4. Lateral aspect of the skull: temporal, infratemporal, and pterygopalatine fossae. Walls, boundaries, communications and elements passing through them.

TEMPORAL FOSSA

• It is a fan-shaped space at the lateral surface of the skull.

Boundaries:

• Superiorly: temporal lines (arching between zygomatic process of frontal bone and supra-mastoid crest of temporal bone.
• Inferiorly: zygomatic arch (laterally) and infratemporal crest of greater wing of sphenoid (medially).
• Anteriorly: frontal process of zygomatic bone and zygomatic process of frontal bone.

• Medially (floor): 4 bones (frontal, parietal, squamous temporal, and greater wing of sphenoid). These bones meet at pterion.

Contents:

• 1 muscle: temporalis muscle.
• 3 nerves: auriculotemporal nerve (superficial to temporal fascia), zygomatico-temporal nerve, and deep temporal nerves (deep to temporalis muscle).
• 3 vessels: superficial temporal vessels (superficial to temporal fascia), deep temporal vessels, and middle temporal artery (deep to temporalis muscle).

INFRATEMPORAL FOSSA

• It is a wedge shaped space inferior to the temporal fossa between ramus of the mandible (laterally) and wall of the pharynx (medially)

Boundaries:

• Roof: infratemporal surface of greater wing of sphenoid. It contains foramen ovale and foramen spinosum through which the fossa communicates with the middle cranial fossa. And lateral to infratemporal crest, the fossa opens to the temporal fossa.
• Anteriorly: posterior aspect of maxilla. At the upper part there is the inferior orbital fissure through which the fossa communicates with the orbit.
• posteriorly: styloid process and its attached structures.
• Medially: lateral surface of lateral pterygoid plate (anteriorly) and wall of the pharynx (posteriorly). Anteriorly, there is pterygo-maxillary fissure through which the fossa communicates with the pterygopalatine fossa.
• Laterally: ramus of the mandible (covered by masseter muscle).

Contents:

• 1 ligament: sphenomandibular ligament, it is one of the extracapsular ligaments of the temporo-mandibular joint (between spine of sphenoid bone and lingula of the mandible).
• 2 muscles: medial and lateral pterygoid muscles.
• Nerves: mandibular nerve and its branches, otic ganglion, glossopharyngeal nerve, and branches from facial nerve (chorda tympani).
• Vessels: maxillary artery (1ˢᵗ and 2ⁿᵈ parts), and pterygoid plexus of veins.