Thymectomy is important in the treatment of myasthenia gravis. Total removal of the gland is considered indicated. Although median sternotomy has been the accepted surgical procedure, the transcervical approach has been advocated as a safer method of achieving total thymectomy. A surgical-anatomical study of the thymus was made in 22 patients. A high incidence of surgically important variations in thymic anatomy was found in the neck and in the mediastinum. We believe wide exposure by way of median sternotomy with direct vision is required to remove all of the extracapsular mediastinal thymus in many patients, and good cervical exposure is required to remove the anomalous tissue in the neck. If a total thymectomy is to be achieved, we recommend a median sternotomy and a cervical incision, using the meticulous dissection described.