Masseter Muscle

Superficial Portion

Origin: anterior 2/3 of zygomatic arch

Insertion: lateral ramus of mandible to angle

masseter muscle

deep portion

origin: medial surface of zygomatic arch

insertion: superior half of mandibular ramus

masseter muscle

Action

elevate mandible in biting and mastication.  

unilaterally, produces transverse movements of mandible

Temporalis Muscle

origin,insertion,action

Origin: whole of temporal fossa and temporalis fascia

Insertion: coronoid process of mandible and anterior and medial border or ramus to behind distal molars

Action: elevates mandible in biting and mastication.  Posterior fibers can retract mandible

Infratemporal Fossa Boundaries 

Roof

Lateral pterygoid plate and pharynx

infratemporal fossa communications

Foramina

Ovale

spinosum

posterior superior alveolar

mandibular 

infratemporal fossa communications

fissures

inferor orbital

pterygomaxillary 

infratemporal fossa contents

Muscles

Muscles of mastication

-tendon of temporalis

-medial pterygoid m

-lateral pterygoid m

infratemporal fossa contents

blood vessels

maxillary artery and vein

infratemporal fossa contents

nerves

-mandibular n and its branches

-posterior superior alveolar n

-chorda tympani n

-otic ganglion

-sympathetics

Lateral Pterygoid Muscle

Superior Head

(origin,insertion,Action)

Origin: Infratemporal crest and greater wing of sphenoid 

Insertion: Articular disc, joint capsule, and anterior condylar neck

action: control position of disc during closing  

Lateral Pterygoid Muscle

Inferior Head

(origin, insertion, action)

Origin: Lateral surface of lateral pterygoid plate

Insertion: Depression on anterior condylar neck (pterygoid fovea)

Action: protrude and depress mandible (bilateral); side-to-side movements (unilateral)

Medial Pterygoid Muscle

Origin, insertion, action

Origin: Medial surface of the lateral pterygoid plate

-posterior portion of the palatine(pyramidal process)

-maxillary tuberosity 

Insertion: Medial aspect of angle of mandible 

-inferior to mandibular foramen

Action: Elevates and protrudes mandible(bilaterally)

-produces side-to-side movements(unilaterally)

Maxillary Artery Branches

First Part-Before the Lateral Pterygoid m

- Inferior alveolar a

-middle meningeal a

-accessory a

-deep auricular a

-anterior tympanic a

Maxillary Artery Branches 

2nd part- in front of behind the lat. pterygoid m

(muscular branches)

-Masseteric a

-deep temporal a

-buccal a

Maxillary artery branches

3rd part-beyond lat pterygoid m.

(in pterygoid maxillary fissure)

Posterior superior alveolar a.

only one mentioned 

-Preganglionic fibers of CN7 to submandibular ganglion(secretomotor to submandibular and sublingual glands)

-Conveys taste sensations from anterior 2/3's of tongue 

-Enters infratemporal fossa via petrotympanic fissure

-Joins lingual n in fossa, carried to tongue and floor of mouth.

Otic Ganglion

-Parasympathetic ganglion from CN9

-Secretomotor to parotid gland

-Located medial to CN V3

Otic Ganglion Course

(preganglionic)

-glossopharyngeal n CN9

-tympanic nerve and then plexus

-lesser petrosal n

Otic Ganglion Course

(postganglionic)

Infratemporal fossa

(sympathetic innervation)

Course and function

-sympathetic postganglionic from superior cervical ganglion

-via external carotid plexus(maxillary a and its branches, including middle meningeal a)

-function: Vasoconstriction