2 4 2 PRACTICAL ANATOMY. 



13. Do the lumbar arteries assist in furnishing the peritoneum with blood / 

 Yes ; the same arteries that supply the walls, supply the peritoneum cover- 

 ing the walls. 



14. What can you say of the lumbar arteries f 



They are four in number on each side. They are analogous to the intercos- 

 tal arteries. They arise from the abdominal aorta. The right are longer than 

 the left lumbar arteries. These arteries are small when compared to their homo- 

 logues, the intercostals. The lumbar arteries lie behind the abdominal sympa- 

 thetic chain. According to their distribution, the lumbar arteries are classified 

 as dorsal branches and abdominal branches. Each has specific relations and 

 course. The dorsal branches pass out between the transverse processes of the 

 lumbar vertebrae, with the posterior primary divisions of the lumbar nerves, and 

 attended by their corresponding lumbar veins, to be distributed to the spinal 

 cord, passing through the intervertebral foramina; to the muscles and skin of the 

 back ; and to the lumbar vertebrae in this region. The abdominal branches of the 

 lumbar arteries pass behind the sympathetic chain and behind the quadratus lum- 

 borum muscle. They are distributed to the quadratus lumborum and psoas 

 magnus muscles and to the abdominal walls. 



I 5 . What can you say of the anastomosis of the lumbar arteries / 

 The dorsal branches anastomose with each other and with the intercostals. 

 The abdominal branches of the lumbar arteries anastomose : (i) Above with the 

 lower intercostal arteries ; (2) below with the ilio-lumbar and circumflex iliac ; 

 (3) in front with the epigastric and internal mammary. 



1 6. If the abdominal aorta were ligated just above the bifurcation, how could 

 the blood reach the loiuer extremities ? 



Through two channels: (i) The epigastro-mammary arch ; (2) the lumbo- 

 circumflex anastomotic arch. 



17. Describe the epigastro-mammary anastomotic arch. 



An arch formed by anastomosis between the deep epigastric artery, a branch 

 of the external iliac, and the internal mammary artery a branch of the subclavian. 

 This union occurs in the rectus abdominis muscle. 



1 8. Describe the lumbo-circumflcx anastomotic arch. 



It is an arch formed by anastomosis between the lumbar arteries, branches 

 the abdominal aorta, and the deep internal circumflex iliac artery a branch of th< 

 external iliac. 



The arteria sacra media is the sacral representative of the lumbar arteries. It 

 is to the aorta what the coccyx is to the vertebral column, what the ensiform car- 

 tilage is to the sternum the exhaustion. It is the representative of the caudal 

 artery of some animals. Its small branches are distributed in the same manner 

 as those of the lumbar region. 



19. What can you say of the lumbar veins f 



They accompany the lumbar arteries arid are tributary to the ascending \vn; 

 cava. 



20. How would you explain the nerve-supply of the peritoneum / 



The same nerves that supply muscles that enclose a serous cavity supplj 

 the serous membrane enclosed. This principle was pointed out by Hilton am 

 Van der Kolk. The full law, as given previously, applies not only to serous 

 but to mucous membranes as well. 



21. What are the functions of peritoneum f 



It secretes serum for lubrication of opposed surfaces. It is a highly absorp- 

 tive structure. It forms ligaments for holding organs in place. It protect 

 organs against violence. It gives strength to organs which it invests. It con 

 serves heat and piwrnts sudden changes of temperature. 



22. Is serum ever secreted in abnormally large quantities f 



