DISSECTION OF FRONT OF FOREARM. 



Long pal mat- 

 muscle 



lies over 

 annular 

 ligament 

 and joins 

 fascia of 

 palm; 



Flexor carpi 

 ulnaris : 

 origin by 

 two heads ; 



insertion 



adjacent 

 parts ; 



Course and 

 extent of 

 the radial 

 artery. 



Situation in 

 the forearm. 



assist in bringing forwards the lower end of the radius in pronation. 

 Still continuing to contract, it bends the elbow. 



The PALM ARTS LONGUS (fig. 24, 5 ) is sometimes absent, or it 

 may present great irregularity in the proportion between the fleshy 

 and tendinous parts. It arises, like the preceding muscle, from 

 the common tendon, the fascia, and the intermuscular septa. Its 

 slender tendon is continued along the centre of the forearm ; and 

 piercing the aponeurosis, it passes over the annular ligament to end 

 in the palmar fascia, sending a slip to the abductor muscle of the 

 thumb. 



The palmaris is situate between the flexor carpi radialis and 

 ulnaris, and rests on the flexor sublimis digitorum. 



Action. Rendering tense the palmar fascia, the palmaris will 

 afterwards bend the wrist and elbow, like the last muscle. 



The FLEXOR CARPI ULNARIS (fig. 24,7) arises by a narrow slip 

 in common with the other muscles from the inner condyle of the 

 humerus, from the intermuscular septum between it and the flexor 

 sublimis digitorum, and by a broad aponeurosis from the inner 

 margin of the olecraiion and the posterior border of the ulna for the 

 upper two-thirds of its length (fig. 36, p. 86). The fibres pass down- 

 wards and forwards to a tendon on the anterior aspect of the muscle in 

 the lower half, some joining it as low as the wrist. The tendon is 

 inserted into the pisiform bone, from which fibrous bands pass on 

 to the hook of the unciform and to the base of the fifth metacarpal 

 bones representing the distal part of the tendon (the pisi-unciform 

 and pisi-metacarpal ligaments). Also a process passes inwards from 

 the tendon near its insertion on to the face of the anterior annular 

 ligament covering over the ulnar artery and nerve. 



One surface of the muscle is in contact with the fascia ; and its 

 tendon, which can be felt readily through the skin, serves as the 

 guide to the ulnar artery. To its radial side are the palmaris and 

 flexor sublimis digitorum muscles. When the attachment to the 

 inner condyle has been divided, the muscle will be seen to conceal 

 the flexor profundus digitorum, the ulnar nerve, and the ulnar 

 vessels ; between the attachments to the condyle and the olecranon 

 the ulnar nerve enters the forearm. 



Action. The wrist is bent, and the hand is drawn inwards by 

 the contraction of the muscle. 



The RADIAL ARTERY (fig. 24, 1 ) is one of the vessels derived 

 from the bifurcation of the brachial trunk, and extends to the palm 

 of the hand. It is placed first along the outer side of the forearm 

 as far as the end of the radius ; next it winds backwards below the 

 extremity of that bone ; and finally it enters the palm of the hand 

 through the first interosseous space. In consequence of this cir- 

 cuitous course, the artery will be found in three different dissections, 

 viz., the front of the forearm, the back of the wrist, and the palm 

 of the hand. 



In the front of the forearm. In this region of the limb the position 

 of the artery will be marked on the surface by a line from the 

 centre of the hollow of the elbow to the fore part of the styloid 



