t76 Mufcles of the Fore-arm, sV. [Book IX k 



thefe the fhorter rifes from the coracoid procefs of the 

 fcapula; the longer and outermoft begins from the 

 upper edge of the glenoid cavity of the fcapula, paries 

 over the head of the os humeri within the joint, and 

 in its defcent without the joint is inclofed, by a mem- 

 branous ligament, in a groove near the head of the os 

 humeri. This mufcle is inferted, by a ftrong roundifh 

 tendon, into the tubercle on the upper end of the radius 

 internally. Its effects are to bend the fore- arm, and 

 to turn the radius outwards, and fo bring the palm of 

 the hand uppermofl. Part of the tendon proceeding 

 from this mufcle is alfo fpent in a tendinous eyxpanfion, 

 wh'ch covers all the mufcles at the mfide of the fore 

 arm, and joins with another tendinous membrane, 

 which is fent off behind from the triceps extenfor cu- 

 biti. The ufe of thefe expanfions, as in other parts of 

 the body, is to confine the motions of the mufcles, to 

 protect them, and to give origin to a number of 

 fibres. 



The brachialis interims arifes from the os humeri at 

 each fide of the infertion of the tendon of the deltoides* 

 Being clofely applied to the inferior and inner part of 

 the os humeri, it runs over the joint, is firmly attached 

 to the ligament, and is inferred into the coronoid pro- 

 cefs of the ulna. It aiT:fts the former mufcle in bend*, 

 ing the fore-arm. 



Behind are 



The triceps extenfor cubiti, which confifts of three 

 heads'; of thefe one proceeds from the inferior cofta 

 of the fcapula, another from the upper and outer part 

 of the os humeri, and the third from the back part of 

 that bone. Thefe three heads, when united, form a 

 large mufcle, which is clofely applied to the pofterior 

 part of. the humerus, from which they receive .fome 

 6 mufcular 



