Anatomic and mechanical properties of the lateral disc attachment of the temporomandibular joint.
OBJECTIVE
This study measured the strength to failure of the human temporomandibular joint (TMJ) lateral disc attachment (LDA) using a tension-compression machine. These data were correlated with the LDA location and its morphologic aspects, the age and sex of the subjects, and the amount of the lateral pterygoid muscle (LPM) inserted in the disc.


METHODS
Forty-two TMJs without any obvious internal damage were carefully dissected to preserve the LDA. The width of insertion of the lateral pterygoid muscle fibers in the anterior band, as well as the width of the disc, were measured. The tension test was performed until the complete failure of the sample using a screw machine.


RESULTS
Two types of LDA were recognized. In LDA 1, the anterior and posterior bands lateral disc junction were directly inserted on the lateral pole, whereas in LDA 2 this lateral junction was attached behind and below the pole through a sheet of fibrous tissue. The breaking points for LDA 1 (55.8 N) and LDA 2 (28.8 N) were significantly different (P = .03). No correlation was found between the amount of LPM discal fibers insertion, sex, age, or the LDA breaking strength point.


CONCLUSIONS
The LDA 2 insertion strongly suggests that the lateral joint ligament together with the capsule may act as a substitute for the original disc attachment to the lateral pole of the condyle.
Department of Oral Anatomy, Faculty of Dental Medicine, Monastir, Tunisia.
F
F
Ben Amor
P
P
Carpentier
J M
JM
Foucart
A
A
Meunier
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D019245:Compressive Strength; D005260:Female; D006801:Humans; D017746:Joint Capsule / Q000033:anatomy & histology / Q000502:physiology; D008023:Ligaments, Articular / Q000033:anatomy & histology; D008297:Male; D008335:Mandibular Condyle / Q000033:anatomy & histology; D008875:Middle Aged; D011247:Pregnancy; D011626:Pterygoid Muscles / Q000033:anatomy & histology; D012737:Sex Factors; D013704:Temporomandibular Joint / Q000033:anatomy & histology* / Q000502:physiology*; D019224:Temporomandibular Joint Disc / Q000033:anatomy & histology; D013718:Tensile Strength