Temporal and Infra Temporal Fossa

Temporal Fossa

• Location: Identified by the yellow arrow in diagrams; known as the inferred temporal fossa.

Infra Temporal Fossa

• Borders:

  • Deep to the zygomatic arch.
  • Posterior to the maxilla.
  • Anterior to the mastoid process of the temporal bone.
  • Lateral to the pterygoid plate of the sphenoid bone.

• Contents:

  • Foramen Ovale: Transmits the mandibular branch of the trigeminal nerve (V3) into the infra temporal fossa.
  • Foramen Spinosum: Transmits the middle meningeal artery, which supplies the dura mater.
  • Infraorbital Fissure: Transmits cranial nerve V2 (maxillary nerve).
  • Petrotympanic Fissure: Transmits the chorda tympani nerve.
  • Mandibular Fossa: Articulation for the temporomandibular joint (TMJ).

Temporomandibular Joint (TMJ)

• Components:
  • Mandibular Fossa: Concave surface for articulation.
  • Articular Disk: Made of fibrocartilage, situated between the mandibular fossa and condyle, forming a synovial hinge joint.
  • Joint Capsule: Extends from the mandibular condyle to the mandibular fossa.

Muscles of Mastication

• Masseter Muscle:

  • Originates from the zygomatic arch.
  • Attaches to the ramus of the mandible.
  • Action: Elevates the mandible (chewing).
  • Innervation: Cranial nerve V3.

• Temporalis Muscle:

  • Originates from the temporal fossa.
  • Attaches to the coronoid process of the mandible.
  • Action: Elevates the mandible.
  • Innervation: Cranial nerve V3.

• Medial Pterygoid Muscle:

  • Attaches deep to the ramus of mandible and pterygoid plate.
  • Action: Side-to-side movement of mandible (chewing).
  • Innervation: Cranial nerve V3.

• Lateral Pterygoid Muscle:

  • Arises from condyloid process and pterygoid plate.
  • Action: Depresses and protracts the mandible.
  • Innervation: Cranial nerve V3.

Nerves of the Infra Temporal Fossa

• Inferior Alveolar Nerve: Branch of V3, innervates mandibular teeth and becomes the mental nerve for chin and lower lip sensation.

• Lingual Nerve: Brings general sensation from the anterior two-thirds of the tongue, part of V3.

• Chorda Tympani Nerve (Cranial nerve VII):

  • Enters the infra temporal fossa via petrotympanic fissure.
  • Innervates sublingual and submandibular glands.
  • Provides taste sensation from anterior two-thirds of the tongue.
  • Hitchhikes on the lingual nerve (V3) to reach its targets.