THE NECK 145 



linguae. Between the same muscular layers lie the lingual 

 nerve above, and the hypoglossal nerve and its accompanying 

 (ranine) vein below. Both nerves at first run horizontally 

 forwards. 



The Lingual Artery lies on a deeper plane in this part of 

 its course. On entering the submaxillary region the vessel is 

 placed deep to the stylo-hyoid and the posterior belly of the 

 digastric, and it passes under cover of the posterior border of the 

 hyo-glossus. It then runs forwards horizontally just above 

 the hyoid bone, giving off its dorsales lingua branches, which 

 reach the tongue by passing upwards and sinking into the genio- 

 glossus muscle. A curved incision is employed to expose the 

 artery. It begins just below the chin, has its mid-point at the 

 greater cornu of the hyoid bone, and extends to near the angle 

 of the mandible. It is carried down through the deep fascia, 

 and the submaxillary gland is then retracted upwards with the 

 flap. The various muscles are identified by the direction of 

 their fibres (vide supra), and the hypoglossal nerve is exposed 

 lying on the hyo-glossus in the angular interval between the 

 two bellies of the digastric. In the cadaver the fascial slip 

 which binds the intermediate tendon of the digastric to the hyoid 

 becomes stretched if the head has been extended for any length 

 of time, and the tendon is carried upwards, covering the hypo- 

 glossal nerve. The hyo-glossus is cut through parallel to and 

 below the nerve (a quarter of an inch above the hyoid in the 

 cadaver). In life its fibres retract upwards and downwards 

 and leave the lingual artery exposed, lying on the genio- 

 glossus. 



Acute inflammatory conditions in the submaxillary region 

 usually arise in connection with the teeth. The pus from an 

 alveolar abscess may make its way through the periosteum, 

 either above or below the attachment of the deep fascia to the 

 mandible (Fig. 45). In the former case it comes to the surface 

 after perforating the platysma, but in the latter case it enters 

 the submaxillary region and gives rise to a cellulitic condition 

 under the deep fascia. Although at first strictly circumscribed, 

 if not released the pus may follow the course of the lingual 

 artery or hypoglossal nerve, and, coming into contact with the 

 carotid sheath, it may give rise to a spreading cellulitis of the 

 neck (Ludwig's angina). These abscesses should be opened 

 by Hilton's method in order to avoid injuring the important 

 structures in this neighbourhood. 



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