Infratemporal fossa

Why this matters

Almost everything a dentist injects, cuts near, or worries about spreading into on the deep side of the face is in this one region: the mandibular nerve and its lingual and inferior alveolar branches, the maxillary artery and the vessel that becomes the middle meningeal artery, the pterygoid venous plexus that the lower teeth drain into, and the pterygomandibular space that is both the target of a mandibular block and a named infection space. It also has no inferior bony or fascial boundary and no continuous posterior wall, which is why an infection that reaches it can descend into the neck.

The big picture

The infratemporal fossa is the deep compartment behind the maxilla and medial to the ramus, roofed by the greater wing of the sphenoid and open below. Structures enter it from above through the foramen ovale and foramen spinosum, leave it forwards through the pterygomaxillary fissure into the pterygopalatine fossa, leave it laterally into the mandible through the mandibular foramen, and leave it downwards into the neck through nothing at all. Learn the doorways and the region organises itself.

The 15 cards in this lesson

1. 01A region with edges, not a box with walls
2. 02The doorways: what goes in, what comes out
3. 03Contents, level by level
4. 04The maxillary artery in three parts
5. 05Three parts, three jobs
6. 06One artery, several answers: how a number gets its value
7. 07The pterygoid venous plexus and where it goes
8. 08Clinical alert — in the lesson
9. 09V3 in the fossa: trunk, then two divisions
10. 10Anterior versus posterior division - and the two exceptions
11. 11The otic ganglion and the road to the parotid
12. 12The chorda tympani joins the lingual nerve
13. 13The pterygomandibular space: the dentally critical corner
14. 14Clinical alert — in the lesson
15. 15How to hold the infratemporal fossa

You have got it when

You can name the walls of the infratemporal fossa and say honestly which ones are structures and which are drawing conventions; trace the maxillary artery in three parts and name what each part feeds; state the four directions in which the pterygoid venous plexus drains; sort V3's branches into its two divisions and give the two exceptions to the motor/sensory rule; and describe the contents of the pterygomandibular…