Temporal & Temporal & infratemporal fossaeinfratemporal fossae Temporal Temporal

fossafossa : :extends above extends above by the by the sup.temporal sup.temporal lineline and below by and below by zygomatic arch.zygomatic arch.

Infratemporal fossaInfratemporal fossa : : lies beneath the base of lies beneath the base of the skull, between the skull, between the the pharynxpharynx (medially) & (medially) & ramus oframus of mandible mandible (laterally). (laterally). or or the space lying below the space lying below the temporal fossa and the temporal fossa and behind the maxilla.behind the maxilla.

Muscles of mastication: 1-Temporalis It lies in the temporal

fossa.

Origin :floor of temporal fossa & temporal fascia.

Insertion :by a tendon into the coronoid process of the mandible.

N.supply : deep temporal nerves from the ant.division of mandibular N.

Action : anterior fibers --- elevate the mandible. posterior fibers--- retract the mandible.

Muscles of Muscles of masticationmastication

2-Masseter muscle :Origin : lower border & inner surface of zygomatic arch.

Insertion : lateral (outer) surface of ramus of the mandible.

N.supply : masseteric N. from anterior division of mandibular N.

Action : raises the mandible.

Muscles of Mastication Muscles of Mastication attached to mandible :attached to mandible :

Lateral Surface

Medial Surface

Contents of the Contents of the temporal fossatemporal fossa1-Temporalis

muscle.

2-Temporal fascia---- covers temporalis muscle, attached above to sup.temporal line and below to upper border of zygomatic arch.

3-Deep temporal nerves : from the ant. division of mandibular N., emerge from upper border of lateral pterygoid, enter the deep surface of temporalis .

Contents of the Contents of the temporal fossatemporal fossa

4-Auriculotemporal nerve : arise from the posterior division of mandibular N. It emerges from upper border of parotid gland , It lies behind superficial temporal artery & TMJ, in front of the auricle. It supplies skin of auricle , ext.auditory meatus and the scalpe over the temporal region.

Contents of the Contents of the temporal fossatemporal fossa

5-Superficial temporal artery : it is a terminal branch of ext.carotid artery.

It Emerges from upper border of parotid gland, behind T.M.J.

It crosses root of zygomatic arch in front of auriculo-temporal N. & auricle ,here its pulsation can be easily felt.

Contents of Contents of Infratemporal fossaInfratemporal fossaLateral & medial

pterygoid muscles (muscles of mastication)

Branches of the mandibular N.

Otic ganglion.

Chorda tympani.

Maxillary artery.

Pterygoid venous plexus.

Lateral pterygoidLateral pterygoidOrigin :upper head---- from the infratemporal surface of the greater wing of sphenoid. Lower head---- from the lateral surface of lateral pterygoid plate.

Insertion :neck of mandible (pterygoid fovea) & articular disc of T.M.J.

N.supply :anterior division.of mandibular N.

Action: 1-Pulls the neck of mandible forward with the articular disc to depress mandible during opening of mouth. 2-Acting with medial pterygoid of the same side during movement of chewing. 3-Acting with medial pterygoid to protrude the mandible.

Medial pterygoidMedial pterygoidOrigin : superficial head----- from the tuberosity of the maxilla. Deep head----- from the medial surface of the lateral pterygoid plate.

Insertion: angle of mandible (medial surface).

N.supply : main trunk of mandibular N.

Action : 1-elevates the mandible. 2-Acting with lateral pterygoid during movement of chewing.

Tempromandibular joint Tempromandibular joint (TMJ)(TMJ) Articlation : between

the articular tubercle & mandibular fossa of temporal bone, and the head of mandible (condyloid process).

Type :condyloid synovial joint.

Capsule :it surrounds the joint.

Synovial membrane--- lines the capsule in upper & lower cavities.

Ligaments of Ligaments of Temperomandibular joint :Temperomandibular joint :Lateral

temporomandibular ligament : lies on the lateral side of joint ,between the tubercle and lateral surface of the neck of mandible.

Sphenomandibular ligament : lies on the medial side of the joint ,it connects the spine of sphenoid to the lingula of mandibular foramen.

Stylomandibular ligament behind & medial .to the joint. it is a band of thickened deep cervical fascia, from apex of styloid process to angle of mandibule.

Intracapsular Intracapsular articular discarticular disc

It is a plate of fibro-cartilage, it divides the joint into upper & lower cavities.

It is attached in front to the tendon of lat. pterygoid , and by fibrous bands to head of mandible.Its upper surface is concavo-convex to fit the articular tubercle & mandibular fossa , while its lower surface is concave to fit the head of mandible.

N.supply-auriculotemporal & masseteric branches

of mandibular N.

Movements:

Depression of mandibule : by lat.pterygoid, helped by digastric, geniohyoid & mylohyoid muscles.

Elevation :by temporalis, masseter, and medial pterygoid.

Protrusion : by lateral + medial pterygoids of both sides.

Retraction :by post.fibers of temporalis .

Lateral chewing movement: by lat.& med. Pterygoids of both sides acting alternately.

Relation of the Relation of the TemporomandibularTemporomandibular joint joint (TMJ) :(TMJ) : Anteriorly :

mandibular notch and masseteric N. & artery (structures passing through mandibular notch).

Posteriorly : ext.auditory meatus, glenoid process of parotid gland., auriculotemporal N., & superficial temporal artery.

Laterally :parotid gland, fascia & skin.

Medially : maxillary vessels.

Clinical significance of the Clinical significance of the TMJ :TMJ : The great strength of the The great strength of the Lat.TM ligamentLat.TM ligament

prevents prevents head of mandible from passing head of mandible from passing backward to cause backward to cause fracture of the tympanic fracture of the tympanic plateplate in case of in case of severe blow on severe blow on the chin.the chin.

The articular discThe articular disc

may be may be partially detachedpartially detached causing causing noisy & audiblenoisy & audible click,click, during during movements movements of the joint. of the joint.

Dislocation of the TMJDislocation of the TMJ Sometimes Sometimes occurs when theoccurs when the

mandible is depressed.mandible is depressed. In case of In case of minor blow on minor blow on

chinchin or or sudden contraction sudden contraction of lateral pterygoids as in of lateral pterygoids as in yawningyawning, leads to , leads to pull the pull the head of mandible & articular head of mandible & articular disc forward beyond the disc forward beyond the summit of tuberclsummit of tubercle.e.

Reduction of disloctionReduction of disloction : by : by pressingpressing the thumbs the thumbs downward ondownward on the lower the lower molar teeth and molar teeth and pushing the pushing the jaw backward.jaw backward.