Infratemporal fossa (110-123)

Question 1

What are the boundaries of the infratemporal fossa?;

Answer 1

Lateral- condylar process and ramus of the mandible bone. Medial- lateral pterygoid plate. Anterior- posterior border of the maxillary sinus. Posterior- styoid process . Roof- greater wing of the sphenoid bone. Floor- medial pterygoid muscle.

The infratemporal fossa can be said to have a wedge shape. It is located deep to the masseter muscle and zygomatic arch (to which the masseter attaches).

Question 2

Name the muscles in the infratemporal fossa;

Answer 2

4 muscles of mastication- Lateral pterygoid, medial pterygoid, masseter, temporalsis.

Question 3

Name the vessels in the infratemporal fossa;

Answer 3

Maxillary artery (branch of external carotid), Maxillary vein, Pterygoid venous plexus, Middle meningeal artery& vein

Question 4

Name the nerves and ganglion in the infratemporal fossa;

Answer 4

Otic ganglion,
Mandibular nerve (CN V3) with sensory terminal branches (BAIL) -> Buccal, Auriculotemporal, Inferior alveloar and Lingual.
Chorda tympnai (sensory branch of facial nerve CN VII).

Question 5

Name the main veins that drain the face;

Answer 5

Facial vein. Retromandibular vein.

Question 6

How is the retromandibular vein formed?;

Answer 6

Maxillary vein and superficial temporal veins

Question 7

How is the external jugular vein formed?;

Answer 7

Posterior auricular vein and retromandibular vein

Question 8

Into where does the external jugular vein drain?;

Answer 8

Subclavian vein

Question 9

What structures pass through the jugular foramen?;

Answer 9

3 nerves- Glossopharyngeal (CN IX), Vagus (CN X), Accessory (CN XI). 2 arteries- ascending occipital and pharygeal arteries. 1 vein- internal jugular (from sigmoid sinus).

Question 10

How is the internal jugular vein formed?;

Answer 10

Unior of sigmoid sinus & inferior pterygoid sinus.

Question 11

Describe the course of the accessory nerve;

Answer 11

2 components (cervical & extracrainial). Cervical (C1-5 neurones from upper spinal cord)- fibres coalesce and then ascends up through formen magnum. The nerve transverses the posterior cranial fossa and exits through jugular foramen.
Extracranial- descends along the internal carotid to reach the sternocleidomastodi muscles and then to trapezius muscle.

Question 12

What does the accessory nerve supply?;

Answer 12

Sternocleidomastoid and trapezium

Question 13

What structures pass through the foramen magnum;

Answer 13

Posteriorly (neurovascular)- medulla, meninges, vertebral arteries, anterior & posterior spinal arteries, the dural veins. Anteriorly (bones & ligaments- Tentorial membrane, apical ligament of dens, dens of axis (C2), atlas C1, crucial ligament of atlas

Question 14

What are the characteristic features of a typical cervical vertbra?;

Answer 14

Small body, short pedicle, bifid spinous process