THE DESCRIPTION OF THE ANATOMY AND (Part 3)

of a triangle, the two lower sides of which are the two bellies of the digastric. The lingual artery would then run under the hyoglossus muscle, below the hypoglossal nerve. (Gray.) 196 THE CIRCULATORY APPARATUS The subclavian arteries are divided into three parts, the first running to the inner margin of the scalenus anticus; the second, behind that muscle; the third, from its outer border to the lower border of the first Fig. 77 Nasal. Palpebral. a-orbital. Anterior ethmoidal. Posterior ethmoidal Temporal branche of lachrymal. Muscvdar Ophthalmic* Internal carotid. The ophthalmic artery and its branches, the roof of the orbit having been removed. (Gray.) rib, where it becomes the axillary artery. The right and left vessels differ only in their first portions, the right arising behind the sternoclavicular joint, from the innominate; the left, from the transverse aorta as a primary branch. DESCRIPTION OF THE ARTERIES 197 The basilar artery, formed by the two vertebrals, runs to the upper border of the pons, and divides into the two posterior cerebrals. It gives off the following branches : (a) Several transverse arteries on each side. One the auditory, enters the internal meatus; another, the anteroinferior cerebellar, to the anterior border of the cerebellum. Fig. 78 The axillary artery and its branches. (Gray.) (6) The superior cerebellar, to the upper surface, joining the inferior cerebellar. (c) The posterior cerebrals, to the under surface of the posterior lobes of the cerebrum, receiving the posterior communicating. They give off the posterior choroid branches and supply the posterior perforated space. 198 THE CIRCULATORY APPARATUS The circle of Willis is situated at the base of the brain, it is an anastomosis formed by the bloodvessels of the brain. The arteries entering into its formation are: In front, the two anterior cerebral arteries, branches of the internal carotid, which are connected by the anterior communicating artery ; behind, by two posterior cerebral arteries, branches of the basilar, and these communicate latterly with the internal carotids through the posterior communicating arteries. The Arteries of the Upper Extermity. — The Axillary Artery. The axillary artery is the continuation of the subclavian. It extends from the lower border of the first rib, where it is deeply placed, to the lower border of the teres major tendon, where it is super- ficial, and there becomes the brachial. It is described in three parts — the first, above the pectoralis minor; the second, behind it; and the third, below it. Branches. — First part, superior and acromial thoracic; second part, long and alar thoracic; third part, sub- scapular and circumflex, posterior and anterior. The Brachial Artery. — The brachial artery extends from the end of the axillary, at the lower border of the teres major, to J inch below the elbow-joint, divid- ing into the radial and ulnar arteries. The branches of the brachial artery are : The superior profunda, nutrient artery, to the humerus, the inferior profunda, anastomotica magna, and muscular.. The Radial Artery. — The radial artery runs from the bifurcation of the brachial along the radial side of the forearm to the WTist, and winds back to its pos- terior surface. It then enters the palm through the first dorsal interosseous, and runs across the hand to form the deep palmar arch by joining the deep branch of the ulnar, and gives off in the ball of the thumb the superficialis volse, a branch which joins with the main termination of the ulnar artery to form the superficial palmar arch. DESCRIPTION OF THE ARTERIES 199 The Ulnar Artery runs along the inner side of the forearm to the wrist, crosses the annular ligament Fig. 79 Anastomotica magna. The brachial artery. (Gray.) and the palm of the hand, and joins the superfieialis volie to form the superficial arch. 200 THE CIRCULATORY APPARATUS Fig. 80 Hadial recurrent. Siiperjiaialis volae The radial and ulnar arteries (Gray.) DESCRIPTION OF THE ARTERIES 201 The superficial palmar arch lies beneath the palmar fascia and above the flexor tendons of the fingers. Fig. 81 The abdominal aorta and its branches (Gray.) The deep palmar arch lies beneath the flexor tendons and rests on the metacarpal bones and palmar inter- osseous muscles. 