UPPER EXTREMITY. 35 



Zygomatic fossa, also called temporal, is the large fossa on either 

 side of the head, formed by the parietal, sphenoid, temporal, and 

 frontal bones, and bounded externally by the zygoma. The tem- 

 poral muscle occupies nearly the whole. 



Pterygo Maxillary Fossa or Fissure. — This is at the bottom of 

 the zygomatic fossa, and formed by the sphenoid, palate, and supe- 

 rior maxillary bones. It is triangular, and the base is upwards. 

 The ganglion of Meckel is contained in it, which gives off branches 

 going through the foramina which open upon this fossa. It is con- 

 tinuous with the foramen lacerum inferius or spheno-maxillary slit. 



Facial Angle. — This is formed by drawing a straight line from 

 the lower part of the frontal bone to the anterior nasal spine, and in- 

 tersecting at this latter point by another drawn through the external 

 meatus auditorius. It establishes a relation between the cranium 

 and the face. The smaller the angle the more inferior is the con- 

 formation. By comparing the heads of the great races of the world, 

 it is found to be 80° to 85° in Europeans, 75° in the copper-coloured 

 or Mongolians, and 70° in Negroes. 



HYOID BONE. 



This bone is isolated in the neck, connected with the root of 

 the tongue and upper part of the larynx. It is shaped like the 

 Greek u, the convexity being in front. It consists of a body and 

 four cornua. The hochj^ is quadrilateral, convex in front, and 

 concave behind. The front surface 

 gives origin and insertion to muscles, '^' 



and has a well-marked projection. The 

 great cornua^ are about an inch in 

 length, and generally united to the body 

 by means of cartilage and ligaments ; 

 they are flattened, project backwards, 

 and terminate in a head or tubercle. 

 They give origin and insertion to 



muscles. The lesser corrnta^ are attached at the junction of the 

 body and great cornu ; it is cartilaginous usually, and of a few 

 lines in length. To it is attached the stylo- by oid ligament. 



UPPER EXTREMITY. 



The upper extremity may be divided into the shoulder, arm, and 

 forearm. 



The shoulder consists of two bones, the scapula and the clavicle. 



Scajjula. — The shoulder blade of common language. Placed on 

 the back part of the thorax between the second and seventh ribs. 

 It is thin, flat, and triangular; has two surfaces, three edges, and 

 three angles. 



