Wrist Sprain: This is the most common injury after a fall onto an outstretched hand, leading to swelling and a bump on the wrist due to ligamentous injury.

Wrist Fracture: A fracture, especially of the distal radius (Colles' fracture), is a common consequence of falling onto an outstretched hand, which could present as a bump or deformity on the wrist.
Hematoma: Blood accumulation under the skin due to injury from the fall, which could appear as a bump.
Contusion: A bruise resulting from blood leakage into the tissues after an injury, which might feel like a bump.

Scaphoid Fracture: Although less common, a fracture of the scaphoid bone is a significant concern because it can lead to avascular necrosis if not promptly diagnosed and treated. It often presents with wrist pain and swelling but might not always have an obvious deformity.
Ganglion Cyst Rupture: If a pre-existing ganglion cyst ruptures due to the fall, it could cause acute swelling and a bump. While not usually dangerous, missing this diagnosis could lead to unnecessary tests or treatments.
Compartment Syndrome: A rare but serious condition where increased pressure within a muscle compartment leads to nerve and muscle damage. It's crucial to identify this condition early to prevent long-term damage.

Osteochondritis Dissecans: A joint condition in which a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone because of inadequate blood supply. It could potentially be exacerbated by a fall.
Infection (e.g., Cellulitis or Abscess): If the skin is broken during the fall, there's a risk of infection, which could present as a bump or swelling on the wrist.
Tumor: Although extremely rare, a pre-existing tumor could potentially be irritated or become more noticeable after a fall, presenting as a new bump on the wrist.