MUSCLES OF THE BODY. 121 
border is attached by strong fascia to the border of the clavo- 
trapezius (Fig. 68, @). The outer surface is in relation with 
the longissimus capitis (Fig. 73, g), clavotrapezius (Fig. 
68, @), cleidomastoid (Fig. 73, d), platysma, and the skin. 
The inner surface is in relation caudad with the supraspinatus 
and with a mass of fat and a lymphatic gland which occupy the 
hollow of the shoulder. Craniad it is in relation with the 
cleidomastoid (Fig. 73, @), the scalenus (Fig. 73, /), the 
longus capitis (Fig. 73, ¢), and the obliquus superior (Fig. 
71, e). 
.4ctzon.—Pulls the scapula craniad. 
M. latissimus dorsi (Fig. 68, m; Fig. 65, g; Fig. 77, ¢). 
—A large triangular sheet covering rather more than the dorso- 
cranial half of the abdomen and thorax. It arises from the 
middorsal line, from the pelvis to the fifth thoracic spine, and 
is inserted into the humerus. 
Origin from the tips of the neural spines of the vertebrz 
from the fourth or fifth thoracic to about the sixth lumbar. 
As far as the tenth or eleventh thoracic vertebra the origin is 
directly by muscle-fibres. Caudad of this is a broad triangular 
tendon which may be so closely united to the tendons of the 
underlying muscles that it cannot be separated. The muscle 
passes cranioventrad, the fibres converging to the axilla. In 
the axilla a part of the cutaneus maximus and the epitrochle- 
aris (Fig. 65, 7) take origin from the outer surface. 
Insertion.—The muscle then ends in a flat tendon, to the 
cranial surface of which the fibres of the teres major (Fig. 
77, c) are attached. Five to ten millimeters from the humerus 
the muscle-fibres of the teres give place to the tendon-fibres. 
and the conjoined tendon of the teres and latissimus which is 
thus formed (Fig. 79, @’) is inserted into a rough elongated 
area (Fig. 82, /) which lies parallel with the pectoral ridge on 
the medial surface of the shaft of the humerus (Fig. 48, g). 
The teres tendon forms the proximal part of the conjoined 
tendon. A part of the tendon of the latissimus may join the 
pectoralis minor at its distal or caudal border (Fig. 65), and 
thus it may contribute to the formation of both pillars of the 
bicipital arch (Fig. 65, 2’). 
