MYOLOGY 73 



Shape. Triangular, fan-shape. 



Relations. Superiorly with the skin. 



Action. Controls the skin in this region. The anterior end being 

 fixed, the muscles are raised; and the posterior end acting as the 

 fixed point, the feathers are caused to lie close to the body. 



Dermo-pectoralis. Location. On each side of the chest, lying 

 in a longitudinal manner. 



Origin and Insertion. Attached to the skin on either side of the 

 thorax corresponding to the dermo-dorsalis. Anteriorly it disap- 

 pears over the region of the origin of the cleido-trachealis, and pos- 

 teriorly just behind the tips of the postpubic parts of the pelvis. 



Shape. Thin, delicate. 



Relations. Superiorly with the skin. 



Action. The anterior part acting as the fixed point, the feathers 

 of the chest are raised; and the posterior end acting as the fixed 

 point, the feathers are made to lie flat. 



THE DERMO-OSSEOUS MUSCLES 



Dermo-temporalis Platysma myoides 



Dermo-cleido dorsalis Cleido-trachealis 



Dermo-spinalis Dermo-iliacus 



Dermo-ulnaris 



Dermo-temporalis (Fig. 18, No. i). Location. From the tempo- 

 ral region down the side of the neck to the anterior part of the 

 thoracic region. 



Origin. By a broad tendinous attachment from a small depres- 

 sion above and anterior to the temporal fossa. From here the 

 fibers pass upward and backward and then downward. 



Insertion. A few fibers blend with those of the cleido-trachealis. 

 The fibers are then lost upon the skin in front and opposite the 

 shoulder-joint. Some of the fibers blend with those of the dermo- 

 tensor patagii. 



Shape. Long, flat, and ribbon-shaped. The lower portion con- 

 sists of delicate fibers. 



Relations.' Superior to the temporal muscle and sphenotic 

 process. Superior to the cleido-trachealis and inferiorly to the 

 shoulder-joint. The superior portion touches the skin throughout 

 its entire length. 



