L11: Infratemporal and pterygopalatine fossa

Question 1

Infratemporal fossa borders

Answer 1

Roof = temporal bone and greater wing of sphenoid
Ant wall = post surface of maxilla
Lat wall = ramus of mandible
Medial wall = lateral plate of pterygoid process

Question 2

Temporomandibular joint features

Answer 2

Atypical synovial joint - fibrocartilage on articular surface (no hyaline)
Intra-articular disc dividing joint cavity into upper and lower cavities
2 heads of lateral pterygoid muscle attach directly into anterior part of joint

Question 3

Ligaments stabilising TMJ

Answer 3

1. Lateral ligament (thickening on lateral
   surface of joint capsule)
2. Sphenomandibular lig
3. Sphenopalatine ligament

Question 4

Movements of TMJ

Answer 4

Depression = gravity, digastric, geniohyoid, mylohyoid
Elevation = temporalis, masseter, medial pterygoid
Protrusion = lateral pterygoid (assisted by medial pterygoid)
Retraction = posterior fibres of temporalis, deep part of masseter, geniohyoid, digastric

Question 5

Muscles of mastication

Answer 5

• Temporalis (within temporalis fossa and extends down to cricoid process)
• Masseter muscle (deep and superficial heads): attaches to angle of mandible and runs up to zygomatic arch
• Pterygoid muscles: lateral (2 heads, directly attached to TMJ), medial (2 heads)

Question 6

Contents of infratemporal fossa

Answer 6

• Pterygoid muscles (not temporalis or masseter)
• Sphenomandibular joint
• Maxillary a: middle meningeal a (trauma to pterion), inferior alveolar a (damage by dentist)
• Nerves: V3 (motor and sensory), VII, IX
• Pterygoid venous plexus

Question 7

Path and supply of [V3]

Answer 7

V3 - enters infratemporal fossa and divides into ant and post trunks
Ant trunk gives off branches to muscles of mastication and buccal nerves (sensation to lower part of face
Post trunk gives off lingual, inferior alveolar, auriculotemporal
(auriculotemporal runs with lesser petrosal n [X] from tympanic plexus which supplies parasympathetic innervation to parotid)

Question 8

Path and supply of [VII]

Answer 8

Chorda tympani [VII] enters infratemporal fossa and joins lingual to travel and supply ant 2/3 of tongue with taste

Damage to lingual = lose of taste from ant 2/3 and loss of general sensation to mouth
Damage higher up to just chorda tympani = loss of taste

Question 9

Pterygoid venous plexus

Answer 9

Found within infratemporal fossa

Formed by maxillary v, infraorbital v and inferior alveolar v

Emissary veins go to cavernous sinus (spread of infection)

Question 10

Pterygopalatine fossa borders

Answer 10

Ant wall = maxilla
Roof = sphenoid bone (foramen rotundum exits through this)
Medial wall = palatine bone

Question 11

Foramina in pterygopalatine fossa

Answer 11

Foramen rotundum: V2 (close to foramen lacerum, carotid canal)

Also sphenopalatine foramen (sphenopalatine a), inferior orbital fissure, pterygoid canal, pterygomaxillary fissure, palatovaginal canal, palatine canal

Question 12

Arteries in pterygopalatine fossa

Answer 12

Maxillary a (15 branches in total)

• -> goes through infratemporal fossa and continues into pterygopalatine fossa
• Branch: sphenopalatine a
• Other branches of maxillary also contribute to blood supply of teeth

Question 13

Nerves in pterygopalatine fossa

Answer 13

V2 is purely sensory, enters via foramen rotundum

Pterygopalatine ganglion (hay fever ganglion)
(running nose and eyes, branches to lacrimal gland))
- Parasymp from greater petrosal n (VII)
- Sympa from deep petrosal n (from superior cervical ganglion (runs with int carotid a)