All 40 subjects will receive an ultrasound guided interscalene nerve block using 20mL "milliliters" of 0.25% bupivacaine with 1:400,000 epinephrine and 1:600,000 clonidine dosed at the upper trunk location near the 6th cervical vertebral level, per standard clinical practice. The intervention arm, consisting of 20 patients, will additionally receive the following: 10mL of 0.25% bupivacaine with 1:400,000 epinephrine and 1:600,000 clonidine at the PECS1 location and 20mL of 0.25% bupivacaine with 1:400,000 epinephrine and 1:600,000 clonidine at the PECS2 location as described by Blanco, et al.3,4 All procedures will be performed under a sterile technique including the use of chlorhexidine prep of the skin, sterile gloves, sterile ultrasound probe covers with sterile ultrasound gel, a cap and a mask. For the interscalene block, a 21 gauge 90mm "millimeter" stimulating block needle will be directed, under real-time ultrasound guidance, into the interscalene muscle space at the level of the 5th and 6th cervical nerve roots. Twenty mL of the above local anesthetic mixture will be dosed incrementally, aspirating every 5 mL, to surround the upper trunk of the brachial plexus. For the PECS 1 & 2 block, a 21 gauge 90mm stimulating block needle will be placed under real-time ultrasound guidance at approximately the level of the 4th and 5th ribs near the mid-axillary line. The needle will be advanced into a tissue plane between the serratus anterior muscle and the pectoralis minor muscle. Twenty mL of the same local anesthetic mixture will be dosed incrementally, every 5 mL, to spread within this PEC2 space. The needle will be withdrawn, following the first injection, to a tissue plane between the pectoralis minor and pectoralis major muscles. Ten mL of the same local anesthetic mixture will be dosed incrementally, every 5 mL, to spread within this PEC1 space.