This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
Aerial anastomosis around the shoulder is between 
Select and explain. 
A. 2nd pa of subclan aery with 2nd pa of axillary aery, B. 1st pa of subclan aery with 3rd pa of axillary aery, C. 3rd pa of subclan aery with 1st pa of axillary aery, D. 3rd pa of subclan aery with 3rd pa of axillary aery
B: 1st pa of subclan aery with 3rd pa of axillary aery
Answer: B: 1st pa of subclan aery with 3rd pa of axillary aery 
Explanation: -Aerial anastomosis around the scapula is principally formed by the first pa of subclan and third pa of axillary aeries. -These anastomosis takes place at 2 sites :around the body of the scapula and over the acromion process of the scapula. -If the subclan and axillary aeries are blocked anywhere between these 2 sitesscapular anastomosis serves as a potential pathway of collateral circulation to ensure adequate blood supply to the upper limb -Reference: Textbook of anatomy,Upper limb and thorax, Vishram Singh, 2nd editon, page no.51