202 THE CIRCULATORY APPARATUS The Thoracic Aorta. — The thoracic aorta descends from the lower border of the fifth to the front of the last dorsal vertebra. Fig. 82 Ctjstic artery. The celiac axis and its branches, the liver having been raised and the lesser omentum removed. The Abdominal Aorta. — The abdominal aorta runs from the last dorsal to the left side of the middle of the fourth lumbar vertebra, there dividing into the two common iliacs. The branches of the thoracic aorta: Nine pairs of intercostal arteries, two subcostal, bronchial, esophageal, mediastinal, and pericardial. DESCRIPTION OF THE ARTERIES 203 The branches of the abdominal aorta : (a) Parietal and (b) visceral. The Parietal Branches. — (1) The phrenic, (2) the lumbar, (3) the middle sacral. The Visceral Branches. — I. The celiac axis, J inch long, divides into the gastric, hepatic, and splenic. It is covered by the lesser omentum, rests below on the pancreas; on each side is a semilunar ganglion and on the right the lobus Spigelii, of the liver on the left the stomach. Branches. — (a) The gastric artery runs to the cardiac orifice of the stomach, thence to the right, along the lesser curvature, in the lesser omentum as far as the pylorus. It supplies both surfaces of the stomach and the esophagus, anastomosing with the splenic, hepatic, and esophageal arteries. (6) The hepatic artery passes below the foramen of Winslow to the pylorus, then ascends in the lesser omentum, anterior to that foramen, and to the left of the gall duct, to the transverse fissure of the liver, and divides into a right and a left branch. Its pyloric branch passes along the lesser curvature to meet the gastric. Its cystic branch from the right division ascends on the neck of the gall-bladder and supplies it by two branches. The other branch of the hepatic, the gastroduodenalis, divides behind the lower part of the duodenum into a superior pancreaticoduodenal branch, descending between the pancreas and duo- denum to join the inferior artery of the same name; and the right gastro-epiploica, passing into the omentum toward the left, along the great curvature, to meet the left. (See Fig. 82.) (c) The splenic runs tortuously to the left, along the upper border of the pancreas, and divides near the spleen into branches which enter at the hilum, some passing to the stomach. Branches. — Pancreatic, numerous, small; and one larger, the pancreatica magna, accompanies the duct of Wirsung. 204 THE CIRCULATORY APPARATUS Five to seven vasa brevia, in the gastrosplenic omen- tum, to great end of the stomach, joining the gastric and gastro-epiploic vessels. (See Fig. 82, page 202.) Fig. 83 Superior mesenteric artery. (Testut.) The left gastro-epiploica runs to the right, along the great curvature, to join the right. DESCRIPTION OF THE ARTERIES 205 II. The superior mesenteric supplies the small intes- tine except the first part of the duodenum, as well as the cecum, appendix, ileum, and ascending and trans- verse colon. Emerging from between the transverse duodenum and pancreas, it crosses the former, and descends in the mesentery to the right iliac fossa with its veins and a plexus of nerves. It ends by anasto- mosing with its own ileocolic branch. (See Fig. 83.) III. The inferior mesenteric supplies the descending colon, sigmoid flexure, and upper part of the rectum, and its continuation. (See Fig. 83.) IV. The suprarenals, to the under surface of the suprarenal capsules, join branches of the phrenic and renal arteries. V. The renal, to the hilum of the kidney, enters by four or five branches, into which each vessel divides close to the kidney. VI. The spermatic, the ovarian in the female, to the testicles or ovaries respectively. The Iliac Arteries. — The common iliac arteries run downward and outward from the division of the aorta to the lumbosacral joint, and divide into the external and internal iliacs. (See Fig. 81, page 201.) The internal iliac artery descends to the upper part of the great sacrosciatic foramen, and divides into an anterior and a posterior trunk. The posterior trunk gives off the following branches: (a) the iliolumbar; (6) the lateral sacral; (c) the gluteal, passes through the great sciatic foramen, and divide into a superficial and' a deep branch. The anterior trunk of the internal iliac gives off the following branches: (a) The superior vesical represents the pervious part of the fetal hypogastric artery. It runs to the apex and body of the bladder and to the ureter, joins its fellow, and gives off the artery of the vas deferens, which accompanies that structure to the testicle. It 206 THE CIRCULATORY APPARATUS also generally gives off the (b) middle vesical to the base of