SUPERIOR PROFUNDA ARTERY. 53 



a iv til nous processes continuous with the investing aponeurosis of 

 the arm, which are fixed to the ridges leading to the condyles of the 

 humerus, separating the muscles of the front and back of the limb, 

 and giving attachment to the fleshy fibres. 



The internal is the stronger, and reaches as high as the coraco- an inner 

 brachialis muscle, from which it receives some tendinous fibres. and 

 The brachialis anticus is attached to it in front, and the triceps 

 behind ; the ulnar nerve and the inferior profunda and anastomotic 

 vessels pierce it. 



The est-riial upturn is thinner, and ceases at the deltoid muscle, an outer. 

 Behind it is the triceps ; and in front are the brachialis anticus 

 and the muscles of the forearm (supinator longus and extensor 

 carpi ratlialis longior) arising above the condyle of the hunierus : 

 it is pierced by the muse ulo- spiral nerve and the accompanying 

 Vessels. 



Dissection. To follow the superior profunda vessels and the Dissection 

 init.:ii.1o-*pir<i.! / rre, the middle and outer heads of the triceps and^erve. 

 should be cut across over them, and the fatty tissue should be 

 removed. The trunks of the artery and nerve are to be afterwards 

 followed below the outer head of the triceps to the front of the 

 humerus. The veins may be taken away. 



To trace out the branches of the nerve and artery which descend 

 to the elbow and the anconeus muscle, the triceps is to be divided 

 along the line of union of the outer with the middle head. 



The SUPERIOR PROFUNDA branch of the brachial artery (see Superior 

 fig. 19, p. 46) turns to the back of the humerus with the musculo- 

 spiral nerve between the inner and outer heads of the triceps ; in 

 this position it supplies branches to the triceps and deltoid muscles, ii e s behind 

 and is continued onwards in the groove in the bone to the outer ^ hume- 

 part of the arm, where it divides in to its terminal offsets (anterior and 

 posterior). One of these, which is very small, courses on the musculo- 

 spiral nerve to the front of the elbow, anastomosing with the recurrent 

 radial branch ; while a larger one descends along the intermuscular 

 septum to the elbow, and joins the anastomotic and posterior inter- 

 osseous recurrent arteries. 



Brandos. Besides the terminal offsets of the vessel, a consider- supplies 

 able branch descends to the elbow in the inner head of the triceps, joSns^anasto- 

 supplying the muscle, and communicating with the inferior profunda moses 

 and anastomotic branches of the brachial artery. One slender twig elbow; 

 accompanies a branch of the musculo-spiral nerve, and ends in the 

 anconeus muscle below the outer condyle of the humerus. 



Two or more cutaneous offsets arise on the outer side of the arm, cutaneous 

 and accompany the superficial nerves. 



The MUSCULO-SPIRAL NERVE (fig. 4, 4 p. 15) is the largest trunk Muscuio- 

 of the posterior cord of the brachial plexus (p. 25), and is continued '^ds" 

 along the back and outer part of the limb to the hand. In the arm 

 the nerve winds witli the superior profunda artery beneath the triceps 

 muscle. At the outer aspect of the arm it is continued between the to outer side 

 brachialis anticus and supinator longus muscles to the external con- fthearm. 

 dyle of the humerus, in front of which it divides into the radial and 



