ANATOMIC VARIATIONS OF MEDIAL PECTORAL NERVE DETECTED DURING 50 MASTECTOMIES

Abstract

Modified radical mastectomy is one of the standard surgical treatments for breast cancer and the difference between modified and radical mastectomy is the preservation of the pectoralis major muscle which is innervated by medial and lateral pectoral nerves. Frequent anatomic variations of localization and number of the medial pectoral nerve may cause its damage during axillary dissection for breast cancer.

In this study the anatomic localization of the nerves of the pectoralis major muscle were reported for 50 patients who had modified radical mastectomy for breast cancer. All cases had lateral pectoral nerve located medial to the pectoralis minor muscle. Single branched medial pectoral nerve was located lateral to the pectoralis minor muscle for 12 (24%) patients, passing through the muscle for 23 (46%) patients and medial to muscle for 2 (4%) patients. On the other hand, double branched medial pectoral nerve of which one lateral and one passing through the muscle was observed for 8 (16%) patients and lastly two or more branches passing through the muscle for 5 (10%) patients. Different localization and number of the medial pectoral nerve of the pectoralis major muscle makes it necessary to dissect axilla near to the pectoralis minor muscle very carefully in order to avoid nerve damage. Otherwise there will be no difference between modified and radical mastectomy as the long term seguela of the operation is concerned.