she, 



THE NECK. 



1389 



sheath is a loose cellular interval which is crossed by branches of the thyreoid 

 arteries and veins on their way to and from the gland. The arteries traverse the 

 space directly, while many of the veins (accessory thyreoid veins of Kocher) ramify 

 for some distance on the surface of the capsule before they pierce the sheath. 



In excising one of the lobes, the surgeon reaches the gland through the 

 median plane in the interval between the infra-hyoid muscles. If, in order to obtain 

 more room, it is found necessary to divide the depressor muscles on one or both 

 sides, this should be done towards their upper attachments, as their nerves of supply, 

 derived from the ansa hypoglossi, enter the muscles nearer their lower attachments. 

 By freely dividing the middle layer of cervical fascia where it forms the anterior 

 portion of the sheath of the thyreoid, the gland can be brought out of the wound 

 and so mobilised that the main vessels may be brought into view and ligatured. 



The superior thyreoid vessels, on each side, are brought into view by freeing 

 and drawing forwards the superior pole of the corresponding lobe. As the inferior 

 thyreoid artery, on each side, arches medially behind the carotid artery it lies in 

 the cellular interval between the carotid sheath and the pretracheal fascia. 

 Immediately after piercing the posterior part of the sheath of the gland the 

 vessel divides into two or more branches which pierce the capsule to enter the gland 



Trachea 



Lobe of thyreoid gland 

 Superior thyreoid veins 



ior deep cervical lymph glands 



Sterno-hyoid muscle 



Sterno-thyreoid muscle 



Recurrent nerve 



5 for lie 



j for ligature of artery - 



(Esophagus 



.Inferior thyreoid artery 

 Sterno-mastoid muscle 







Carotid sheath - 



Vagus nerve 

 or deep cerv 

 lymph glands 



, Phrenic nerve 



'Scalenus anterior 

 Omo-hyoid 



IG. 1088. A DIAGRAM OF THE RELATIONS OF THE CERVICAL FASCIA TO THE THYREOID GLAND. 



lue = deep cervical fascia (sterno-mastoid layer). Red = outer capsule of thyreoid gland (pretracheal 

 layer of cervical fascia). Yellow = capsule proper of the thyreoid gland. 



substance. The recurrent nerve, which also lies between the posterior part of 

 the sheath and the postero-medial aspect of the corresponding lobe, ascends, either 

 posterior to the inferior thyreoid artery or between its main divisions. 



The parathyreoids can generally be distinguished from the thyreoid tissue itself, 

 and from the lymph glands, by their grayish -yellow colour as well as by their 

 smooth and shining surfaces. The superior parathyreoid is found on each side 

 usually, one at the posterior border of the corresponding lobes, about opposite the 

 cricoid cartilage. It is in close relation to the pharyngo-oesophageal junction, 

 from which it is separated by the posterior part of the sheath of the thyreoid 

 gland. The inferior parathyreoid gland, on each side, is supplied by a small 

 vessel from one of the branches of the inferior thyreoid artery ; it occupies the 

 same cellular interval at the posterior aspect of the inferior pole of the gland, a 

 little lateral to the inferior thyreoid artery and the recurrent nerve. It is this 

 close relationship of the recurrent nerves and the inferior parathyreoid glands to 

 the posterior aspect of the lobes of the thyreoid gland which has induced surgeons, 

 in excising one of the lobes, to make the resection intracapsular at the posterior aspect 

 of the gland, the posterior part of the capsule along with a layer of thyreoid sub- 



; stance being left behind, attached to the trachea. In this way injury to the recurrent 

 nerve and inferior parathyreoid gland is avoided, as the branches of the inferior 



i thyreoid artery are ligatured after they have pierced the capsule. De Quervain, 

 on the other hand, prefers to ligature the main trunk of the inferior thyreoid 



