Head and Neck Anatomy Notes

NORMA BASALIS EXTERNA

• Definition: Outer surface of the skull base; divides into anterior, middle and posterior parts.

ANTERIOR PART OF NORMA BASALIS EXTERNA

• Formed by hard palate bounded anteriorly and on two sides by the alveolar margin of the maxilla (arch).
• On both sides, formed by:
  • Palatine process of the maxilla
  • Horizontal plate of the palatine bone
• General features:
  • a) Alveolar margin (arch) carries $16$ sockets of teeth roots.
  • b) Posterior nasal spine is a median projection from the posterior border of the hard palate and gives origin to the muscles of the soft palate and musculus uvulae.
  • c) Maxillary tuberosity at the posterior end of the alveolar arch of the maxilla gives origin to the superficial head of the medial pterygoid muscle.
• Foramina in the anterior part of the base:
  • 1- Incisive fossa at the anterior end of the inter-maxillary suture; has $4$ small foramina.
  • Two small median incisive foramina (anterior and posterior) transmitting left and right nasopalatine nerves.
  • Also two lateral foramina transmitting terminal branches of the greater palatine nerves and vessels.
  • 2- Greater palatine foramen: lower opening of the greater palatine canal; transmits the greater palatine nerve and vessels which pass forward along a groove on the bone.
  • 3- Lesser palatine foramina: transmit the lesser palatine nerves and vessels which pass forward along a palatine groove on the bone.

MIDDLE PART OF NORMA BASALIS EXTERNA

• Forms the anterior part divided into:
  • Anterior laterally: contains the pterygoid process, infratemporal surface, and greater wing of the sphenoid.
  • Anterior middle: contains the vomer and body of the sphenoid.
  • Posterior laterally: contains the mastoid, petrous and tympanic parts of the temporal bone.
  • The posterior part includes basilar part and two lateral parts of the occipital bone.
• Main features:
  • 1- Posterior nasal openings (choanae) separated by the vomer; the vomer is the median vertical bony plate between the two posterior nasal openings.
  • 2- Pterygoid process of the sphenoid: formed laterally, medially, and the pterygoid plates with the pterygoid fossa between them.
  • Lateral pterygoid plate: its lateral surface gives origin to the lower head of the lateral pterygoid muscle; its medial surface gives origin to the deep head of the medial pterygoid muscle.
  • Medial pterygoid plate: has a sharp posterior border that projects inferiorly to form the pterygoid hamulus, giving origin to the superior constrictor muscle of the pharynx and the pterygo-mandibular ligament; the upper end of the posterior end splits to form the scaphoid fossa, giving origin to tensor palati.
  • Pterygoid fossa: V-shaped space between the medial and lateral pterygoid plates.
  • 3- Infratemporal surface of the greater wing of sphenoid: bounded laterally by infratemporal crest (origin of lateral pterygoid) and medially by the groove for the pharyngeal-tympanic tube (between greater wing and petrous temporal bone); shows the spine of sphenoid with attachments for sphenomandibular ligament and two foramina (oval and spinosum).
  • 4- Petrous part of temporal bone: features include
  • a) Foramen lacerum: located between the apex of the petrous temporal bone posteriorly, the pterygoid process anteriorly, and the basilar part of the occipital bone medially. In life, the lower part is filled by fibrocartilage. Transmits meningeal branches of ascending pharyngeal artery from cavernous sinus to pterygoid plexus.
  • b) Carotid canal: transmits internal carotid artery and surrounding sympathetic nerves.
  • c) Jugular foramen: lodges inferior petrosal sinus antero-medially and IX, X, XI cranial nerves and the internal jugular vein posterior-lateral.
  • 5- Styloid and mastoid parts of temporal bone:
  • a) Styloid process: pointed, anterior to the mastoid; attachments for styloglossus, stylohyoid, stylopharyngeal muscles and ligaments (stylohyoid, stylomandibular).
  • b) Mastoid process: nipple-like posterior to the styloid; lateral surface for splenius capitis, longissimus capitis; mastoid notch for posterior belly of digastric; occipital groove medial to notch for occipital artery. The stylo-mastoid foramen transmits the extracranial part of the facial nerve.
  • c) Tympanic (tympanic plate) part: lies behind the articular fossa and is separated from it by the squamous-tympanic fissure which transmits the chorda tympani.
  • 6- Basilar part of occipital bone: articulates with the body of the sphenoid; pharyngeal tubercle is a median elevation on the basilar part in front of the foramen magnum.
• Foramen magnum: lies between the occipital condyles; communicates the posterior cranial fossa with the vertebral canal.
• Condylar fossa: depression behind the occipital condyle; transmits emissary vein; hypoglossal canal lies above the occipital condyle transmitting the hypoglossal nerve.

