134 THE HEAD AND NECK 



the remainder are in contact with the anterior surface of the 

 muscle. They may be infected secondarily to the upper anterior 

 and lower posterior groups, or they may be alone involved 

 following ascending infection from the mediastinal lymph 

 glands. 



Surgical Approach to the Deep Cervical Lymph 

 Glands. If, when the upper group is involved, the enlarged 

 lymph glands do not- extend into the posterior triangle, an 

 oblique incision running downwards and forwards in the skin 

 creases of the neck, towards the laryngeal prominence,, may 

 be utilised. It should not approach nearer than one finger's 

 breadth to the angle of the mandible, lest the cervical branch 

 of the facial nerve be cut, with subsequent paralysis of the 

 muscles of the lower lip (p. 108). 



If the enlarged glands extend far into the posterior triangle 

 an inverted ^-shaped incision (Stiles) gives the best access. 

 Starting near the greater cornu of the hyoid, it passes obliquely 

 upwards towards the mastoid process and is then carried down- 

 wards along the anterior border of the trapezius. The latter 

 part of the incision may be carried as far as the clavicle, if 

 necessary, and, as it passes through the investing layer of the 

 deep cervical fascia, care must be taken to avoid injuring the 

 accessory nerve (p. 125). 



In both cases the external jugular vein is liable to injury. It 

 is exposed when the margins of the oblique incision are undercut, 

 or when the curved flap, which includes the platysma, is turned 

 downwards. It is advisable to secure the vein at once, as high 

 up and as low down as possible. The intervening portion can 

 then be removed, usually together with the great auricular nerve 

 (p. 108). Excessive bleeding at this stage is suggestive of 

 glandular pressure on the internal jugular vein, with consequent 

 engorgement of the collateral channels of venous return. In the 

 subsequent stages of the operation the structures most liable 

 to injury are the internal jugular vein and the accessory nerve. 

 They are therefore identified as soon as the skin flaps, along 

 with the investing layer of the deep fascia, have been under- 

 mined and retracted. In tuberculous lymph-adenitis the caseous 

 glands are commonly adherent to the carotid sheath, and this 

 structure should be opened below the diseased area. The 

 internal jugular vein can then be dissected free without injury, 

 while the caseous glands and the adherent sheath can be re- 

 moved. In malignant disease, however, the vein and sometimes 



