146 THE MUSCLES. 
(v). Inner surface with the deep portion (/), the fibres of 
which it crosses obliquely. 
The deep portion (/) is a flat band of parallel fibres about 
three times as broad as the superficial portion. 
Origin.—The ventral surface of the manubrium and of the 
first three divisions of the sternum, and the median raphe for 
about one centimeter craniad of the manubrium. It passes 
directly laterad. 
Insertion (Fig. 81, ¢) along a line which begins at the 
infraspinatus fossa of the great tuberosity, and runs parallel to 
the deltoid ridge until it reaches the pectoral ridge at the junc- 
tion of the second and third fourths of the humerus and then 
continues in the direction of the pectoral ridge as far as the 
junction of the third and fourth fourths of the humerus. Some 
of its fibres may pass caudad of the biceps and be inserted with 
the epitrochlearis. Into the part of the line which is parallel 
to the deltoid ridge the muscle is inserted by a flat tendon; 
into the remainder of the line it is usually inserted directly by 
muscle-fibres, though at its caudal end its insertion may again 
be tendinous. 
Relations.—Outer surface with the cutaneus maximus, the 
outer layer of the pectoralis major (Fig. 65, 7’), the pectoanti- 
brachialis (7), and the clavobrachial (#). Inner surface with 
the pectoralis minor (0), the proximal end of the humerus, the 
coracobrachialis (Fig. 77, /), and the supraspinatus (Fig. 
77, @) at the insertion of the latter. At the cranial part of its 
origin it touches the sternomastoid (Fig. 65, ¢) and sternohyoid 
(Fig. 65, ¢). 
Action.—Draws the arm mediad and turns the foot forward. 
M. pectoralis minor, or entopectoralis (Fig. 65, 0).—This 
is a fan-shaped mass of fibres, flat but thicker than the pec- 
toralis major. , 
Origin from the lateral half of the first six divisions of the 
body of the sternum and sometimes from the xiphoid process. 
The fibres are divisible into several bundles which vary in 
extent and distinctness and are sometimes described as separate 
muscles. They pass craniolaterad and converge so that the line 
of insertion is about one-half as long as that of the origin. 
