Development of the human sphenomandibular ligament.

The development and arrangement of the sphenomandibular ligament of 60 human embryos and fetuses were studied. Meckel's cartilage appeared as a single, continuous fibrous structure lying between the mandibular lingula and the malleus of the middle ear in fetuses of 210 mm crown-rump length (22 weeks of age) and over. This structure constitutes the malleolomandibular ligament, and two clearly differentiated portions bound by the tympanosquamosal fissure could be seen: a juxtaarticular portion, inserted on the posterior edge of the interpterygoid aponeurosis, and a tympanic portion, onto which the disc of the temporomandibular joint inserted. Some of the authors consider that if tension is applied to the sphenomandibular ligament this may injure the middle ear. The anatomical arrangement of the sphenomandibular ligament could explain these injuries.