Anatomy: Head, Neck, Face, and Skull

• Anatomy III covers the head and neck, the face, and the skull in detail.
• The course includes 3 credit hours, split into 2 hours of lecture and 1 hour of lab work.

Course Outline

• Head and neck muscles, triangles, main arteries, and veins are discussed.
• The course includes the cervical part of the sympathetic trunk, the cervical spine (vertebrae), and joints of the neck.
• The face topics covered are sensory nerves, bones, muscles, and facial nerve.
• The course includes muscles of mastication, the mandible, the temporomandibular joint, a description of the orbit and nasal cavity, and eye muscles.
• Skull studies covers bones of the skull, anterior cranial fossa, middle cranial fossa, and posterior cranial fossa.
• The topics covered are the base of the skull and structures passing through foramina.

Osteology: The Skull

• The skull is divided into two parts: the neurocranium and the viscerocranium.
• The neurocranium forms a protective case or "vault" around the brain.
• The viscerocranium forms the anterior part of the skull including the orbits, nasal cavities, and upper/lower jaw bones.
• The cranium consists of the frontal bone (1), parietal bones (2), occipital bone (1), temporal bones (2), sphenoid bone (1), and ethmoid bone (1).
• The facial bones consist of the zygomatic bones (2), maxillae (2), nasal bones (2), lacrimal bones (2), vomer (1), palatine bones (2), inferior conchae (2), and mandible (1).

Frontal Bone

• The squamous (flat) portion forms the skeleton of the forehead.
• The frontal bone forms the roof of the orbit.
• The nasion is an area where the frontal bone intersects with the nasal bones.
• The glabella is a smooth, slightly depressed area just superior to the nasion.
• A supraorbital margin marks the boundary between the squamous and orbital portions.
• The supraorbital notch or foramen is for the passage of the supraorbital nerve and vessels.
• A prominent ridge just superior to the supraorbital margin is the superciliary arch, which is more pronounced in males.
• The zygomatic process of the frontal bone articulates with the zygomatic bone.

Zygomatic Bones

• These form the cheek bones.
• This segment forms a portion of the lateral wall of the orbit.
• The frontal process of the zygomatic bone articulates with the frontal bone.
• The temporal process of the zygomatic bone articulates with the temporal bone.
• The zygomaticofacial foramen is a small foramen for passage of the zygomaticofacial nerve.

Maxilla bone

• This bone forms the upper jaw.
• Alveolar processes of the maxillae include the sockets and supporting bone for the maxillary teeth.
• The maxillae form the floor of the orbit.
• The large infraorbital foramen allows passage for infraorbital nerve & vessels
• The bone surrounds most of the pear-shaped piriform aperture.
• The frontal processes of the maxillae articulates with the frontal bone.
• The zygomatic processes of the maxillae articulates with the zygomatic bones.
• The anterior nasal spine is a sharp prominence on the inferior aspect of the piriform aperture.
• The intermaxillary suture is the site where the two maxilla are united in the median plane.
• Seen within the piriform aperture are the scrolled middle nasal conchae and the inferior nasal conchae
• The vomer bone along with the perpendicular plate of the ethmoid bone form the bony nasal septum.

Mandible

• It is U-shaped with alveolar process that houses the mandibular teeth.
• The mental foramen is located inferior to the 2nd premolar for passage of the mental nerve and vessels.
• The mental protuberance is a triangular elevation forming the prominence of the chin.
• The mental tubercle is located just lateral to the protuberance.
• The body represents the horizontal portion.
• The Ramus is the vertical portion.

Skulls: Lateral Aspect

• Bones include Parietal bone, Frontal bone, Occipital bone, Temporal bone, Sphenoid bone, Mandible, Zygomatic bone, Maxillae, Lacrimal bone and Nasal bone.

Parietal Bones

• These are paired bones that form the lateral & superior cranium.
• Temporal Lines mark the attachment site of the temporalis muscle & fascia.
• These bones articulates with frontal bone via the coronal suture.
• It articulates with occipital bone via lambdoid suture.
• Pterion-site is where 4 cranial bones articulate, which has implications for the epidermal hematoma

Temporal Bones

• Paired bones that form the inferior lateral aspect of skull.
• The temporal bone is described as having a flat squamous portion and a mastoid process, which is an attachment site for several muscles.
• Zygomatic arch extends anteriorly to articulate with the zygomatic bone.
• The external acoustic meatus (ear canal) and the pointed styloid process are considered to be located the tympanic portion of the temporal bone.
• The styloid process serves as the attachment site for several muscles and the stylohyoid ligament.
• Mandible and a portion of the zygomatic arch have been removed in this view
• The inferior aspect of the arch is a small bony protrusion or articular tubercle, importnat to the mechanics of the TMJ.
• Mandibular fossa- deep recess that accepts the condyle of the mandible, also important region of the TMJ.

