HEAD AND NECK 



to the insertions of the prevertebral muscles and posterior to 

 the superior constrictor of the pharynx. Below, it blends 

 with the fascia on the anterior aspect of the vertebral column 

 in the posterior mediastinal region. 



The Carotid Sheath. The term carotid sheath is applied 

 to the fascia which surrounds and embeds the carotid arteries, 

 the internal jugular vein, and the vagus nerve. Part of it has 

 been removed already, and the dissector will have noted that 

 it is in no sense a membrane, but merely the fibro-areolar 

 tissue which fills the interval between the transverse processes 

 of the vertebrae posteriorly, the trachea, larynx, pharynx, 

 oesophagus, and the lateral lobe of the thyreoid gland medially, 

 and the sterno-mastoid laterally ; that it is continuous with 

 the fascial planes in its immediate neighbourhood, and that 



First layer of deep fascia 

 Sterno-mastoid 



Second layer of deep fascia 

 Omo-hyoid 



Infra-hyoid muscles 

 Scalene muscle 



Omo-hyoid 

 Trapezius 



FIG. 97. Diagram of the deep cervical fascia in a transverse 

 section of the lower part of the neck. 



through it run the carotid arteries, the internal jugular vein, 

 and the vagus nerve, each in its own special compartment. 



Dissection. Remove the areolar tissue and the glands which lie under 

 cover of the sterno-mastoid ; stitch together the two parts of the divided 

 anterior belly of the omo-hyoid muscle and fix the muscle to the common 

 carotid artery and the internal jugular vein with one or two stitches ; then 

 proceed to display the structures which lie under cover of the sterno-mastoid. 

 A glance at the following list will convince the dissector that they are 

 extremely numerous. 



Structures beneath the Sterno-Mastoid 



Muscles. The upper part of the splenius capitis ; the 

 upper and posterior part of the posterior belly of the digastric; 

 the origins of the levator scapulae, the scalenus medius, the 

 longus capitis (O.T. rectus capitis anticus major), the rectus 

 capitis lateralis and the scalenus anterior ; the intermediate 



