Final answer:
The deltoid and portions of the pectoralis major are potential muscle sites for control of a myoelectric elbow following a shoulder disarticulation, as they are likely unaffected by the disarticulation and can provide reliable EMG signals.
Step-by-step explanation:
For individuals with a shoulder disarticulation, muscles suitable for the control of a myoelectric elbow would likely include those that are unaffected by the disarticulation and have consistent, distinguishable electromyography (EMG) signals. Considering the anatomy, muscles such as the deltoid, which is involved in arm movements, or portions of the pectoralis major, which are part of the muscles that move the humerus, could be potential sites for myoelectric control points.
These muscles remain intact in most shoulder disarticulations, and their activity could be harnessed to control a prosthetic elbow. However, it's critical to evaluate each individual's remaining musculature to determine the best sites for electrode placement to ensure effective control of the myoelectric prosthetic.