Final answer:
An anteromedial supracondylar fracture can affect the ulnar collateral ligament, while an anterolateral supracondylar fracture may involve the lateral collateral ligament complex and possibly the radial nerve, leading to potential elbow instability and risk of muscle damage and ligament integrity issues.
Step-by-step explanation:
In the context of elbow fractures, an anteromedial supracondylar fracture primarily affects structures such as the ulnar collateral ligament, while an anterolateral supracondylar fracture might affect other ligaments and possibly the radial nerve. The immediate concerns are arterial compression leading to forearm ischemia and potential nerve damage.
In the case of an anteromedial fracture, the ulnar collateral ligament, arising from the medial epicondyle of the humerus and attaching to the proximal ulna, is particularly at risk. As this ligament resists hyperextension of the elbow, damage to this area can be critical. Conversely, an anterolateral supracondylar fracture may pose risks to the lateral collateral ligament complex and the radial nerve which traverses the lateral aspect of the elbow.
Both types of fractures are serious and can lead to instability of the elbow joint, and necessitate prompt medical attention to minimize complications such as muscle damage and issues with ligament integrity.