[Annals N. Y. Acad. Sci., Vol. XIV, No. 2, pp. 53-66, June 5, 1901.] 



THE MORPHOLOGICAL SIGNIFICANCE OF 

 CERTAIN PERICLAVICULAR SUPER- 

 NUMERARY MUSCLES 



With a Report of a New M. Supraclavicularis Pro- 



PRius Posterior 



Geo. S. Huntington 



• . [Plates IV~V.] 



(Read February 12, 1900) 



Among the muscular variations of the human pectoral girdle 

 the group of periclavicular supernumerary muscles possesses a 

 peculiar morphological interest, by reason of the complex myo- 

 logical character of the region involved and the importance of 

 correctly interpreting the significance of the variant conditions. 



The abnormal muscle, of which this paper treats, is now 

 described and figured for the first time as the M. sitpra- 

 clavicularis propritis posterior. It was found as a nearly sym- 

 metrical bilateral muscular slip in a male subject, of German 

 birth, 43 years of age, arising by a slender tendon from the 

 upper surface of the sternal extremity of the clavicle, under cover 

 of the sterno-cleido-mastoid and extending laterad across the 

 supraclavicular fossa to be inserted behind the clavicular attach- 

 ment of the trapezius into the superior surface of the acromial 

 end of the clavicle by a narrow tendon which on the left side 

 can be followed nearly to the extremity of the bone. 



SUPERNUMERARY CLAVICULAR MUSCLES 



The nearest approach to the conditions presented by this 

 variant muscle — as regards the attachment by both extremities 

 to the clavicle — is afforded by a group of supernumerary cla- 

 vicular muscles, of which five instances have been recorded, 

 possessing the following common characters : Origin from the 



(53) 



