THE ANTERIOR PART OF THE NECK 237 



First layer of deep fascia 

 Thyreoid gland 



Pretracheal fascia 



Prevertebral 

 layer 



border of the tympanic plate and the anterior part to the 

 posterior border of the petro-tympanic fissure (O.T. Glaserian). 

 It also gains an intermediate attachment to the styloid 

 process and to the posterior border of the angle of the 

 mandible. This particular portion is relatively thick ; it lies 

 in relation with the lower part of the antero-medial surface of 

 the parotid and is known as the stylo-mandibular ligament. 



When the superficial layer is traced downwards it is found 

 to split, between the cricoid cartilage and the sternum, into two 

 lamellae. The more superficial of the two lies superficial to 

 the sterno-mastoid and is at- 

 tached below to the upper 

 border of the sternum and the 

 upper border of the clavicle. 

 In the anterior region the 

 deeper lamella descends upon 

 the anterior surfaces of the 

 infra-hyoid muscles and is at- 

 tached below to the posterior 

 surface of the manubrium ; 

 laterally it passes deep to the 

 sterno-mastoid and is fused 

 with the lateral border of the 

 carotid sheath. In the posterior 

 triangle the deeper lamella 

 ensheaths the posterior belly 

 of the omo-hyoid and binds it 

 down to the posterior border 



Of the Clavicle. The Space FlG - 96. Diagram of deep cervical 



between the two lamellae has 



been called the supra-sternal 



space. Its boundaries and contents have been fully described 



already (p. 224). 



The upper attachment of the pretracheal layer is to the 

 cricoid cartilage and to the laminae of the thyreoid cartilage 

 below the insertion of the sterno-thyreoid muscle. At its 

 lower end it blends with the fibrous pericardium in the 

 middle mediastinum. 



The prevertebral layer can be followed upwards to the 

 base of the skull, where it is attached, in the anterior cervical 

 region, to the posterior and medial margins of the jugular 

 foramen and to the basilar part of the occipital bone, anterior 



fascia in transverse section at the 

 level of the thyreoid gland. 



