Temporomandibular Joint - Clinical Tree

Clinical Summary and Recommendations

Patient History
Questions	Screening instruments have been shown to be very good at identifying temporomandibular disorder (TMD) pain (+LR [likelihood ratio] of 33). A subject complaint of “periodic restriction” (the inability to open the mouth as wide as was previously possible) has been found to be the best single history item to identify anterior disc displacement, both in patients with reducing discs and in those with nonreducing discs.
Physical Examination
Palpation	Reproducing pain during palpation of the temporomandibular joint (TMJ) and related muscles has been found to be moderately reliable and appears to demonstrate good diagnostic utility for identifying TMJ effusion confirmed by magnetic resonance imaging (MRI) and TMD when compared with a comprehensive physical examination. We recommend that palpation at least include the TMJ (+LR = 4.87 to 5.67), the temporalis muscle (+LR = 2.73 to 4.12), and the masseter muscle (+LR = 3.65 to 4.87). If clinically feasible, pressure pain threshold (PPT) testing is helpful because it demonstrates superior diagnostic utility in identifying TMD when compared with a comprehensive physical examination.
Joint Sounds	Detecting joint sounds (clicking and crepitus) during jaw motion is a generally unreliable sign demonstrating moderate diagnostic utility except in attempts to detect moderate to severe osteoarthritis (+LR = 4.79) and nonreducing anterior disc displacement (+LR = 2.6 to 15.2).
Range-of-Motion and Dynamic Movement Measurements	Measuring mouth range of motion appears to be a highly reliable test, and when the range of motion is restricted or deviated from the midline, the measurement has moderate diagnostic utility in identifying nonreducing anterior disc displacement. Detecting pain during motion is a less reliable sign, but it also demonstrates moderate to good diagnostic utility in identifying nonreducing anterior disc displacement and self-reported TMJ pain. The combination of motion restriction and pain during assisted opening has been found to be the best combination for identifying nonreducing anterior disc displacement (+LR = 7.71). Consistent with assessment of other body regions, assessment of “joint play” and “end feel” is highly unreliable and has unknown diagnostic utility.
Combination of Tests	A combination of clinical examination findings has been shown to be beneficial in identifying disc displacement without reduction (5 positive tests +LR = 7.9)
Interventions	Patients with TMD who report (1) symptoms ≥4/10 ( 10 being severe pain) and (2) pain for 10 months’ duration or less may benefit from nightly wearing of an occlusal stabilization splint, especially if they have (3) nonreducing anterior disc displacement and (4) show improvement after 2 months (+LR = 10.8 if all four factors are present).

Anatomy

Osteology

Figure 2-1, Bony framework of head and neck.

Arthrology

The temporomandibular joint (TMJ) is divided by an intraarticular biconcave disc that separates the joint cavity into two distinct functional components. The upper joint is a plane, or gliding, joint that permits translation of the mandibular condyles. The lower joint is a hinge joint that permits rotation of the condyles. The closed pack position of the TMJ is full occlusion. A unilateral restriction pattern primarily limits contralateral excursion but also affects mouth opening and protrusion.

Figure 2-5, Temporomandibular joint mechanics.

During mandibular depression from a closed mouth position, the initial movement occurs at the lower joint as the condyles pivot on the intraarticular disc. This motion continues to approximately 11 mm of depression. With further mandibular depression, motion begins to occur at the upper joint and causes anterior translation of the disc on the articular eminence. Normal mandibular depression is between 40 and 50 mm.

Ligaments

Ligaments	Attachments	Function
Temporomandibular	Thickening of anterior joint capsule extending from neck of mandible to zygomatic arch	Strengthen the TMJ laterally
Sphenomandibular	Sphenoid bone to mandible	Serve as a fulcrum for and reinforcer of TMJ motion
Stylomandibular	Styloid process to angle of mandible	Provide minimal support for joint

Muscles

Muscles Involved in Mastication

Muscle	Proximal Attachment	Distal Attachment	Nerve and Segmental Level	Action
Temporalis	Temporal fossa	Coronoid process and anterior ramus of mandible	Deep temporal branches of mandibular nerve	Elevate mandible
Masseter	Inferior and medial aspects of zygomatic arch	Coronoid process and lateral ramus of mandible	Mandibular nerve via masseteric nerve	Elevate and protrude mandible

Figure 2-8, Muscles involved in mastication, lateral and posterior views.

Muscle	Proximal Attachment	Distal Attachment	Nerve and Segmental Level	Action
Medial pterygoid	Medial surface of lateral pterygoid plate, pyramidal process of palatine bone, and tuberosity of maxilla	Medial aspect of mandibular ramus	Mandibular nerve via medial pterygoid nerve	Elevate and protrude mandible
Lateral pterygoid (superior head)	Lateral surface of greater wing of sphenoid bone	Neck of mandible, articular disc, and TMJ capsule	Mandibular nerve via lateral pterygoid nerve	Acting bilaterally: protrude and depress mandible
Lateral pterygoid (inferior head)	Lateral surface of lateral pterygoid plate	Neck of mandible, articular disc, and TMJ capsule	Mandibular nerve via lateral pterygoid nerve	Acting unilaterally: laterally deviate mandible

Muscles of the Floor of the Mouth

Figure 2-9, Floor of mouth, inferior view.