POSTERIOR PART OF NORMA BASALIS EXTERNA

• Formed by squamous part of the occipital bone and mastoid part of the temporal bone; features to see in norma occipital.
• Related structures as described in the occipital area (detailed in figures in original text).

CRANIAL CAVITY

• The cranial cavity is the internal part of norma basilis externa, divided into $3$ fossae: A, B, C.
• A- ANTERIOR CRANIAL FOSSA
  • Contains the frontal lobes of the brain.
  • Floor largely formed by orbital plates of the frontal bones; separates frontal lobes from orbits.
  • Frontally, the fossa is separated from the nasal cavity by the cribriform plates of the ethmoid bone; olfactory nerves pass through these plates.
  • Fracture of cribriform plate tears meninges and may allow CSF to escape.
  • Cribriform plate contains foramina for olfactory nerves.
  • Crista galli projects upwards in the midline and provides attachment for the anterior end of the falx cerebri.
  • Posterior part of the fossa formed by the body of the sphenoid and the lesser wing; the lesser wing’s medial trace ends in the anterior clinoid process.
• B- MIDDLE CRANIAL FOSSA
  • Divided into a median part and two lateral parts.
  • Median part: formed by the body of the sphenoid; in front a shallow groove and behind a deeper groove—the sellar (hypophyseal) fossa.
  • The shallow groove leads laterally to the optic canal (opens into the back of the orbit).
  • The optic chiasma lies behind the groove; the sella turcica is separated from the posterior cranial fossa by the dorsum sellae; corners of the dorsum sellae form the posterior clinoid processes.
  • Lateral surface of the body of the sphenoid contains the cavernous venous sinus and the internal carotid artery (which often grooves the bone) and several cranial nerves.
  • The sphenoidal air sinuses lie within the body of the sphenoid and communicate with the nasal cavity.
  • Lateral part: lodges the temporal lobe; border anteriorly by the posterior margin of the lesser wing of the sphenoid and posteriorly by the superior border of the petrous part of the temporal bone.
  • Floor: formed by the greater wing of the sphenoid (anterior), the anterior surface of the petrous temporal bone (posterior), and the squamous part of the temporal bone (lateral).
  • The greater wing openings (five):
  • $1.$ Overhanging lesser wing separated by the superior orbital fissure (transmits nerves and vessels).
  • $2.$ Foramen rotundum (transmits maxillary nerve; opens anteriorly into the pterygopalatine fossa).
  • $3.$ Foramen ovale (transmits the mandibular nerve).
  • $4.$ Foramen spinosum (transmits middle meningeal vessels from the infratemporal fossa; vessels groove the bone).
  • $5.$ Foramen lacerum (large irregular opening; filled in life by fibrocartilage; internal carotid artery enters via carotid canal and passes forward in the carotid groove; pterygoid canal also present).
  • Internal carotid artery: enters skull by the carotid canal in the petrous temporal bone; emerges at the foramen lacerum region, then courses anteriorly and medially to the anterior clinoid process.
  • The pterygoid canal runs forward from the foramen lacerum towards the pterygopalatine fossa; transmits the nerve of the pterygoid canal (formed by the greater petrosal nerve and deep petrosal nerve).
  • The petrous temporal bone: on its anterior surface, near the apex, a shallow depression for the trigeminal ganglion; the arcuate eminence marks the underlying superior semicircular canal.
  • Tegmen tympani forms the roof of the middle ear cavity and tympanic antrum; superior border of the petrous temporal is grooved by the superior petrosal venous sinus.
  • Infection in ear cavities may spread through bone to meninges, sinuses and brain.
• C- POSTERIOR CRANIAL FOSSA
  • Houses the hindbrain (pons, cerebellum, medulla oblongata).
  • Boundaries: anterior by dorsum sellae; anterolateral by superior border of the petrous temporal bones; posterior by margins of the parietal/occipital bones (transverse sinus impression).
  • Floor: formed by petro-mastoid temporal bone laterally and occipital bone posteriorly; foramen magnum slopes upward in this region.
  • The medulla, pons, and basilar artery rest on this floor.
  • Internal acoustic meatus (on the posterior surface of the petrous temporal bone): transmits facial nerve (CN VII) and vestibulocochlear nerve (CN VIII) and labyrinthine artery.

