THE NECK. 167 



On removal of panniculus we disclose, at tlie postero- 

 superior part, the sterno-maxillaris shortly after its origin 

 from the anterior extremity of the cariniform cartilage, 

 blended with its fellow along the middle line, thus forming 

 a sling underneath the trachea, about the anterior part of 

 the posterior third of the neck, they separate, and, becom- 

 ing round muscular cords, run forwards to be inserted each 

 by.a broad tendon, which, after separating the parotid from 

 the submaxillary salivary glands, i^asses over stylo-maxil- 

 laris, and becomes attached to posterior margin of the lower 

 jaw about three inches below its articulation with the 

 squamous temporal bone. 



The ti-achea at the middle third of the neck is covered 

 by the sterno-thyro-hyoideus muscle, which, passing from 

 the anterior extremity of the cariniform cartilage, here 

 divides into two parts ; the thimier runs underneath sub- 

 scapulo-hyoideus to the lateral part of the external surface 

 of the ala of the thyroid cartilage, where it terminates, 

 being inserted between the muscles proper to the larynx : 

 just above this termination is situated the thyroid body, a 

 small dark-red body of a rounded form attached to the 

 lateral aspect of the anterior part of the trachea. The 

 thyroid body under the microscope presents a number of 

 vesicular cavities lined by tesselated epithelium embedded 

 in a somewhat soft stroma. It is one of the so-called vas- 

 cular glands, the use of which is not distinctly understood, 

 and receives a large hranch from the carotid arteri/, the only 

 constant one given off from that vessel in its course up 

 the neck ; this branch frequently sends off a twig to the 

 larynx which receives the name of the laryngeal artery. 

 The broader division of sterno-thyro-hyoideus runs to- 

 wards the centre of the submaxillary space, where it 

 becomes inserted into the under surface of the body of os 

 sphenoides, together with subscapulo - hyoideus, which, 

 however, occupies a much larger surface of attachment, 

 and which puts in its appearance about the anterior third 

 of the neck, running from rmderneath sterno-maxillaris 

 to meet its fellow at its attachment. By removal of 

 parotideo-auricularis and panniculus, the parotid gland is 

 exposed. It is an irregular- shaped organ of a dirty white 

 colour, composed of numerous minute lobules, which fit in 

 between the different structures it covers. Anteriorly it 

 extends a little on to the surface of masseter externus, 



