Occlusion occurs at the 2nd part of axillary artery, blood flow is maintained by anastamosis between :
Anastomosis around scapula maintains the blood supply when there is an obstruction at 2nd part of axillary artery.
Anastomosis around body of scapula :
This is formed by

Suprascapular branch of subclavian artery.
Deep branch of transverse cervical artery which is a branch of thyrocervical trunk from subclavian artery and
Circumflex scapular branch of subscapular artery from 3rd part of axillary artery.

Anastomosis on the acromion process :
This is formed by

Acromial branch of thoracoacromial artery from 2nd part of axillary artery.
Ascending branch of posterior circumflex humeral artery from 3rd part of axillary artery and
Acromial branch of Suprascapular artery from subclavian artery.
Anterior and posterior circumflex humeral artery
Circumflex scapular and posterior circumflex humeral artery
Deep branch of the transverse cervical artery and subscapular artery
Anterior circumflex artery and subscapular artery