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CHAPTER XL 
Plate XIII. —the muscles of the arm. 
Fig. 1. a, the biceps , (biceps flexor cubiti) arise by two portions 
from the scapula; they form a thick mass of flesh in the middle 
of the arm, which is finally inserted into the upper end of the ra¬ 
dius; 6, the brachiceus interims, arises from the middle of the 03 
humeri , and is inserted into the ulna. Both these muscles bend the 
fore-arm. c, the longus et brevis brackiceus extemus; these are bet¬ 
ter named as one muscle, triceps extensor cubiti. It is attached to 
the inferior edge of the scapula, and to the os humeri, by three 
distinct heads, which unite and invest the whole back part of the 
bone, becoming a strong tendon which is implanted into the elbow. 
It is a powerful extensor of the fore-arm. d, the anconceus , a small 
triangular muscle, situated at the outer side of the elbow: it assists 
the last muscle. 
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Fig. 1 and 2. e, c, the annular ligament of the wrist, under 
which pass the tendons of the muscles of the fingers. 
Fig. 1. f, the deltoid muscle; the muscle at the shoulder by 
which the arm is raised. 
