THE MUSCLES AND FASCIA OF THE TRUNK 137 



unless seen, either in a diagram, or the human body. 

 Other muscles arising from the cervical vertebrae pass 

 to the ribs and aid in forced inspiration and expiration ; 

 still others posteriorly pass to the scapulae and thoracic 

 vertebras and assist in shrugging the shoulders, flexing 

 and extending spinal column, rotating the vertebras, etc. 



THE MUSCLES AND FASCLE OF THE TRUNK 



In speaking of the trunk we include that part of the 

 human body consisting of the back, thorax, abdomen, 

 and perineal region. 



The Muscles of the Neck and Back 



The muscles of these regions are in layers, their 

 actions and relations are too complex to include here 

 except the ones described below. It is sufficient to 

 state that they consist of five layers, in which are 

 thirty-two or more pairs of muscles. These muscles 

 are covered by a superficial fascia which is continuous 

 with the fascia over the rest of the body; and a deep 

 fascia, which is thick and fibrous, and curves over and 

 forms sheaths for the muscles, being attached to the 

 following bony prominences: occipital bone, crest of 

 ilium, spines of vertebras, and the spines of the scap- 

 ulas. In the neck it forms the posterior portion of the 

 deep cervical fascia, in the thorax blends with the 

 axillary fascia and deep fascia of the thorax; it is 

 continuous with the abdominal fascia, also forms the 

 back layer of the lumbar fascia, and covers the erector 

 spines mass of muscles. 



The Trapezius. This is the muscle situated at the 

 back of the neck and shoulders. There are two. Origin, 

 inner third of the superior curved line of the occipital 

 bone, ligamentum nuchae, spinous processes of the 

 seventh cervical and all the thoracic vertebras and 



