162 SURGICAL ANATOMY OF THE PALM. 



cesses of the radius and ulna require removal, and the 

 vessels which would be ligatured are the superficialis 

 volse, some branches of the ulnar in the palm, and per- 

 haps an abnormal median. 



For the operation of excision of the joint, an accurate 

 knowledge of its component parts and relations is of the 

 utmost importance, as this excision, like that of the 

 ankle, reduces itself to an anatomical problem viz., to 

 remove the disease, and at the same time to preserve to 

 the hand the tendons passing from the arm to it, and if 

 possible to retain their functions. It is difficult to lay 

 down any distinct rules, as obviously each case has its 

 own peculiarities ; but by far the most scientific pro- 

 ceeding is that of Professor Lister, for an account of 

 which somewhat complicated but most successful opera- 

 tion, reference must be made to special works on opera- 

 tive surgery. 



SURGICAL ANATOMY OF THE PALM. 



Surface Markings. This region extends from the wrist 

 to the web of the fingers. It is concave, and presents 

 two muscular eminences: one on the radial side, due to 

 the mass of muscles acting on the thumb, called the 

 .thenar prominence, and the other due to muscles of the 

 little finger, the hypothenar. The intermediate space is 

 marked by several furrows, indicating the more marked 

 flexions of the hand, one of which, the oblique central 

 one, lies almost in the course of the superficial palmar 

 arch. The deep palmar arch may be referred to the 

 surface marking, by an imaginary line drawn between 

 the centres of those circles, which form the bases of the 

 thenar and hypothenar eminences. The bifurcation of 



