QUESTIONS AND ANSWERS 69 



Give the course and relations of the jugular vein. 



Formed by the union of the superficial temporal and internal 

 maxillary veins, behind the inferior maxilla. It passes downward 

 and backward, lodged at first in the substance of the parotid gland, 

 afterward in the jugular furrow (the muscular interspace between 

 the mastoidohumeralis and the sternomaxillaris) . At the inferior 

 extremity of the neck, it unites with its mate to form the confluent 

 of the jugulars. After leaving the parotid gland, the jugular is 

 covered externally by the cervical panniculus. Inwardly and 

 above, it is related to the subscapulohyoideus muscle, which separates 

 it from the carotid, but in its inferior part it is in direct relation 

 with that vessel, the trachea and the oesophagus. 



Branches : maxillomuscular, posterior auricular, occipital, glosso- 

 facial, thyroid, cephalic, parotidean and many small muscular veins. 



Describe the course and the function of the portal vein. 



It begins in the sublumbar region, by the union of the anterior 

 and posterior mesenteries and the splenic veins ; it is then directed 

 forward, traversing the pancreatic ring, below the vena cava, and 

 is afterward lodged in the great fissure of the liver, where it ramifies 

 by forming the interlobular veins. It receives on its course the 

 right gastro-omental and anterior gastric veins. Its function is to 

 carry the blood which comes from the intestinal walls, charged with 

 assimilable substances, that are absorbed by the veins of the villi, 

 to the liver. 



Give a general description of the lymphatics. 



The Ijrmphatics are vessels with very thin and transparent walls, 

 found all over the body, except in blood-vessels, nervous tissue, 

 bone, muscles, eyeball, cartilage, tendons, the membranes of the 

 ovum, placenta, umbilical cord, cuticle and hair. They possess 

 nutrient vessels, no nerves, have valves, and carry lymph or chyle 

 into the vascular system. Like the veins, the lymphatics terminate 

 in two principal trunks, resembling the vena cava; and, like the 

 veins, have three tunics. The lymphatics originate from capillaries 

 which form networks or terminal culs-de-sac. They terminate, as 

 before stated, by emptying into the vascular system; the union of 

 the blood with the lymphatic system takes place at the origin of the 

 anterior vena cava. 



Give the course and the termination of the thoracic duct. 



The thoracic duet receives all the lymphatics except those of the 

 right side of the head, neck and thorax and the right anterior 

 limb. It originates beneath the vertebral column, near the first 

 lumbar vertebra, where it is marked by a very irregular dila- 



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