54 HUNTINGTON 



sternal extremity of the clavicle, ventrad to the clavicular at- 

 tachment of the sterno-cleido-mastoid. The muscle, fleshy in 

 the middle and tendinous at either end, passes laterad, above 

 the clavicle, inserting at the acromial end of the bone, between 

 the trapezius and the deltoid. 



Wenzel Gruber described the first of these instances under 

 the name of M. siipra-clavicidaris propriits, s. prcEclavicularis 

 siibciitaneiis^ in 1865, in Reichert's Archiv, p. 703. The same 

 author subsequently in 1877 observed a second instance of the 

 variation which is recorded in Virchow's Archiv, Vol. LXXII, 

 p. 496. Bardeleben has recorded an example of the muscle in 

 the " Sitzun^sberichte d. Jenaischen Gesellschaft fiir Med. und 

 Naturwiss.," March, 1877. 



Knott (Jour. Anat. and Phys., Vol. XV, p. 139) observed 

 the fourth case, which he reports as M. supraclaviailaris pro- 

 priiis, vcL Tensor fascice colli (Gruber). The muscle in this 

 instance had a medial attachment in front of the clavicular head 

 of the sterno-cleido-mastoid, about i y^" outside the sterno- 

 clavicular articulation, while the lateral extremity, at a distance 

 of about 2" from the acromial end of the bone, had a somewhat 

 broader attachment in front of the trapezius. The muscle was 

 enclosed in a sheath formed by the deep cervical fascia, a con- 

 dition also noted in Gruber's cases, whence this author defines 

 the muscle as a " Tensor of the cervical fascia." 



DuBAR (Soc. Anat. Paris, 1880) described a " muscle ansi- 

 form sus-claviculaire " which presented the same connection 

 with the clavicle at both ends and was enclosed in a sheath de- 

 rived from the cervical fascia. 



While the clavicular attachments of these five muscles agree 

 with those of the variation above described, their position ven- 

 trad of sterno-cleido-mastoid and trapezius differentiates them 

 sharply from the muscle here under consideration whose course is 

 dorsad to both. I consider this S2iperficial i^osx'ixow of the snpra- 

 clavicnlaris proprius of Gruber and of the other authors quoted, 

 as determining the definite relationship of the five variations re- 

 corded to the other members of the prceclavicular group of 

 supernumerary muscles. In spite of the similarity of attach- 