MANDIBLE

• The mandible features a horizontal body and an upright ramus on each side.
• Lateral surface (external) is attachment for the masseter; medial surface (internal) shows the mandibular foramen (transmits the inferior alveolar nerve and vessels, leading to the mandibular canal).
• Lingula: a spur of bone anteromedial to the mandibular foramen.
• Mylohyoid groove: passes downward and forward from the lower margin of the mandibular foramen; transmits the mylohyoid nerve and vessels.
• Medial surface behind the midline shows a groove containing the lingual nerve (risk during dental extractions).
• Angle: where the lower border of the body meets the posterior border of the ramus.
• Two processes on the upper border of each ramus:
  • Anterior: coronoid process (muscular attachment).
  • Posterior: condylar process with an articular head; neck below the head with the pterygoid fossa.
• Mandibular notch separates the two processes (houses branches of the posterior division of the mandibular nerve and termination of the external carotid artery).
• Alveolar margin of the body contains sockets for teeth.
• Lateral surface: mental foramen (midway between the upper and lower borders; or near the midline, depending on measurement) transmits the mental nerve and vessels; mental protuberance forms the chin.
• Inner surface behind the midline features the mylohyoid line, sublingual fossa (for sublingual gland) above the line, and submandibular fossa (depression for submandibular gland).
• The mandible articulates with the temporal bone at the temporomandibular joint (TMJ).

TEMPO- MANDIBULAR JOINT (TMJ)

• Type: synovial joint of the condylar variety.
• Articular surfaces:
  • a) Mandibular fossa with articular tubercle of temporal bone.
  • b) Head of the mandible.
• The joint surfaces are covered by a fibrous layer predominating over the cartilage.
• The joint is divided into upper and lower cavities by an articular disc.
• Capsule: attaches to the margins of the articular surfaces.
• Synovial membrane: lines the inner surface of the capsule; covers the intracapsular part of the neck of the mandible and the tendon of the lateral pterygoid; does not cover the articular surfaces.
• Articular disc: fibrous plate; divides the joint into two cavities; upper surface concavo-convex to fit the fossa and tubercle; lower surface concave to fit the head; circumference adherent to capsule and provides attachment for the tendon of the lateral pterygoid muscle anteriorly.
• Accessory ligaments:
  • 1- Lateral (temporo-mandibular) ligament: short; attached superiorly to the root of the zygoma and inferiorly to the lateral neck of the mandible; fibers directed downward and backward.
  • 2- Sphenomandibular ligament: medial to the capsule; attaches superiorly to the spine of the sphenoid and inferiorly to the lingula of the mandible.
  • 3- Stylomandibular ligament: from the styloid process to the posterior border of the ramus (above the angle).
  • 4- Pterygomandibular ligament: extends from the pterygoid hamulus to the posterior end of the mylohyoid line of the mandible.

