6o 



HEAD AND NECK 



surfaces of the lower four ribs. The superior serratus elevates 

 the ribs to which it is attached, and is therefore a muscle of 

 inspiration. It is supplied by the anterior rami of the second, 

 third, and fourth thoracic nerves. The inferior serratus helps 

 to fix the lower ribs and so facilitates the action of the 

 diaphragm. Therefore, indirectly, it also is a muscle of 

 inspiration. It is supplied by the anterior rami of the lower 

 thoracic nerves. 



Fascia Lumbo-dorsalis. After the posterior serrate muscles 

 have been displayed and examined on the third day after the 



M. serratus 

 post. inf. 



M. sacro- 

 spinalis 



M. quadrati 

 lumborum 



"' M.psoasma 



FIG. 1 8. Diagram to show the Connections of the Lumbo-dorsal Fascia. 



body is placed upon its face, the dissector of the head and 

 neck should associate himself with the dissector of the 

 abdomen in the examination of the lumbo-dorsal fascia. It 

 is an aponeurotic layer, thin in the thoracic portion of its 

 extent, but thick and strong in the lumbar and sacral regions. 

 In all three regions it binds down the deeper muscles of the 

 back to the sides of the spinous processes and to the trans- 

 verse processes of the vertebrae. 



The Thoracic Part of the Lumbo-dorsal Fascia (O.T. 

 Vertebral Aponeurosis] is a thin transparent lamina which 

 extends from the tips of the spines and the supraspinous 

 ligaments to the angles of the ribs. At the upper end of 



