - the carotid canal, passing forwards, for the internal carotid artery, and the jugular foramen,


Inferior Aspect of the SkullInferior Aspect of the Skull


The Sphenoid Bone The Sphenoid Bone

• Spans the width of the cranial floor

• Resembles a butterfly or bat

• Consists of a body and three pairs of processes

• Contains five important openings


The Sphenoid BoneThe Sphenoid Bone


The Ethmoid Bone The Ethmoid Bone

• Lies between nasal and sphenoid bones

• Forms most of the medial bony region between the nasal cavity and orbits


Facial Bones Facial Bones

• Unpaired bones

• Mandible and vomer

• Paired bones

• Maxillae, zygomatics, nasals, lacrimals, palatines, and inferior nasal conchae


Mandible Mandible

• The lower jawbone is the largest and strongest facial bone

• Composed of two main parts

• Horizontal body

• Two upright rami


Mandible Mandible


Maxillary Bones Maxillary Bones

• Articulate with all other facial bones except the mandible

• Contain maxillary sinuses – largest paranasal sinuses

• Forms part of the inferior orbital fissure


Maxillary Bones Maxillary Bones


Maxillary BonesMaxillary Bones


Other Bones of the Face Other Bones of the Face

• Zygomatic bones – form lateral wall of orbits

• Nasal bones – form bridge of nose

• Lacrimal bones – located in the medial orbital walls

• Palatine bones – complete the posterior part of the hard palate


Other Bones of the Face Other Bones of the Face

• Vomer – forms the inferior part of the nasal septum

• Inferior nasal conchae

• Thin, curved bones that project medially form the lateral walls of the nasal cavity


The Hyoid Bone The Hyoid Bone

• Lies inferior to the mandible

• The only bone with no direct articulation with any other bone

• Acts as a movable base for the tongue


FORAMINA OF SKULLFORAMINA OF SKULL

Various holes, or foramina are found in the base of the skull.

* 1 Foramen Caecum* 2 Optic Canal* 3 Superior orbital fissure* 4 Foramen rotundum* 5 Foramen ovale* 6 Foramen Spinosum* 7 Foramen Lacerum* 8 Carotid Canal* 9 Foramen magnum* 10 Hypoglossal Canal* 11 Jugular Foramen* 12 Internal acoustic meatus


The skin of the scalp continues from the front and lateral side of the face into the occipital region of the skull posteriorly. The makeup of the scalp is important clinically because trauma to the scalp is frequent

The scalp is made of 5 layers and they spell scalp: S -- skin C -- dense Connective tissue A -- aponeurosis L -- loose connective tissue P -- periosteum

The Scalp


The Scalp

S -- skin C -- dense connective tissue A -- aponeurosis L -- loose connective tissue P -- periosteum


The AortaThe Aorta

• Ascending aorta – arises from the left ventricle

• Branches – coronary arteries

• Aortic arch – lies posterior to the manubrium

• Branches

•Brachiocephalic trunk

•Left common carotid

•Left subclavian arteries

GREAT VESSELSGREAT VESSELS


The AortaThe Aorta((AORTIC BRANCHES: ABC'S Aortic arch gives off the Bracheiocephalic trunk, the left Common Carotid, and the left Subclavian artery


Arteries of the Head and NeckArteries of the Head and Neck

Branches of the External Carotid Artery (ECA)STAPLe OF PAM STSuperior ThyroidAscending PharyngealLingualOccipitalFacialPosterior AuricularMaxillarySuperficial Temporal



Branches of the Internal Carotid Artery (ICA)OPAAMOphthalmicPosterior CommunicatingAChorACAMCA



Superior thyroidAscending pharyngealLingualFacialOcciptalPosterior auricularMaxillarySuperficial temporal


Major Arteries Serving the BrainMajor Arteries Serving the Brain


The Parotid Region

The parotid gland is a superficial structure located in the upper neck above the posterior belly of the digastric muscle.

It is a salivary gland that has a large duct (pd) which crosses the masseter muscle to pierce the buccinator muscle opposite the upper 2nd molar tooth. Facial nerve appearing at the

upper and anterior edges of the gland are shown in yellow.


If the parotid gland is carefully removed, you can identify the structures located within it. The first plane is the venous plane and consists of the retromandibular vein (rm) and its tributaries and branches

The common facial vein empties into the internal jugular vein and the external jugular into the subclavian vein near its junction with the internal jugular.

The Parotid Region


The Parotid Region

external carotid artery (EC) occipital artery (oc) maxillary artery (m) transverse facial artery (tf) superficial temporal artery

When the venous plane is removed we reach the important nervous plane. The importance of this plane is the presence of the facial (VII) nerve. The facial nerve leaves the skull through the stylomastoid foramen and immediately enters the deep part of the parotid gland where it gives off its branches. Deep to the nerves lies the arterial plane which includes terminal parts of the external carotid artery and its branches:


The infratemporal fossaThe infratemporal fossa

The lateral wall of the infratemporal fossa consists of the

ramus (4) coronoid process (1) head of condyle (2) neck of condyle (3)

body (5) angle (6)

The infratemporal fossa is a small space between the ramus of the mandible and the lateral pterygoid plate of the sphenoid.



Medial wall: lateral pterygoid plate (1)

Roof; greater wing of sphenoid (3) includes foramen ovale & foramen spinosum

Posteriorly: styloid process (4)



The artery entering the infratemporal fossa is the maxillary branch of the external carotid artery.

It has many branches (11 in all).


Anterior Neck

Common carotid artery (cc) Internal carotid artery (ic) External carotid artery (ec) Carotid sinus (cs)


Neck

Reflection of sternomastoid and removal of common facial vein

cca-common carotid artery eca-external carotid artery sta-superior thyroid artery oa-occipital artery la-lingual artery fa-facial artery ica-internal carotid artery


Neck

Thyroid gland and it arterial supply

When the strap muscles are reflected, we can see the thyroid gland (tg) with its arteries (superior thyroid artery from the external carotid (sta) and the inferior thyroid artery from the thyrohyoid trunk from the subclavian (ita).


Structures Found AT the Root of the Neck

The root of the neck is bounded by the manubrium of the sternum anteriorly, the first rib laterally and the first thoracic vertebra posteriorly. All structures passing from the head through the neck to lower regions pass through this area as well as structures arising in the thoracic cavity and passing out through this region. The following description of the root of the neck starts with the most anteriorly placed structures and proceeds to the most posteriorly placed ones.

Most anterior structures: 1. brachiocephalic vein 2. vertebral vein 3. internal jugular vein 4. subclavian vein 6. thoracic duct 7. thymus gland


Structures Found AT the Root of the Neck

The next layer can be considered the artery-nerve layer:

1. lung 2. vagus nerve 3. common carotid artery 4. subclavian artery 5. ansa subclavius 6. thyrocervical trunk 7. vertebral artery 8. internal thoracic artery 9. trachea 10. esophagus

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Head and neck rs

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