Fig. 2. Blood vessels passing through the umbilical cord in a human fetus. (From Quain's Anatomy, vol. 2.) _L_, liver; _K_, kidney; _I_, intestines; _U C_, umbilical cord; _Ua_, umbilical arteries. The posterior aorta coming from the heart passes backward and gives rise to the internal iliac arteries, and of these the umbilical arteries are branches. _Uv_, umbilical vein; this joins the portal vein, passes onward to the liver, breaks up into smaller vessels, which reunite in the hepatic vein; this empties into the posterior vena cava, which carries the blood back to the heart. * * * * * [Illustration: PLATE XII. FETAL CALF WITHIN ITS MEMBRANES.] [Illustration: PLATE XIII. PREGNANT UTERUS WITH COTYLEDONS.] [Illustration: PLATE XIV. VESSELS OF UMBILICAL CORD.] [Illustration: PLATE XV.] [Illustration: PLATE XVI.] [Illustration: PLATE XV. NORMAL POSITION OF CALF IN UTERO.] [Illustration: PLATE XVI. ABNORMAL POSITIONS OF CALF IN UTERO.] [Illustration: PLATE XVII. ABNORMAL POSITIONS OF CALF IN UTERO.] * * * * * PLATE XV. Normal position of calf in utero. This is the most favorable position of the calf or fetus in the womb at birth, and the position in which it is most frequently found. This is known as the normal anterior position. The back of the fetus is directly toward that of the mother, the forelegs are extended back toward the vulva of the mother, and the head rests between them. The birth of the calf in this position usually takes place without artificial assistance. PLATE XVI. Abnormal positions of calf in utero. (Figs. 1, 2, 3, and 5 from Fleming's Veterinary Obstetrics; fig. 4 after St. Cyr, from Hill's Bovine Medicine and Surgery; fig. 6 from D'Arboval, Dictionaire de MÈdecine et de Chirurgie.) Fig. 1. Anterior presentation; one fore limb completely retained. The retained limb must be reached if possible and brought forward joint by joint and the fetus then extracted. Fig. 2. Anterior presentation; fore limbs bent at knee. The limbs must be extended before delivery can be accomplished. Fig. 3. Anterior presentation; fore limb crossed over neck. The leg should be grasped a little above the fetlock, raised, drawn to its proper side, and extended in genital canal. Fig. 4. Anterior presentation; downward deviation of head. The head must be brought into position seen in Plate XV before delivery can take place. Fig. 5. Anterior presentation; deviation of the head upward and backward. Retropulsion is the first indication, and will often bring the head into its normal position. Fig. 6. Anterior presentation; head presented with back down. The fetus should be turned by pushing back the fore parts and bringing up the hind so as to make a posterior presentation. PLATE XVII. Abnormal positions of calf in utero. (Figs. 2 and 3 from Fleming; figs. 4, 5, and 6 from D'Arboval.)