Branches of the tibialis anterior: _a._ =A. tibialis recurrens.=--Immediately after passing through the interosseous membrane the anterior tibial sends a small artery proximad to the knee-joint. _b._ =Rami musculares.=--Numerous short branches throughout the course of the artery, to the muscles about it. _c._ =Ramus superficialis.=--A larger branch leaves the lateral surface of the artery about one-third the distance from the knee to the ankle and passes along with the superficial peroneal nerve, at first beneath M. peroneus longus, then superficially. It passes onto the dorsal surface of the foot and becomes connected with terminal branches of =A. saphena=. _d._ =A. tarsea medialis.=--This arises from the tibialis anterior just distad of the transverse ligament through which it passes at the ankle, passes over the medial surface of the astragalus, and is distributed to the ligaments about the ankle-joint. It anastomoses with the plantar branch of A. saphena. _e._ =A. metatarsea.=--The metatarsal artery passes laterad from the tibialis anterior at the distal boundary of the tarsus, on the dorsal surface of the foot. It sends branches distad in the intervals between the third and fourth and the fourth and fifth metatarsals. The distal branches (Fig. 128) of the tibialis anterior have been described in the general description of the artery. THE VEINS. VENÆ. =Venæ pulmonales. The Pulmonary Veins.= The pulmonary veins follow in the lungs the course of the bronchi. They enter the left auricle in three groups (Fig. 116, page 276). The first of these (_i_) comes from the anterior and middle lobes of the right side, the second (_h_) from the corresponding lobes of the left side, and the third (_g_) from the terminal lobes of both sides. Each group is composed of two or three veins and opens into a sinus or extension of the auricle. The sinuses are from their position dextral (_i_), sinistral (_h_), and dorsal (_g_). =The Veins of the Body.= The veins of the body may be classified into three main groups: (1) the veins of the heart; (2) the superior vena cava and its branches; (3) the inferior vena cava and its branches. The portal system of veins will be considered with the inferior vena cava. 1. Veins of the Heart. The veins of the heart consist of one large vein, the =vena cordis magna=, and a number of small veins.