HYOID BONE. 18 i 



CHAPTER IV. 



THE HYOID BONE, (OS HYOIDES, HYOIDE.) 



THE Os Hyoides is placed at the root of the tongue, within 

 the circle of the lower jaw. It is ah insulated bone, having no 

 connexion with any other, except by muscles and ligaments. 

 It is said, very properly, to resemble the letter U, and consists 

 of a body and two cornua. 



The body is in the middle; it is the largest part of the bone, 

 and forms nearly a semicircle. Its anterior face is convex, and 

 its upper part is flattened by the insertion of the muscles from 

 the lower jaw. The posterior face is concave. 



The cornua, one on either side, are about an inch long, and 

 are placed at the extremities of the body, being united to it by 

 the interposition of cartilage and ligamentous fibres. They are 

 somewhat flattened rather than cylindrical, and diminish to- 

 wards the posterior extremities, where they terminate in a 

 round enlargement like a head. 



At the cartilaginous junction of the cornu and body, on each 

 side, there is a small cartilaginous body three or four lines long, 

 fastened by ligamentous fibres. It is frequently found ossified. 

 This is the appendix or lesser cornu. A round ligament passes 

 from it to the extremity of the styloid process of the temporal 

 bone. 



The texture of this bone is cellular, with a thin compact la- 

 mina externally. M. Portal says, that he has found it carious 

 from venereal contamination; in which case, the patient had 

 been afflicted with violent sore throat and purulent expectora- 

 tion. Sauvages and Valsalva have met with a case, where, 

 from luxation of the cornu, the patient spoke with great diffi- 

 culty. The ligament to the styloid process is, in some rare in- 

 stances, ossified to a considerable extent, which produces diffi- 

 culty in swallowing and in talking. 



VOL. I. 16 



