Clinically Relevant Anatomy
ligaments of the shoulder
The shoulder joint is a synovial joint made up of three bones: the humerus, the scapula, and the clavicle. Overall stability is achieved through static and dynamic constraints. Normally, the head of the humerus is located in the center of the glenoid socket. This allows the joint surfaces to be aligned consistently with a other. In addition, glenohumeral reaction forces are contained within the glenoid arc .
However, in the case of shoulder dislocation, the net glenohumeral reaction forces are compromised. This causes the humeral head to fall outside the glenoid arc. Static constraints include joint integration adhesion/cohesion limited joint volume and ligament stability including Labrum. The inferior glenohumeral ligament (IGHL) is the primary ligamentous constraint  to anterior glenohumeral translation, especially during arm abduction and external rotation.  Due to this forward movement, the anterior lower lip and joint capsule may separate. this is called Bankart damage. Dynamic restraint consists primarily of the rotator cuff muscles, but also includes the scapular stabilizers and biceps. 
Injury Mechanism/Pathological Process
Shoulder dislocations can occur in both anterior and posterior positions. The most common is trauma due to direct posterolateral force of the shoulder. Individuals may also exhibit erratic orientation, making them prone to misalignment. In this condition, the muscles are not ready or strong Overwhelm the muscles. Its incidence of primary shoulder dislocations varies between 15.3 and 56.3 per 100 000 per year .
Anterior shoulder dislocations Anterior dislocations account for 97% of recurrent or first-time dislocations. This is the most common dislocation and is caused by excessive abduction and external rotation of the arm. In this position the glenohumeral complex Serves as the primary constraint for anterior glenohumeral translation.  The glenohumeral joint is most prone to dislocation during 90° abduction and 90° external rotation due to lack of ligamentous support and dynamic stability.
Supporting structures that may be absent in anterior dislocations are the long head of the anterior capsule of the subscapularis biceps muscle and the middle glenohumeral ligament. When the anterior capsule is thinned, it may appear between the superior glenohumeral and middle ligaments. as a Due to its inherent weakness, the humeral head is more prone to dislocation at this interval.
When a traumatic event results in an anterior dislocation, the anteriorly and inferiorly displaced humeral head stretches and often tears, resulting in loss of integrity of the anterior ligament capsule, often resulting in detachment of the anterior inferior labrum, and possibly a Hill-Sachs injury Currently.  In severe cases, simultaneous rotator cuff injuries may occur.
Posterior shoulder dislocation Posterior dislocation is less common as it accounts for 3% of shoulder dislocations. It is caused by an external blow to the front of the shoulder. There is an indirect force acting on the humerus combining flexion adduction and internal rotation. This is usually The result of a person falling on an outstretched hand (FOOSH injury) MVA or seizure. Posterior dislocation may also be accompanied by labral or rotator cuff lesions due to the traumatic mechanism of injury.
After acute anterior glenohumeral dislocation (Fig. 5):
- Arm held in an abducted and ER position
- Loss of normal contour of the deltoid and acromion, protruding posteriorly and laterally
- Humeral head palpable anteriorly
- All movements limited and painful
- Palpable fullness under the coracoid process and in the armpits 
On a thorough examination, patients may also have damage to the rotator cuff musculature, bone, blood vessels, and neural structures. Vascular structure damage is the result of stretching of the brachial plexus and axillary vessels during dislocation. Clinicians can determine whether Axillary artery injury is present by looking for decreased pulse pressure or brief coolness in the hands.  Peripheral nerve injuries after anterior dislocation are common due to the proximity to the brachial plexus (Fig. 6).
Acute posterior glenohumeral dislocation:
- Arm is abducted and IR
- May or may not lose deltoid contour
- A protruding head of the humerus may be noted
- Subscapularis tear (weakness or inability to internally rotate)
A literature review of recent research suggests that people between the ages of 15-25 should undergo surgical repair of dislocations, as those in this group are considered high-risk. However, limited evidence exists in this population. Dislocation recurrence rate Young active individuals can be as high as 92-96%.  In the 25-40 age group, the initial recommendation is to try conservative rehabilitation, as the risk of redislocation is reduced by around 40%.  People 40 and older also have a very low recurrence rate, about less than 15%.  this Recommended management is ineffective and addresses related issues.  For surgical repair, it is best to perform surgery within 2 weeks because the tissue is still in optimal condition. 
If dislocation is suspected, refer to ruling out a fracture.
- Prereduction radiographs are necessary to determine the direction of the dislocation and to assess any associated fractures. If a glenoid rim fracture is observed on the initial x-ray. A CT scan may be done to determine the size of the fracture. MRI can be used to rule out or rule out Any soft tissue lesion.  As clinicians, it is important for us to understand imaging results to help guide our course of treatment. Medical diagnosis will depend largely on local protocol but may include plain film (A/P stryker notch or Westpoint view) CT or MRI scan.
