Anatomic basis for disk displacement in temporomandibular joint (TMJ) dysfunction.

This study was designed to investigate the site of lateral pterygoid muscle insertion into the temporomandibular joint (TMJ) disk, and the relationship between that attachment and the disk displacement. One hundred and ten TM joints from 78 cadavers were collected and sectioned in the sagittal plane. Sixty-two unilateral specimens were available and 16 additional specimens were selected randomly from the remaining cadavers in which both condyles were available. Thus statistical comparisons were not confounded by autocorrelation and were based on 78 independent specimens. The sites of muscle attachment in relation to the disk were identified histologically. Of the 78 joints 49 had anterior disk displacement. Of the 42 cases with insertion directly into the disk, 30 had anterior disk displacement. In contrast, only 19 of the 36 disks without direct muscle insertion were displaced. This finding indicated a statistically significant relationship between functional muscle attachment and disk displacement (chi 2 = 9.28, df = 1, p = 0.006). However, the superior head of the lateral pterygoid muscle (SLP) may not be the precipitating factor for anterior disk displacement even though it does coordinate disk movement on closure. Since other factors (e.g., trauma) can result in disk displacement, the SLP can maintain disk displacement only when it inserts directly into the disk. In cases of normal disk arrangement and condylar attachment, the muscle may not play a clinically significant role in disk displacement because disk attachment at the medial and lateral poles of the condyle allows the disk to move freely with the condyle.(ABSTRACT TRUNCATED AT 250 WORDS)

Nontuberculous mycobacterial infection of the lung in a chest hospital in Thailand.

In a continuing study on the occurrence of nontuberculous mycobacterial lung disease by screening sputum cultures and from clinical judgement, from 1979 to 1987, a second series of 42 patients were suspected of having pulmonary infection caused by nontuberculous mycobacteria. As identified by the WHO Collaborating Center for Mycobacteria in Prague, Mycobacterium avium complex was isolated from the greatest number of patients (21 or 50%); M. scrofulaceum from seven; M. kansasii from six, and M. gorgonae from four. The remaining four patients yielded one strain each of M. fortuitum, M. asiaticum, M. szulgai, and one with suspected M. simiae. However, clinical significance was confirmed in only 30 patients, 20 of whom had M. avium complex; three had M. scrofulaceum; three had M. kansasii, and one each had M. gordonae, M. asiaticum, M. szulgai, and suspected M. simiae. Retrospective analysis revealed that 24 of the 30 patients had pre-existing disease, including 20 who had tuberculosis. Blood examinations of 10 patients recalled so far proved negative for HIV infection. Diseases caused by nontuberculous mycobacteria is still rare in Thailand.

Pulmonary infection caused by atypical mycobacteria: a report of 24 cases in Thailand.

From 1969 to 1978, 24 patients were suspected of having pulmonary disease caused by atypical mycobacteria. Seven were infected with Mycobacterium avium-intracellulare, six with Mycobacterium avium, six with Mycobacterium scrofulaceum, two with Mycobacterium fortuitum, and one with Mycobacterium gordonae. One patient had a strain of scotochromogens antigenically related to Mycobacterium simiae. Mycobacterium kansasii was found in only one patient. Retrospective analysis revealed that 20 of the patients had preexisting pulmonary diseases, including 16 who had tuberculosis. Disease caused by atypical mycobacteria is rare in Thailand, and possible reasons for the rarity are discussed.