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Temporomandibular Joint (TMJ) Lec 8, Temporal Fossa lec 4, Mandibular…
Temporomandibular Joint (TMJ)
Lec 8
Definition & Type
Modified hinge synovial joint
Movements: gliding + slight rotation
Also allows: elevation, depression
Articular Surfaces
Temporal bone (superior)
Mandibular fossa
Articular tubercle
Mandible (inferior)
Head of mandible (condyle)
Articular Cartilage & Cavity
Covered by fibrous cartilage (not hyaline)
Articular disc (fibrocartilage)
Divides joint into:
Upper cavity
Lower cavity
Articular Disc
Dense fibrous connective tissue
Non-vascularized & non-innervated
Regions:
Anterior band
Intermediate zone (thinnest & functional)
Posterior band
Shapes:
Upper surface: concavoconvex
Lower surface: concave
Retrodiscal Tissue (Bilaminar Zone)
Highly vascular & innervated
Produces synovial fluid
Superior retrodiscal lamina
Elastic fibers
Limits extreme translation
Inferior retrodiscal lamina
Collagen fibers
Limits extreme rotation
Capsule
Surrounds the joint
Attachments:
Above: articular tubercle & mandibular fossa
Below: neck of mandible
Allows: side-to-side, protrusion, retrusion
Contains:
Superior synovial membrane
Inferior synovial membrane
Synovial Membrane & Fluid
Thin, vascular, richly innervated
Lines the capsule
Synovial fluid:
High hyaluronic acid
High viscosity (↑ at load areas)
Functions:
Lubrication
Phagocytosis
Nutrition of cartilage
Capable of regeneration
Ligaments
Lateral temporomandibular ligament
Strengthens lateral capsule
Prevents posterior displacement
Stylomandibular ligament
Styloid process → angle of mandible
Limits excessive protrusion
Sphenomandibular ligament
Sphenoid spine → lingula
Acts as a pivot
Nerve Supply
Auriculotemporal nerve (main)
Masseteric nerve (anterior)
Posterior deep temporal nerve
Vascular Supply
Superficial temporal artery
Maxillary artery
Masseteric artery
Venous plexus (posterior)
Movements
Depression & elevation
Protrusion & retrusion
Rotation (chewing)
Muscles involved:
Muscles of mastication
Suprahyoid & infrahyoid (assist)
Platysma (assist)
Important Relations
Anterior: mandibular notch, masseteric nerve & artery
Posterior: external auditory meatus, tympanic plate
Lateral: parotid gland, fascia, skin
Medial: maxillary vessels, auriculotemporal nerve
Clinical Notes
Located anterior to external auditory meatus
Strong lateral ligament protects tympanic plate
Disc displacement → clicking sound
TMJ Dislocation
Usually anterior (yawning / large bite)
Caused by lateral pterygoid spasm
Symptoms:
Mouth open
Unable to close
Reduction:
Downward pressure on molars
Push mandible backward
Surgery of TMJ
Risk to facial nerve
Risk to auriculotemporal nerve
Arthritis of TMJ
Degenerative arthritis
Abnormal joint function
Dental occlusion problems
Crepitus (joint clicking)
Temporal Fossa
lec 4
Definition & Location
Lateral side of skull
Above external auditory canal
Covered by temporalis muscle
Boundaries
Posterosuperior: superior temporal line
Inferior: infratemporal crest (greater wing of sphenoid)
Anterior: frontal process of zygomatic bone
Lateral: zygomatic arch
Floor:
Frontal bone
Parietal bone
Temporal bone
Sphenoid bone
Pterion (thin area)
Overlies middle meningeal artery
Temporalis Fascia
Tough fascia covering temporalis
Superior attachment: superior temporal line
Inferiorly splits into two layers
Lateral surface of zygomatic arch
Medial surface of zygomatic arch
Function:
Resists downward pull of masseter on zygomatic arch
Contents
Temporalis muscle
Deep temporal nerves & vessels
Auriculotemporal nerve
Superficial temporal vessels
Infratemporal Fossa
Definition & Location
Irregular deep space
Inferior to zygomatic arch
Deep to ramus of mandible
Posterior to maxilla
Boundaries
Lateral: ramus of mandible
