Quick Facts
Origin: Lateral pectoral nerve.
Course: In the axilla, from near the proximal end of the lateral pectoral nerve medially and inferiorly, across the axillary artery, to the proximal portion of the medial pectoral nerve.
Branches: None.
Supply: Motor innervation. Supplies the pectoralis minor and major muscles.
Origin
The ansa pectoralis originates as a branch from the proximal portion of the lateral pectoral nerve.
Course
The ansa pectoralis runs from its origin on the lateral pectoral nerve inferiorly and medially. It crosses anterior to the second segment of the axillary artery and continues to the proximal region of the medial pectoral nerve. Here it joins to the medial pectoral nerve and continues with it anteriorly into both pectoralis minor and major muscles.
Branches
There are no branches to the ansa pectoralis. It is a single loop, sending axons from the lateral pectoral nerve to the medial pectoral nerve.
Supplied Structures
The ansa pectoralis carries motor fibers from the lateral pectoral nerve to the medial pectoral nerve. These fibers innervate first the pectoralis minor muscle, and then the pectoralis major muscle.
