FOREARM AND HAND 115 



remove the ligament. The digital arteries and nerves for the medial side of 

 the little finger, and the lateral side of the index, appear beyond the area of 

 the intermediate part of the palmar aponeurosis, more proximal than the 

 others, and are consequently liable to injury, unless the positions they 

 occupy are kept in mind. 



Aponeurosis Palmaris (O.T. Palmar Fascia). The palmar 

 aponeurosis is composed of three portions an intermediate, a 

 medial, and a lateral. The lateral and medial are thin and 

 weak, and are spread over the muscles which constitute the 

 thenar and hypothenar eminences on the lateral and medial 

 margins of the palm. The intermediate portion of the palmar 

 aponeurosis, on the other hand, is exceedingly strong and 

 dense, and is spread out over the middle of the palm. It 

 counteracts the effect of pressure in this region, and effectually 

 protects the vessels, nerves, and tendons over which it is 

 stretched. Its strength differs considerably in different hands, 

 and it is seen to best advantage in the horny hand of a 

 labourer, or of a mechanic who has been in the habit of 

 handling heavy implements. In shape it is triangular. 

 Above, it is narrow and pointed, and at the wrist it is 

 attached to the transverse carpal ligament, and receives the 

 insertion of the flattened tendon of the palmaris longus. As 

 it approaches the heads of the metacarpal bones it expands, 

 and finally divides into four slips, which separate slightly 

 from each other and pass to the roots of the four medial 

 digits. It gives no slip to the thumb. For the most part 

 it is composed of longitudinal fibres, but, where it divides, a 

 series of strong and very evident transverse fibres pass across 

 it in relation to its deep surface, and bind together its diverg- 

 ing slips. 



In the three intervals between the digital slips of the 

 palmar aponeurosis, the digital arteries and nerves, together 

 with the corresponding lumbrical muscles, make their appear- 

 ance. 



The connections of the four digital slips of the palmar 

 aponeurosis must be closely examined. Each lies in front of the 

 two flexor tendons proceeding to the finger with which it is 

 connected, and each will be observed to divide into two 

 portions, so as to form an arch under which these tendons 

 pass. This arch is connected with the flexor sheaths, which 

 bind the tendons to the front of the finger, and the two 

 portions which form it are carried backwards, to obtain 

 attachment to the transverse metacarpal ligament, which 

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