MUSCLES 27 



of the sternum and to the interclavicular ligament, whilst 

 the posterior one is connected to the posterior edge of the 

 upper part of the same bone. A small interval (Burn's space) 

 is thus left, triangular in vertical section with the base at 

 upper border of the sternum, which contains some loose 

 areolar tissue, some fat, and often a lymphatic gland, with 

 the anterior jugular veins. 



Superiorly this anterior layer passes over the parotid and 

 masseter, forming the parotid, and masseteric fascia, and is 

 attached above and behind to the lower border of the 

 zygoma, and below and in front to the lower edge of the 

 body of the lower jaw. 



From the posterior surface of the fascia covering the 

 anterior triangle a septum passes inwards, separating the 

 submaxillary and parotid glands, and forms the stylo- 

 maxillary ligament. 



Processes given off from the deep cervical fascia. 



From the layer passing behind the sterno-mastoid there 

 proceed : 



1. A layer which passes behind carotid vessels. 



2. A layer which passes in front of carotid vessels. 

 These two layers blend together at the inner border of the 



carotid artery, forming the carotid sheath to enclose carotid 

 artery, internal jugular, and pneumogastric nerve. The 

 united layers pass upwards and inwards in front of the 

 longns colli and behind the pharynx and O3sophagus, to blend 

 with like process from opposite side and form the prevertebral 

 fascia. 



This layer separates the prevertebral muscles from the 

 pharyngeal fascia on the pharynx and oasophagus (retro- 

 pharyngeal space continuous with the posterior mediastinum) 

 and is prolonged laterally over the scaleni, brachial plexus, and 

 subclavian vessels to help form the axillary sheath. 



The cervical fascia is attached in the middle line to the 

 symphysis menti, the hyoid bone, and the anterior edge of 

 the upper border of the sternum. 



3. A layer in front of thyroid body and trachea, but behind 

 the sterno-hyoid and thyroid muscles, which joins with a 

 corresponding process of the opposite side, and passing down 

 to the root of the neck in front of the trachea and large vessels, 

 blends with the fibrous layer of the pericardium. 



4. A process to enclose the omo-hyoid tendon, which binds 

 it down to the clavicle and first rib, blending with the costo- 

 coracoid membrane. 



