-214 



A MANUAL OF ANATOMY 



- • Ungual Process 



Proximal Extremity 



Proximal Extremity 



ring, and little, respectively. The number of phalanges is fourteen, 

 three for each of the four inner fingers, and two for the thumb. 

 They are arranged in rows, both longitudinally and transversely, 

 and they diminish in length from above downwards. They are 

 distinguished as first or proximal, second or intermediate, and 

 third, distal, or ungual, except in the case of the thumb, where the 

 second is wanting. 



The First Phalanx. — The shaft is compressed from before back- 

 wards, fiat and concave longitudinally on the palmar aspect, and 

 convex on the dorsal. The palmar surface presents at either side a 

 rough border for the sheath of the flexor tendons. The proximal end 

 or base is enlarged, and presents 

 superiorly a concave articular sur- 

 face, transversely oval, for the 

 head of a metacarpal bone, and 

 at either side a slight tubercular 

 enlargement. The distal end is 

 small, and presents a trochlear 

 surface, grooved at the centre and 

 elevated at either side of this into 

 a small condyle, for articulation 

 with the second phalanx, except 

 in the case of the thumb, where 

 it articulates with the ungual 

 phalanx. The cartilage of the 

 distal end is prolonged more on 

 the palmar aspect than on the 

 dorsal. At either side it presents 

 a depression for the lateral inter- 

 phalangeal ligament. 



The Second Phalanx. — ^This is 

 shorter and smaller than the first, 

 from which it is distinguished by 

 having on its proximal end or base 

 two shallow articular depressions, 



separated by a median antero- middle Finger (Dorsal View), 

 posterior ridge, for the distal end 



of the first phalanx. The distal end resembles that of a first 

 phalanx, except that it is smaller. The shaft resembles that of a 

 first. Its palmar surface presents at the centre of the lateral borders 

 two rough impressions, one at either side, which give insertion to the 

 divisions of a superficial flexor tendon. The dorsal surface of the 

 base is marked by a rough transverse ridge for the insertion of 

 the middle division of a common extensor tendon. 



The Third Phalanx.— This is of small size. The proximal end or 

 base resembles that of a second phalanx, and has in front a rough 

 transverse ridge for the insertion of a deep flexor tendon, whilst the 

 dorsal surface gives insertion to the two lateral divisions of a common 

 extensor tendon. The distal end presents a rough, tapering, convex 



Proximal Extremity 



Fig. 127. — The Phalanges of the 



