104 OF THE MUSCLES. 



Flexor radialis accessorius. Origin. From the middle 

 of the hind surface of the radius. Inserted. Into the per- 

 forans by long thin tendon, on a level with the os trape- 

 zium. 



Action of the perforans and perforatus with the tivo acces- 

 sory muscles. They flex the cannon ; bend the pastern ; 

 and curve backwards the foot, which they assist in raising 

 from the ground. 



NECK AND BREAST. 



Pectoralis transversus. Origin. From the fascia upon 

 the inside of the arm. Insertion. Over the cariniform pro- 

 cess of the sternum ; where it joins its fellow, and has a 

 certain degree of motion. Action. To adduct and to retract 

 the limb. 



Pectoralis anticus. Origin. From the anterior half of 

 the cariniform process of the sternum ; and from the body 

 of the sternum ; and cartilages of the first four ribs. In- 

 sertion. Into both sides of the scapulo-humeral joint ; and 

 into the tendon covering the antea spinatus. Action. To 

 draw the shoulder back ; or, the leg being fixed, to pull the 

 body forward. 



Pectoralis magnus {Plate II. J). Origin. From the 

 yellow aponeurosis of the external oblique ; from the ensiform 

 cartilage ; from the cariniform process ; and from the fifth, 

 sixth, seventh, and eighth ribs. Insertion. Into the inner 

 tubercle of the humerus ; and by tendon, which unites wath 

 that of the coraco-humeralis, into the coracoid process of 

 the scapula. Action. To co-operate with, but to act with 

 more activity than, the pectoralis anticus. 



The great use of the pectoral muscles is to aid the mus- 

 cles of the haunch in the propulsion of the trunk. Their 

 blood is supplied by the external pectoral artery, and by 

 branches coming from the internal artery. The nerves are 

 twigs originating from the intercostals. The veins empty 

 into the axillary root. 



Splenius {Fig 4 . 1. Plate II. 13). Origin. By fine 

 tendon, common also to the complexus major, from the 

 anterior six dorsal spines. Insertion. Into the ligamentum 

 colli ; into the occipital ridge, by tendon, common also to 

 the trachelo mastoideus ; into the petrous temporal bone ; 



