Basicranial flexion, facial reduction and temporomandibular joint dysfunction.
Although dysfunction is the major condition affecting the bilateral temporomandibular joint (TMJ), it has defied previous attempts to explain, predict, or prevent its clinical manifestations. A hypothesis is developed that there is an anatomical predisposition to TMJ dysfunction which should be sought in the phylogenetic flexing of the hominid basicranium. It is argued that the glenoid fossa, caught between an ever-increasing brain size and more ventrally oriented facial apparatus, has become deepened and hence labile to dysfunction.