Which muscle divides the axillary artery into three parts?

Ans. is 'a' i.e., Pectoralis Minor Axillary artery* It is the main artery of upper limb. It begins at the level of outer border of first rib as a continuation of subclavian artery.It ends at the level of lower border of teres major to continue as brachial artery.* The axillary artery is covered anteriorly by pectoralis minor, which divides it into three parts:-1) First part# This part is proximal to upper border of pectoralis minor, i.e. extends from outer border of first rib to upper border of pectoralis minor.# The branch of first part is Superior thoracic artery.2) Second part# This part is behind pectoralis minor.# It gives following branches.a) Thoracoacromial artery:- It pierces clavipectoral foscia and gives following branches (i) Acromial (ii) Pectoral, (iii) Clavicular and deltoid.b) Lateral thoracic artery3) Third part:-# This part is distal to lower border of pectoralis minor, i.e. extends from pectoralis minor (lower border) to teres major (lower border).# It gives following branches -a) Subscapular artery: - It gives off circumflex scapular artery and then continues us thoracodorsal artery.b) Anterior circumflex humeral artery.c) Posterior circumflex humeral artery.