FOREARM AND HAND 149 



1. Palmaris brevis muscle and the palmar cutaneous nerves. 



2. Palmar aponeurosis. 



3. Superficial volar arch and its branches. 



4. Median and ulnar nerves and their branches. 



5. Volar carpal ligament, transverse carpal ligament, the flexor tendons, 



and their mucous sheaths. 



6. The lumbrical muscles. 



7. Short muscles of the thumb and little finger. 



8. Deep volar arch and its branches. 



9. Princeps pollicis artery and radial volar artery of the index finger. 



Before proceeding with the dissection of the palm the 

 student should revise the surface anatomy of the region, 

 making use of his own hands as well as of his " part " for 

 the purpose ; and he should re-study the superficial vessels 

 and nerves, and the deep fascia which have already been 

 displayed (p. 73). After the revision is completed, the 

 attachments and relations of the palmaris brevis muscle 

 must be noted. 



Surface Anatomy. In the centre of the palm the depres- 

 sion, known as the "hollow of the hand," may be noted. 

 Along the medial border of the palm the hollow is bounded by 

 a rounded elevation, called the hypothenar eminence, which is 

 produced by the subjacent short, intrinsic, muscles of the little 

 finger. The thenar eminence, or ball of the thumb, formed by 

 the short muscles of that digit, is the marked prominence which 

 limits the palmar hollow proximally and on the lateral side ; 

 whilst the transverse elevation at the roots of the fingers, 

 which corresponds to the metacarpo-phalangeal articulations, 

 constitutes the distal boundary of the central palmar depres- 

 sion. Two pronounced bony projections on the anterior aspect 

 of the wrisr cannot fail to attract attention when the hand is 

 bent dorsally. The more prominent of the two is situated at 

 the proximal extremity of the thenar eminence, and is formed 

 by the tubercle of the navicular bone and the vertical ridge on 

 the volar surface of the os multangulum majus ; the other is 

 placed at the proximal end of the hypothenar eminence, and 

 is somewhat obscured by the soft parts attached to it. It is 

 caused by the pisiform bone, and when taken firmly between 

 the finger and thumb a slight degree of gliding movement can 

 be communicated to it. Traversing the thick integument of 

 the palm, three strongly marked furrows are apparent. One 

 begins at the elevation formed by the navicular and os mult- 

 angulum majus and curves distally and laterally, round the 

 base of the thenar eminence, to the lateral margin of the 

 1106 



