Fig. 69. Larynx from behind - Goitre. 



From the body of an old woman, the enlarged Thyreoid Gland (Goitre) was 

 removed with the Larynx and the Trachea, and hardened in Formalin ; only a 

 small portion of the Oesophagus remains; the posterior wall of the Larynx is 

 dissected. The Parathyreoids are or an ge, the lymphatic glands, red. The larger 

 left lobe of the Thyreoid Gland caiised the Trachea to rotate around its axis. 

 The Recurrent Laryngeal Nerve has been drazvn aside, on both sides, in order 



to more clearly show its branches. 



The topographical position of the Thyreoid Gland is shewn in Fig. 6. 

 Fig. 60 indicates those structures which must be divided in exposure of the gland. 

 The topographical relations at the point where the Superior Thyreoid Artery 

 enters the gland, are most important (cf. Fig. 66). The difficulty in removal of 

 the Thyreoid Gland is to avoid the Recurrent Lar3mgeal Nerve, injury to which 

 causes paralysis of the Vocal Cords. This nerve ascends in the groove between 

 the Trachea and Oesophagus, supplies these structures and enters into the formation 

 of the Oesophageal Plexus (Plexus Gulae). It then follows the Inferior Thyreoid 

 Artery, in some cases running upwards in front of the Artery, or — more often — , 

 it passes between its branches at the point of bifurcation ; it onl}' lies in a 

 few cases behind this vessel, always closely applied to the Thyreoid Gland. For 

 the removal of the gland, the nerve must be freed, and great care taken, to 

 avoid inclusion with the Ugature for the Artery. It then passes under the Inferior 

 Constrictor Muscle and ends at the Crico-Thyreoid articulation by dividing into 

 its terminal branches; one of these joins the descending branch of the Superior 

 Laryngeal Nerve, thus forming the loop of Galen — Ansa Galeni — , the other 

 supplies the muscles of the Larynx, except the Crico-Thyreoid. This muscle is 

 supplied by the External branch of the Superior Laryngeal Nerve (cf. Fig. 66), 

 whilst the bulk of that nerve pierces (internal branch) the Thyreo-hyoid Membrane 

 together with the Superior Thyreoid Artery and supplies the lar3mgeal mucous 

 membrane with sensation. 



Of great practical importance are the Parathyreoid Glands. When enlarged 

 or the seat of a tumour, they may cause great diagnostic difficulties. 



Usually, their position is as shewn in the figure near the Thyreoid Gland ; 

 but there may be Parathyreoids anywhere between the frenum of the tongue and 

 the h3?oid bone, and between the lower border of the Mandible, the Clavicle and 

 the Trapezius Muscle. 



