264 SKELETON. 



into the spine bordering the posterior mental foramen, and for 

 some distance lower down on the ramus of the jaw. It is placed 

 between the two pterygoid muscles, and is in contact with 

 the maxillary vessels and nerves, as they run between it and 

 the condyle to the posterior mental foramen. It is thought by 

 Caldani to be not so useful in restricting the motion of the jaw 

 forwards, as in holding the vessels and nerves, and regulating 

 their position, lest in the various motions of the lower jaw 

 they should be displaced and injured. 



The Stylo-maxillary Ligament is thinner than the above. It 

 arises from the external side of the styloid process, and is in- 

 serted into the posterior margin of the jaw, near its angle, be- 

 tween the masseter and internal pterygoid muscles. The sty- 

 lo-glossus muscle is much connected with it, and is thereby as- 

 sisted in elevating the base of the tongue, the fascia profunda 

 of the neck is in continuation with it. 



There are two synovial membranes, the one reflected be- 

 tween the glenoid cavity and the upper surface of the inter- 

 articular cartilage, and the other between this latter substance 

 and the condyle of the lower jaw. They may be seen at differ- 

 ent points protruding between the fibres of the capsular liga- 

 ment. 



The Inter-articular cartilage, by being placed between the 

 two synovial membranes, separates completely the two bones. 

 Above, its surface corresponds to the convexity of the tubercle 

 of the temporal bone, and to the glenoid cavity; below, it is 

 simply concave for receiving the condyle. It is thicker at the 

 circumference than in its middle, and at the posterior than the 

 anterior margin. Sometimes it is open in the centre, in which 

 case the two synovia! membranes run into one another. Its 

 structure is fibro-cartilaginous. It moves very readily back- 

 wards and forwards. 



On the posterior face of the capsular ligament, I have found, 

 in several cases, indeed, on all occasions of special examination 

 for it, since the first observation, an erectile tissue or structure 

 resembling the corpus cavernosum penis. It has not been 



