In post-ductal coarctation of aoa, blood flow to the lower limbs is maintained by increased blood flow through
The blood flow to the lower limb is maintained more likely by intercostal and superior epigastric aeries than veebral and anterior spinal aeries. In the postductal coarctation of the aoa, an extensive collateral circulation develops from the axillary aery, subclan aery, and costocervical trunk to send blood into the distal branches of the aoa- the posterior intercostal and inferior epigastric aeries. The axillary aery branches involved are : Thoraco-acromial Lateral thoracic Subscapular The enlarged branches of the subclan aery are : Suprascapular Costocervical (1st and 2nd Posterior intercostals) Internal thoracic aeries. The internal thoracic aeries gives rise to : Anterior intercostal aeries that carry blood to the posterior intercostals (3rd-6th) and thence into the descending aoa. Superior epigastric aeries that anastomoses with the inferior epigastric (in the rectus sheath) and sends blood into the external iliac aery and thence towards the lower limb. High vascularity is observed in the anterior thoracic wall as well as over the posterior thoracic wall especially in the interscapular area. The scapular anastomosis is opened up and both scapulae become pulsatile. Radiographic evidence of "rib notching" is seen in the inferior margins of the rib due to greatly enlarged posterior intercostal aeries. Also, the radiographic shadow of the enlarged shadow of the enlarged left subclan aery is quite evident clinically. Ref: Gray's Anatomy 41st edition Pgno: 1025
Inferior phrenic and pericardio phrenic aery
Intercostal and superior epigastric aery
Subcostal and umbilical aery
Veebral and anterior spinal aery
Thorax