Final answer:
A transhumeral amputation is the removal of the humerus bone at the proximal level of the shaft, above the middle of the upper arm but below the shoulder joint.
Step-by-step explanation:
An amputation at the proximal level of the shaft of the humerus would be designated as a transhumeral amputation. This type of amputation involves the removal of the humerus bone at or above the midpoint of the upper arm but below the shoulder joint. This contrasts with other types of amputations such as supracondylar amputation (occurring just above the elbow joint), shoulder disarticulation (removal of the entire arm including the shoulder joint), and forequarter amputation (removal of the entire arm along with shoulder blade and collar bone).