The glenohumeral joint is the primary joint of the shoulder complex. It is a ball-and-socket joint formed by the head of the humerus, which is the upper arm bone, and the glenoid fossa, which is the socket on the scapula. The bones of the glenohumeral joint are held together by a surrounding capsule and several ligaments, while the surfaces of the bones that come into contact with each other are covered in cartilage.
Shoulder Anatomy
The shoulder is a complex joint that includes four bones – the humerus, scapula, clavicle, and the sternum. The glenohumeral joint, as mentioned earlier, is formed where the humerus and scapula meet. The acromioclavicular joint is where the acromion process of the scapula and the clavicle meet. The sternoclavicular joint is where the clavicle meets the sternum. All of these joints work together to enable movement and support for the upper extremity and to allow the arm to move freely in many directions.
Glenohumeral Joint Movements
The glenohumeral joint allows for a wide range of movements that are necessary for everyday activities. It allows the arm to move in multiple directions and planes, including flexion, extension, abduction, adduction, internal and external rotation. Flexion occurs when you raise your arm, while extension is the opposite, the lowering of the arm. Abduction is the movement of the arm out sideways from the body, while adduction is bringing it back in. Internal rotation occurs when the arm moves inward toward the center of the body, and external rotation when it moves outward.
Rotator Cuff Muscles
The glenohumeral joint is stabilized by the rotator cuff muscles, which originate from the scapula and attach to the humerus. The four rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. The muscles work in harmony to keep the humerus within the glenoid fossa during movement and prevent it from dislocating.
Shoulder Blade Muscles
Also, shoulder blade muscles attach from the scapula to the thoracic wall and the clavicle, and help to stabilize the scapula during movements of the arm. The muscles include the trapezius, seratus anterior, levator scapulae, and rhomboid muscles.
Common Injuries of the Glenohumeral Joint
The glenohumeral joint is susceptible to several injuries, including dislocations, rotator cuff tears, tendonitis, and frozen shoulder.
Dislocations
A dislocation of the glenohumeral joint occurs when the humerus is forced out of the glenoid fossa. This can happen due to a fall or injury, and the joint will need to be reduced, which involves manipulating the bones back into their proper position. Recurrent dislocations can lead to instability of the joint and the possible need for surgery.
Rotator Cuff Tears
Rotator cuff tears are common and are often due to repetitive overhead movements. They can range in severity from small tears to complete ruptures. The resulting pain and weakness can severely impact the patient’s daily activities. The treatment will depend on the severity of the tear and may include rest, physical therapy, or surgery.
Tendonitis
Tendinitis is an inflammation of the tendons that attach the muscles to the bones. It can be caused by overuse, injury, or aging. Symptoms include pain and tenderness in the shoulder area that increases with movement. Treatment may include rest, ice, anti-inflammatory medication, and physical therapy.
Frozen Shoulder
Frozen shoulder, also known as adhesive capsulitis, is a condition where pain and stiffness develop in the shoulder joint. The cause of frozen shoulder is not well understood, but it is more common in individuals with a history of diabetes, thyroid dysfunction, or after a shoulder injury. Treatment may include pain management, physical therapy, and in severe cases, surgery.
Prevention and Treatment of Injuries
Prevention
Preventative measures can be taken to help prevent injuries to the glenohumeral joint. Maintaining proper posture, using proper technique when lifting, and avoiding repetitive overhead motions can help reduce the incidence of injuries. Additionally, participating in a regular exercise program that includes strengthening exercises that target the rotator cuff muscles can help prevent injuries.
Treatment
Treatment for injuries to the glenohumeral joint varies depending on the severity of the injury. Treatment options might include rest, physical therapy, anti-inflammatory medication, or surgery. Surgery may be indicated for severe injuries, but most can be managed conservatively with physiotherapy and rehabilitation.
Conclusion
The glenohumeral joint is a vital joint in the upper extremity, with key roles in the performance of day-to-day activities, such as lifting objects and reaching for overhead items. Injuries to the glenohumeral joint are common and can be extremely debilitating, resulting in severe pain and functional limitations. Proper prevention and treatment of injuries can help to prevent long-term complications and restore function to the shoulder complex.
Questions and Answers
- Q: What is the Glenohumeral Joint?
- A: The glenohumeral joint is the primary joint of the shoulder complex, formed by the humerus and glenoid fossa.
- Q: What movements does the Glenohumeral Joint allow?
- A: The glenohumeral joint allows for a wide range of movements such as flexion, extension, abduction, adduction, internal and external rotation.
- Q: What are the rotator cuff muscles?
- A: The four rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. They help to stabilize the joint and keep the humerus within the glenoid fossa during movement.
- Q: What are some common injuries to the Glenohumeral Joint?
- A: Common injuries to the glenohumeral joint include dislocations, rotator cuff tears, tendonitis, and frozen shoulder.
- Q: How can we prevent injuries to the Glenohumeral Joint?
- A: Proper posture, using proper technique when lifting, avoiding repetitive overhead motions, and exercise programs can help prevent injuries to the glenohumeral joint.
- Q: What is the treatment for injuries to the Glenohumeral Joint?
- A: Treatment for injuries to the glenohumeral joint varies depending on the severity of the injury, but may include rest, physical therapy, anti-inflammatory medication, or surgery.
References
1. Sarwahi, V., Mupparapu M. Glenohumeral joint assessment. StatPearls
2. Terry, G. Complications and pitfalls of shoulder arthroscopy. Oper Tech Sports Med 2009;17:88-96.
3. Yamamoto, A., Takagishi, K., Osawa, T., et al. Prevalence and risk factors of a rotator cuff tear in the general population. J Shoulder Elbow Surg 2010;19:116-20.
4. Chuang, T. Y., Ho, C. P., Yu, B., et al. Risk factors for frozen shoulder in patients with traumatic brain injury after stroke: A nationwide population-based study. Arch Phys Med Rehabil 2017;98:2313-20.