Formed between the branches of the first part of the subclavian and the third part of the axillary arteries.
takes place at two sites:
around the body of scapula
occurs between
Circumflex scapular artery,
Suprascapular artery,
Deep branch of the transverse cervical artery,
over the acromion process
It occurs between the
(a) acromial branch of thoraco-acromial artery,
(b) acromial branch of the suprascapular artery
(c) acromial branch of the posterior circumflex humeral artery.
