MUSCLES OF THE FORE ARM. 423 



The tendons of this muscle are different from those of the 

 other; they commence in front of it, like a tendinous membrane, 

 which is gradually divided into several fasciculi, adhering to 

 each other by cellular membrane. The fasciculated character 

 of the tendons is still preserved when they go under the ante- 

 rior carpal ligament, and until they begin to disperse as distinct 

 tendons to each of the fingers. 



Each tendon, going in front of its metacarpal bone and of the 

 corresponding phalanges, gets through the slit in the flexor sub- 

 limis, and is inserted into the front part of the root of the third 

 phalanx of its respective finger. 



It bends the last phalanges of the fingers, and may, by in- 

 creased action, flex the hand like the preceding muscle.* 



7, The Flexor Longus Pollicls, 



Lies in front of the radius, but beneath the flexor sublimis. 

 It arises by an acute fleshy beginning, from the radius just be- 

 low its tubercle; also fleshy from the middle two-thirds of the 

 front of this bone, and from the radial portion of the interosse- 

 ous ligament. The body of the muscle is joined by a small 

 fleshy slip having a tendinous origin from the internal condyle 

 of the os humeri. 



A tendon is formed early on the ulnar margin of this mus- 

 cle, and to which the fibres pass obliquely. The tendon goes 

 under the annular ligament of the wrist, through the fossa formed 

 in the short flexor muscle of the thumb, and between the sesa- 

 moid bones, to be inserted into the base of the second phalanx 

 of the thumb. 



From the inferior end of the fore arm to the middle of the 

 first phalanx, the tendon is invested by its appropriate bursa. 



It bends the last joint of the thumb. 



The several Flexor tendons, as they pass under the anterior 

 annular ligament of the wrist, are surrounded by the superior 

 Bursa Mucosa. It begins about an inch and a half above the 



* Varieties. Sometimes a distinct fasciculus comes from the internal condyle 

 to join it; sometimes a fasciculus comes from the flexor longus pollicis, and ter- 

 minating in a tendinous expansion, is inserted into the tendon which the flexor 

 profundus sends to the fore finger. 



