ARTERIES 79 



anterior annular ligament, and, forming an arch with the con- 

 vexity downwards, is directed to the thumb, where the arch 

 becomes completed by joining the superficialis volae, radialis 

 indicis, or princeps pollicis. From the convex side of the 

 arch it gives off four digital branches to supply three inner 

 fingers and inner side of index-finger ; anas, palmar interossei 

 of deep arch, inferior perforating of dorsal interosseous. 



The deep branch of ulnar artery or communicating branch 

 is given off at commencement of arch, passes down with 

 the deep branch of ulnar nerve between abductor and short 

 flexor of little finger to complete deep palmar arch. 



ARTERIES OF BODY. 



THE AORTA. 



Large main trunk of systemic arteries, situated partly in 

 thorax and partly in abdomen, commences at left ventricle, 

 arches over root of left lung, descends in front of vertebral 

 column, through diaphragm into abdomen, ending opposite 

 body of 4th lumbar vertebra by bifurcating into two common 

 iliacs. Conveniently divided into three parts: arch of aorta, 

 descending thoracic aorta, abdominal aorta. 



ARCH OF AORTA : divided, according to the direction, into 

 ascending and transverse portions. In the concavity of the 

 arch are contained root of left lung, branching of pulmonary 

 artery with ductus arteriosus, cardiac plexuses, left recurrent 

 laryngeal nerve, oesophagus and thoracic duct. 



Ascending part : Extent and Course. Two inches in length. 

 From base of left ventricle, opposite lower border of 3rd left 

 costal cartilage, passing behind pulmonary artery, upwards 

 and to the right, crossing the posterior surface of the sternum 

 obliquely, and extending as high as superior border of 2nd 

 right costal cartilage. At its root it presents three bulgings, 

 the sinuses of Valsalva, and along the right side is a dilatation, 

 the great sinus of the aorta. 



Relations. Is contained nearly completely in pericardium. 



In Front. Behind. Right Side. Left Sidt. 



Pulmonary artery. Left auricle. Superior cava. Pulmonary ar 



Right auricular ap- Right pulmonary Right auricle. tery. 



pendix. vessels. 



Pericardium. Root of right lung. 



Right lung and 



pleura. 

 Sternum. 