Medial: lateral pterygoid plate
Anterior: posterior surface of maxilla
Posterior: tympanic plate + mastoid & styloid processes
Superior: infratemporal surface of greater wing of sphenoid
Inferior:
Medial pterygoid attachment near angle of mandible
Communications
With temporal fossa
Via descent of temporalis muscle
Foramen ovale
Mandibular nerve (V3) exits skull
Accessory meningeal artery enters skull
Foramen spinosum
Middle meningeal artery enters skull
Inferior orbital fissure
Maxillary nerve (V2)
Zygomatic nerve
Pterygomaxillary fissure
Communication with pterygopalatine fossa
Maxillary artery passes medially
Contents
Muscles of mastication (partially)
Lower part of temporalis
Lateral pterygoid
Medial pterygoid
Mandibular nerve (V3) & branches
Chorda tympani
Otic ganglion
Maxillary artery
Pterygoid venous plexus
Muscles of Mastication
Temporalis
Origin:
Temporal fossa
Temporal fascia
Insertion:
Coronoid process & anterior ramus of mandible
Action:
Elevation (closes jaw)
Posterior fibers retract mandible
Innervation:
Deep temporal nerves (V3)
Masseter
Origin:
Superficial: anterior 2/3 of zygomatic arch
Deep: posterior & medial side of arch
Insertion:
Superficial: angle & lower lateral ramus
Deep: upper lateral ramus
Action:
Elevates mandible (closes jaw)
Innervation:
Masseteric nerve (V3)
Medial Pterygoid
Origin:
Deep head:
Medial surface of lateral pterygoid plate
Pyramidal process of palatine bone
Superficial head:
Tuberosity of maxilla
Insertion:
Medial surface of angle of mandible
Action:
Elevates mandible
Protrusion
Side-to-side movement
Innervation:
Nerve to medial pterygoid (V3)
Lateral Pterygoid
Origin:
Superior head:
Inferior surface of greater wing of sphenoid
Inferior head:
Lateral surface of lateral pterygoid plate
Insertion:
Superior head:
Articular disc of TMJ
Inferior head:
Pterygoid fossa on neck of mandible
Action:
Protrusion of mandible
Depression (opening mouth)
Side-to-side movement
Innervation:
Nerve to lateral pterygoid (V3)
Mandibular Nerve (V3)
Lec 6&7
General Features
Largest & inferior division of Trigeminal nerve
Formed in foramen ovale
Sensory root (from trigeminal ganglion)
Motor root
Only trigeminal division with motor fibers
Supplies:
Sensory (face, oral cavity)
Motor (muscles of mastication)
Divisions
Main Trunk
Anterior Division (mainly motor)
Posterior Division (mainly sensory)
Main Trunk Branches
Meningeal branch
Through foramen spinosum
Supplies dura mater & mastoid air cells
Nerve to medial pterygoid
Medial pterygoid muscle
Tensor tympani
Tensor veli palatini
Anterior Division
Masseteric nerve
Masseter muscle
TMJ
Deep temporal nerves
Temporalis muscle
TMJ
Nerve to lateral pterygoid
Buccal nerve
Sensory to cheek skin & mucosa
Does NOT supply buccinator
Posterior Division
Auriculotemporal nerve
Auricle & external auditory meatus
TMJ & scalp
Parasympathetic fibers to parotid gland
Lingual nerve
Anterior 2/3 of tongue (sensation)
Floor of mouth
Joined by chorda tympani
Parasympathetic fibers → submandibular ganglion
Inferior alveolar nerve
Mandibular teeth
Mental nerve → chin skin
Mylohyoid nerve
Mylohyoid muscle
Anterior belly of digastric
Communicating branch
Between inferior alveolar & lingual nerves
Otic Ganglion
Parasympathetic ganglion
Medial to mandibular nerve
Preganglionic fibers
Glossopharyngeal nerve → lesser petrosal
Postganglionic fibers
Auriculotemporal nerve → parotid gland
Clinical Notes (Mandibular Nerve)
Lingual nerve injury
Near lower third molar
Risk during extraction
Mandibular nerve lesion
Unilateral paralysis of mastication
Muscle atrophy
Sunken appearance of face
Maxillary Artery
Largest terminal branch of external carotid
Arises behind neck of mandible
Runs medial to mandible
Enters pterygopalatine fossa
Parts of Maxillary Artery
Mandibular Part
