4 Muscles of Head and Neck 



sterno-thyroid, and omo-hyoid muscles ; the posterior belly of the 

 digastric ; scaleni, levator anguli scapulas, and splenius ; the common, 

 and perhaps the beginning of external and internal carotid arteries ; 

 the internal and anterior jugular veins ; vagus ; descendens and com- 

 municantes noni ; spinal accessory ; cervical nerves ; occipital artery, 

 lymphatic glands, and the deep part of the parotid. Beneath the 

 muscle also, in contact with the scalenus anticus, are the subclavian 

 vessels and the phrenic nerve. 



Though contraction of the cicatrix left after congenital rupture of 

 the muscle is the commonest cause of wry-neck, the deformity may 

 also be determined by ulceration of the cervical vertebrae, in which 

 case complaint will be made of peripheral neuralgias. 



Tenotomy of the sterno-mastoid. When the contraction of the 

 muscle is such that the head cannot be brought straight, both slips 

 of origin of the sterno-mastoid must be divided subcutaneously. 



Operation. The muscle having been put upon the stretch, a strong 

 and slender blade is passed close beneath each band in turn, the 

 section being made towards the skin. But the procedure is not devoid 

 of risk, as the anterior jugular (p. 36) or some other large tributary of 

 the subclavian or external jugular vein may be in the way of the knife. 

 Should this happen, the wound in the vessel is held wide open, on 

 account of the head being tightly dragged up, and thus air may pass 

 by the subclavian vein into the heart, where, being churned up with 

 the blood, it may cause a fatal arrest of the circulation. 



As the anterior jugular and the subclavian are close behind the 

 clavicle, the risk of wounding an important vessel is diminished if 

 the tenotomy is done half an inch above that bone. The external 

 jugular descends close by the posterior border of the clavicular head 

 of the muscle. 



Section of the clavicular part of the muscle may be conveniently 

 and safely effected by a free and open wound above and parallel with 

 the clavicle. In a case in which I recently operated by this method 

 I found the internal jugular vein so close beneath the contracted band 

 that, had I performed subcutaneous tenotomy, I could hardly have 

 failed to wound it. Subcutaneous surgery has no doubt played a use- 

 ful part, but at the present day it is an anachronism in many cases of 

 wry-neck and in most cases of club-foot. 



When spasmodic contraction is deemed to be due to irritation of 

 the spinal accessory nerve, excision of half an inch of nerve as it is 

 entering the muscle may be resorted to with some hope of success 



(P- 7i). 



The levator anguli scapulae arises from the posterior tubercles 

 of the four upper cervical vertebrse, and is inserted into the upper 

 part of the vertebral border of the scapula. It is supplied by the 

 anterior divisions of the middle cervical nerves. 



