While fireman Fred is fighting a fire in a building, part of the ceiling collapses, and a beam strikes him on his left shoulder. He is rescued, but has a great deal of pain in his shoulder. He cannot move his arm properly, especially in the anterior direction. His clavicle is not broken, and his humerus is intact. What is the probable nature of Fred’s injury?

Verified step by step guidance

1. Consider the anatomy of the shoulder joint, which includes the clavicle, scapula, and humerus, along with associated muscles, tendons, and ligaments.
2. Since the clavicle and humerus are intact, focus on the soft tissues, such as the rotator cuff muscles, which are crucial for shoulder movement.
3. The inability to move the arm properly, especially in the anterior direction, suggests a possible injury to the rotator cuff, particularly the muscles responsible for forward movement, like the supraspinatus or subscapularis.
4. Evaluate the possibility of a rotator cuff tear or strain, which can occur due to trauma and result in pain and limited range of motion.
5. Consider the need for imaging studies, such as an MRI, to confirm the diagnosis and assess the extent of any soft tissue damage.

Key Concepts

Shoulder Anatomy

The shoulder is a complex joint involving the humerus, scapula, and clavicle, allowing a wide range of motion. Key structures include the rotator cuff, which stabilizes the shoulder, and the glenohumeral joint, which facilitates movement. Understanding the anatomy helps in identifying potential injuries, especially when movement is restricted.

Rotator Cuff Injuries

Rotator cuff injuries are common in shoulder trauma and can result from acute impacts or chronic wear. These injuries often lead to pain and limited range of motion, particularly in lifting the arm. Given Fred's inability to move his arm anteriorly, a rotator cuff strain or tear is a likely consideration.

Shoulder Dislocation

A shoulder dislocation occurs when the humerus is forced out of its socket in the scapula, often due to trauma. Symptoms include severe pain, swelling, and an inability to move the arm. Although Fred's humerus is intact, the mechanism of injury suggests a possible subluxation or partial dislocation, which could explain his restricted movement.