MOVEMENTS OF THE TMJ

• Rest position: lower teeth do not contact upper teeth; they lie slightly behind the upper teeth.
• Opening of the mouth: initial rotation of the mandible head on the articular disc; the head and disc are pulled forward by the lateral pterygoid so the head lies on the articular tubercle.
• Closing of the mouth: reverse movements; the head and disc glide backward; the head may rotate on the disc.
• Retraction: pulling the mandible back to rest position.
• Lateral movements (chewing): forward gliding of the head and disc on one side, rotation around a vertical axis on the other side.
• Muscles producing movement:
  • Depression: lateral pterygoid (assisted by digastric, geniohyoid, mylohyoid).
  • Elevation: temporalis, masseter, medial pterygoid.
  • Protraction: lateral and medial pterygoids.
  • Retraction: posterior fibers of temporalis aided by middle/deep fibers of masseter, digastric, and geniohyoid.
• Nerve supply of the joint: auriculo-temporal nerve and masseteric nerve.

CERVICAL VERTEBRAE

• Transverse foramen: each transverse process (except the 7th) transmits the vertebral artery and veins; the 7th transmits the vein only.
• Spinous processes: the C2 (Axis) has a dens projecting upwards from the body.
• The first cervical vertebra (Atlas) has no body or spine; it has anterior and posterior arches; the superior facets receive the occipital condyles (large, kidney-shaped, concave); the inferior facets are nearly round.
• Transverse processes of Atlas contain a groove behind and lateral mass for the vertebral artery; the lateral mass bears the articular facets and the upper surface of the posterior arch.
• The second cervical vertebra (Axis) bears the dens (odontoid process).
• The seventh vertebra resembles an upper thoracic vertebra with a long, directly downward-tilted spine.

ATLANTO-OCCIPITAL AND ATLANTO-AXIAL JOINTS

• ATLANTO-OCCIPITAL JOINTS
  • Type: synovial joint of the condylar variety.
  • Articulations: between the superior articular facets of the atlas and the occipital condyles.
  • Capsule attached around the articular surfaces; ligaments:
  • a) Anterior atlanto-occipital membrane: connects the anterior arch of the atlas to the anterior margin of the foramen magnum.
  • b) Posterior atlanto-occipital membrane: connects the posterior arch of the atlas to the posterior margin of the foramen magnum.
  • Movements: flexion (nodding) via longus capitis and rectus capitis anterior; extension via rectus capitis posterior muscles; slight lateral rotation.
• ATLANTO-AXIAL JOINTS
  • A- Two lateral atlanto-axial joints: plane synovial joints between the inferior articular facet of the atlas’ lateral mass and the corresponding facet on the axis’ superior body; each with a thin capsule.
  • B- Median atlanto-axial joint: a pivot synovial joint between the odontoid process (dens) of the axis and an osseous ring formed by the anterior arch of the atlas and the transverse ligament of the atlas.

SCALP

• Definition: soft tissue covering the skull vault from the eyebrows to the superior nuchal line; temple region between temporal line and zygomatic arch.

LAYERS OF THE SCALP

1) Skin – contains hair and adherent to the superficial fascia.
2) Superficial fascia – fibro-fatty layer containing vessels and nerves.
3) Occipitofrontalis aponeurosis (galea aponeurotica) – a broad musculo-fibrous layer.
4) Loose connective tissue – allows movement of the overlying muscles and skin; potential space for blood/pus.
5) Pericranium (periosteum) – outer periosteum of skull bones.

