Temporomandibular Joint

TEMPOROMANDIBULAR JOINT
  • Temporomandibular joint is a Condyloid and Synovial joint.
  • It is a joint between the temporal bone (mandibular fossa) and the mandibular condyle.
  • The main components are the joint capsule, articular disc, mandibular condyles, articular surface of the temporal bone, temporomandibular ligament, stylomandibular ligament, sphenomandibular ligament, and lateral pterygoid muscle.
CAPSULE AND ARTICULAR DISC OF TEMPOROMANDIBULAR JOINT
  • The temporomandibular joints are one of the few synovial joints in the human body with an articular disc, another being the sternoclavicular joint.
  • The disc divides each joint into two.These two compartments are synovial cavities, which consists of an upper and a lower synovial cavity.
  • The lower joint compartment formed by the mandible and the articular disc is involved in rotational movement.
  • The upper joint compartment formed by the articular disc and the temporal bone is involved in translational movement.
LIGAMENTS OF TEMPOROMANDIBULAR JOINT
  • There are three ligaments associated with the temporomandibular joints: one major and two minor ligaments.
  • The major ligament is the temporomandibular ligament.This ligament prevents the excessive retraction or moving backward of the mandible.
  • The two minor ligaments, the stylomandibular and sphenomandibular ligaments.
NERVE SUPPLY OF TEMPOROMANDIBULAR JOINT
  • Sensory innervation of the temporomandibular joint is derived from the auriculotemporal and masseteric branches or mandibular branch of the trigeminal nerve.
BLOOD SUPPLY OF THE TEMPOROMANDIBULAR JOINT
  • Its arterial blood supply is provided by branches of the external carotid artery, predominately the superficial temporal branch.
MUSCLES ACTING ON THE TM JOINT(MUSCLES OF MASTICATION)
  • The muscles acting upon the TM Joint are Temporalis,Masseter,Medial Pterygoid and Lateral Pterygoid.
  • Temporalis muscle: It elevates the mandible.
  • Masseter muscle: It elevates the mandible. It works functionally with the temporalis and pterygoid muscles to move the mandible at the TM Joint.
  • Lateral pterygoid muscle: Contraction causes the mandibular condyle and the articular disc to move anteriorly, resulting in both protraction and depression of the mandible. It works synergistically with the medial pterygoid muscle to move the mandible from side to side.
  • Medial pterygoid muscle: It elevates the mandible and moves it from side to side.
CLINICAL SIGNIFICANCE OF THE TEMPOROMANDIBULAR JOINT
Dislocation of the jaw:
  • In dislocation of the jaw, displacement of the articular disk beyond the articular tubercle of the temporomandibular joint result from spasm or excessive contraction of Lateral pterygoid Muscle.
Costen's Syndrome:
  • Costen's syndrome refers to neurological pain associated with Temporomandibular joint.
  • It is characterized by otalgia, feeling of blocked ear, tinnitus and sometimes vertigo. Pain also radiates to frontal, parietal and occipital region.
  • Caused by over closure of the Jaw causing excessive backward movement of head of condyle.
TM joint ankylosis:
  • Blind intubation techniques are those methods of airway management that are done without visualization of the larynx or glottis. 
  • Blind nasal intubation is indicated in TM joint ankylosis.
Referred pain in ear:
  • Referred pain in ear may occur due to TM joint Problems.
  • It occurs via Trigeminal nerve [cranial nerve V].
Radiological Visualisation:
  • Pantomography is done to visualise TM Joint.
Exam Question
  • Temporomandibular joint is a Condyloid and Synovial joint.
  • The muscles acting upon the TM Joint are Temporalis,Masseter,Medial Pterygoid and Lateral Pterygoid.
  • In dislocation of the jaw, displacement of the articular disk beyond the articular tubercle of the temporomandibular joint result from spasm or excessive contraction of Lateral pterygoid Muscle.
  • Costen's syndrome refers to neurological pain associated with Temporomandibular joint.
  • Blind nasal intubation is indicated in TM joint ankylosis.
  • Referred pain in ear may occur due to TM joint Problems.
  • Pantomography is done to visualise TM Joint.

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