168 THE MUSCLES. 
Origin (Fig. 81, 2').—By a flat tendon trom the proximal 
portion of the deltoid ridge and the distal border of the teres 
minor tubercle. 
Insertion (Fig. 86, c) by a thin, flat tendon into the lateral 
border of the dorsal surface of the ulna between a point oppo- 
site the distal margin of the semilunar notch and the proximal 
end of the olecranon. 
Relations.—Lateral surface with the integument, and at the 
proximal end with the spinodeltoid and acromiodeltoid (Fig. 
75,eand f). Medial surface with the brachialis (Fig. 75, 2), 
the caput longum (g), the caput mediale, the brachioradialis (2), 
the anconeus (Fig. 80, /), and the origins of the extensor carpi 
radialis longus (Fig. 75, 7), the extensor communis digitorum 
(m), and the extensor digitorum lateralis (v). 
Caput longum (anconeus longus) (Fig. 75, ¢; Fig. 68, 2; 
Fig. 77, 2).—A prismatic, fusiform mass connecting the scapula 
with the olecranon. 
Origin (Fig. 78, 27) by a thick, flat tendon from a triangular’ 
area one or two centimeters long at the glenoid end of the 
scapula on the glenoid border. The base of the area is about 
one millimeter from the margin of the glenoid fossa. 
Insertion (Fig. 86, 6).—The muscle ends in a thick tendon 
which passes over the bifurcated ventral end of the olecranon 
and is inserted upon the rounded tuberosity which forms the 
dorsal angle of the olecranon. 
Relations.—Lateral surface with the caput laterale (Fig. 
75, #), a portion of the caput mediale (Fig. 77, 7 and &), the 
spinodeltoid (Fig. 75, ¢), the infraspinatus (Fig. 75, ¢), and 
the integument. Medial surface with the epitrochlearis (Fig. 
65, ~) and the conjoined portions of the latissimus dorsi and 
teres major (Fig. 79, @'). Ventral border with the caput 
mediale (Fig. 77, 7 and &£). 
Caput mediale.—The medial head consists of three portions 
(Fig. 79, £) 4,7). 
(1) The long portion (anconeus posterior) (Fig. 77, 7; Fig. 
79, g; Fig. 80, /). 
Origin (Fig. 83, e) from a triangular area on the dorsal sur- 
face of the humeral shaft. The base of the area is against the 