OCCIPITOFRENALIS MUSCLE

• A sheet consisting of four bellies: two occipital and two frontal, connected by the epicranial aponeurosis.
• Occipital bellies: arise from the superior nuchal line; pull the scalp backward.
• Frontal bellies: fan-shaped, with no bony attachments; connected to the skin via galea; frontal bellies raise the eyebrows.
• Epicranial aponeurosis: connects the four bellies; anterior portion encloses the frontal bellies; posterior portion extends to the external occipital protuberance and highest nuchal lines; lateral extensions over the temporal fascia to the zygomatic arch.
• Nerve supply:
  • Occipital belly: posterior auricular nerve (branch of facial nerve).
  • Frontal belly: temporal nerve (branch of facial nerve).
• Action:
  • Occipital bellies pull scalp backward.
  • Frontal bellies raise eyebrows and create transverse forehead wrinkles when muscles pull forward from below.

NERVES AND ARTERIES OF THE SCALP

• Nerves: ten nerves on each side; five anterior to the auricle (branches of trigeminal nerve) and five behind the auricle (branches of C2–C3). Motor nerves to the front and back are branches of the facial nerve.
• Nerves of the scalp include:
  • Supratrochlear
  • Supraorbital
  • Zygomaticotemporal
  • Auriculotemporal
  • Temporal branches of facial nerve (to frontalis and orbicularis oculi, etc.)
  • Great auricular (C2–C3)
  • Lesser occipital (C2)
  • Greater occipital (C2)
  • Third occipital (C3)
  • Posterior auricular (facial nerve branch)
• ARTERIES OF THE SCALP
  • Supratrochlear and supraorbital arteries (from the ophthalmic artery)
  • Superficial temporal artery (terminal branch of external carotid)
  • Posterior auricular artery (branch of external carotid)
  • Occipital artery (branch of external carotid)
  • The superficial temporal artery also gives branches: transverse facial, anterior auricular, zygomatico-orbital, middle temporal, and frontal/parietal terminals.
• The arteries form extensive anastomoses, contributing to potential heavy bleeding if injured.

ARTERIAL SUPPLY OF THE SCALP (SUMMARY)

• The scalp is supplied by: $5$ arteries on each side (supratrochlear, supraorbital, superficial temporal, posterior auricular, occipital).
• Additional branches accompany nerves (e.g., zygomaticotemporal, auriculotemporal).

FACE – GENERAL STRUCTURE AND NERVES/ARTERIES

• FACE components: skin, superficial fascia, deep fascia (absent except over the parotid gland and over the buccinator where buccopharyngeal fascia is present).
• Facial muscles (muscles of expression): insert into skin and move skin for facial expressions; all supplied by terminal branches of the facial nerve.
• Facial muscle groups (three main groups):
  • Muscles of the eyelids: Levator palpebrae superioris, Orbicularis oculi, Corrugator supercilii
  • Muscles of the mouth around the mouth opening: Orbicularis oris, Buccinator, others involved in lip movement
  • Additional facial muscles: various muscles around the nose and cheeks contributing to expressions
• Nerves of the face (sensory and motor):
  • Sensory: branches of trigeminal nerve (ophthalmic, maxillary, mandibular)
  • Motor: facial nerve (CN VII) supplying all facial muscles

BRANCHES OF OPHTHALMIC NERVE (V1)

• Supratrochlear nerve
• Supraorbital nerve
• Palpebral branch of lacrimal nerve
• Infratrochlear nerve (nasociliary branch)
• External nasal nerve (terminal branch of anterior ethmoidal nerve)

BRANCHES OF MAXILLARY NERVE (V2)

• Infraorbital nerve: exits infraorbital foramen; gives:
  • Palpebral branches (lower eyelid)
  • Nasal branches (ala and dorsum of nose)
  • Labial branches (cheek and upper lip)
• Zygomaticofacial nerve: passes through zygomatico-facial canal to supply cheek skin.
• Zygomaticotemporal nerve

BRANCHES OF MANDIBULAR NERVE (V3)

• Buccal nerve: passes deep to ramus; supplies skin over buccinator and mucosa of the cheek.
• Mental nerve: exits mental foramen; supplies skin of chin and lower lip mucosa.
• Auriculotemporal nerve

MOTOR NERVE SUPPLY OF THE FACE

• The facial nerve supplies motor fibers to facial muscles; exits the parotid gland and divides into five terminal branches: temporal, zygomatic, buccal, mandibular, cervical.

