THE MTTSOLES. 



General arrangement of the muscles of the shoulder-blade. 



The muscles attached to the scapula and suprascapula are : 



1. Muscles of the back (;;;. cucullaris and m. retrahcnx scap.}. 



2. Muscles of the neck (m. omohyoideus). 



3. Muscles of the abdomen (portio scapularis of the m. 

 externuti). 



4. True shoulder muscles (m. levator anyiili scapulae m. 

 domastoidems ; m.protrahens scapulae ; mm. transverso-scapularis major, 

 minor, and tertins s. serratua ; m. interscapularis ; m. subscapularis \ 

 and the long head of the m. triceps], 



From above the following- are visible : m. cucullaris, a portion of 

 the m. subscapularis, and the transverso-scapularis maior. 



From below (after cutting 1 through and drawing aside the two 

 halves of the sternum) may be seen : the omohyoideus, sternocleido- 

 mastoideus, levator ant/nil scapulae, protrahens scapulae, tranftrn-so- 

 scapti/aris minor and terfiiis, intergcapulari* and subscapularis. 



B. VENTRAL MUSCLES OF THE SHODLDKR (PECTORAL 

 MUSCLES) 



These arise from the sternum or shoulder-girdle and are inserted 

 either into the humerus or into the radio-ulnar. 



52. M. pectoralix (Fig. 72). 



This is placed on the ventral surface of the shoulder-girdle and 

 consists of the following parts : 



(a) Port'io sternafis anterior (Ecker), (Figs. 72, 73 p'}, 



Duges, clavi-hum^ral, n. 70 (port, clavic. du grand pectoral). 



This is the anterior portion of the m. pectoralis, it arises from the 

 sternum proper and the epicoracoids. Broad at the origin, it be- 

 comes narrower as it runs outwards into a tendon attached to the 



crista deltoidea Jmmeri. 



(ft) Portio sternalis posterior (Ecker), (Figs. 72, 73 p"}. 



Duges, sterno-humeral, n. 71 (port, sternal du grand pectoral). Klein, 

 hiimero-sternali>t. 



This muscle is placed immediately behind the porlio sfcnialis 

 anterior, it has a somewhat broad origin from the sternum and 

 xiphisternum ; the muscle runs outwards and slightly forwards to 

 be inserted into the groove beside the crisfa delto'tilea hinncn. The 

 tendon of the m. sterno-radiali* passes between these two portions 

 of the m, pectoralis. 



