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8 Articles in Volume 5, Issue #2
Considerations in Treating Intractable Pain
Hospice Care Evolution
Myofascial Elements of Low Back Pain
Radiofrequency Neuroablation in Chronic Low Back Pain
State Pain Laws: A Case for Intractable Pain Centers Part III
Temporomandibular Joint Referred Pain
The ABC’s of Pain
Therapies for Chronic Pain and Fibromyalgia

Temporomandibular Joint Referred Pain

This retrospective study examined charts of 445 TMD patients to identify and categorize sites of referred pain.

Temporomandibular Joint Dysfunction (TMD) is a disorder of the muscles of mastication, the TM joints, and related ligaments and tendons. TMD may be characterized by any of the following: pain in the jaw moving muscles or in the TM joints, joint noises, mandibular restrictions, and/or deviations with jaw movement. Symptoms include headaches, facial and jaw pain in addition to ear and neck complaints.

A number of studies have found referred pain to distal sites to be associated with internal TM joint disorders.1-6 Additionally, Danzig et al found that an anesthetic injection into the temporomandibular joint space of patients with TMD decreased the pain located in the head, facial and neck regions on the ipsilateral and contralateral sides.7 Montgomery and co-researchers reviewed fifty-one subjects that had temporomandibular joint disc repositioning surgery and found they experienced a significant decrease in headaches, TMJ pain, ear pain, and neck/shoulder pain.8 Steigerwald et al assessed forty-three patients who underwent arthroscopic surgery for arthrogenous TMJ to determine what effects the surgery had on their symptoms of headache, neck pain, shoulder pain, dizziness and tinnitus. They found a significant symptom reduction for all symptoms reviewed on these patients. They suggested that a substantial number of these symptoms were created by temporomandibular joint pathology acting on central neural processes.9

The sipila and co-workers study concluded that facial pain can be associated with TMD as well as pain and muscle tenderness in the neck area.10 Cimino et al revealed that neck and shoulder symptoms are frequently seen in subjects that they evaluate with mandibular dysfunction.11 de Wijer et al concluded that the function of the masticatory system should be evaluated in patients with neck complaints in order to rule out a possible involvement of the masticatory system.12 Mahan and Alling suggested that pathological changes in the TM joint can refer pain to the orbit that has a lancinating or piercing quality.13 Subjects with TM dysfunction can have pain that radiates to the ear, temporal, ramus, neck and other areas.6

TM joint pain can arise from a number of primary and referred sources. The examiner should be aware that the area of pain may — or may not — be source of the subject's presenting pain complaint.14,15 Usually a thorough history and clinical evaluation will determine if the TM joint pain is from arthrogenous or myogenous causes, or both. Arthralgia is a term used to describe pain that originates from a joint. There are several types of pain can originate from the TM joint structures (see Table 1).

Acute TM joint pain can induce a defensive muscle response called protective muscle splinting which is a myalgia-type pain. Pain from muscle trigger points can be referred to the TM joint in addition to other areas.

The sternocleidomastoid, masseter, medial pterygoid, and lateral pterygoid muscles may also refer pain to the TM joint, especially when myofascial trigger points are involved. Trigger points can develop from painful temporomandibular joint conditions such as inflammation, displaced disc disorders and osteoarthritis. Other syndromes such as temporal tendonitis and Ernest syndrome have the TM joints in their zone of referral.16 The main objective of the examination is to identify the source of pain and reach a diagnosis.17

Classification of TM Joint Pains
Ligament pain
Retrodiscal pain
Capsular pain
Arthritic pain
Referred TMD Pain Findings
Sites Occurrences Prevalence
Head 160 41.2%
Face 124 31.0%
Ear 78 20.0%
Mandible 35 9.0%
Neck 22 5.6%
Eye 14 3.6%
Teeth 2 .005%
Table 1. Patient Characteristics Prior to Prolotherapy
Inflammatory disorders
Disc-reducing disorders
Non disc-reducing disorders
Degenerative disorders

Methods

The charts of 445 consecutive patients who reported with TM Dysfunction had their charts reviewed retrospectively to investigate if referred TMJ pain was present. Those charts with positive findings of referred pain had the sites of referral noted. The following sites were found to have referred pain: head, face, ear, mandible, neck, eyes, and teeth.

The examination for referred pain was done using Okeson's method of applying firm continuous pressure over the TM joint lateral poles (see Figure 1), and the retrodiscal areas (see Figure 2), for a few seconds.2 This allows the examiner to elicit a pain referral pattern, if one existed, and provided an opportunity to reproduce the subject's chief complaint.14

Results

Of the 445 TMD pain subjects examined, 388 (87.1%) were found to have referred TM joint pain. The sites of referral and prevalence are noted in (Table 2). The results showed that 160 (41.2%) had referred temporal pain, 124 (31.9%) had referred facial pain, 78 subjects had (20%) had referred ear pain, 35 (9%) had referred mandible pain, 22 (5.6%) had referred neck pain, 14 (3.6%) had referred eye pain, and two (

Discussion

Patients with internal TM joint pain and pathology may experience referred pain symptoms. These pains can emanate from the joint itself or from myogenic trigger points. A number of studies have shown a correlation between the TM joint and the identified sites of referred pain found in this study. Head pain was the most common finding in this study and this correlates with findings of others.1-6 There are multiple areas in the TM joints from which referred pain can originate. These are the discal ligaments, retrodiscal tissues (posterior attachments), and articular capsules. Osteoarthrosis of the TM joint comprises a fourth source of dysfunction.

