212 FLEXOR PROFUNDUS DIGITORUM. 



/ 



/divides into four tendons, which pass beneath the annular ligament 



\ I into the palm of the hand, and are inserted into the base of the 



O/ I second phalanges of the fingers, splitting at their terminations to 



V * \ give passage to the tendons of the deep flexors ; thence its designa- 



\ tion perforatus. 



Relations. In the fore-arm. By its anterior surface with the 

 pronator radii teres, flexor carpi radialis, palmaris longus, flexor 

 carpi ulnaris, and the deep fascia of the fore-arm. By its posterior 

 surface with the flexor profundus digitorum, flexor longus pollicis, 

 ulnar artery, veins, and nerve, and median nerve. This muscle 

 usually sends a fasciculus to the flexor longus pollicis. In the hand: 

 tts tendons, after passing beneath the annular ligament, are in rela- 

 iion superficially with the superficial palmar arch, and palmar fascia; 

 and deeply with the tendons of the deep flexor and lumbricales. 

 /" The Flexor carpi ulnaris arises by two heads, one from the inner 

 < condyle, the other from the olecranon and upper two-thirds of the 

 inner border of the ulna. Its tendon is inserted into the pisiform 

 bone, and base of the metacarpal bone of the little finger. 



Relations. By its anterior surface with the fascia of the fore-arm, 

 with which it is closely united superiorly. By its posterior surface 

 with the flexor sublimis digitorum, flexor profundus, pronator quad- 

 ratus, and ulnar artery, veins, and nerve. By its radial border with 

 the palmaris longus, and in the lower third of the fore-arm with the 

 ulnar vessels and nerve. The ulnar nerve, and the posterior ulnar 

 recurrent artery, pass between its two heads of origin. 



Deep layer. 



Flexor profundus digitorum, 

 Flexor longus pollicis, 

 Pronator quadratus. 



Dissection. This group, is brought into view by removing the 

 flexor sublimis, and drawing aside the pronator radii teres. 

 f Flexor profundus digitorum (perforans) arises from the upper two- 

 ,' thirds of the ulna and part of the interosseous membrane, and termi- 

 nates in four tendons, which pass .beneath the annular ligament, and 

 between the two slips of the tendons of the flexor sublimis (hence 

 its designation, perforans), to be inserted into the base of the last 

 phalanges. The tendon of the index finger is always distinct from 

 the rest, the other three tendons being more or less intimately con- 

 nected by cellular tissue and tendinous slips. 



Four little muscular fasciculi, called lumbricales, are connected 

 with the tendons of this muscle in the palm. They will be described 

 with the muscles of the hand. 



Relations. In the fore-arm. By its anterior surface with the 

 flexor sublimis digitorum, flexor carpi ulnaris, medi'an nerve, and 

 ulnar artery, veins, and nerve. By its posterior surface with the 

 ulna, the interosseous membrane, the pronator quadratus, and the 



