ABSTRACT
Ansa pectoralis is the loop of communication between medial and lateral pectoral nerves, seen anterior to the second part of axillary artery. It carries C7 ?bres from the lateral cord to the medial pectoral nerve and supplies sternocostal part of pectoralis major muscle. Its damage can cause weakness of the sternocostal part of pectoralis major muscle. Section of the ansa pectoralis is done as a treatment modality to reduce spasm of pectoralis major after strokes. It is also used as nerve graft. There are only few articles which describe the anatomy of Ansa pectoralis. We conducted a dissection study in 36 pectoral regions of embalmed human cadavers to ?nd out the number, location, formation and branches of Ansa pectoralis. During dissection of the pectoral region, the formation of Ansa was seen to be of four different types. 72.2%(26 out of 36) was either between inferior or deep branch of lateral pectoral nerve and medial pectoral nerve or between the inferior lateral pectoral nerve and medial pectoral nerve (type A). In 6 cases (16.7%) it was between trunk of the lateral pectoral nerve and medial Pectoral nerve (type B). In 3 cases (8.3%), it was arising from lateral cord itself (Type C). In one case (2.7%) it was found to be arising from trunk and inferior branch of lateral pectoral nerve (Type D). The communicating loop was on the axillary artery in about 52.8% percentage of specimens, distal and plastered to the deep surface of pectoralis minor muscle in the 30.5% and multiple in 16.7%. The anatomy of Ansa pectoralis shows many variations. These are important while planning surgeries in pectoral region like breast augmentation, pectoral nerve blocks and harvesting pectoral nerve grafts.