Ligamentous Pain

The ligamentous structures of the joint are innervated for proprioceptive function. Ligamentous pain usually begins after the discal ligaments become elongated. They cannot be described as stretched because this implies lengthening and suggests a return to the original length. These ligaments do not have elasticity and therefore, once elongated, generally remain at that length. Once the discal anatomy is altered and its ligaments become elongated, the disc can reposition itself across the articular surface of the condyle. This type of repositioning does not exist in the normal joints. This malpositioning of the disc allows changes in the way the teeth meet. The pain results from stress or injury to the neural structures of the joint and discal ligament attachments.5

Retrodiscal Pain

The retrodiscal tissues or posterior attachments are found in between the disc and the posterior wall of the articular capsule. These tissues are highly vascularized, well-innervated, loose connective tissue. Synovial membranes cover the posterior attachment where it interfaces with the joint spaces. The retrodiscal tissue is sometimes referred to as the posterior attachment of the disc.2

Retrodiscal pain can arise when inflammatory response occurs in the retrodiscal tissues. Swelling often accompanies retrodiscal inflammation and pain can arise when the condyle presses against these distended tissues during maximum tooth contact. Mandibular trauma can often cause an acute retrodiscitis. If the pain is intermittent, secondary central excitatory effects such as referred pain may not occur. However, if pain becomes continuous and constant, referred pain may develop. Acute retrodiscitis from trauma, however, may induce both referred pain and secondary co-contraction of the masticatory muscles.14,17

Capsular Pain

Capsular pain results when inflammation occurs in the fibrous capsules and the condition is called capsulitis. Protrusion, contralateral excursion, and opening wide stretch the capsule resulting in pain. Tenderness is present when palpating directly over the condyle and swelling may exist. Acute capsulitis may present with restrictions in condylar movement due to swelling, but most chewing difficulties result from pain.

Capsulitis may develop from capsular ligament injuries as a consequence of acute trauma or natural strains. Frequently, inflammatory conditions develop in the discal ligaments and the temporomandibular ligaments. Bruxism and bite instability may be aggravating factors. Additionally, capsulitis may result from jaw habits that use excessive mandibular movements and joint hypermobility.2

Osteoarthrosis Pain

Osteoarthrosis of the TM joint (degenerative joint disease) is a non-inflammatory condition. This disorder usually results from excessive stress to the articulating joint surfaces when they are not properly aligned. The tissue breakdown is more likely to occur when the disc is out of position and not protecting the articulating surfaces. Mechanical overload causes the articulating surfaces and the underlining bone to deteriorate. Pain with limited opening is not uncommon with these conditions.18

Sub-types of TMD

The above pain categories can originate from the more common types of TMD (see Table 3), which are listed below. Inflammatory TM joint pain (capsulitis, retrodiscitis, and ligament inflammation) can be identified by the presence of pre-auricular pain when palpating the lateral condylar poles or when the subject bites his/her teeth together. Pain occurs with function and swelling may also be present. Hard tissue imaging may reveal minor degenerative changes.

Table 1. Classification of temporomandibular joint pains. Table 2. Referred TMD pain findings for this study.

Displaced TM joint discs with reduction are characterized by joint noises with mandibular movement. Deviations in opening to the involved sides are common and, if the condition is acute, pain with jaw movement may be seen clinically. As the condition becomes more chronic, some catching or interference with smooth jaw movement may occur. Hard tissue imaging may reveal minor degenerative changes.

Clinically, subjects with displaced TM discs without reduction present with pain and limited opening, usually less then 35 mm. Pain occurs with jaw movement. Deflection on opening of the mandibular mid-line to the involved side is a distinguishing sign but no deflection may be observed if the opening is very limited (15-20 mm) or if the condition exist bilaterally. These cases usually begin with joint noises and later progress to this state. Hard tissue imaging can reveal minor to mild degenerative changes.

Degenerative changes of the osteoarthrosis type occur when the joint is subjected to stress that exceeds the subject's ability to adapt and the disc and the bony joint surfaces begin to remodel. Usually the opening movement is painful and a course sound called crepitus is present as the bony surfaces of the condyle and eminence rub against each other. If severe bony changes occur unilaterally, then displacement of the chin to the ipsilateral side can occur. These subjects may exhibit some facial asymmetry. There is tenderness with palpation of the lateral condylar pole and radiological evidence of changes in the hard tissues of the TM joint.2,19

Conclusion

The temporomandibular joints previously have been reported to be a source of referred head, facial, ear and neck pain when normal function is interrupted. Previous studies have found tenderness in the TM joints to be associated with pain in a number of distal sites since the TM joint capsules, retrodiscal tissues, and TM joint ligaments are innervated structures that can initiate afferent nociceptive pain impulses.

The results from this retrospective study confirm that painful internal TMD can be associated with referred pain to distal sites. The temporal area was the most frequent referred site and this is consistent with published findings that head pain is one of the most common TMD complaints. Pressure to the lateral condylar poles or the retrodiscal tissue areas of the TM joints will help the examiner to determine if tenderness and referred pain is present.

Last updated on: December 28, 2011
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