ANATOMY OF A MONODACTYLOUS FOETUS 395 



DISSECTION OF LEFT ARM 

 MUSCLES 



In describing the muscular system in this hmb frequent refer- 

 ence to variations and to comparative anatomy are made, 

 where it would be tiresome to keep repeating the authority for 

 such statements. In such cases it is to be considered that Le 

 Double's book ''Variations du Systeme Musculaire de I'Homme" 

 has been followed. 



Where no comments are offered regarding the variations of 

 origin or insertion, or additional attachments of any muscle 

 noted here, it is to be inferred that such departures from normal 

 have been frequently noted before by others, and are not of 

 great significance. 



As is to be expected, there is little change and abnormality 

 in the muscles belonging to the upper part of the limb, but great 

 structural differences become increasingly evident as one proceeds 

 distally. 



MUSCLES FROM AXTAL SKELETON TO SHOULDER GIRDLE AND 



HUMERUS 



All the following muscles are present and exhibit normal 

 origins and insertions (figs. 7 to 10). 



Sternocleidomastoid. 

 Subclavius. 



Trapezius. Muscle fibers end at level of ninth thoracic vertebra, below this 

 point there is only a thin aponeurosis. 

 Rhomboidei, minor et major. 

 Levator scapulae. 

 Serratus anterior. 



Latissimus dorsi — with an accessory head from the lower angle o' the scapula. 

 The two pectoral muscles exhibit some variations from the normal. 



Pectoralis major (figs. 7 and 8, P. Ma) 



Origin. Normal. , 



Insertion. Into the outer lip of the bicipital sulcus by a heavy 

 sheet of tendon. From the deep surface of this tendon two ab- 



