306 A MANUAL OF ANATOMY. 



ligament will be found the muscular branches to the thumb 

 muscles. From the ulnar there passes into the palm with 

 the deep communicating artery the deep palmar branch of 

 the ulnar nerve. It also sends branches to the palmaris 

 brevis and little finger muscles. 



Superficial Layer of Palmar Muscles. 



Abductor Pollicis. Fig. 66. 



Origin. From the tuberosity of scaphoid, ridge of trape- 

 zium, and fibres of palmar fascia, annular ligament, and 

 tendon of the extensor ossis metacarpi pollicis. 



Insertion. Into the anterior side of the base of the first 

 phalanx of the thumb and the aponeurosis of the extensor 

 longus pollicis. 



Nerve Supply. Median. (Filaments from the sixth cer- 

 vical nerve.) 



Action. To abduct, flex thumb, and (through its attach- 

 ment to the thumb extensor) it will slightly extend the iast 

 phalanx of the thumb. (See action of lumbricales and 

 interossei.) 



Outer Head of the Flexor Brevis Pollicis. (For the 

 inner see page 308.) Fig. 66. 



Origin. From the annular ligament and ridge of trape- 

 zium. 



Insertion. The outer side of the base of the first phalanx 

 of the thumb. 



Nerve Supply. From the median (filaments from the 

 sixth cervical). 



Action. Flexion of the carpometacarpal and metacar- 

 pophalangeal articulations of the thumb. Acts with ab- 

 ductor pollicis. For deeper muscles of thumb see page 308. 



Abductor Minimi Digiti. Fig. 66. 

 Origin. From the pisiform bone. 



