Individual variations in the vascular content of retrodiscal tissue in the temporomandibular joint: a study using histological sections of human foetuses and magnetic resonance images of adults without pathology.

The vascular content of retrodiscal tissue in the temporomandibular joint (TMJ) plays a critical role in joint function, and its morphology is therefore likely relatedto TMJ pain. Using histological sections of human foetuses as well as T2-weighted magnetic resonance images (MRI), we measured the vascular content of retrodiscal tissue. MRI showing no pathology in and around the TMJ were obtained from18 young patients who had been suffering from headache. In 10 small foetuses (12-14 weeks of gestation) as well as 10 larger foetuses (30-37 weeks), the vascular content showed individual variations exceeding 5 times the minimum value (0.24 vs. 0.04 mm2 per 1 mm²), but no difference between foetal stages was evident. In the MRI from young adults, the variation was less than twice the minimum value (13.6 vs. 8.7 mm² per 100 mm²). The vascular density appeared to be lower in adults than in foetuses. In both foetuses and adults, the thickness (anteroposterior length) of the tissue did not correlate with the vascular sectional area. These findings suggest that the considerable inter-individual differences evident in the vascular content of foetal retrodiscal tissue may be reduced during further development.