Enters foramina
Supplies:
Dura mater
Mandibular teeth & gums
Ear
Chin
Pterygoid Part
Supplies muscles of mastication & buccinator
Pterygopalatine Part
Maxillary teeth & gums
Orbit (floor)
Nose & paranasal sinuses
Palate
Auditory tube
Upper pharynx
Pterygoid Venous Plexus
Venous equivalent of maxillary artery
Located between temporalis & pterygoid muscles
Valveless veins (bidirectional flow)
Communications:
Cavernous sinus (emissary veins)
Facial vein (deep facial vein)
Inferior ophthalmic vein
Pharyngeal plexus
Drainage:
Maxillary vein
Maxillary Vein
Runs with first part of maxillary artery
Passes deep to neck of mandible
Joins superficial temporal vein
Forms retromandibular vein
Pterygopalatine Fossa
lec 5
Location
Beneath posterior surface of maxilla
Between maxilla & pterygoid process of sphenoid
Contents (Main)
Maxillary nerve (V2)
Maxillary artery (3rd part)
Pterygopalatine parasympathetic ganglion
Boundaries
Anterior: posterior surface of maxilla
Posterior:
Pterygoid process (below)
Greater wing of sphenoid (above)
Medial: perpendicular plate of palatine bone
Superior: greater wing of sphenoid
Lateral:
Pterygomaxillary fissure → infratemporal fossa
Communications & Openings
Pterygomaxillary fissure
Maxillary artery
Posterior superior alveolar nerves
Sphenopalatine veins
Inferior orbital fissure
Infraorbital nerve
Zygomatic nerve
Orbital branches of ganglion
Infraorbital vessels
Foramen rotundum
Maxillary nerve (V2)
Pterygoid canal
Greater petrosal nerve
Deep petrosal nerve
Artery of pterygoid canal
Sphenopalatine foramen
Nasopalatine nerve
Posterior superior nasal nerves
Sphenopalatine vessels
Palatine canal
Greater palatine nerve
Lesser palatine nerve
Accompanying vessels
Pharyngeal canal
Pharyngeal artery
Maxillary Nerve (V2)
Purely sensory
Supplies:
Maxillary teeth & gingiva
Hard & soft palate
Maxillary sinus
Nasal cavity
Middle face skin
Course
Trigeminal ganglion
Cavernous sinus wall
Foramen rotundum → PPF
Branches from main trunk
Meningeal nerve
Ganglionic branches
Zygomatic nerve
Zygomaticotemporal
Zygomaticofacial
Infraorbital nerve
Middle superior alveolar
Anterior superior alveolar
Posterior superior alveolar nerve
Pterygopalatine Ganglion Branches
Orbital nerve
Nasopalatine nerve
Posterior superior nasal nerve
Posterior inferior nasal nerve
Greater palatine nerve
Lesser palatine nerve
Pharyngeal branch
Pterygopalatine Ganglion
Parasympathetic ganglion
Below maxillary nerve
Supplies:
Nose
Palate
Lacrimal gland
Fibers entering
Parasympathetic (synapse)
Sympathetic
Sensory
Preganglionic parasympathetic
Superior salivatory nucleus
Facial nerve
Greater petrosal nerve
Sympathetic fibers
Superior cervical ganglion
Deep petrosal nerve
Nerve of pterygoid canal
Greater + deep petrosal nerves
Path to lacrimal gland
Ganglion → maxillary → zygomatic → lacrimal nerve
Pterygopalatine Part of Maxillary Artery
Enters via pterygomaxillary fissure
Lies anterior to ganglion
Branches accompany nerves (same names)
Veins of Pterygopalatine Fossa
Sphenopalatine vein
Drains posterior nasal cavity
→ pterygoid venous plexus
Inferior ophthalmic vein
Connects orbit to plexus
Drainage
Pterygoid venous plexus
The Scalp
lec 1
Layers of the Scalp (SCALP)
S – Skin
Thick
Hair bearing
Rich in sebaceous glands
C – Connective Tissue
Dense fibrofatty layer
Fibrous septa bind skin to aponeurosis
Contains numerous blood vessels
Arteries from:
External carotid
Internal carotid
Free anastomosis between arteries
A – Aponeurosis (Epicranial)
Thin tendinous sheet
Unites frontal & occipital bellies
Laterally attached to temporal fascia
L – Loose Areolar Tissue
Subaponeurotic space
Allows movement of scalp
Contains emissary veins (valveless)
Connects:
Superficial scalp veins
Diploic veins
Intracranial venous sinuses
