A 55-year-old woman undergoes a modified radical mastectomy for breast cancer. Postoperatively, she is unable to abduct her arm beyond 90 degrees and has difficulty combing her hair. Which nerve is most likely injured?

• A Long thoracic nerve
• B Nerve to latissimus dorsi
• C Intercostobrachial nerve
• D Thoracodorsal nerve ✓

Explanation

Injury to the thoracodorsal nerve results in paralysis of the latissimus dorsi muscle, leading to loss of adduction and medial rotation of the shoulder, which manifests as difficulty in abduction beyond 90 degrees. Long thoracic nerve injury causes winging of the scapula, while intercostobrachial nerve injury causes numbness of the upper medial arm.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.