Chia ER ay 
WOUSCLES‘OP TITE SIOULDER ANDAR: 
MUSCLES OPN THE SHOULDER: 
Dissect off the skin together with the underlying skin 
muscles from the neck, shoulder and arm. Legin to 
dissect from the dorsal side, placing the animal upon 
ats right or left side. | 
I. The Trapezius Muscle arises from the occipital 
bone, and from the dorsal mid-line above the spv- 
nous processes of the cervical and anterior thoracic 
vwertebree: ° From, this “extensive .line of oriem the 
fibres converge toward the scapula and humerus. Care- 
fully cleaning the muscle from fat, fascia, etc., it will 
be found to be composed of three divisions. 
a. THE ANTERIOR TRAPEZIUS is the most anterior 
division; it arises from the occipital bone, and from 
the dorsal mid-line of the neck above the spinous pro- 
cesses of all but the last cervical vertebrae. The mus- 
cular fibres converge toward the humerus, where they 
fuse with a long muscle, the levator humeri, and are 
inserted with it into the lower part of the shaft of the 
humerus. 
b. THE Mipp.Le TRAPEzIvs arises from the dorsal 
mid-line above the spinous processes of the posterior cer- 
vical and anterior thoracic vertebre in a continuous line 
with the insertion of the anterior trapezius. Its fibres 
