LYMPHATICS OF I'PPKR EXTREMPPV 653 



the hyo-gl()Ssiis and genio-hyo-glosi^us muscles. They receive lymi^hatics from the 

 upper surface and i)osterior part of the substance of the tongue. Their efferent 

 vessels terminate in tlie superior glands of tlie deep cervical chain. 



(2) The internal maxillary or deep facial glands, three to six innumlier, are 

 situated by the side of the jiharynx innnediately bcliind the buccinator muscle. 

 They receive the lym})hatics from the orltit, the nose, the temporal and spheno- 

 maxillary fossiB, the upper jaw, the })alate, and the pharynx. Their efferent 

 vessels join the superior glands of the deep cervical chain. 



(8) The post-pharyngeal gland is situated behind the pharynx on the rectus 

 capitis anticus major near the base of the skull. It receives lymphatics from 

 the upper part of the pharynx, from the nose, and from the deej) })revertebral 

 nuiscles. 



2. The deep lymphatic glands of the neck are divided into the upper and 

 the lower. 



The upper set extend along the course of the internal jugular vein from the 

 base of the skull to about the level of tlie thyroid cartilage. They receive the 

 lymi)hatics from the interior of the cranium above; the lymphatics from the deep 

 muscles of the upper part of the neck behind; and the lymphatics from the internal 

 maxillary glands, the posterior half of the tongue, the middle portion of the 

 pharynx, the upper part of the larynx, the upper part of the thyroid body, aiid 

 some of the efferent vessels from the submaxillary lymphatic glands in front and 

 internally. Their efferent vessels pass downwards to the lower deep cervical 

 glands. 



The lower deep cervical glands follow the course of the internal jugular vein 

 from the thyroid cartilage to near the clavicle. They receive the lymphatics from 

 the lower part of the neck, the efferent vessels from the superior set of deep 

 cervical glands, the lymphatics from the lower part of the larynx, the lower part 

 of the thyroid body, the upper part of the trachea and oesophagus, and the efferent 

 vessels from the superficial cervical glands. Their efferent vessels end in the jugular 

 lymphatic trunk, which unites with the subclavian lymphatic trunk, on the right 

 side to form the right lymphatic duct, and on the left side to end in the thoracic 

 duct. The right jugular trunk may also receive the lymphatics coming from the 

 right half of the supei'ior and anterior mediastina. 



The right lymphatic duct. — The right lymphatic duct is a short vessel 

 from half to three-quarters of an inch long. It receives the lymphatics from 

 the right side of the head and neck, from the right upper extremity, most 

 of the lymphatics from the right side of the thorax, the right lung and pleura 

 and from the right side of the heart and part of the lymphatics from the convex 

 surface of the liver. It passes downwards and inwards from its formation at 

 the union of the subclavian and jugular lymphatic trunks, and ends at the 

 confluence of the right internal juguhir and subclavian veins. Its entrance is 

 guarded Ijy a double valve. 



THE LYMPHATICS OF THE UPPER EXTP EMPTY 



The lymphatics of the upper extremity — consisting of ])oth lymjihatic ves- 

 sels and lymphatic glands — are arranged in two sets, a suj^erflcial and a deep. The 

 former are situated in the subcutaneous tissue l)etween the skin and the deep or 

 muscular fascia, the latter along the course of the arteries of the limb. Both sets 

 converge as they approach the axilla, and unite in the axillary glands. The 

 efferent vessels of these glands form one or more trunks, which oi^en, on the left 

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

 duct. 



