A shoulder can dislocate during sleep, though it’s less common than dislocations from direct trauma. This painful event, known as atraumatic instability, occurs when underlying conditions or sleeping habits cause the shoulder joint to come out of its socket.
The Possibility of Nocturnal Dislocation
A shoulder dislocation during sleep often arises from specific positions that place unusual stress on the joint. For instance, sleeping with the arm extended overhead or tucked awkwardly beneath the body can create leverage that forces the humerus, or upper arm bone, out of its socket. Involuntary movements or sudden muscle spasms during sleep can also act as a trigger, particularly if the shoulder is already in a vulnerable position. The shoulder joint, being a highly mobile ball-and-socket joint, relies on surrounding structures for stability, and extreme positions can compromise this balance.
Factors Increasing Risk
Several factors can increase an individual’s susceptibility to a shoulder dislocation while sleeping. A history of previous shoulder dislocations is a significant risk factor, as the ligaments and tissues supporting the joint may have been stretched or damaged, leading to recurrent instability. Individuals with generalized ligamentous laxity, meaning naturally stretchy ligaments throughout their body, are also at higher risk because their joints have increased range of motion and less inherent stability. Weakness in the rotator cuff muscles, which are important for stabilizing the shoulder, can further predispose someone to dislocation. Certain neurological conditions that cause uncontrolled muscle movements, such as seizures, can also lead to dislocating the shoulder during sleep.
Recognizing a Dislocation and What to Do
Waking up with severe pain in the shoulder is a primary indicator of a dislocation. The shoulder may appear visibly deformed, often described as having a “squared-off” appearance, and there might be a noticeable lump where the bone has displaced. Movement of the arm becomes nearly impossible, and attempts to move it can cause significant pain. Numbness or tingling sensations in the arm and hand, along with muscle spasms around the joint, are also common symptoms.
If a shoulder dislocation is suspected, seek immediate medical attention, usually at an emergency room. Do not attempt to “pop” the shoulder back into place yourself or allow an untrained person to do so, as this can cause further damage to nerves, blood vessels, ligaments, or even lead to fractures. While waiting for medical help, try to keep the arm as still as possible, perhaps by using a sling or supporting it close to the body. Applying an ice pack to the affected area can help reduce pain and swelling. Healthcare professionals will perform a closed reduction, a procedure to gently manipulate the bone back into its socket, often with pain relief or sedation.
Strategies for Prevention
Implementing strategies can significantly reduce the risk of nocturnal shoulder dislocations, especially for those prone to them. Modifying sleeping positions is often recommended; back sleeping is generally considered the most stable position, as it evenly distributes weight and minimizes pressure on the shoulder joint. If sleeping on the side, sleep on the non-affected side and use a pillow to support the injured arm in front of the chest or between the arm and torso. Avoiding sleeping on the stomach or with the arm extended overhead can prevent awkward positioning that stresses the joint.
Regularly performing strengthening exercises for the rotator cuff and surrounding shoulder muscles can enhance joint stability. These exercises should ideally be guided by a physical therapist to ensure proper technique and to address any specific muscle imbalances. A physical therapist can also recommend specific stretches and provide advice on gradually increasing shoulder mobility. Addressing any underlying medical conditions that contribute to joint instability, such as generalized ligamentous laxity, through targeted physical therapy can also be beneficial in long-term prevention.