70 



DISSECTION OF THE HAND. 



digital 

 vessels and 

 nerves ; 



and expose 



digital 



sheaths. 



Cutaneous 



palmar 



nerves, 



one from 

 median, 



the other 

 from ulnar. 



Palmaris 



brevis is a 

 cutaneous 

 muscle ; 



Palmar 

 fascia. 



Its central 

 part 



ends in a 

 piece for 

 each finger, 



and in the 

 skin. 



Dissection. 



Deep ending 



Of till- ])ii'ci-s 



of fascia. 



from the palmar fascia he will recognise, opposite the clefts between 

 the fingers, the digital vessels and nerves, and must be especially 

 careful of two, viz., those of the inner side of the little finger and 

 outer side of the index finger, which appear higher up in the hand 

 than the rest, and are more likely to be injured. By the side of 

 the vessels and nerves to the fingers four slender lumbricales muscles 

 are to be exposed. 



Lastly, the skin and the fat may be reflected from the thumb and 

 fingers by an incision along each, in order that the sheaths of the 

 tendons with the collateral vessels and nerves may be laid bare. 



Cutaneous palmar nerves. Small twigs are furnished to the integu- 

 ment from both the median and ulnar nerves in the hand ; and two 

 branches descend from the forearm. 



One is the offset of the median nerve (p. 67) which crosses the 

 annular ligament ; it extends to about the middle of the palm, and 

 is united with the palmar branch of the ulnar ; a few filaments are 

 furnished to the ball of the thuml >. 



The other palmar branch is derived from the ulnar nerve (p. 66). 

 and has been traced on the ulnar artery to the hand ; it is distributed 

 to the upper and inner part of the palm. 



The PALMARIS BREVIS (fig. 28, H) is a small flat muscle, about an 

 inch and a half wide, the fibres of which are collected into separate 

 bundles. It arises from the palmar aponeurosis, and its fibres are 

 directed transversely to their insertion into the skin at the inner 

 border of the hand. 



This muscle lies over the ulnar vessels and nerve. After it has 

 been examined it may be thrown inwards with the skin. 



Action. It draws outwards and wrinkles the skin of the inner 

 side of the palm. 



The PALMAR FASCIA or aponeurosis consists of a central and two 

 lateral parts ; but the lateral, which cover the muscles of the 

 thumb and little finger, are so thin as not to require a special 

 notice. 



The central part is a strong, white layer, which is pointed at the 

 wrist, but expanded towards the fingers, where it nearly covers the 

 palm of the hand. Above, the fascia receives the tendon of the 

 palmaris longus, and is connected to the annular ligament ; and 

 below, it ends in four processes, which are continued downwards, 

 one for each finger, to the sheaths of the tendons. At the point of 

 separation of the pieces from one another some transverse fibres are 

 placed, which arch over the lumbricalis muscle and the digital 

 vessels and nerve appearing at this spot. From the pieces of the 

 fascia a few superficial longitudinal fibres are prolonged to the 

 integument near the cleft of the fingers. 



Dissection. Now follow one of the digital processes of the 

 fascia to its termination. First remove the superficial fibres, and 

 then divide the process longitudinally by inserting the knife 

 beneath it opposite the head of the metacarpal bone. 



Ending of the processes. Each process of the fascia sends back- 

 wards an offset on each side of the tendons, which is fixed to the 