Muscle	Proximal Attachment	Distal Attachment	Nerve and Segmental Level	Action
Mylohyoid	Mylohyoid line of mandible	Hyoid bone	Mylohyoid nerve (branch of cranial nerve [CN] V ₃ )	Elevates hyoid bone
Stylohyoid	Styloid process of temporal bone	Hyoid bone	Cervical branch of facial nerve	Elevates and retracts hyoid bone
Geniohyoid	Inferior mental spine of mandible	Hyoid bone	C1 via hypoglossal nerve	Elevates hyoid bone anterosuperiorly
Digastric (anterior belly)	Digastric fossa of mandible	Intermediate tendon to hyoid bone	Mylohyoid nerve	Depresses mandible; raises and stabilizes hyoid bone
Digastric (posterior belly)	Mastoid notch of temporal bone	Intermediate tendon to hyoid bone	Facial nerve	Depresses mandible; raises and stabilizes hyoid bone

Figure 2-10, Floor of mouth, anteroinferior and posterosuperior views.

Nerves

Mandibular Nerve

Nerves	Segmental Levels	Sensory	Motor
Mandibular	CN V ₃	Skin of inferior third of face	Temporalis, masseter, lateral pterygoid, medial pterygoid, digastric, mylohyoid
Nerve to mylohyoid	CN V ₃	No sensory	Mylohyoid
Buccal	CN V ₃	Cheek lining and gingiva	No motor
Lingual	CN V ₃	Anterior tongue and floor of mouth	No motor
Maxillary	CN V ₂	Skin of middle third of face	No motor
Ophthalmic	CN V ₁	Skin of superior third of face	No motor

CN V, trigeminal nerve.

Patient History

Initial Hypotheses Based on Patient History

Patient Reports	Initial Hypothesis
Patient reports jaw crepitus and pain during mouth opening and closing. Might also report limited opening with translation of the jaw to the affected side at the end range of opening	Possible osteoarthrosis Possible capsulitis Possible internal derangement consisting of an anterior disc displacement that does not reduce
Patient reports jaw clicking and pain during opening and closing of the mouth	Possible internal derangement consisting of anterior disc displacement with reduction ^, ^,
Patient reports limited motion to about 20 mm with no joint noise	Possible capsulitis Possible internal derangement consisting of an anterior disc displacement that does not reduce

The Association of Oral Habits with Temporomandibular Disorders

Figure 2-12, Frequent leaning of head on the palm.

Gavish and colleagues investigated the association of oral habits with signs and symptoms of TMDs in 248 randomly selected female high school students. Although sensitivity and specificity were not reported, the results demonstrated that chewing gum, jaw play (nonfunctional jaw movements), chewing ice, and frequent leaning of the head on the palm were associated with the presence of TMJ disorders.

Reliability of Patient’s Reports of Pain in Temporomandibular Dysfunction

Figure 2-13, Temporomandibular joint pain.

Historical Finding and Study Quality	Description and Positive Findings	Population	Test-Retest Reliability
Visual analog scale (VAS)	A 100-mm line, with ends defined as “no pain” and “worst pain imaginable”	38 consecutive patients referred with TMD	κ = .38
Numerical scale	An 11-point scale, with 0 indicating “no pain” and 10 representing “worst pain”		κ = .36
Behavior rating scale	A 6-point scale ranging from “minor discomfort” to “very strong discomfort”		κ = .68
Verbal scale	A 5-point scale ranging from “no pain” to “very severe pain”		κ = .44

Diagnostic Utility of Patient History in Identifying Anterior Disc Displacement

Figure 2-14, Anterior disc displacement.

Historical Finding and Study Quality	Description and Positive Findings	Population	Reference Standard	Sens	Spec	+LR	−LR
Clicking	Momentary snapping sound during opening or functioning	70 patients (90 TMJs) referred with complaints of craniomandibular pain	Anterior disc displacement via MRI	In presence of reducing disc
				.82	.19	1.01	.95
				In presence of nonreducing disc
				.86	.24	1.13	.58
Locking	Sudden onset of restricted movement during opening or closing			In presence of reducing disc
				.53	.22	.68	2.14
				In presence of nonreducing disc
				.86	.52	1.79	.27
Restriction after clicking	Inability to open as wide as was previously possible after clicking			In presence of reducing disc
				.26	.40	.43	1.85
				In presence of nonreducing disc
				.66	.74	2.54	.46
Periodic restriction	Periodic inability to open as wide as was previously possible			In presence of reducing disc
				.60	.90	6.0	.44
				In presence of nonreducing disc
				.12	.95	2.4	.93
Continuous restriction	Continuous inability to open as wide as was previously possible			In presence of reducing disc
				.35	.26	.47	2.5
				In presence of nonreducing disc
				.78	.62	2.05	.35
Function related to joint pain	Not reported			In presence of reducing disc
				.82	.10	.91	1.8
				In presence of nonreducing disc
				.96	.24	1.26	.17
Complaint of clicking				In presence of reducing disc
				.28	.24	.37	3.00
				In presence of nonreducing disc
				.82	.69	2.65	.26
Complaint of movement-related pain				In presence of reducing disc
				.71	.31	1.03	.94
				In presence of nonreducing disc
				.74	.36	1.16	.72
Complaint of severe restriction				In presence of reducing disc
				.60	.65	1.71	.62
				In presence of nonreducing disc
				.38	.93	5.43	.67

Self-Reported Temporomandibular Pain

Reliability of Self-Reported Temporomandibular Pain

Figure 2-15, Temporomandibular arthrosis.

Historical Finding and Study Quality	Description and Positive Findings	Population	Reliability
TMD pain screening questionnaire	See diagnostic table on following page. Participants were asked same questions 2 to 7 days apart	549 participants: 212 with pain-related TMD, 116 with TMD, 80 with odontalgia, 45 with headache without TMD pain, and 96 healthy controls	ICC = .83
Self-report of TMJ pain	See diagnostic table on following page. Participants were asked same questions 2 weeks apart	120 adolescents: 60 with self-reported TMJ pain and 60 age- and sex-matched controls	Test-retest κ = .83 (.74, .93)

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