THE ANTERIOR PART OF THE NECK 137 



Capsule of thyreoid gland 

 First layer of deep fascia 

 Thyreoid gland 



Sheath of thyreoid 

 gland formed by 

 pretracheal fascia 



mediate attachment to the styloid process and to the posterior 

 border of the angle of the mandible. That 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 and the cartilage FIG. 47. Diagram of deep Cervical 



Of the first rib. The Space fascia in transverse section at 



. .. , the level of the thyreoid gland. 



between the two lamellae has 



been called the supra-sternal space. Its boundaries and con- 

 tents have been fully described already (p. 122). 



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 

 to the insertions of the prevertebral muscles and posterior to 

 the superior constrictor of the pharynx. Below, it blends 



