MUSCLES. 



in front of costo-clavicular ligament. Insertion; groove in 

 middle third of under surface of clavicle. [324] 



Serratus Magnus. Origin; external aspect of eight upper 

 ribs, by fleshy slips, the first slip being double and coming 

 from the two upper ribs and intervening fascia. Insertion; 

 (from upper two ribs) ventral aspect of upper angle of scap- 

 ula; (three slips from second, third, and fourth ribs) vertebral 

 border of scapula; (four slips from fifth to eighth ribs) ven- 

 tral aspect of lower angle of scapula. [325] 



Muscles of Respiration. 



External Intercostals. There are eleven pairs, each ex- 

 tending from the tubercle of the rib nearly to the costal car- 

 tikge, where it is continuous with the anterior intercostal fascia 

 extending to the side of the sternum. Origin; sharp lower bor- 

 der of one rib. Insertion ; outer edge of upper border of rib 

 below. [422] 



Internal Intercostals. There are eleven pairs, each ex- 

 tending from the side of the sternum to the angle of the rib, 

 where it is continuous with the posterior intercostal fascia ex- 

 tending to the tubercle of the rib. Origin ; costal cartilage and 

 inner edge of subcostal groove of one rib. Insertion; upper 

 border of rib and costal cartilage below. [422] 



Levatores Costarum. Twelve slips, in series with the Ex- 

 ternal intercostals. Origin; transverse processes (of seventh 

 cervical and upper eleven thoracic vertebrae) . Insertion ; outer 

 surface of each rib below, behind its angle. [422] 



Infra-costales. Slips on the inner surface of the lower ribs, 

 near their angles, passing over several ribs. [422] 



Triangularis Sterni. Origin; back of ensiform cartilage and 

 sternum, up to the third costal cartilage. Insertion; second 

 to sixth costal cartilages. [422] 



Diaphragm. Origin; (anteriorly) back of ensiform carti- 

 lage, by two fleshy slips ; (laterally) deep surface of lower six 

 ribs, by fleshy slips interdigitating with the Trans versalis; (pos- 



[115] 