ARTERIAL SUPPLY OF THE FACE

• Facial artery (main artery): from external carotid; crosses the mandible at the anterior border of the masseter; ascends toward the lacrimal sac; anastomoses with dorsal nasal artery (from ophthalmic).
• Branches of facial artery:
  • Superior labial artery (to upper lip; gives alar and nasal septum branches)
  • Lateral nasal artery (to ala and dorsum of nose)
• Transverse facial artery (branch of facial or superficial temporal)
• Infraorbital artery (branch of maxillary artery): exits infraorbital foramen; supplies face.
• Mental artery (branch of inferior alveolar): exits mental foramen; accompanies mental nerve in face.
• Note: The arterial branches freely anastomose with contralateral counterparts, increasing bleeding risk if damaged.

VEINS OF THE FACE AND SCALP

• Main veins run with arteries and drain into the facial vein system.
• Anterior facial vein: formed at medial angle of the eye by union of supratrochlear and supraorbital veins; runs with facial artery; at the lower border of the mandible joins the anterior division of the retromandibular vein to form the common facial vein, which ends in the internal jugular vein.
• Posterior facial vein (retromandibular): formed from maxillary vein and superficial temporal vein; divides into anterior and posterior divisions; the anterior division joins with the facial vein to form the common facial vein.
• Retromandibular vein: formed in the parotid; crosses the gland; joins with the superficial temporal vein to form the posterior facial vein.
• Occipital vein: descends along the occipital artery, ends in the suboccipital plexus.
• The facial and scalp venous systems communicate widely, contributing to potential for significant bleeding when injured.

LYMPHATIC DRAINAGE OF THE SCALP AND FACE

• Lymphatic drainage is organized into two groups: superficial cervical nodes and deep cervical nodes, plus a circular drainage at the head–neck junction.
• Drainage pathways:
  • Side of scalp and face → parotid lymph nodes (in front of tragus) → submandibular lymph nodes.
  • Front of scalp/forehead/external nose → buccal lymph nodes → submandibular nodes (along facial artery).
  • Medial cheek, upper lip, lateral lower lip → submandibular lymph nodes.
  • Central lower lip → submental lymph nodes (beneath the chin).
  • Submandibular and submental nodes drain into deep cervical nodes.
  • Occipital lymph nodes along the superior nuchal line drain the back of the scalp.
  • Posterior auricular nodes (mastoid region) drain the side of the scalp and back of the auricle and external auditory canal.

PAROTID GLAND

• The largest salivary gland; lies below the external acoustic meatus, between the mandible and the sternomastoid.
• Enclosed in a capsule from deep cervical fascia that splits into two layers at the lower border: superficial layer over the gland and masseter; deep layer over the inner surface attached to the skull base. The deep layer forms the stylomandibular ligament (from the styloid process to the posterior border of the mandible).
• The gland is related to the facial nerve branches in the parotid and contains 3 important intraglandular structures:
  • Terminal part of the external carotid artery (deep) that splits within the gland.
  • Retromandibular vein (posterior facial vein) formed within the gland by the union of superficial temporal and maxillary veins; divides into anterior and posterior divisions.
  • Terminal part of the facial nerve (within the gland, dividing into five terminal branches: temporal, zygomatic, buccal, mandibular, cervical).
• Parotid duct (Stensen’s duct): about two inches long, arises from the anterior part of the gland, runs forward across the masseter muscle, pierces buccal pad of fat and buccopharyngeal fascia, traverses the buccinator, and opens opposite the second upper molar tooth.
• Accessory part of the gland and transverse facial artery lie above the gland; the buccal nerve (branch of V3) lies below the duct.
• Nerve supply: sensory fibers from the auriculotemporal nerve; sympathetic fibers from the plexus around the external carotid; parasympathetic (secretory) fibers from the otic ganglion run with the auriculotemporal nerve.
• The gland’s relations and branches are clinically important due to the risk of nerve injury and salivary function disruption.

