ADDUCTORS OF THE THUMB. 



237 



nlnar side, and is inserted with the adductor obliquus into the inner side of the base 

 of the first phalanx. 



The adductor obliquus pollicis is the largest of the thumb-muscles. It arises 

 in several slips from the upper ends of the second and third metacarpal bones, the 

 os magnum, the anterior carpal ligaments, and the sheath of the flexor carpi radialis. 

 It passes obliquely downwards on the inner side of the tendon of the long flexor, 

 and is inserted into the inner side of the base of the first phalanx of the thumb, in 

 union with the adductor transversus and the deep head of the flexor brevis. The 

 inner sesamoid bone of the thumb is formed in the tendon of insertion. A con- 

 siderable fasciculus of the adductor obliquus usually inclines outwards behind the 



PISI-UNCINATE LIGT. 



BREV. WIN. DIG. 



NIETAC. LIGT. 



ORS. INTOSS. 



Fig. 244. DEEP MUSCLES OP THE PALM. (G. D. T.) 



The anterior annular ligament has been divided, and its outer part reflected. The middle portions 

 of the abductor pollicis, and of the abductor and flexor brevis minimi digiti have been removed. The 

 opponens minimi digiti consists of two parts, which are separated by a cleft*, giving passage to the deep 

 branches of the ulnar nerve and vessels ; f, interval through -which the deep palmar arch passes. 



long flexor tendon to join the superficial head of the flexor brevis and the outer sesa- 

 moid bone. 



It has been customary to describe the adductor obliquus pollicis as the deep head of the 

 flexor brevis. The present description follows the division and nomenclature of Cunningham 

 ("Challenger" Reports, Zoology, xvi ; Anatom. Anzeiger, 1887). 



The adductor transversus pollicis muscle arises from the ridge on the lower 

 two-thirds of the palmar aspect of the third metacarpal bone, and is inserted into 

 the base of the first phalanx of the thumb along with the adductor obliquus and the 

 inner head of the short flexor ; from the common insertion a slip is continued to 

 the long extensor tendon of the thumb. The deep palmar arterial arch passes 

 between the two adductors. 



MUSCLES OF THE LITTLE FINGER. The fleshy mass at the inner border of the 

 hand (hypothenar eminence) consists of three muscles passing to the little finger. 



