PROFESSOR WOOD ON THE NECK- AND SHOULDER-MUSCLES. 
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out below so as to cover the clavicular fibres of the sterno-cleido-mastoid and to join, 
finally, its sternal origin. This also may have been the double-headed variety of the 
cleido-occipital just described (Encyclop. Anatom, pp. 163, 164, 165). 
Macwhinnie mentions the clavicular origin of the sterno-cleido-mastoid as occasionally 
forming two distinct muscles, and sometimes blending with the fibres of the trapezius 
(op. cit. p. 186). 
Hallett found, in three subjects, a muscle arising from the clavicle, separate from 
the sterno-cleido-mastoid and the trapezius respectively. He also found a muscular slip 
joining the trapezius at the occiput, and the sterno-cleido-mastoid at the clavicle, and 
also more frequently (1 in 16 cases) meeting the clavicular insertion of the trapezius 
(Edinburgh Medical and Surgical Journal, 1846, p. 6). R. Wagner discovered a similar 
slip, joining the trapezius at the clavicular insertion, on both sides of a female subject 
(Heusinger’s Zeitschrift, Bd. iii. S. 337). Gruber found a slip of muscle arising from the 
clavicle, completely separate from the sterno-cleido-mastoid and trapezius , in 2 subjects 
out of 40, and with a separation less complete in 1 out of every 3 subjects. In 7 out 
of 70 subjects this observer found the same muscle joined above more or less with the 
trapezius (Vier Abhandlungen, S. 16, 17, 18). IIenle mentions it as an occasional 
abnormality of the sterno-cleido-mastoid (Muskellehre, S. 110), and Quain as a variety 
of the trapezius (Arteries, pi. 25). Flower and Murie found a good specimen of the 
formation on both sides in the Bushwoman. It was best marked on the left side, and 
consisted of a long narrowish band of fibres attached above to the occiput half an inch 
from the trapezius. It crossed the posterior triangle, and was inserted into the clavicle an 
inch from its outer end (Journal of Anatomy and Physiology, May 1867, pp. 197, 198). 
In connexion with this muscle we must place also, I believe, the occasional remark- 
able formation of the clavicular fibres of the trapezius described as an occasional human 
variety by Quain, Macwhinnie, ITallett, and Gruber (op. cit.), and in my own paper in 
the Royal Society’s ‘ Proceedings’ for 1867 (No. 93, p. 522). In these cases, which have 
a considerable resemblance to each other, the anterior border and clavicular insertion 
of the trapezius appears to be prolonged over the posterior triangle, so as more or less 
completely to cover it, and to become connected with the origin of the cleido-mastoid. 
Opposite the middle of the clavicle a tendinous arch, thrown over the middle and 
j sternal divisions of the descending cervical nerves and over the external jugular vein, 
i affords attachment to the median portion of the muscular fibres in place of the clavicle 
itself. In the instances I have myself met with, an areolar interval more or less marked 
has usually existed between this irregular extension of the insertion and the normal 
fibres of the trapezius. The superficial insertion into the aponeurotic arch, formed in 
the deep fascia of the part, is connected below to the fascia of the arm, and indicates an 
homology with the brachial prolongation of the levator humeri of the lower animals. 
The intimate connexion of this abnormal part with the trapezius indicates its relation 
to those formations in which the so-called “ trapezius clavicularis ” of the Carnivora and 
Rodents is entirely absorbed in the formation of the great “ cephalo-liumeraV ’ muscle. 
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