COMPARATIVE ANATOMY 59 



common carotid artery and the vagus nerve. A large lymph 

 vessel, the thoracic duct, enters the external jugular near the 

 place of union with the internal jugular. This is sometimes 

 mistaken for a blood vessel. 



9. Transverse Scapula Vein. — This vein returns blood 

 from the arm and shoulder region. It joins the external jugular 

 on the lateral side. 



10. Anterior Facial and Posterior Facial Veins. — The 

 external jugular is formed by the union of these two vessels. 

 The posterior facial brings blood from the dorsal side of the 

 head, ear, masseter muscle, parotid gland, and adjacent regions. 

 The anterior facial collects blood from the face, tongue, jaws, 

 and nasal region. A transverse vein connects the anterior 

 facials of the two sides. 



Turn now to the veins of the posterior part of the body. 

 Before dissecting them certain of the urogenital organs should 

 be located. If you have not already done so identify the kidneys, 

 large bean-shaped organs on the dorsal wall; adrenal glands, 

 small structures just anterior to the kidneys; urinary bladder in 

 the lower part of the abdomen; ureters, ducts from the kidneys 

 to the bladder; uterus, a branched structure of variable size in 

 the female; spermatic cord and vas deferens of the male. The vas 

 deferens loops over the ureter near where the latter joins the 

 bladder. 



11. Femoral Vein. — In company with the femoral artery 

 and the saphenous nerve this vein extends across Scarpa's 

 triangle on the inner side of the thigh. The femoral vein, after 

 receiving several smaller veins, enters the body cavity and then 

 becomes known as the external iliac vein. Trace the femoral 

 backward down the leg, dissecting out the larger branches. 



12. Hypogastric (internal iliac) Vein. — Bringing blood 

 from various pelvic organs the hypogastric unites with the exter- 

 nal iliac just inside the body cavity. Tracing it backward it 

 extends medially and dorsally. 



13. Common Iliac Vein. — ^This is formed by the union of 

 the hypogastric and external iliac veins. The two common 

 iliac veins unite in the median line. 



14. Inferior Vena Cava. — Formed by the union of the two 

 common iliac veins, it passes directly forward, through the liver. 



