ANA 301 Temporal Fossa & TMJ Flashcards
What is the temporal fossa?
The temporal fossa is a narrow fan-shaped space that covers the lateral surface of the skull
Describe the margins of the temporal fossa
its upper margin is defined by a pair of temporal lines that arch across the skull from the zygomatic process of the frontal bone to the supra mastoid crest of the temporal bone;
*its inferior margin is marked by the zygomatic arch laterally and by the infratemporal crest of the greater wing of the sphenoid medially.
*it is limited laterally by the temporal fascia,
which is a tough fan-shaped aponeurosis.
*anteriorly, it is limited by the posterior surface of the frontal process of the zygomatic bone and the posterior surface of the zygomatic process of the frontal bone, which separate the temporal fossa behind from the orbit in front;
Contents of the temporal fossa
•The major structure in the temporal fossa are the temporalis muscle.
•Also passing through the fossa is the zygomaticotemporal branches of the maxillary nerve [V2].
•Deep temporal arteries
Origin of temporalis muscle
bony surfaces of the fossa superior to the inferior temporal line
Insertion of temporalis muscle
coronoid process of the mandible.
Innervation of temporalis muscle
deep temporal nerves
Action of temporalis muscle
Temporalis is a powerful elevator of the mandible
Describe the Zygomaticotemporal nerve:
Zygomaticotemporal nerve:
It is a branch of the zygomatic nerve-The zygomatic nerve is a branch of the maxillary nerve [V2].
Branches of the zygomaticotemporal nerve pass superiorly between the bone and the temporalis muscle to penetrate the temporal fascia and supply the skin of the temple.
Describe the Deep temporal arteries:
Deep temporal arteries:
•Normally two in number, these vessels originate from the maxillary artery in the infratemporal fossa and travel with the deep temporal nerves around the infratemporal crest of the greater wing of the sphenoid to supply the temporalis muscle .
•They anastomose with branches of the middle temporal artery.
Define the TMJ
The two temporomandibular joints allows opening and closing of the ‘mouth’ and complex ‘chewing’ or ‘side-to-side’ movements of the lower jaw.
•DEFINITION: the temporomandibular joint is a type of synovial joint. The articular disc divides the joint into upper and lower cavities
Articulation of TMJ
Add information on how the upper and lower parts allow movement
ARTICULATION: between the head of the mandible and the articular fossa and articular tubercle of the temporal bone
the joint is completely divided by a fibrous articular disc into two parts:
●the upper part of the joint allows the head of the mandible to translocate forward (protrusion) onto the articular tubercle and backward (retraction) into the mandibular fossa.
●the lower part of the joint allows mainly the hinge-like depression and elevation of the mandible;
Capsule of TMJ
CAPSULE:
•The capsule surrounds the joint and is attached above to the articular tubercle and the margins of the mandibular fossa and below to the neck of the mandible
The fibrous membrane of the joint capsule encloses the temporomandibular joint complex and is attached:
●above along the anterior margin of the articular tubercle;
●laterally and medially along the margins of the articular fossa;
●posteriorly to the region of the tympanosquamous suture;
●below around the upper part of the neck of the mandible.
Ligaments of TMJ
LIGAMENTS:
●the lateral ligament is closest to the joint, is just lateral to the capsule, and runs diagonally backwards from the margin of the articular tubercle to the neck of the mandible;
●the sphenomandibular ligament is medial to the temporomandibular joint, runs from the spine of the sphenoid bone at the base of the skull to the lingula on the medial side of the ramus of the mandible;
●the stylomandibular ligament passes from the styloid process of the temporal bone to the posterior margin and angle of the mandible
Innervation of TMJ
INNERVATION: sensory innervation of the TMJ is from the auricotemporal and masseteric branches of mandibular branch of trigeminal nerve.
•Except for the geniohyoid muscle, which is innervated by the C1 spinal nerve, all muscles that move the temporomandibular joints are innervated by the mandibular nerve [V3] by branches that originate in the infratemporal fossa.
Blood supply of TMJ
BLOOD SUPPLY:
•provided by branches of the external carotid artery, predominately by the superficial temporal branch.
•Other branches like the deep auricular artery, anterior tympanic, ascending pharyngeal and maxillary arteries may also contribute as they pass through the region
