Formed by branches of- Subclan aery - first pa - Suprascapular aery - Deep branch of transverse cervical aery Axillary aery - third pa - Subscapular aery & its circumflex scapular branch There are other smaller anastomoses over the acromion process, which also helps to maintain .flow to arm. (BDC Vol I, 4/e, p 82) Anastomoses over the acromion process Formed by - a)Acromial br. of thoraco-acromial aery b)Acromial br. of suprascapular aery c)Acromial br. of posterior circumflex humeral aery The subscapular aery also forms anastomoses with intercostal aeries