What type of nerve injury may cause paraesthesia in the armpit after breast surgery?

The presence of paraesthesia in the armpit following breast surgery is most commonly associated with an injury to the intercostobrachial nerve. This nerve arises from the T2 spinal nerve and supplies sensation to the skin of the axilla and the upper medial arm. During breast surgery, particularly in procedures involving the axillary region, this nerve can be accidentally disrupted or severed, leading to loss of sensation or altered sensation, which manifests as paraesthesia.

In contrast, while an axillary nerve injury can cause sensory loss in the lateral aspect of the shoulder, it does not typically result in symptoms localized to the armpit area. Radial nerve injuries mainly affect the posterior arm and forearm, causing wrist drop and loss of ability to extend the forearm and hand, but again, do not relate to the armpit. The median nerve injury primarily affects the hand and forearm control, having no involvement with armpit sensation. Thus, the intercostobrachial nerve is the most relevant choice when considering paraesthesia specifically located in the armpit after breast surgery.