Shoulder anatomy explained
The shoulder joint is a complex ball (humeral head) and socket (glenoid) joint with many associated soft tissue structures that can be injured.
The structure of the shoulder joint allows for a great deal of upper extremity mobility, but because of its anatomy, gains in shoulder mobility are offset by a reduction in stability.
9 most common shoulder injuries
Shoulder stability is provided statically and dynamically by the many soft tissue structures within and surrounding the joint. These tissues can easily become injured due to trauma or over time from everyday wear and tear.
Some of the most common shoulder injuries include the following:
Impingement syndrome
Impingement syndrome occurs when the supraspinatus tendon is impinged (pinched) between the humeral head and the acromion’s underside when lifting the arm. It is typically caused by weakness or dysfunction of the rotator cuff and poor scapular mechanics, but it can also be influenced by the acromion’s shape (bony structure).
Symptoms include a painful arc of motion during arm elevation, lateral shoulder pain while at rest, and night pain. This condition typically responds well to conservative therapy.
Rotator cuff tear
The rotator cuff refers to four muscles – the supraspinatus, infraspinatus, teres minor, and subscapularis – that originate on the scapula and have tendons that insert on the humeral head. The rotator cuff complex provides dynamic stability to the glenohumeral joint and depresses the humerus’ head during arm elevation.
Rotator cuff injuries can be chronic or the acute result of a fall or other trauma. Symptoms can include shoulder pain or lateral arm pain with or without motion, sharp shoulder pain with movement, night pain, and in severe cases, the inability to elevate the arm.
Non-operative treatment includes attempts to improve scapular mechanics, strengthen the rotator cuff through specific cuff exercises, and reduce symptoms to improve function.
Labrum tear
The labrum is cartilage that serves to deepen the socket (glenoid) and provide additional stability to the glenohumeral joint. The wedge-shaped labrum sits along the entire rim of the glenoid, and combined with the joint capsule and rotator cuff, it is a passive stabilizer of the glenohumeral joint. Injuries to the labrum can be acute or chronic.
- Acute injuries can occur from a sudden jerk of the arm.
- Chronic labral injuries are often seen in overhead athletes (throwers, weightlifters), gymnasts, or football players.
Labrum tears present with dull, aching shoulder pain, a “dead arm” feeling, and weak feelings. Often, patients aren’t able to perform their work-related or athletic activity without pain or discomfort.
Labrum Repair
A surgical procedure is done arthroscopically to reattach the labrum to the glenoid through anchors and suture placement.
Depending on the tear’s size and location, the surgical approach and procedure may vary and affect post-operative rehabilitation. Because of the need to protect the repaired soft tissue, the physical therapist must carefully follow post-operative guidelines and restrictions.
Rehabilitation will focus on protecting the repair, restoring range of motion (ROM) within surgeon guidelines, and improving rotator cuff strength and scapular mechanics. Return to full activity will require good surgeon/therapist communication and patient compliance during rehabilitation.
Biceps tendonitis
The long head of the biceps tendon can be a common source of anterior shoulder pain for many patients. Many factors affect predisposition to developing biceps tendon-related issues, including activity level, types of activity (sports/work), posture, and scapular mechanics.
Biceps tendon issues are commonly seen along with labral pathology, mostly SLAP tears. Conservative care for biceps tendonitis is geared towards removing the aggravating factors through the following:
- Activity modification
- Postural exercises
- Soft tissue mobilization
- Scapulohumeral exercises
- Anti-inflammatory modalities
Shoulder dislocation
A term often confused with a “shoulder separation,” a shoulder dislocation is specific to the glenohumeral joint. A dislocation occurs when the head of the humerus is forced off the edge of the glenoid.
Dislocations can occur in any direction (anterior, inferior, or posterior), although dislocations are most commonly anterior, meaning the head has been forced in front of the joint.
Most primary dislocations are traumatic. Dislocations can spontaneously reduce themselves or may require reduction by a physician. Due to the strong force needed to dislocate the shoulder, there is usually associated soft tissue trauma, including labrum tears and capsular tears. In severe cases, there can also be tendon rupture.
Depending on the severity, dislocations can be treated conservatively. Treatment includes bracing, positioning, pain reduction, strengthening, and activity modification.
The goal of conservative treatment is to allow the soft tissue to heal and scar down while minimizing dislocation recurrence through aggressive strengthening and stabilization.
Recurrent dislocation can become problematic and may require surgical intervention. Rehabilitation post-surgery requires protection of the repair through strict management of range of motion (ROM) restrictions progressing to ROM and strengthening and dynamically stabilizing the glenohumeral joint.
Multidirectional instability
Refers to a glenohumeral joint that is unstable in more than one direction. Often seen in athletes with or without traumatic injury, these patients will complain of pain with activity, pain at rest, a “dead arm,” and inability to perform daily or sport-specific activities. These patients can pop their shoulder in and out of the socket at will and do so often without discomfort.
Rehabilitation focuses on total body dynamic strengthening, dynamic shoulder/scapular stabilization, rotator cuff strengthening, and patient education.
Surgical intervention can be warranted if conservative treatment fails, although these patients may also suffer from associated soft tissue/connective tissue disorders that make them hyper-mobile.
Frozen shoulder
A controversial term that refers to a stiff (frozen) shoulder with a predictable loss of motion and the inability to perform simple, functional tasks. This condition is associated with significant pain, especially with movement, night pain, and inability to sleep. Rehabilitation is geared towards restoring motion through joint mobilization and ROM. Unfortunately, this condition is painful, and recovery can take time.
What is shoulder manipulation?
Restoration of a full range of motion while the patient is under general anesthesia. Includes tearing and breaking of adhesions in the joint capsule. Daily physical therapy follows for two weeks.
Osteoarthritis (OA)
OA is a degenerative disease process otherwise known as “wear and tear.” Chronic shoulder injuries, a history of frequent dislocations, or rotator cuff pathology can lead to excess wear and tear in the shoulder’s ball and socket.
Total Shoulder Arthroplasty/Reverse Total Shoulder Replacement
Surgical procedure in which the surgeon removes the humeral head and the glenoid and replaces them with a prosthesis. Typically, patients can expect a reduction in pain and improved function following a shoulder replacement. Physical therapy plays a role after surgery in restoring ROM and strength and improving the ability to perform daily activities.
Muscle imbalances
As experts in movement dysfunction, PTs can identify underlying muscle imbalances that lead to shoulder dysfunction. Because of the shoulder’s mobility and intrinsic lack of stability, muscular function is critical.
A physical therapist is best suited to identify muscle imbalances and faulty movement patterns that can lead to more severe injury if not addressed. If you are experiencing chronic shoulder pain or recovering from shoulder surgery, , schedule a consultation with an Alves & Martinez Physical Therapist today.