SHOULDER, ARM, FOREARM, AND HAND. 



I prefer to have my students begin a dissection of the upper extremity on 

 the fingers and hand. The liability of these parts to become dry, to say nothing 

 of the great practical importance of this region, is sufficient apology. Any dis- 

 section of the hand without a review of the salient osteological landmarks will 

 be, in a measure, a poor dissection, unsatisfactory alike to teacher and student. 

 The student should become master of the following points in osteology before 

 he begins work on the cadaver : 



OSTEOLOGICAL POINTS ON THE HAND. 



The Carpus and Hand (Figs. 108 and 109). 



Name the points on the bones of the carpus and hand of importance in practical 

 anatomy. 



The carpo-metacarpal articulations. 



The base of the first or thumb metacarpal. 



The base of the second metacarpal, radial side. 



The base of the third metacarpal, radial side. 



The base of the fifth metacarpal, ulnar side. 



The pisiform bone of the carpus. 



The groove in the os trapezium. 



The unciform process of the unciform bone. 



The base of the first thumb phalanx. 



The base of the second thumb phalanx. 



The dorsal bases of index, middle, and ring fingers. 



The dorsal bases of second and third phalanges. 



The palmar bases of second and third phalanges. 



What is the importance of the groove in the os trapezium at the base of the 

 thumb f 



It transmits the tendon of the flexor carpi radialis to its insertion into the 

 base of the index metacarpal bone. 



What is the importance of the base of the fifth metacarpal ? 



On its palmar side is inserted the flexor carpi ulnaris ; on its dorsal the ex- 

 tensor carpi ulnaris. These muscles are antagonized by radial and ulnar carpal 

 extensors. 



Name the radial and ulnar extetisors of tJie carpus. 



There are two radial extensors of the carpus : the extensor carpi radialis 

 longior and brevior, inserted into the bases of the second and third metacarpals 

 respectively, on the radial side. The extensor carpi ulnaris is inserted into the 

 base of the fifth metacarpal on the ulnar side. 



Give the importance of the pisiform bone and the unciform process of the unciform 

 bone on the ulnar side of the carpus, in conjunction ~^ilh t/ic scaphoid and trapezium 

 on the radial side. 



It is these bones that give attachment to the anterior annular ligament of tlu- 



152 



