1362 



CLINICAL AND TOPOGRAPHICAL ANATOMY 



lie some fat, a small gland, a communicating branch between the anterior jugulais and a small 

 portion of the veins, and the sternal heads of the sterno-mastoids. The sheath to the depressors 

 of the hyoid bone is partly derived from this layer, partly from the next. Laterally, this layer 

 gives a sheath to the posterior belly of the omo-hyoid, is attached to the clavicle, and passing on, 

 is continuous with the sheath to the subclavius and coraco-clavicular fascia. 



(ii) Pretracheal or middle. This lies under the depressors of the hyoid, over 

 the trachea, also encasing the thyreoid gland. Farther laterally it helps, to- 

 gether with the prevertebral, to form the carotid sheath. Traced downward, 

 the pretracheal layer passes over the trachea into the thorax (middle mediastinum) 



As it descends, it encases the left innominate vein, and ends by blending with the fibrous 

 layer of the pericardium. Hilton suggested that the attachment of this fascia above, and that 

 of the central tendon of the diaphragm below, to the pericardium served to keep this sac duly 

 stretched, and so prevented any pressure of the lungs upon the heart. 



Fig. 



1103. — Section of Neck through the Sixth Cervical Vertebra. (Braune.) 



Larynx 



Pharynx 

 Longus colli 

 Inferior laryngeal 



Pervertebral layer of deep cervical fascia 



Pretracheal layer of deep cervical fascia 



Sup. thyreoid art. 

 Desc hypoglossi 

 Sterno-mastoid 



Vagus 

 Sympathetic 

 Phrenic 

 Scalenus 

 anterior 

 Brachial plexus 

 Scalenus 

 medius 

 External 

 jugular 

 Part of articu- 

 lar process 

 Spinal 

 accessory 



Thyreo-arytsenoid 



Cricoarytaenoideus lateralis 

 Cricoid 



Sterno-hyoid, just posterior 

 are seen the thyreo- and 

 omo-hyoid muscles 



Thyreoid cartilage 



Muscular process of 



arytaenoid 

 Cervical fascia 



Thyreoid 



gland 

 Common 

 carotid 

 Carotid sheath 

 y-, \ Internal 



jugular 

 •>I?^i\ ' \ Brachial 

 plexus 

 Scalenus medius 

 External jugular 

 Iliocostalis 



cervicis 

 Scalenus posterior 

 Spinal accessory 



Levator 

 scapulae 



Deep cervical vessels 



Superficial layer of deep cervical fascia on 

 Splenius ' the deep aspect of the trapezius which 



Semispinalis colli and multifidus I SemispinaUs capitis it here encloses 



Sixth cervical vertebra 



(iii) Prevertebral. This layer passes over the longus colli and capitis upward 

 to the base of llic skull, and downward over the longus colli behind the oesophagus 

 into the posterior mediastinum. Laterally it helps to form the carotid sheath, 

 and, lower down, gives a slieath to the subclavian artery and so to the axil- 

 lary, (iv) The carotid sheath. This is formed by septa from i, ii, and iii, meeting 

 under the sterno-mastoid (fig. 1108). 



The following uses and important points witli regard to the anatomy of th(Mic('i) cervical fascia 

 should be noted: — (A) It forms certain definitely enclosed spaces in which i)us or growths 

 inay form, and l)y tlu; walls of which these morbid structures may be tied down and thus rendered 

 difficult of diagnosi.s, while tlxsir iueroasiiig pressure may embarrass the air-passages, etc. 

 Thus: (\) In the first si)aee, which lies between No. 1 an(i the skin, the structures met with, 

 the platysma and superficial l)raiieh('s of the cervical i)iexus, are unimportant. Any abscess 

 here is [jroiio to extend, l)ut superficijilly. (2) In t h(^ second si)ace, between t lie superficial and 

 midfllo layers, lies a narrow .sj)ac(! containing loose cellular tissue ;uid lympliatic glands. Sup- 

 puration here is very common, but usually comes forward. Ci) 'i'liis is tli(> largest and most 

 important of all. From its contents it has been called the visceral compartment. (Stiles.) 



