LYMPHATIC SYSTEM OF THE OX AND SHEEP 725 



The costo-cervical l5rmph gland (Lg. costo-cervicalis)i is situated lateral to the 

 trachea and oesophagus and dorsal to the carotid artery and the vago-sympathetic 

 trunk. It lies usually just in front of the first rib, under cover of the scf,;||!nus 

 muscle, but it may be partly medial to the first rib. Its length varies from about 

 half an inch to an inch or more (1.5-3 cm.). Its afferent vessels come from the 

 muscles of the neck and shoulder, the costal pleura, the trachea, and the intercostal 

 and anterior mediastinal glands. The efferent vessels on the right side usually go 

 to the right tracheal duct or join the efferent vessel of the prescapular gland; on the 

 left they go most often to the end of the thoracic duct, but are very variable. 



-The tracheal lymph ducts (Ductus tracheales), right and left, are formed 

 essentially by the confluence of efferent vessels from the atlantal gland. They 

 usually receive efferent vessels from the cervical, costo-cervical, and prescapular 

 glands. The ducts pass along each side of the trachea and oesophagus; the right 

 one usually opens into the right common jugular vein; the left one joins the terminal 

 part of the thoracic duct or opens into the left common jugular vein. 



These ducts are very variable in regard to formation affluents, and termination. There 

 may be an accessory tracheal duct, which receives part of the lymph vessels that otherwise go to 

 the chief duct; this accessory duct runs a variable distance along the neck practically parallel 

 with the chief duct, and unites with the latter. 



A short right lymphatic duct may be formed by the junction Avith the terminal 

 part of the right tracheal duct of efferent vessels from the right cervical, costo-cer- 

 vical, and prescapular lymph glands. It also usually receives an efferent vessel 

 from the anterior sternal lymph gland. 



' The prescapular or posterior superficial cervical lymph gland (Lg. cervicalis 

 superficialis caudalis) is situated at the anterior border of the supraspinatus, a little 

 above the level of the shoulder joint; it is covered by the omo-transversarius and 

 brachiocephalicus muscle. It is elongated and may attain a length of four or five 

 inches (ca. 10-12 cm.) and a width of an inch or more (ca. 3 cm.). Its deep face 

 has a long and distinct hilus. It receives afferents from the skin of the neck, 

 shoulder, part of the ventral and lateral surfaces of the thorax, and the thoracic 

 limb; from the muscles of the shoulder-girdle, and from the external scapular 

 muscles; from the tendons of the muscles of the forearm and digit and the fascia 

 of the forearm; from the joints of the carpus and digit. The efferent vessel de- 

 scends over the scalenus muscle and opens on the right side into the end of the right 

 tracheal duct, on the left into the terminal part of the thoracic duct or the left 

 tracheal duct. 



In one case Baum found two efferent vessels on the right side: one opened into the end of 

 the tracheal duct, the other went to a posterior cervical gland. 



A chain of small nodes, five to ten in number, extends along the border of the supraspmatus, 

 dorsal to the prescapular gland, and covered by the trapezius and omo-transversarms. These 

 ' nodes termed by Baum lymphoglandulie cervicales nuchales, are in most cases dark red in color, 

 and most of them are hajmolymph glands. But some are lymph glands, since they receive afferent 

 vessels from adjacent muscles and send efferent vessels to the prescapular lymph gland or to 

 another gland of the group. 



The intercostal l5rmph glands are situated in the dorsal ends of the intercostal 

 spaces, on the course of the intercostal vessels, and embedded in fat. Most of them 

 are small, but some may be nearly an inch (ca. 2 cm.) long. Not all of the spaces 

 contain glands, and quite exceptionally two may occur in one space. Associated 

 with them are hsemolymph glands. The afferent vessels come chiefly from the 

 intercostal and spinal muscles, the serrati, latissimus dorsi, trapezius, subscapularis, 

 longus colli, obhquus abdominis externus; from the costal pleura and the peri- 

 toneum; from the thoracic vertebras and the ribs. The efferent vessels go to the 

 mediastinal lymph glands. 



1 This gland has been included in the posterior cervical group, but forms a connecting link 

 as it were, between the cervical and mediastinal glands. Baum has given it the above name and 

 has shown that it receives lymph vessels from the pleura. 



