Radical mastectomy is a type of surgery for breast cancer that involves removing

The most prominent impairements are loss of shoulder flexion and abduction. This makes it difficult for the patient to reach overhead or out to the side. They often have difficulty pulling a sweater over their head, grooming their head and face and reaching overhead.

Treatment is often aimed at reducing scar tissue in the upper quadrant. Range of motion is important.

Research also shoulder than women who undergo mastectomy often develop abnormal scapulohumeral dyskinesia (can't control the shoulder blade well during shoulder elevation). Although the long term effects are unknown at this point, it may make one more prone to dyskinesia related shoulder problems such as impingement. Therefore, control of the scapular stabilizers might be important as well.

Then there is just the loss of the pectoralis major itself which can often lead to difficulty pushing objects. Pec minor, anteiror deltoid and perhaps brachialis may assist in recovery of this function.