THE ANTERIOR PART OF THE NECK 123 



below, to the posterior surface of the manubrium sterni and to 

 the posterior border of the clavicle, to which it binds the posterior 

 belly of the omo-hyoid (p. 34). Above, it fuses with the more 

 superficial layer, along an oblique line which ascends from the 

 level of the coracoid process to the level of the upper end of the 

 trachea.* Above that level it forms, with the superficial layer, 

 a common lamella, which ascends on the infra-hyoid muscles 

 to gain attachment to the body and greater cornu of the hyoid 

 bone. The space between the two layers contains, in the region 

 of the anterior triangle, the lower parts of the anterior jugular 

 veins, the anastomosis between them, and the areolar tissue in 

 which they are embedded. In the posterior triangle its contents 

 are the lower end of the external jugular vein, the terminations 

 of the transverse cervical and transverse scapular veins, the 

 transverse scapular artery, and areolar tissue. Note that the 

 anterior jugular vein, on each side, arises in the superficial fascia 

 of the submental region and descends superficial to the deep 

 fascia in the upper part of the neck ; then it pierces the first 

 layer of deep fascia and lies between the two layers, where it 

 anastomoses with its fellow of the opposite side ; finally, it turns 

 laterally, deep to the sterno-mastoid, and terminates in the 

 external jugular vein at the anterior boundary of the subclavian 

 part of the posterior triangle. 



Make two incisions through the deep fascia of the upper part of 

 the anterior triangle, one along the lower border of the mandible, 

 from the angle to a point 12.5 mm. (half an inch) from the 

 chin, and a second at right angles to the first, from its middle to 

 the greater cornu of the hyoid bone. Whilst making the hori- 

 zontal incision avoid injuring the external maxillary artery 

 (O.T. facial) and the anterior facial vein, which pierce the deep 

 fascia at the level of the anterior border of the masseter. Reflect 

 the two triangular flaps of fascia marked out by the incisions, 

 and expose the lower surface of the submaxillary salivary gland, 

 the submaxillary lymph glands, the anterior and posterior bellies 

 of the digastric muscle, the lower part of the stylo-hyoid muscle, 

 and a further part of the anterior facial vein. 



The majority of the submaxillary lymph glands lie along 

 the lower border of the mandible, on the superficial surface of 

 the submaxillary gland. The anterior facial vein crosses the 

 posterior part of the submaxillary gland superficially. The 

 external maxillary artery dips deeply between the lower border 

 of the mandible and the submaxillary gland. The posterior and 

 lower part of the submaxillary gland usually overlaps the stylo- 

 hyoid and the posterior belly of the digastric muscles, and not 

 infrequently it overlaps the greater cornu of the hyoid bone also. 

 Its anterior border may overlap the anterior belly of the digastric. 

 Raise the lower border of the gland and expose another layer 

 of deep fascia covering the muscles which lie deep to the gland. 

 Place the handle of the knife on that fascia and push it gently 

 upwards. Note that it passes upwards to the level of the mylo- 

 hyoid line on the medial surface of the mandible, to which the 

 mylo-hyoid muscle is attached. The fascial sheath in which 

 the submaxillary gland is enclosed consists, therefore, of a 

 superficial layer of deep fascia which extends from the greater 

 cornu of the hyoid bone to the lower border of the mandible, 

 and a deeper layer which passes from the greater cornu of the 



