Infratemporal fossa

Kittikun Viwatpinyo, Ph.D.

BMES216 Human Skeletal and Muscular Systems

Infratemporal region

• The area in the head medial

to zygomatic arch and

ramus of mandible, and

inferior to temporal fossa

Bony framework

Bony framework

Bony framework : Temporal

• Mandibular fossa

• Articular tubercle

• Zygomatic process

• Tympanic part

Bony framework : Sphenoid

• Greater wing & Infratemporal crest

• Lateral pterygoid plate : attachment of pterygoid muscles

• Spine of sphenoid

Bony framework : Sphenoid

• Foramen spinosum : Middle meningeal a.

• Foramen ovale : Mandibular n.

Bony framework : Zygomatic

Bony framework : Maxilla

• Tuberosity of maxilla

• Posterior superior alveolar foramen

• Pterygomaxillary fissure

Bony framework : Mandible

• Ramus, angle and body of mandible

• Upper border of ramus of mandible

• Coronoid process

• Condylar process : head and neck of mandible

Bony framework : Mandible

• Medial surface of mandible

• Mandibular foramen and canal

• Lingula

• Mylohyoid groove (for N. to mylohyoid)

Temporomandibular joint

• TMJ is a modified hinge type synovial joint between

mandibular fossa of temporal bone and head of mandible

• Articular disc between articular surfaces separates joint

capsule into 2 compartments :

• Lower compartment : Hinge movement

• Upper compartment : Gliding movement

Temporomandibular joint

• Opening of jaw ➔ Transition of head of mandible anteriorly

toward articular tubercle

Temporomandibular joint

Temporomandibular joint

• Extracapsular ligaments :

support joint stability

• Lateral (temporomandibular)

ligament

• Sphenomandibular ligament

• Stylomandibular ligament

Temporomandibular joint

• Movements of mandible

through TMJ :

• Depression

• Elevation

• Protrusion

• Retraction

• Side-to-side

Temporomandibular joint

• Overt movement

➔ Head of

mandible moves

anterior to

articular tubercle

➔ Dislocation of

TMJ

Muscles of mastication

• Masseter muscle

Muscles of mastication

• Temporalis muscle

Muscles of mastication

• Medial pterygoid muscle

Muscles of mastication

• Lateral pterygoid muscle

Muscles of mastication (All innervated by CN. V3)

Muscle Origin Insertion Action via TMJ

Masseter Zygomatic arch and

maxillary process of

zygomatic bone

Lateral surface of ramus

and angle of mandible

Elevation

Temporalis Temporal fossa and

fascia

Coronoid process and

anterior margin of ramus

of mandible

Anterior fibers : Elevation

Posterior fibers : Retraction

Medial

pterygoid

Tuberosity of maxilla

Medial surface of

lateral pterygoid plate

Medial surface of angle

of mandible

Elevation and side-to-side

movements

Lateral

pterygoid

Infratemporal crest

Lateral surface of

lateral pterygoid plate

Pterygoid fovea on neck

of mandible and fibrous

capsule of TMJ

Protrusion and side-to-side

movements

Masticator spaces

• Infratemporal space

• Temporal space

Masticator spaces

• Submasseteric space

• Pterygomandibular space

Nerves of infratemporal region

• Mandibular division of Trigeminal nerve (CN. V3)

• Autonomic nervous system

• Chorda tympani

• Lesser petrosal nerve

• Otic ganglion

Nerves of infratemporal region

Nerves of infratemporal region

CN. V3 : Anterior trunk

• Buccal nerve

• sensory nerve to buccal mucosa, buccal surface of gingiva of lower molars and

skin of cheek

• Masseteric nerve, Deep temporal nerve, Nerve to lateral pterygoid

CN. V3 : Posterior trunk

• Auriculotemporal nerve

• Sensory from TMJ and skin of anterior part of external ear, parotid

region and temporal region

CN. V3 : Posterior trunk

• Lingual nerve

• Sensory from anterior 2/3 of tongue (general sense), oral mucosa of

floor of oral cavity and lingual surface of gingiva

CN. V3 : Posterior trunk

• Inferior alveolar nerve

• Sensory from lower teeth and skin of

lower lip and chin (from mental n.)

• Nerve to mylohyoid muscle

• Motor to mylohyoid muscle and

anterior belly of digastric muscle

CN. V3 : Posterior trunk

• Inferior alveolar nerve block

Autonomic fibers

• Parasympathetic supply to salivary glands

• Chorda tympani n. Lingual n. Submandibular gg.

Submandibular & sublingual glands

• Lesser petrosal n. Otic gg. Auriculotemporal n.

Parotid gland

Autonomic fibers

• Parasympathetic supply to salivary glands

Autonomic fibers

• Chorda tympani (branch from CN. VII)

• Carries two types of nerve fibers :

• Taste sensory from anterior 2/3 of tongue

• Preganglionic parasympathetic fibers to submandibular gg

Autonomic nerves

• Lesser petrosal nerve

• A branch of glossopharyngeal nerve (CN. IX) via tympanic plexus

• Carries preganglionic para-sympathetic fibers to otic ganglion

Maxillary artery

• Maxillary artery is the largest branch of external carotid artery,

and a major artery in infratemporal region

• Three parts (according to relationship with lateral pterygoid m.)

Maxillary artery

• Middle meningeal artery

• Mostly from 1st part

• Passes upward and enters

cranial cavity through

Foramen spinosum

• Supplies major parts of

meninges

• Damage of artery : Epidural

hemorrhage

Maxillary artery

• Inferior alveolar artery

• Passes downward into mandibular foramen with inferior alveolar n.

• Supplies lower teeth, buccal side of gingiva, and also lower lip and chin

(by mental artery)

Pterygoid venous plexus

• Pterygoid plexus is a major venous drainage of infratemporal region

• drains into retromandibular vein and deep facial vein

• Route of infection from superficial head into deep head