American Board of Surgical Assistants (ABSA) Orthopedic Practice Test

Which of the following behaviors may cause a humeral shaft fracture?

1. Overhead lifting

2. Direct blow to the arm

3. Rotational injuries

4. All the above

The correct answer is: All the above

A humeral shaft fracture can occur due to various types of mechanical stresses placed on the humerus, and all the listed behaviors contribute to the potential for such an injury. Overhead lifting places significant stress on the upper extremities, and if done improperly or with excessive weight, it can lead to structural failure in the humerus. This type of lifting often involves extreme angles and forces that can contribute to fracture. Direct blows to the arm are another clear mechanism for humeral shaft fractures. Such trauma can occur in sports, falls, or accidents, where an impact on the arm can cause the bone to fracture due to the concentrated force. Rotational injuries involve twisting movements that can create substantial stress on the humeral shaft. These injuries can occur during certain sports activities or accidents, leading to a spiral fracture due to the torsional forces applied to the bone. Given that each behavior listed can independently contribute to the risk of a humeral shaft fracture, it is accurate to conclude that all the options collectively represent potential causes of this type of injury.