Left infratemporal fossa.
The infratemporal fossa is an irregularly shaped cavity, situated below and medial to the zygomatic arch. It is not fully enclosed by bone in all directions, and it contains superficial muscles that are visible during dissection after removing skin and fascia: namely, the lower part of the temporalis muscle, the lateral pterygoid, and the medial pterygoid.
Its boundaries may be defined by:
- anteriorly, by the infratemporal surface of the maxilla and the ridge which descends from its zygomatic process
- posteriorly, by the articular tubercle of the temporal and the spina angularis of the sphenoid
- superiorly, by the greater wing of the sphenoid below the infratemporal crest, and by the under surface of the temporal squama, containing the foramen ovale, which transmits the mandibular branch of the trigeminal nerve, and the foramen spinosum, which transmits the middle meningeal artery
- inferiorly, by the medial pterygoid muscle attaching to the mandible
- medially, by the lateral pterygoid plate
- laterally, by the ramus of mandible, which contains the mandibular foramen, leading to the mandibular canal through which the inferior alveolar nerve passes. This also contains the lingula, a triangular piece of bone that overlies the mandibular foramen antero-medially. Finally, the mylohyoid groove descends obliquely transmitting the mylohyoid nerve the only motor branch of the posterior division of the trigeminal nerve.
Contents of the infratemporal fossa
- Lower part of the Temporalis and masseter muscles (origin of massetar muscle:lower margin of the inner surface of zygomatic bone insertion : outer surface of the ramus of the mandible )
- Lateral and medial pterygoid muscles
Internal maxillary branches found within the infratemporal fossa including the
- pterygoid venous plexus
- retromandibular vein
- Mandibular nerve which is the third branch of the trigeminal nerve (CN V3), also known as the "inferior maxillary nerve" or nervus mandibularis, enters infratemporal fossa from middle cranial fossa through foramen ovale.
Its motor fibers innervate all the muscles of mastication plus the mylohyoid, anterior belly of the digastric, and the tensores veli palati and tympani
- meningeal nerve
- buccal nerve
- auriculotemporal nerve
- lingual nerve
- inferior alveolar nerve
- external acoustic meatus
- tympanic membrane
- temporal region
- skin overlying the mandible (except at the angle of the mandible)
- floor of mouth
- lower teeth
Communications to nearby spaces
- Cranial cavity (through foramen ovale and spinosum).
- Temporal fossa (deep to zygomatic arch).
- pterygopalatine fossa (through pterygomaxillary fissure).
- Orbit (through inferior orbital fissure).
- parapharyngeal space.
- Moore, Keith L & Dalley, Arthur (2006). Clinically oriented anatomy (5th ed.), Lippincott Williams & Wilkins.