P – Pericranium
Periosteum of skull bones
Continuous with endosteum at sutures
Clinical Notes
Sebaceous cysts common
Due to many sebaceous glands
Scalp wounds bleed heavily
Arteries fixed by fibrous septa
Cannot retract → pressure needed
Infections usually localized & painful
Spread of infection
Via emissary veins (valveless)
→ Skull osteomyelitis
→ Venous sinus thrombosis
Blood/pus may collect
In subaponeurotic (L) space
Arterial Supply of the Scalp
Rich supply → profuse bleeding
Arteries lie in superficial fascia
From Internal Carotid:
Supratrochlear artery
Supraorbital artery
From External Carotid:
Superficial temporal artery
Anterior branch
Posterior branch
Posterior auricular artery
Occipital artery
Venous Drainage of the Scalp
Supratrochlear + Supraorbital veins
Form facial vein
Superficial temporal vein
Maxillary vein → Retromandibular vein
Posterior auricular vein
posterior retromandibular → External jugular vein
Occipital vein
→ Suboccipital venous plexus
→ Vertebral veins / Internal jugular vein
Lymph Drainage of the Scalp
Anterior scalp & forehead
Submandibular nodes
Lateral scalp above ear
Superficial parotid (preauricular) nodes
Above & behind ear
Mastoid nodes
Back of scalp
Occipital nodes
Sensory Nerve Supply of the Scalp
Nerves run in dense connective tissue (C layer)
Trigeminal nerve branches:
Supratrochlear (V1)
To vertex
Supraorbital (V1)
To vertex
Zygomaticotemporal (V2)
Temple region
Auriculotemporal (V3)
Temporal region & side of head
Cervical nerves:
Lesser occipital (C2)
Lateral occipital region & auricle
Greater occipital (C2)
Back of scalp to vertex
Functional Grouping
First 3 layers (S + C + A)
Bound together & move as one unit
Movement enabled by:
Loose areolar tissue (L layer)
Muscles of the Scalp
Occipitofrontalis
Moves first 3 layers
Frontal belly:
Raises eyebrows (surprise / horror)
Action facilitated by loose areolar tissue
The Face
lec 2
Muscles of the Face (Facial Expression)
General Features
Skeletal muscles in superficial fascia
Arise from skull bones
Insert into skin
Developed from 2nd pharyngeal arch
Supplied by facial nerve (CN VII)
Functions
Sphincters & dilators of facial orifices
Orbit → eyelids
Nose → nostrils
Mouth → lips
Facial expression
Muscles of Eyelids
Sphincter: Orbicularis oculi
Dilators:
Levator palpebrae superioris
Occipitofrontalis
Muscles of Nostrils
Sphincter: Compressor naris
Dilator: Dilator naris
Muscles of Lips & Cheeks
Sphincter: Orbicularis oris
Dilators: Radiating muscles from lips
Muscles of the Lips
Orbicularis oris
Fibers encircle oral orifice
Contributions from maxilla & mandible
Fibers from skin → mucosa
Fibers from buccinator
Dilator muscles
Levator labii superioris alaeque nasi
Levator labii superioris
Zygomaticus minor
Zygomaticus major
Levator anguli oris
Risorius
Depressor anguli oris
Depressor labii inferioris
Mentalis
Nerve Supply (motor)
Buccal & mandibular branches of facial nerve
Buccinator Muscle
Origin:
Alveolar margins of maxilla & mandible
Pterygomandibular raphe
Insertion:
Fibers decussate at angle of mouth
Blend with orbicularis oris
Pierced by parotid duct
Sensory Nerves of the Face
Supplied mainly by trigeminal nerve (CN V)
Exception:
Angle of mandible & parotid region
Great auricular nerve (C2, C3)
Also provide proprioception to facial muscles
Ophthalmic Nerve (V1)
Supplies:
Forehead
Upper eyelid & conjunctiva
Side & tip of nose
Branches:
Lacrimal
Supraorbital
Supratrochlear
Infratrochlear
External nasal
Maxillary Nerve (V2)
Supplies:
Lower eyelid
Cheek
Upper lip
Side of nose
Branches:
Infraorbital
Zygomaticofacial
Zygomaticotemporal
Mandibular Nerve (V3)
Supplies:
Lower lip
Lower face
Temporal region
Part of auricle & scalp
Branches:
Mental nerve
Buccal nerve
Auriculotemporal nerve
Skin of the Face
Rich in sweat & sebaceous glands
