74 THE SUPERIOR EXTREMITY 



of the palm. The distal margin or base lies at the level of 

 the heads of the metacarpal bones, and it divides into five 

 processes, one for each finger and a more slender process for 

 the thumb. Each process passes to the corresponding digit 

 where it blends with the volar surface of the sheath of the 

 flexor tendons, and it sends a process on each side of the 

 digit which join the deep fascia on the dorsal surface. 



The dorsal carpal ligament is attached on the radial side 

 to the volar margin of the styloid process of the radius and 

 on the ulnar side to the fascia on the medial side of the 

 wrist. The space between it and the distal ends of the 

 radius and ulna is divided into six compartments by septa, 

 which pass from its deep surface to the ridges on the radius 

 and to the head and styloid process of the ulna. The com- 

 partments transmit the tendons which pass from the dorsum 

 of the forearm to the dorsum of the hand and to the dorsal 

 aspects of the fingers. Its superficial surface is crossed by 

 the terminal branches of the superficial division of the 

 radial nerve and by the cephalic and basilic veins. The 

 distal border of the dorsal carpal ligament is continuous 

 with the thin deep fascia of the hand, which is prolonged 

 into the dorsal aspects of the digits. 



When the study of the deep fascia of the superior 

 extremity has been completed return to the shoulder region ; 

 verify again the attachments of the muscles which connected 

 the scapula and the clavicle with the trunk ; afterwards cut 

 away the superfluous parts of the muscles, leaving about one 

 inch of each for revision. Then proceed to the general 

 study of the shoulder region. 



Muscles inserted into the Clavicle and Scapula. The insertions of 

 the muscles which have already been divided must first engage the 

 attention of the student. They should be carefully defined and the 

 precise extent of each studied. Begin with the omo - hyoid, which 

 springs from the superior border of the scapula ; then deal in the same 

 way with the levator scapula, rhomboideus minor and major, which 

 are attached to the vertebral border of the bone, and the serratus anterior, 

 which is inserted into the costal aspect of the medial and inferior angles, 

 and the intervening portion of the vertebral border of the scapula. The 

 insertion of the pectoralis minor into the coracoid process, and of the 

 trapezius into both clavicle and scapula, should also be thoroughly re- 

 examined. 



