1034 



THE NERVE SYSTEM 



The Musculocutaneous (n. musculocutaneus) (Figs. 759 and 704) fmw.s from 

 the outer cord of the brachial plexus, opposite the lower border of the Pectoralis 



minor muscle, receiving fila- 

 ments from the fifth, sixth. 

 and seventh cervical nerves. 

 It perforates the C ora co- 

 bra chia Its muscle (Fig. 704), 

 passes obliquely between the 

 Biceps and Brachial is anticus 

 muscles to the outer side of 

 the arm, and, a little above 

 the elbow, winds around the 

 outer border of the tendon of 

 the Biceps, and, perforating 

 the dee]) fascia, becomes cu- 

 taneous (Fig. 700). In its 

 course through the arm this 

 nerve supplies the ( "oraco- 

 brachialis, Biceps, and the 

 greater part of the Brachialis 

 anticus muscles. The branch 

 to the Coracobrachialis is 

 given off from the nerve 

 close to its origin, and in 

 some instances as a separate 

 filament from the outer cord 

 of the plexus. The branches 

 to the Biceps and Brachialis 

 anticus are given off after the 

 nerve has pierced the Coraco- 

 brachialis. The nerve also 

 sends a small branch to the 

 humerus, which enters the 

 nutrient foramen with the 

 accompanying artery, and a 

 filament from the branch 

 supplying the Brachialis anti- 

 cus goes to the elbow-joint. 

 The musculocuta neons fur- 

 nishes the chief nerve supply 

 to this 



The cutaneous portion of 

 the musculocutaneous nerve 

 (n. cutaneus anfebrach/i lat- 

 eralis) passes behind the 

 median cephalic vein, and 

 divides, opposite the elbow- 

 joint, into an anterior and a 

 posterior branch. 



The anterior branch de- 

 scends along the radial i:order 

 of the forearm to the wrist, and supplies the integument over the outer half of 

 its anterior surface! At the wrist-joint it is placed in front of the radial artery, and 

 some filaments, piercing the deep fascia, accompany that vessel to the dorsum of 



FIG. 702. Cutaneous nerves of the upper limb, anterior aspect. 

 (W. Keiller, in Gerrish's Text-book of Anatomy.) 



