THE MUSCLES. 
I. THE MUSCLES OF THE SKIN. (Fig. 62.) 
M. cutaneus maximus (Fig. 62, 4).—This is a very large, 
thin muscle which covers almost the whole side of the body. 
It arises from the outer surface of the latissimus dorsi (Fig. 68, 
m) near its ventral end and from the bicipital arch (Fig. 65, 7’) 
in the axilla; from the linea alba for a considerable distance 
(two or three inches) caudad of the base of the xiphoid process, 
and from the thorax over a line joining the axilla and the base 
of the xiphoid. Sometimes a few fibres take origin from the 
fascia which covers the pectoantibrachialis on the ventral side 
of the arm. 
From their origin the fibres diverge. The cranial ones 
curve about the base of the forelimb and are inserted into the 
skin at or near the middle line caudad of the first thoracic 
vertebra. The most cranial fibres of all are inserted about one 
to one and a half centimeters from the middorsal line; thence 
the line of insertion approaches the middorsal line to reach it 
at about the eighth or ninth thoracic vertebra. The middle 
fibres run parallel to the middorsal line in the lumbar and 
sacral regions as far as the root of the tail, a small bundle 
passing onto the dorsal side of the tail, another onto the ventral 
side. The fibres of the caudal portion pass onto the thigh, the 
ventral ones running in the fold of skin which stretches from 
thigh to abdomen, and are finally lost in the fascia along a line 
connecting the knee and the root of the tail. A strong fascia 
connects the adjacent borders of the cutaneus and platysma and 
lies over the scapular region. 
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