Disability of Arm, Shoulder and Hand (DASH)
Shoulder Pain and Disability Index (SPADI)
Numeric Pain Rating Scale (NPRS)
Management / Interventions
There is limited evidence or consensus regarding optimal treatment for anterior dislocations. Nonsurgical treatment may be preferred initially, but surgical revision may be required for those who fail conservative management or who require extreme use of the upper body (ie, elite level athletes). postoperative Protocol is largely surgeon-dependent and may vary based on a number of factors, including age, tissue quality, type of repair, and fixation. For anterior dislocations, the recommended non-surgical intervention is closed reduction by a physician. Anterior dislocation can be treated with surgery Fixed by stabilization program. As with any intervention plan, a physician should be contacted for specific options. Furthermore, management was similar after either intervention. However, if it was surgery, knowing what type of surgery was performed and Postoperative precautions. Typical precautions are:
- If the subscapularis is severed Internal rotation without resistance within 4-6 weeks
- External rotation is usually limited initially to 30 degrees, then to 45 degrees at 6 weeks
Wang and colleagues  proposed a three-phase protocol and discussed some suggestions for this phased approach. Phase 1 (up to 6 weeks): The goal is to maintain anterior-inferior stability
It is traditionally thought of as fixation with internal rotation, but according to Miller, fixation in external rotation is beneficial because there is greater contact force between the labrum and glenoid.  Itoi showed that fixed at 10 degrees External rotation has a lower recurrence rate than 10° internal fixation.  There is currently no consensus on the duration of sling immobilization.  However, the typical time frame for a sling is 3-6 weeks if under 40 and 1-2 weeks if over 40.  During immobilization, the focus is on AROM of the elbow and hand and pain relief. Axonometric diagrams are available for the rotator cuff and biceps musculature.
- Codman Exercises
- AAROM for external rotation (0-30º) and rake (0-90º)
Phase 2 (6-12 weeks) : The goal is to regain adequate movement, especially external rotation
- The AAROM achieves a full range of motion while allowing stretch, by passively stretching the posterior joint capsule using joint mobilization or self-stretching.
- Strengthening or repetitive exercises should not be initiated until a full range of motion has been achieved
Phase 3 (12-24 weeks) : Successful return to sport or physical activity of daily living
- Start Strengthening Exercises Strengthening exercises should focus on the injury. Strengthening exercises usually begin with pain-free movements, followed by stabilization exercises. Possible progression can begin by focusing on the rotator cuff musculature and scapular stabilizers, which include the trapezius Levator scapulae and rhomboids. Then progress to the larger musculature such as the deltoids, lats and pecs.
- Begin to focus on functional exercises, including tailored proprioceptive training to promote patient mobility and social engagement
Management of posterior dislocations follows the same progression as for anterior dislocations, except for the following guidelines: a. Swiping backwards is contraindicated. Avoid flexion adduction and internal rotation c. 3-6 weeks if younger than 40, 2-3 weeks if older than 40 age. Strengthening will focus primarily on the posterior musculature such as: infraspinatus teres minor and posterior deltoid
- Fracture (clavicular glenohumeral head greater tuberosity and proximal humerus)
- Rheumatoid Arthritis
- Rotator Cuff Injury
- Acromioclavicular Joint Dislocation
- Labral Pathology
- Shoulder Subluxation
- Axillary/suprascapular nerve palsy
- Cuéllar R, Ruiz-Ibán MA, Cuéllar A. Suppl-6, M10: Anatomy and Biomechanics of the Unstable Shoulder. The open orthopaedics journal. 2017;11:919.
- Wang RY, Arciero RA, and Mazzocca AD. The recognition and treatment of first-time shoulder dislocation in active individuals. JOSPT. 2009;39(2):118-123
- Kavaja L, Lähdeoja T, Malmivaara A, Paavola M. Treatment after traumatic shoulder dislocation: a systematic review with a network meta-analysis. British journal of sports medicine. 2018 Dec 1;52(23):1498-506.
- Boone JL, Arciero RA. First-time anterior shoulder dislocations: has the standard changed? Br J Sports Med. 2010;44:355-360.
- Miller BS, Sonnabend DH, Hatrick C, O’Leary S, Goldberg J, Harper W, et al. Should acute anterior dislocations of the shoulder be immobilized in external rotation? A cadaveric study. J Shoulder Elbow Surg. 2004; 13: 589-592
- Itoi E, Hatakeyama Y, Sato T, Kido T, Minagawa H, Yamamoto N, Wakabayashi I, et al. Immobilization in external rotation after shoulder dislocation reduces the risk of recurrence. A randomized controlled trial. J Bone Joint Surg Am. 2007; 89:2124-2131
- Scheibel M, Kuke A, Nikulka C, Magosch P, Ziesler O, and Schroeder J. How long should acute anterior dislocations of the shoulder be immobilized in external rotation? Am J Sports Med. 2009; 37:1309-1316.