the bladder. (c) The inferior vesical — vaginal in the female — joins its fellow. It supplies the bladder, prostate gland, and seminal vesicles; in the female, vagina, and rectum. (d) The middle hemorrhoidal arises with the pre- ceding, and runs to the rectum to join other hemor- rhoidal arteries. (e) The uterine in the female ascends in the broad ligament from the cervix along the side of the uterus, and joins the ovarian artery. (/) The obturator runs forward below the pelvic brim, between the peritoneum and pelvic fascia below the nerve, then through the upper part of the obtura- tor foramen, dividing beneath the obturator externus into an external and an internal branch. The termination of the anterior trunk of the internal iliac then divides into two branches, the sciatic and the internal pudic arteries. The external iliac artery extends from the division of the common iliac to the midpoint between the symphysis of the pubis and the anterior superior spine of the ilium, behind Poupart's ligament. The Arteries of the Lower Extremity. — The Femoral Artery. — ^The femoral artery continues the external iliac artery down into the thigh to end at the opening in the adductor magnus at the junction of the upper three-fourths and lower one-fourth of the femur. From its beginning to the point where the profunda femoris is given off, it is called the common femoral, below this the superficial femoral. Its upper part lies in Scarpa's triangle, bounded above by Poupart's ligament, the inner side formed by the inner margin of the adductor longus, the outer by the sartorius. Its floor, from without inward, is made up of the iliacus, psoas, pectineus, and adductor brevis. The lower part runs in Hunter's canal, a depression between DESCRIPTION OF THE ARTERIES 207 the vastus internus and the adductores magnus and longus, covered by a strong fascia passing between them. Fig. 84 Long saphenous nerve. Superior external articular. Inferior external articular. Anterior tibial (\ \ \j recurrent. Ana^iomolica magna. —Superior inicrnal articular. Inferior internal ariiada/r. The femoral artery. (Gray.) 208 THE CIRCULATORY APPARATUS The Popliteal Artery. — ^The popliteal artery runs from the adductor opening to the lower border of the popliteus, passing through the popliteal space at the back of the knee-joint, where it divides into the ante- rior and posterior tibial. The anterior tibial artery runs from the lower border of the popliteus, between the heads of the tibialis posticus and above the interosseous membrane, to the front of the leg, then descends as far as the ankle, ending in the dorsalis pedis. The dorsalis pedis is the continuation of the anterior tibial, and runs from the bend of the ankle to the first interosseous space, where it divides into the dorsalis hallucis and plantar digital. The plantar digital branch of the dorsalis pedis artery passes between the heads of the first dorsal interosseous, joins with the external plantar to form the plantar arch, and after supplying the inner side of the great toe, divides into two branches for the adjacent sides of the great and second toes. The posterior tibial artery runs from the lower border of the popliteus to divide, between the inner malleolus and heel, into the external and internal plantar arteries. The plantar arteries are the terminal branches of the posterior tibial. The internal is at first under cover of the abductor pollicis, and then between it and the flexor brevis digitorum, anastomosing at the inner border of the great toe with its digital artery. The external, the larger, passes to the base of the fifth metatarsal, then to the space between the first and second metatarsals, and joins the plantar digital, from the dorsalis pedis, to form the plantar arch. The plantar arch supplies the muscles, fascia, and skin of the sole of the foot, and gives off the posterior perforating. These pierce the three outer spaces between the heads of the dorsal interossei and join the dorsal interosseous arteries. The digital, four in number, supply the three outer DESCRIPTION OF THE ARTERIES Fia. 85 209 CommumiciUing. Applied anatomy of the anterior tibial and dorsalis pedis arteries. (Gray.) 1-4 210 THE CIRCULATORY APPARATUS toes and the outer half of the second toe; the first runs to the outer side of the little toe, the others bifurcate to the adjacent sides of the fourth and fifth, fourth and third, third and second toes. At the point of bifurcation each sends a small branch to join the dorsal interosseous