Ansa Pectoralis

Description

Medial and lateral pectoral nerves and ansa pectoralis in relation to their surrounding structures

Illustration of ansa pectoralis

Schematic drawing of the cut edges of the pectoralis minor (asterisks) and the relationships of the muscle. Note the attachment onto the coracoid process and innervation by the medial pectoral nerve. Also, note the relationship between the brachial plexus and axillary artery (AA) and axillary vein (AV)

Name

• Ansa Pectoralis
• Pectoral Loop
• Pectoral Nerve Loop
• Ansa Pectoralis Nerve

General

• Represents a coalescence of the fibers of the lateral pectoral nerve and medial pectoral nerve

Gross Anatomy

• Originates a branch of the lateral pectoral nerve
• Crosses anterior to the second segment of the axillary artery
• Continues to the proximal region of the medial pectoral nerve
• They coalesce and then run together into both pectoralis muscles

Motor innervation

• Pectoralis Minor
• Pectoralis Major

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Clinical Significance

Surgical

• Important surgical landmark during axillary and breast surgeries to avoid nerve injury
• Can be injured operatively, lead to weakness of the pectoralis major and minor muscles
• Considered in pectoral nerve transfers or flaps for restoring upper limb function

Procedural

• Brachial plexus blocks should include ansa pectoralis to ensure adequate anesthesia of pectoral muscles
• May influence interpretation of pectoral muscle innervation patterns

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See Also

• Shoulder Anatomy Main
• Neuropathies Main
• Nerve Anatomy Main

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