TEMPORAL AND INFRATEMPORAL REGION

• Temporal fossa:
  • Boundaries: superior temporal line (superiorly), temporal arch (laterally), zygomatic arch (inferiorly), frontal process of zygomatic bone (anteriorly).
  • Temporal muscle (temporalis) originates from the floor of the temporal fossa; masseter originates from the lower border and inner surface of the zygomatic arch.
• Infratemporal fossa:
  • Boundaries: anterior – posterior surface of the maxilla; medial – lateral surface of the lateral pterygoid plate; superior – infratemporal surface of the greater wing of the sphenoid; lateral – zygomatic arch and coronoid process of the mandible.
  • Contents: medial and lateral pterygoid muscles; mandibular nerve (V3); maxillary artery; pterygoid plexus of veins.
• The infratemporal fossa communicates with:
  • Temporal fossa through space under cover of the zygomatic arch.
  • Pterygomaxillary (pterygopalatine) fossa through the pterygo-maxillary fissure.
  • Orbit through the inferior orbital fissure.
  • Middle cranial fossa through foramen ovale and foramen spinosum.

SUMMARY OF VESSELS AND NERVES IN REGIONS (KEY NAMES TO REMEMBER)

• Major arteries: internal carotid artery (via carotid canal), middle meningeal artery (through foramen spinosum), facial artery, superficial temporal artery, posterior auricular artery, occipital artery.
• Major nerves: facial nerve (CN VII) with its branches in the parotid; auriculotemporal nerve; branches of trigeminal nerve (V1, V2, V3) supplying face/scalp sensation; hypoglossal nerve (CN XII) near occipital region; accessory nerve (CN XI) in posterior cranial region; glossopharyngeal and vagus nerves in the posterior fossa region.

IMPORTANT CLINICAL CONNECTIONS

• Fractures involving the cribriform plate may tear meninges and cause CSF leakage.
• Infection in the ear can spread to meninges via the petrous temporal bone and tegmen tympani.
• The extensive anastomoses of scalp arteries can lead to heavy bleeding from scalp wounds.
• The facial nerve’s course through the parotid gland means injuries here can affect facial expression muscles.
• The TMJ’s disc and ligaments are essential for smooth movement; dysfunction can cause jaw pain, restricted movement, or clicking.
• Lymphatic drainage patterns are clinically important for staging facial/scalp cancers and planning surgical dissections.

SUMMARY OF KEY LA TEX-POWERS (EXAMPLES)

• Foramina and openings in the skull:
  • The greater wing of the sphenoid has five openings: $ext{(1) Superior orbital fissure}, ext{(2) Foramen rotundum}, ext{(3) Foramen ovale}, ext{(4) Foramen spinosum}, ext{(5) Foramen lacerum}.$
• Cranial fossae divisions: $3$ fossae: anterior, middle, posterior.
• Teeth sockets in the maxillary arch: $16$ sockets in the alveolar margin.
• Incisive foramina and nasopalatine nerves: the anterior inter-maxillary region contains $4$ foramina, with two median incisive foramina transmitting nasopalatine nerves and two lateral foramina transmitting branches of the greater palatine nerves.

NOTE

• This set of notes reproduces the major and many minor points from the provided transcript, organized for study and exam preparation. Some OCR errors or typos in the source text have been interpreted into standard anatomical terms where feasible (e.g., nasopalatine nerves, pterygoid canal, sphenomandibular ligament).
• If you’d like, I can convert these notes into a printable PDF or tailor them to specific exam questions (e.g., “Describe the contents of the infratemporal fossa” or “List the branches of the facial artery and their distribution”).