TMJ Flashcards
What are unique features of the TMJ?
It’s divided into an upper and lower joint cavity by a fibrocartilage disk. Anteriorly the disk is attached to the superior belly of the lateral pterygoid muscle. Medially and laterally the disk is attached to the poles of the condylar head through collateral ligaments.
Describe the innervation of the TMJ.
By 3 nerves originating form the mandibular branch of the trigeminal nerve.
What are the kinematic movements of the TMJ.
During the first 1-2.5 cm of mouth opening, the condyle rotates anteriorly. The remainder of motion is anterior translation.
What is the functional range and normal range of mouth opening?
Functional: 2 knuckles width
Normal: 3 knuckles width
The normal lateral deviation is 1/4th of normal opening.
What are the major elevators of the mandible?
The masseter, temporalis, and medial pterygoid. The superior pterygoid is active in stabilizing the disk.
What are the depressors of the mandible?
The inferior belly of the lateral pterygoid, digastric, mylohyoid, geniohyoid, and stylohyoid
How does an anteriorly displaced disk present clinically with TMJ?
pain and limited opening with deviation to the involved side. May click once in early phases, at opening and closing in reducing phases, and no joint noise in nonreducing pain
Explain the significance of mouth opening with a C curve or S curve.
C curve: indicates capsular pattern, S curve indicaes muscle imbalance. With joint noises, suspect disk displacement.
Describe the connection between TMD and forward-head posture.
Tight suboccipital muscles caused by forward head posture rotate the head posteriorly, causing the mandible to either be depressed by gravity and overstretching the masseter/temporalis muscles or by causing tightness in these same muscles. Also increases strain on the hyoid muscles.
How can TMJ problems cause headache, dizziness, and ear pain?
The spinal nucleus of the trigeminal nerve and the dorsal horns of the upper three cervical segments form the trigeminocervical nucleus (considered to be the nociceptive center for the entire head and upper neck).
The auriculotemporal nerve (branch of the trigeminal nerve) innervates the posterior TMJ and parts of the tympanic membrane, so pain may cause earaches or tinnitus.
What is the effectiveness of PT in TMD?
postural exercises can decrease symptoms. Can try rocabodo 6 or other protocols
Describe the suprahyoids.
Digastrics, mylohyoid, geniohyoid, stylohyoid. Originates from the mandible and inserts into the hyoid. They depress and retract the mandible and are innervated by the facial nerves, the mylohyoid nerve, and the first and second cervical nerves.
Describe the infrahyoids.
Sternohyoid, thyrohyoid, and omohyoid.
Originates from the sternum, hyoid, upper scapular border and inserts into the hyoid. Innervated by the first, second, and third cervical nerves.