Zygomatic bone

• It forms major portion of the cheek.
• The temporal process that articulates with the zygomatic arch.
• The Frontal process that articulates with the frontal bone
• The Zygomaticofacial foramen is a small foramen generally visible.

Occipital Bone.

• Forms the posterior aspect of the skull.
• Articulates with the parietal bone via the lambdoid suture.
• Prominent palpable elevation located posteriorly as the is external occipital protuberance

Sphenoid Bone

• An Irregular shaped bone that forms a portion of the orbit, lateral aspect of skull and a portion of the cranial base
• The bone can be divided into 4 parts: Greater wing, Lesser wing, Pterygoid processes and the body.

4 portions of Sphenoid

• Portion of zygomatic arch and mandible removed in this view.
• Greater wing articulates with the temporal, parietal & frontal bones at the pterion
• Pterygoid processes are two thin plates of bone that serve as attachment sites for muscles.
• Pterygoid hamulus is a small hook of bone extending from the medial pterygoid plate, with the tensor veli palatini tendon courses around this

Maxilla

• Portion of zygomatic arch and mandible removed in this view.
• Posterior aspect of the maxillae has tuberosity of maxillae
• Small alveolar foramina are present for the posterior superior alveolar nerves & vessels
• The Pterygomaxillary fissure is a tear-drop shaped fissure between the sphenoid and tuberosity of the maxillae
• Pterygopalatine fossa is a small but important space located medial to the fissure

Lateral Aspect of Skull

• Nasal bone can be identified and articulates with the frontal bone and the maxillae -Lacrimal bone-is identified and houses lacrimal sac that can be identified within the orbit
• Prominent anterior nasal spine at the inferior aspect of the piriform aperture

Mandible

• Condylar process is located at the superior part of the ramus and involved in the articulation of the mandible with the temporal bone (TMJ)
• Coronoid process is located just anterior and serves as the attachment site for the temporalis muscle
• Angle of mandible is located between the ramus and body

Calvaria

• Emissary foramen are small, inconsistent (not always present) foramina for passage of emissary veins
• Bregma is a landmark formed by the intersection of the sagittal & coronal sutures
• Lambda is a landmark formed by the intersection of the sagittal & lambdoid sutures
• The inferior aspect of the skull cap presents, Vascular grooves, Granular Foveolae, Groove for the superior sagittal sinus and Diploe

Infant Skull

• Bones forming the calvaria & some parts of the cranial base develop by intramembranous ossification
• Whereas-most parts of the cranial base develop by endochondral ossification
• Bones in the infant skull are separated by areas of fibrous tissue membranes - these are the fontanelles.
• Fontanelles- membranous gaps (soft spots) in skull that permit growth

Infant Calvaria

• The Anterior Fontanelle (soft spot) is the future site of the bregma
• This measurement is useful as, By about 18-24 months- the surrounding bones fuse together and is no longer palpable
• The posterior Fontanelle is triangular and marks the future site of the lambda
• Fusion of surrounding occurs by about 12 months.
• Mastoid & sphenoidal fontanelles fuse early in infancy
• Palpation of fontanelles during infancy enables physicals to determine: Growth progress of frontal & parietal bones, Degree of hydration of infant, Intracranial pressure

External Aspect of the Cranial Base

• Inferior aspect of the skull presents six different bones, palatine processes of the maxillae, Palatine bone, Sphenoid bone, Vomer, Temporal and Occipital bones Hard Palate- Is formed by, The palatine processes of the maxillae and the horizontal plates of the palatine bone

Cranial Base- Palate

• Hard palate is formed by the palatine processes of the maxillae and the horizontal plates of the palatine bone.
• Medial plane small prominence is projecting posteriorly. Called, posterior nasal spine

Postior Part of the Central incisors

• There is a small depression or incisive fossa, with pair of canals or the incisive canals for passage of the nasopalatine nerves
• Postiolaterally there's Greater & Lesser palatine foremen For passage of. The nerves and the vessels of the same name.

