Temporal, Infratemporal and Submandibular Regions, and the Temporomandibular joint Flashcards
State the boundaries of the temporal fossa.
Anterior: Zygomatic and frontal bones
Posterior: Inferior temporal line and supramastoid crest
Superior: Superior temporal line
Inferior: Zygomatic arch
Floor: Parts of frontal, parietal and temporal bones and greater wing of sphenoid bone
What forms the zygomatic arch?
Anteriorly by the temporal process of zygomatic bone
Posteriorly by the zygomatic process/zygoma of temporal bone
[Diagram]
List the contents of the temporal fossa.
- Temporalis muscle
- Temporal fascia (overlies the temporalis muscle)
- Superficial temporal artery [one of the terminal branch of ________________ artery]
- Superficial temporal vein [unites with maxillary vein to form the ________________ vein]
- Auriculotemporal nerve [branch of mandibular nerve]
- Zygomaticotemporal nerve
- Temporal branch of facial nerve
- [Diagram]
State the clinical relevance of temporal fossa.
Temporalis flap
List the boundaries of the infratemporal fossa.
Laterally (superficial): ramus of the mandible
Medially (deep): lateral pterygoid plate
Anteriorly: posterior aspect of the maxilla
Posteriorly: tympanic plate, mastoid and styloid processes of the temporal bone
Superiorly: the inferior (infratemporal) surface of the greater wing of sphenoid [Notice the infratemporal crest on the infratemporal surface of greater wing of sphenoid]
State the contents of the infratemporal fossa.
- Inferior part of the temporalis muscle
- Lateral and medial pterygoid muscles
- Maxillary artery
- Pterygoid venous plexus
- Mandibular, inferior alveolar, lingual, buccal, chorda tympani nerves
- Otic ganglion
- [Diagram: Some of the contents of infratemporal fossa]
The medial and lateral plates of pterygoid process are parts of the ________________ bone.
sphenoid
[Diagram]
List the muscles of mastication.
- Medial pterygoid muscle
- Lateral pterygoid muscle
- Masseter
- Temporalis
- [Diagram]
Medial pterygoid muscle
1. Origin
2. Insertion
3. Innervation
4. Action
-
Origin:
Deep head—medial surface of lateral plate of pterygoid process and pyramidal process of palatine bone
Superficial head—tuberosity of the maxilla and pyramidal process of palatine bone - Insertion: Medial surface of mandible near angle
- Innervation: Nerve to medial pterygoid from the mandibular nerve [V3]
- Action: Elevation and side-to-side movements of the mandible. It can assist in protrusion of mandible, but that is a weak action of medial pterygoid.
- [Diagram 1] [Diagram 2]
Side-to-side movement is done during chewing.
Lateral pterygoid muscle
1. Origin
2. Insertion
3. Innervation
4. Action
-
Origin:
Upper head—roof of infratemporal fossa
Lower head—lateral surface of lateral plate of the pterygoid process - Insertion: Capsule of temporomandibular joint in the region of attachment to the articular disc and to the pterygoid fovea on the neck of mandible
- Innervation: Nerve to lateral pterygoid directly from the anterior division of the mandibular nerve [V3] or from the buccal branch
- Action: Protrusion, side-to-side movements and depression of the mandible
- [Diagram 1] [Diagram 2]
Further notes:
✓ Side-to-side movement is done during chewing.
✓ Among all the four muscles of mastication (medial pterygoid, lateral pterygoid, masseter, and temporalis), the lateral pterygoid is the only muscle that participates in depressing the mandible.
Masseter
1. Origin
2. Insertion
3. Innervation
4. Action
- Origin: Zygomatic arch and maxillary process of the zygomatic bone
- Insertion: Lateral surface of ramus of mandible
- Innervation: Masseteric nerve from the anterior division of the mandibular nerve [V3]
- Action: Elevation of mandible
- [Diagram: Masseter]
Temporalis
1. Origin
2. Insertion
3. Innervation
4. Action
- Origin: Bone of temporal fossa and temporal fascia
- Insertion: Coronoid process of mandible and anterior margin of ramus of mandible almost to last molar tooth
- Innervation: Deep temporal nerves from the anterior division of the mandibular nerve [V3]
- Action: Elevation and retraction of mandible
- [Diagram: Temporalis]
a) What type of joint is the temporomandibular joint (TMJ)?
b) Articular surfaces of the TMJ?
a) (Compound) Condylar synovial joint
b) Superiorly: mandibular fossa and articular tubercle.
Inferiorly: head of the mandible.
[Diagram: TMJ] [Diagram: Mandible]
Note: The articular tubercle prevents dislocation.
The articular disc divides the synovial cavity into an upper and lower cavity. State the actions that each facilitate.
- Upper cavity: for protrusion and retraction
- Lower cavity: for elevation and depression
[Diagram]: compare the sizes of the superior and inferior synovial cavities during depression of mandible.
(a) List 3 accessory ligaments of the TMJ and their functions.
(b) State the:
(i) arterial supply to the TMJ.
(ii) nerve supply to the TMJ.
(a) Ligaments and their functions
✓ Lateral temporomandibular ligament: prevents posterior displacement of mandible
✓ Sphenomandibular ligament (from spine of sphenoid to lingula of mandible): limits distension of the mandible in an inferior direction
✓ Stylomandibular ligament: limit excessive protrusion of the mandible
[Diagram: Accessory ligaments of the TMJ]
(b) Neurovascular supply
(i) maxillary and superficial temporal arteries
(ii) auriculotemporal nerve and masseteric nerve
Name the structure that attaches at the lingula of the mandible.
sphenomanibular ligament
For the following movements of the TMJ, list the muscles involved:
(a) protrusion
(b) retraction
(c) elevation
(d) depression
(e) side to side movement (chewing)
(a) protrusion: lateral pterygoid, medial pterygoid, superficial fibers of masseter
(b) retraction: posterior fibers of temporalis
(c) elevation: temporalis, masseter, medial pterygoid
(d) depression: lateral pterygoid, digastric, geniohyoid, mylohyoid and gravity
(e) side to side movement (chewing): medial pterygoid, lateral pterygoid
State the origin and course of maxillary artery.
✓ the larger terminal branch of external carotid artery
✓ arises behind the neck of the mandible, runs horizontally forward up to the lower border of lower head of lateral pterygoid.
✓ now it turns upwards and forwards, crosses the lower head of lateral pterygoid superficially (sometimes deep).
✓ after emerging between the two heads of lateral pterygoid it enters the pterygopalatine fossa by passing through pterygomaxillary fissure. Here it ends by giving its terminal branches.
Note:
The maxillary artery enters the infratemporal fossa by passing forwards, between the neck of mandible and the sphenomandibular ligament.
[Diagram 1]; shows the relation of the parts of the maxillary artery to the lateral pterygoid.
[Diagram 2]
[Diagram 3]
[Radiograph]
The maxillary artery has a wide territory of distribution. What does it supply?
(a) upper and lower jaws,
(b) muscles of temporal and infratemporal fossae,
(c) nose and paranasal sinuses,
(d) palate and roof of pharynx,
(e) external and middle ear,
(f) pharyngotympanic tube, and
(g) dura mater.