Attachment of the sphenomandibular ligament to bone during intrauterine embryo development for the control of mandibular movement.

The present study examined the relationship between jaw movement and the site of attachment of the sphenomandibular ligament, which is involved in the control of lateral jaw movement. Major fibers of this ligament are attached to the sphenoid spine and the mandibular lingula. During early stages of embryonic development, however, this ligament is not attached to the sphenoid spine. No consensus has yet been reached concerning the time at which this ligament becomes attached to this spine. The present study was performed to resolve this question and to analyze the relationship of this event of jaw movement. Attachment of the sphenomandibular ligament to the sphenoid spine was observed in fetuses at a gestational age of about 8 months (32 weeks). This may be because fetuses undergo functional changes (initiation of jaw movement such as mastication and swallowing) at this gestational age. This finding suggests that the attachment of the sphenomandibular ligament to the sphenoid spine may be related to fetal jaw movements.