Cranial Base- Vomer

• Vomer- a thin, flat unpaired bone in the midline and forms a major portion of the bony nasal septum
• Sides of Vomer: With two large openings, called, Choanae Also, has posterior nasal apertures

Cranial Base- Sphenoid

• Three parts of the sphenoid bone that can be appreciated when looking on the inferior aspect of skull: Greater wing, Medial pterygoid plate and Lateral pterygoid plate
• Pterygoid fossa is, Between the two pterygoid plates

Important parts of the Sphenoid

• Foramen; ovale for passage of, Mandibular division (V3) of the trigeminal nerve.

External Aspect of Skulls - Temporal

• The mastoid serves as the attachment site for the SCM and posterior belly of the digastric muscles.
• The prominence is called, mastoid process
• The External acoustic meatus ( EAM) Is, Located just anterior to the mastoid

Important parts regarding the Temporal Area

• Temporal fossa (tossa) or the Styloid processis, Thin, bony. extending inferior and anteriorly
• Serves as the Attachment site for: numerous muscles and Ligaments.,

Inner surface of the Skulls , Temporal

• There are two portant Foramen that can be identified,On The inferior aspect:
• Stylomastoid Foremen - Is a Small Foramen for passage of The facial Nerve (CN VII) Located between the Mastoid & Styloid process
• Other Important canals include, Carotid for the Internal passage to the cranial cavity artery Internal aspect of the skulls, that looks at Occiptal

Occipital

• The bone: Forms the posterior and inferior
• The passage Of Spinal and is Located from in the Foramen - Called, Foramen Magnum
• Basilar: Includes the tube attached for pharyngeal constrictors. Also a small tubercle - Called , Pharyngeal Tubercle

Hypoglossal canal

• The part of the canal for the Passage of the Hypogossal Nerve that Looks in at part The internal canal of (CN XII) to the vein
• Condylar: includes two different Types of Foramen Between Temporal Nerves 9 ,10 , &11

Skull: Internal Aspect

• Squamous portion, Presents External Occipital, and has Project Lateral and are Muscular and Site where a Site muscular the Lines Nunchal
• Clivus is the Anterior, In order: And the Trans Medulla
• There are 3 parts: Where Magnum - Medella , With spinal. Cord & Foramen

Internal Aspect of the Cranial Base

• Divided into three parts:Anterior cranial fossa, Middle cranial fossa , and Posterior cranial fossa

Anterior Cranial Fossa

• The Fossal or the part of the Frontal Lobes as an occupier Brain space and or a Anterior Crain - From, the Orbital Portion, Ethmoid bone, Lesser Winy (which is, an area o sphenoid)

Frontal: Frontal

• Bony Median is extended from the the base Crests. Called: Frontal Crests Crista Gallihas : The ridge as the the cerebra

Anterial of, Internal Skull

• Ethmols of : Side crista, With galli For the 2 Olfactory/sieve like. Also has olffactory to Crainial V

Middle Cranial Fossa

• Includes Temporal lobes that Occupy The middle as the ,The Greater ,Bone as An part with Wing ,Sphen, Squamous Temporal and Has Petrous bone
• Sella -Is at Saddle Bony superior: Form Body

5 Important Features for: Middle

• Superior .Nissure * Rotundum ,Ovale ** , ,Lacerun ***
• 3 Portions as, (Body ) Sella, Houses Gland for Pituitary gland *
• Foramen where are passes *Trigemmal, petrusal of the Temporal

Posterior Cranial Fossa

• Large and has Includes The three part of of three Fossal . This has The 3 includes, Cereb and , Meduall and Pons to Fossal to has been from as of : Mastoid Portio and Pterousal, Bone in occipital
• Cliviu is marks Anterior of, in has Crest has Crest bone of internal proturberance to spinals in area
• Portions to Grooves is used for the, Sigmiod where are Dural Venousis, for transverse or has Sinuseis used is for and also trans ,
• Sigmoid also empty, The for Jug and Also where transmits is used for VII** ,IX*** .XI** Internal
• The internal Acoustic to located The for Meatu. From has. The Labyrinth of arterial .

7 Seven Articulate Orbit

• Bones that are used include: Front -Zygon ,Ethm, Sphen - Are bone of Orbit of Artic
• The Optic: Where is the used Nerve and The Superior is Trans the.

Skull Features

• Canal and, VI** &V1 ( 5th N- and is from .Also Trans: Groove -Ethmodial is Foramina