Connected to bones by loose connective tissue
Contains muscles of facial expression
No deep fascia
Wrinkle lines
Due to repeated muscle contraction
Loss of skin elasticity
Surgical scars
Less visible if parallel to wrinkle lines
Arterial Supply of the Face
Main arteries
Facial artery
Superficial temporal artery
Facial Artery
Branch of external carotid
Crosses mandible anterior to masseter
Tortuous course to medial eye angle
Branches:
Submental
Inferior labial
Superior labial
Lateral nasal
Angular (terminal)
Superficial Temporal Artery
Terminal branch of external carotid
Branch:
Transverse facial artery
Ophthalmic Artery Branches
Supraorbital
Supratrochlear
Facial Nerve (CN VII)
Passes through parotid gland
Supplies muscles of facial expression
No cutaneous sensory supply
Terminal branches:
Temporal
Zygomatic
Buccal
Mandibular
Cervical
Lymph Drainage
Forehead & anterior face → Submandibular nodes
Lateral face & eyelids → Parotid nodes
Central lower lip & chin → Submental nodes
Venous Drainage
Facial vein
Formed at medial angle of eye
Connected to cavernous sinus
Via superior ophthalmic vein
Descends behind facial artery
Drains into internal jugular vein
Transverse facial vein
Joins superficial temporal vein
Lec 3
Parotid Gland
General Features
Largest salivary gland
Mainly serous acini
Enclosed in parotid sheath
From deep cervical fascia
Facial nerve divides gland into:
Superficial lobe
Deep lobe
Parotid Space Relations
Superior: external auditory meatus
Anterior: ramus of mandible
Posterior: sternomastoid & mastoid process
Medial:
Styloid process
Lateral pharyngeal wall
Parotid Duct (Stensen’s Duct)
Length: ~5 cm
Course
From anterior border of gland
Crosses masseter muscle
Turns medially
Pierces buccinator
Opens into oral vestibule
Opposite 2nd maxillary molar
Function
Oblique course → valve-like mechanism
Innervation
Facial nerve (CN VII)
Passes through gland (NO secretomotor)
Sensory
Auriculotemporal nerve
Gland
Parotid sheath
Overlying skin
Sympathetic
Plexus around middle meningeal artery
Parasympathetic (Secretomotor)
Preganglionic
Glossopharyngeal nerve (CN IX)
Tympanic branch
Tympanic plexus
Lesser petrosal nerve
Otic ganglion (synapse)
Postganglionic
Auriculotemporal nerve → parotid gland
Produces watery saliva
Blood Supply
Arterial
External carotid artery & terminal branches
Venous
Retromandibular vein
Lymphatic Drainage
Parotid lymph nodes
Deep cervical lymph nodes
Buccal Fat Pad
Location
Superficial to buccinator muscle
Features
Encapsulated fat
Larger in infants
Supports cheeks during suckling
Blood Supply
Buccal & deep temporal branches (maxillary artery)
Transverse facial artery
Branches of facial artery
Innervation
Buccal branches of mandibular nerve
Functions
Chewing & suckling
Gliding pad for muscles of mastication
Cushion protecting facial muscles
Clinical Notes
Parotid Duct Injury
Trauma or surgical damage
Parotid Tumors & Facial Nerve
Benign tumor → rarely facial palsy
Malignant tumor → facial nerve invasion
Parotid Gland Infections
Ascending infection via duct
Bloodborne (e.g. mumps)
Painful swelling (tight capsule)
Frey’s Syndrome
After parotid injury
Misrouting of parasympathetic fibers
Salivation stimulus → sweating
Affects skin over parotid region
Regions of the Head
Parotid Region
Location
Posterolateral part of facial region
Boundaries
Superior: zygomatic arch
Inferior: angle & inferior border of mandible
Medial: ramus of mandible
Anterior: anterior border of masseter
Posterior:
External ear
Anterior border of sternocleidomastoid
Contents of Parotid Region
Parotid gland
Parotid duct
Facial nerve plexus (CN VII)
Retromandibular vein
External carotid artery
Masseter muscle
Parotid lymph nodes
Facial Nerve
5 terminal branches exit anterior border of gland (radiating)