ABDOMEN. 



15 



wall of the inguinal canal between the two 

 rings ; it is distributed in the integuments and 

 fascia of the iliac and umbilical regions, and anas- 

 tomoses with its fellow of the opposite side, and 

 by deep branches which pierce the aponeuroses, 

 with the deep epigastric artery. In the epigas- 

 trium and hypochondria the superficial fascia 

 and integument are supplied by cutaneous 

 branches from the internal mammary and the 

 inferior intercostals. The deep-seated parts of 

 this region are likewise supplied from the last- 

 named arteries ; the largest and most constant of 

 which is the abdominal branch of the internal 

 mammary, which in the sheath of the rectus 

 supplies that muscle, and establishes an im- 

 portant communication with the epigastric : 

 this anastomosis is said to have been known to 

 Galen, who by it proposed to account for the 

 sympathy which exists between the uterus and 

 the breasts.* Another branch of the mammary 

 supplies the muscles external to the rectus ; it 

 runs between the obliquus internus and trans- 

 versalis, and is lost in anastomosing with the 

 inferior intercostal, the lumbar, and the circum- 

 flexa ilii arteries. 



Inferiorly, the abdominal wall is supplied 

 by two considerable and very constant arteries, 

 viz. the epigastric, which may be distinguished 

 from the artery that supplies the integuments 

 by the appellation deep, and the circumflexa ilii. 

 The epigastric artery arises in general from the 

 external iliac a little way above Poupart's liga- 

 ment; it at first inclines downwards to that 

 ligament, and then turns upwards, and directs 

 itself forwards and inwards, crossing the iliac 

 vein ; it then runs along the posterior surface of 

 the anterior wall of the abdomen, inclosed be- 

 tween the peritoneum and fascia transversalis, 

 at first situated between the external and inter- 

 nal abdominal rings, and on arriving at the 

 rectus muscle, the sheath of which it enters 

 about two inches above the pubis, it gives off 

 branches from either side to the abdominal 

 muscles and peritoneum, and behind the linea 

 alba, establishes a very free inosculation with 

 its fellow of the opposite side. As it lies behind 

 the inguinal canal, the epigastric artery is much 

 nearer to the internal than to the external abdo- 

 minal ring, being to the pubic side of the 

 former ; here the vas deferens, as it passes up 

 from the pelvis to the inguinal canal, hooks 

 over it, and receives one or two small branches 

 from it. In passing to the rectus muscle, this 

 artery lies internal to the linea semilunaris. It 

 enters the sheath of the rectus, and then termi- 

 nates by anastomosing with the internal mam- 

 mary. The course of this artery demands par- 

 ticular attention from the surgical anatomist in 

 reference to the operations for inguinal herniae, 

 and to that for paracentesis abdominis, when 

 the abdomen is perforated in the linea semilu- 

 naris. The trunk of the artery is so distant 

 from the linea alba in its whole course, that it 

 is free from danger in any operation performed 

 in that line, or in the internal half of the rectus 

 muscle, and its security in such operations is 

 increased under the altered state of parts con- 



* Diet, de Medecine, art. Abdomen. 



sequent on pregnancy, ascites, or any abdomi- 

 nal tumour pressing similarly on the abdominal 

 wall. In these cases the distance of the artery 

 from the linea alba is increased by the flattening 

 of the rectus muscle, which results from its 

 compression. (See GROIN, REGION OF; 

 HERNIA; ILIAC ARTERY.) 



The circumflexa ilii artery comes likewise 

 from the external iliac, near to the origin of the 

 epigastric ; it passes upwards and outwards to- 

 wards the spine of the ilium, runs along the 

 line of junction of the fascia iliaca with the 

 fascia transversalis, covered by the fascia, and 

 follows the circumference of the iliacus internus 

 muscle to end in anastomosing with theiliolum- 

 bar artery. From that part of the artery which 

 intervenes between its origin and the spine of 

 the ilium, come the principal branches which 

 it supplies to the abdominal muscles. 



The lateral and posterior walls of the abdo- 

 men are supplied by the inferior intercostals, the 

 lumbar, the iliolumbar, the circumflexa ilii arte- 

 ries ; the superior walls by the phrenic branches 

 of the internal mammary and by those of the 

 aorta. It is in cases where the aorta has been 

 obliterated that we can see best the extent of 

 arterial ramification on the abdomen, and can 

 appreciate the benefit of these numerous anas- 

 tomoses, and the connexion which they esta- 

 blish between the upper and lower portions of 

 the aorta.* 



b. The veins. The veins of the abdominal 

 parietes are much more numerous than the 

 arteries ; each artery has its accompanying vein 

 or veins, but those which are especially de- 

 serving of attention are the tegumentary veins 

 which accompany the superficial epigastric 

 artery, and those which ramify along with the 

 deep epigastric and mammary. The subcuta- 

 neous veins demand attention in consequence 

 of the considerable size which they sometimes 

 attain ; this enlargement is commonly attendant 

 on ascites and on pregnancy, and is occasionally, 

 to a remarkable extent, a consequence of some 

 irregularity, obstructionf or retardation of the 

 circulation, in the deep-seated veins of the ab- 

 domen, more especially the inferior vena cava. 

 The veins which accompany the superficial 

 epigastric artery empty themselves by one or 

 more trunks into the vena saphena at the upper 

 part of the thigh. 



Two veins generally accompany the deep 

 epigastric artery, which empty themselves into 

 the external iliac vein. These veins are equally 

 subject to enlargement with the preceding, and 

 from similar causes, and they are often found 

 in a varicose condition in women who have 

 borne many children. 



Some curious anomalies have been observed 

 in the venous circulation of the anterior abdo- 

 minal wall, which, as being calculated to in- 

 terfere with the operator, the practitioner would 



* See the interesting case of obliterated aorta re- 

 corded by Messrs. Crampton and Goodissen. Dub. 

 Hosp. Reports, vol. ii. 



t As in the case of obliteration of the inferior 

 vena cava from the pressure of an aneurismal 

 tumour observed by Reynaud. Journal Hebdom. 

 de Med. vol. ii. p. 110. 



