292 CLINICAL APPLIED ANATOMY. 



the posterior surface of the gland. The left lateral lobe is 

 normally in contact with a small portion of the front of the 

 oesophagus where that tube deviates somewhat to the left at the 

 root of the neck, whilst the upper extremities of the lateral lobes 

 may actually embrace portions of the larynx and pharynx. 

 Pressure on the ossophagus and dysphagia may thus result from 

 thyroid swellings. 



The pressure exerted by the enlarged gland on the trachea is of 

 serious importance and may cause death. The trachea is usually 

 compressed laterally and not often antero-posteriorly. The 

 lateral compression is no doubt aided by the pressure exerted by 

 the sterno-mastoid and infra-hyoidean muscles which cross the 

 lateral lobes. The lateral compression is often associated with 

 a certain amount of lateral twisting of the trachea on its long 

 axis, and in unilateral enlargements of the gland the air tube 

 may be displaced towards the opposite side of the neck. Sub- 

 sternal goitres, being unable to enlarge forwards, compress the 

 trachea antero-posteriorly. 



Signs of pressure on neighbouring nerve trunks may be present. 

 Alteration of the voice and various forms of laryngeal paralysis 

 may result from pressure on the recurrent nerves. Contracted 

 pupil, enophthalmos and narrowing of the palpebral fissure, 

 indicate pressure on the cervical sympathetic which lies at the 

 back of the carotid sheath. Numbness and tingling in the neck 

 or arm may be produced by pressure on the branches of the 

 cervical or brachial plexus. Irregularity of the heart is attributed 

 to vagus compression. 



The close relation of the cervical lymph glands to the lateral 

 lobes of the thyroid gland gives rise to some difficulty in dis- 

 tinguishing malignant or tuberculous enlargements of the lymph 

 glands in this position from actual disease of the thyroid. 



The parathyroid bodies are difficult to recognise. Two of them 

 may sometimes be found amongst the terminal branches of the 

 inferior thyroid arteries, and the other two are usually situated 

 at the lower extremities of the lateral lobes. 



Myxoedema and cretinism are usually associated with atrophy 