arteries {anterior perforating). Fig. 86 ZIommuuicating branch of dorsalis pedis. Its digital branches. The plantar arteries. Deep view. (Gray.) DESCRIPTION OF THE VEINS The Systemic Veins. — These are divided into three sets: superficial, deep, and sinuses. DESCRIPTION OF THE VEINS 211 The superficial veins are usually found between the layers of the fasciae just beneath the skin. The deep veins accompany the arteries, as a rule, and are usually found in the same sheath, derived from the deep fascia. They are generally in pairs, one on each side of the artery, and are termed venae comites. The larger arteries have only one accom- panying vein — as the axillary, subclavian, popliteal, femoral. Sinuses are venous channels found in the skull, which drain the blood from the brain and its mem- branes, and ultimately communicate with the right and left internal jugular veins at the base of the skull. Some are found between two layers of the dura, and others lodged in grooves on the inner surfaces of the cranial bones, ensheathed by the dura. They are lined by endothelial cells continuous with that which lines the veins. They are sixteen in number — six single and ten paired. Venous plexus is the name given to a number of small veins communicating with each other and arranged in a net-work surrounding or within any organ or part of the body. The Veins of the Heart. — ^The great cardiac vein ascends in the anterior interventricular groove from the apex of the heart to the left auriculoventricular groove ; along this latter it runs to the posterior surface of the heart, to end in the coronary sinus. At its termination it is provided with a valve. The right (small) coronary vein in the right auriculo- ventricular groove to the sinus. The coronary sinus, one inch long, is placed at the back part of the auriculoventricular groove, on the left side, and opens into the right auricle in front of the inferior vena cava. The Superior Vena Cava and Innominate Veins. — ^The superior vena cava is a large trunk formed by the union of the two venae innominatae, and returns the 212 THE CIRCULATORY APPARATUS blood from the head and neck, the thoracic walls, and the upper extremities. It is about three inches long, and descends from the junction of the first right costal cartilage with the sternum to its termination in the right auricle, opposite the upper border of the third right cartilage. The Veins of the Head and Neck. — The facial vein runs from the inner angle of the eye to the anterior border of the masseter muscle, then backward below the jaw, joining the anterior division of the temporo- maxillary trunk to form the common facial, which joins the internal jugular. The temporomaxillary vein (posterior facial) is a short trunk, formed by the temporal and internal maxillary veins. The temporal vein is formed by the union of the superficial with the middle temporal vein, and crosses over the zygoma and under the parotid to join the internal maxillary vein. The external jugular vein is formed by the union of the posterior auricular and the posterior division of the temporomaxillary trunk. It descends obliquely across the sternomastoid, lying betw^een the platysma and fascia. Above the clavicle it pierces the fascia and joins the subclavian at the outer border of the scalenus anticus; sometimes it joins the internal jugular. The internal jugular vein commences at the jugular foramen just below the junction of the inferior petrosal with the lateral sinus, and descends with the external carotid, then with the common carotid, to join at a right angle with the subclavian vein behind the clavicle, thus forming the innominate vein. It is placed external to the carotid vessels, lying in the same sheath with each in turn. The Veins of the Upper Extremity. — The Superficial Veins. — They commence from a plexus on the back DESCRIPTION OF THE VEINS 213 of the hand mostly, but to some extent from the palm. They comprise the following: The ulnar, anterior and posterior, uniting above in the common ulnar. The radial vein is situated on the outer side, and the median ascends mesially, receives a deep median vein, and divides at the bend of the elbow into the median basilic and median cephalic. The median basilic joins the common ulnar to form the basilic. The bicipital fascia separates it from the brachial artery. The median cephalic crosses the external cutaneous nerve, and joins the radial to form the cephalic. The basilic runs along the inner side of the biceps, pierces