II02 A MANUAL OF ANATOMY 



lip; and their efferent lymphatics pass to the submaxillary lym- 

 phatic glands. 



The prelaryngeal glands, when present, are situated in front of 

 the crico-thyroid membrane, and are one or two in number. They 

 receive their afferent lymphatics from the interior of the larynx, 

 below the rima glottidis, and from the adjacent part of the thyroid 

 body. Their efferent lymphatics pass to the inferior group of deep 

 cervical glands. 



The pretracheal glands lie in front of the cervical portion of the 

 trachea, from which, as well as from the adjacent part of the 

 thyroid body, they receive their afferent lymphatics. Their 

 efferent lymphatics pass to the inferior group of deep cervical 

 glands. 



Occasionally a few lymphatic glands are met with along the 

 course of the anterior jugular vein. 



Deep Cervical Glands. — ^These glands lie beneath the sterno- 

 cleido-mastoid muscle, and are about twenty-five in number. 

 They are arranged in two groups, superior and inferior. 



The superior group lie along the internal jugular vein above the 

 level of the upper border of the thyroid cartilage. They receive 

 their afferent lymphatics from the cranial cavity, the internal 

 maxillary glands, some of the parotid and submaxillary lymphatic 

 glands, the root of the tongue, the upper part of the thyroid body, 

 the larynx, and the lower part of the pharynx. Their efferent 

 lymphatics pass to the glands of the inferior group. 



The inferior group lie along the lower part of the internal jugular 

 vein, and extend outwards and backwards beneath the sterno- 

 cleido-mastoid, as far as its posterior border, where they give rise 

 to a chain known as the glandules concatenatce. The glands of this 

 chain are continuous interiorly with the supraclavicular glands, 

 and, through these,, with the external axillary glands. They 

 receive their afferent lymphatics from the superior group of deep 

 cervical glands, the upper superficial cervical glands, the lower 

 part of the thyroid body, and the cervical portions of the trachea 

 and oesophagus. Their efferent lymphatics unite to form a single 

 vessel, called the jugular lymphatic trunk, which opens on the left 

 side into the thoracic duct, and on the right side into the right 

 lymphatic duct. 



Infrahyoid Muscles. — ^These are four in number, on either side, as 

 follows : the omo-hyoid, sterno-hyoid, sterno-thyroid, and thyro- 

 hyoid. 



Omo-hyoid. — This muscle consists of two bellies, anterior and 

 posterior, and an intervening tendon. Origin. — By means of the 

 posterior belly from (i) the upper border of the scapula close to 

 the inner side of the suprascapular notch, and (2) the supra- 

 scapular or transverse ligament, which bridges over the supra- 

 scapular notch. 



Insertion. — By means of the anterior belly into the outer third 

 of the lower border of the body of the hyoid bone, immediately 

 external to the insertion of the sterno-hyoid muscle. 



