124 SURGICAL APPLIED ANATOMY. [Chap. ix. 



cervical plexus, and the sterno-mastoid muscle, 

 although it is supplied mainly by the spinal accessory 

 nerve, receives a nerve from that plexus (viz., from 

 the second cervical). The course of the reflex dis- 

 turbance in such cases is therefore not difficult to 

 follow. A like contraction has also been produced 

 by direct irritation of the second cervical nerve in 

 cases of disease of the first two cervical vertebrae. 

 For the relief of some forms of wry-neck, the sterno- 

 mastoid muscle is divided subcutaneously, as in an 

 ordinary tenotomy operation, about half-an-inch above 

 its attachment to the sternum and clavicle. Two 

 structures stand considerable risk of being wounded 

 in this operation, viz., the external jugular vein lying 

 near the posterior border of the muscle, and the ante- 

 rior jugular which follows its anterior border, and 

 passes behind the muscle, just above the clavicle, to 

 terminate in the first-named vein. With common 

 care, there should be no risk of wounding the great 

 vessels at the root of the neck. 



There is a curious congenital tumour, or indura- 

 tion, sometimes met with in this muscle in the newly 

 born. It is usually ascribed to syphilis, but, in most 

 cases, is probably due to some tearing of the muscle 

 fibres during the process of delivery. 



The cervical fascia. The layers of fascia that 

 occupy the neck, and that are known collectively as 

 the deep cervical fascia, are dense structures, having a 

 somewhat complex arrangement and a great amount 

 of importance from a surgical point of view. This 

 fascia limits the growth of cervical tumours and 

 abscesses, and modifies the direction of their progress, 

 but I do not think that its effect in this matter is 

 quite so definite as is usually maintained. It is true 

 that deep-seated cervical abscesses are often found to 

 follow just such a course as the arrangement of the 

 fascise would lead us to suppose, while, on the other 



