The morphogenesis of the human discomalleolar and sphenomandibular ligaments.

The morphogenesis of the discomalleolar ligament and its relationship with the sphenomandibular ligament were studied in human embryos and fetuses, on histological grounds. Total number of 18 embryos and fetuses, ranging from 6.5 to 230 mm (5-25 weeks of fertilization age) were examined. The discomalleolar ligament emerged from the posterior part of the temporomandibular joint capsule and disc, passing through the squamotympanic fissure, joined the malleus. The superior fibres of the ligament inserted on the anterior process of the malleus and on the bony wall of the squamotympanic fissure. The inferior fibres of the discomalleolar ligament encircles the anterior malleolar ligament, the remnant of Meckel's cartilage, and chorda tympani, and inserted on the tympanic wall of the temporal bone. Within the tympanic cavity, the discomalleolar ligament and the anterior malleolar ligament, a continuation of the sphenomandibular ligament, formed a horizontal 'V' shape at the attachment site on the ventral surface of the malleus. The study shows that the discomalleolar ligament is an embryological continuation of the sheath of the lateral pterygoid muscle. The sphenomandibular ligament derives from Meckel's cartilage.