210 ANTERIOR BRACHIAL REGION. 



Jlnterior Brachial region. 

 Superficial layer. 



Pronator radii teres, 

 Flexor carpi radialis, 

 Palmaris longus, 

 Flexor sublimis digitorum, 

 Flexor carpi ulnaris. 



Dissection. These muscles are seen by making an incision 

 through the integument along the middle line of the fore-arm, cross- 

 ing each extremity by a transverse incision, and turning aside the 

 flaps. The superficial and deep fascia are then to be removed. 



The Pronator radii teres arises by two heads ; one from the inner 

 condyle of the humerus, fascia of the fore-arm and intermuscular 

 aponeurosis ; the other, from the coronoid process of the ulna ; the 

 \ median nerve passing between them. Its tendon is inserted into the 



middle third of the oblique ridge of the radius. The two heads of 

 this muscle are best seen, by cutting away that which arises from 

 the inner condyle, and turning it aside. The second head will then 

 be seen with the median nerve lying across it. 



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

 the supinator longus, extensor carpi radialis longior and brevior, 

 radial artery and veins, and radial nerve. By its posterior surface 

 with the brachialis anticus, flexor sublimis digitorum, the ulnar 

 artery and veins, and the median nerve after it has passed between 

 the two heads of the muscle. By its upper border it forms the inner 

 boundary of the triangular space, in which the termination of the 

 brachial artery is situated. By its lower border it is in relation with 

 the flexor carpi radialis. 



The Flexor carpi radialis arises from the inner condyle and the 

 . sheath of fascia which surrounds it. Its tendon passes through a 

 groove formed by the scaphoid bone and trapezium, to be inserted 

 into the base of the metacarpal bone of the index finger. 



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

 and at the wrist with the tendinous canal through which its tendon 

 passes. By its posterior surface with the flexor sublimis digitorum, 

 flexor longus pollicis, wrist-joint, and groove in the scaphoid and 

 trapezium bones. By its outer border with the pronator radii teres, 

 and radial artery and veins. By its inner border with the palmaris 

 longus. The tendon is surrounded by a synovial membrane where 

 it plays through the tendinous canal of the wrist. 



The Palmaris longus muscle arises from the inner condyle, and 



Hfrom the sheath of fascia which surrounds it. It is inserted into the 

 palmar fascia. Occasionally this muscle is wanting. 



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

 By the posterior surface with the flexor sublimis digitorum; to the 

 external side by the flexor carpi radialis ; and to the internal side 

 by the flexor carpi ulnaris. 



