422 MUSCLES. f.- . 



5. The Flexor Digitorum Sublimis Perforates, 



Is concealed very much by the muscles just enumerated, in 

 consequence of being placed between them. To get a good 

 view of its origin, they all should be cut away from the os hu 

 meri. It arises, tendinous and fleshy, from the internal con- 

 dyle of the os humeri, tendinous from the coronoid process of 

 the ulna, and fleshy from the tubercle of the radius; the latter 

 part of its origin being extended, tendinous obliquely, for three 

 or four inches from that line of the radius which is at the upper 

 margin of the supinator radii brevis. With these origins the 

 muscle spreads over the front of the fore arm at its upper part, 

 from the radial to the ulnar margin. 



Four distinct tendons pass from the lower end of the muscle? 

 which commence much above the wrist, pass beneath its ante- 

 rior ligament, and, having reached the palm of the hand, diverge 

 to the several fingers. A tendon is appropriated to each finger, 

 and passes in front of the metacarpal bone to the phalanges, be- 

 ing inserted, after having split into two, into the angles formed 

 by the junction of the cylindrical and flat surface of the second 

 phalanx near its middle. 



It bends the second phalanges on the first; its action may also 

 be continued so as to clench the hand and to bend it on the fore 

 arm.* 



6. The Flexor Digitorum Profttndus Perforates, 



Is beneath the flexor sublimis and the flexor ulnaris. It arises, 

 fleshy, from the oblong concavity of the ulna, along the inner 

 side of the coronoid and the olecranon process, fleshy from 

 the lower margin of the base of the coronoid process, from the 

 ulnar portion of the interosseous ligament, and from the front of 

 the upper two-thirds of the ulna. 



* Varieties. The tendon to the little finger is sometimes wanting, in which 

 case the deficiency is supplied by the tendon of the flexor profunchis. Some- 

 timjs the section of this muscle which belongs to the fore finger, is insulated 

 from the rest of it, by a long fissure, and, moreover, divided by a middle tendon, 

 into two fleshy portions. 



