534 ARTERIES. 



metatarsal bones, and is covered by the Adductor Pollicis, the flexor tendons 

 of the toes, and the Lumbricales. 



Branches. The plantar arch, besides distributing numerous branches to the 

 muscles, integument, and fasciae in the sole, gives off the following branches: 



Posterior perforating. Digital Anterior perforating. 



The posterior perforating are three small branches, which ascend through the 

 back part of the three outer interosseous spaces, between the heads of the 

 Dorsal Interossei muscles, and anastomose with the interosseous branches from 

 the metatarsal artery. 



The digital branches are four in number, and supply the three outer toes and 

 half the second toe. The first passes outwards from the outer side of the plantar 

 arch, and is distributed to the outer side of the little toe, passing in its course 

 beneath the Abductor and short Flexor muscles. The second, third, and fourth 

 run forwards along the metatarsal spaces, and on arriving at the clefts between 

 the toes, divide into collateral branches, which supply the adjacent sides of the 

 three outer toes and the outer side of the second. At the bifurcation of the 

 toes, each digital artery sends upwards, through the fore part of the correspond- 

 ing metatarsal space, a small branch, which inosculates with the interosseous 

 branches of the metatarsal artery. These are the anterior perforating branches. 



From the arrangement already described of the distribution of the vessels to 

 the toes, it will be seen that both sides of the three outer toes, and the outer side 

 of the second toe, are supplied by branches from the plantar arch ; both sides 

 of the great toe, and the inner side of the second, being supplied by the dorsal 

 artery of the foot. 



PULMONARY ARTERY. 



The Pulmonary Artery conveys the venous blood from the right side of the 

 heart to the lungs. It is a short wide vessel, about two inches in length, arising 

 from the left side of the base of the right ventricle, in front of the aorta. It 

 ascends obliquely upwards, backwards, and to the left side, as far as the under 

 surface of the arch of the aorta, where it divides into two branches of nearly 

 equal size, the right and left pulmonary arteries. 



Relations. The greater part of this vessel is contained, together with the 

 ascending part of the arch of the aorta, in the pericardium, being inclosed with 

 it in a tube of serous membrane, continued upwards from the base of the heart, 

 and has attached to it, above, the fibrous layer of the membrane. Behind, it 

 rests at first upon the ascending aorta, and higher up lies in front of the left 

 auricle. On either side of its origin is the appendix of the corresponding 

 auricle, and a coronary artery ; and higher up it passes to the left side of the 

 ascending aorta. A little to the left of its point of bifurcation, it is connected 

 to the under surface of the arch of the aorta by a short fibrous cord, the remains 

 of a vessel peculiar to foetal life, the ductus arteriosus. 



The right pulmonary artery, longer and larger than the left, runs horizontally 

 outwards, behind the ascending aorta and superior vena cava, to the root of the 

 right lung, where it divides into two branches, of which the lower, which is 

 the larger, supplies the lower lobe ; the upper giving a branch to the middle 

 lobe. 



The left pulmonary arten/, shorter but somewhat smaller than the right, passes 

 horizontally in front of the descending aorta and left bronchus to the root of 

 the left lung, where it divides into two branches for the two lobes. 



The terminal branches of the pulmonary artery will be described with the 

 anatomy of the lung. 



The author has to acknowledge valuable aid derived from the following works : Harrison's 

 "Surgical Anatomy of the Arteries of the Human Body." Dublin, 1824. Richard Quain's 

 " Anatomy of the Arteries of the Human Body." London, 1844. Sibson's "Medical Anatomy," 

 and the other works on General and Microscopic Anatomy before referred to. 



