Ansa pectoralis

The ansa pectoralis is a nerve loop that connects the lateral pectoral nerve and the medial pectoral nerve. This anatomical structure plays an important role in the coordinated innervation of the pectoral muscles.

The lateral pectoral nerve arises from the lateral cord of the brachial plexus and primarily innervates the upper portions of the pectoralis major muscle. In contrast, the medial pectoral nerve originates from the medial cord of the brachial plexus and innervates both the pectoralis minor muscle and the lower portions of the pectoralis major.

The ansa pectoralis typically forms immediately distal to the thoracoacromial artery, creating a neural communication between the lateral and medial pectoral nerves. This connection enhances the functional integration of the innervation between the upper and lower sections of the pectoralis major and the pectoralis minor muscles, supporting their coordinated actions.