**2. Pathoanatomy**

Being a major synovial joint of the body and also because of its inherent unstable nature, the shoulder joint is affected by many pathologies.

Adhesive capsulitis which is commonly called as a frozen shoulder is an inflammatory response to systemic or local painful pathologies like diabetes mellitus, hypothyroidism, hypertension, etc. As the frozen shoulder progresses, movement in the shoulder can be severely limited. In the later stage as the pain decreases, range of motion improves but never to the original level. Medications, injections, physiotherapy, and home exercises usually help in most of the patients. If it is not, arthroscopic capsular release followed by rehab gives well to excellent results [2].

Primary osteoarthritis of the shoulder is quite rare, but secondary osteoarthritis due to trauma, rotator cuff insufficiency, RA, gout, etc. is quite common. As we all know, it is painful and is a debilitating condition affecting day-to-day activities. Total shoulder and reverse shoulder are the modalities of treatment when the patient does not improve by conservative ways.

Rotator cuff tears can be traumatic or degenerative in older age groups from repeated overuse. It causes pain, functional, and motion restrictions. As per the recent research publications, many patients with full-thickness rotator cuff showed fair to good functional results. These are called compensated rotator cuff tears. On the contrary tear goes on progressing over the period. Patients who do not improve with all these conservative measures are treated with either open or arthroscopic repair techniques. Arthroscopic techniques are far better than the open one, giving the patient the benefits of minimally invasive surgery, anatomic repairs, and rapid recovery (**Figure 2**).

Shoulder dislocation can be anterior, posterior, or multidirectional. It can be traumatic or due to generalized ligament laxity. Traumatic dislocations are usually associated with tear of the labrum, humeral head bony defect, capsular tears, and muscle and nerve injuries. In emergency settings it is reduced under anesthesia, and sling is applied followed by physiotherapy. Most of the patients do well with this, but if it becomes recurrent due to capsulolabral nonhealing, big humeral bone defect (Hill-Sachs lesion), and/or glenoid bone loss, surgery is indicated. Most of the patients can be managed with arthroscopic repair, but few may require bony procedures like Latarjet, etc. (**Figure 3**).

Since the biceps plays an important role in shoulder stability and function, many biceps pathologies may cause pain and disability. Biceps tendon problems like tendinopathy or tenosynovitis as well as SLAP lesions compromise optimal shoulder function and may result in impingement. Biceps tenotomy in older population and tenodesis in younger patients are the treatments of choice (**Figure 4**) [3].

Glenohumeral internal rotation deficit, often referred to as GIRD, is a sport-specific adaptation of posterior shoulder structures to chronic excessive overload of these structures during frequent throwing. Burkhart et al. [13] report that GIRD occurs before any other motion adaptation, suggesting that contracture of the posterior capsule is to blame for this change in range

**Figure 2.** Arthroscopic view of Rotator cuff tear.

On the inner most aspect of the joint is an intracapsular structure called glenoid labrum which not only deepens the glenosphere but also provides strong all-round stability to the shoulder joint through the tension and compression it creates through capsular ligaments like superior, middle, and inferior glenohumeral ligaments in association with rotator cuff. The anterior part of inferior glenohumeral ligament is the most important anteroinferior stabilizer. Long

The shoulder joint is surrounded by many neurovascular structures like the brachial plexus, axillary nerve, suprascapular nerve, musculocutaneous nerve, brachial artery, and lungs.

Being a major synovial joint of the body and also because of its inherent unstable nature, the

Adhesive capsulitis which is commonly called as a frozen shoulder is an inflammatory response to systemic or local painful pathologies like diabetes mellitus, hypothyroidism, hypertension, etc. As the frozen shoulder progresses, movement in the shoulder can be severely limited. In the later stage as the pain decreases, range of motion improves but never to the original level. Medications, injections, physiotherapy, and home exercises usually help in most of the patients. If it is not, arthroscopic capsular release followed by rehab gives well

Primary osteoarthritis of the shoulder is quite rare, but secondary osteoarthritis due to trauma, rotator cuff insufficiency, RA, gout, etc. is quite common. As we all know, it is painful and is a debilitating condition affecting day-to-day activities. Total shoulder and reverse shoulder are

the modalities of treatment when the patient does not improve by conservative ways.

head of biceps originating from the superior labrum helps in shoulder stability.

These structures are always vulnerable to injury in shoulder trauma.

shoulder joint is affected by many pathologies.

**2. Pathoanatomy**

**Figure 1.** Muscles and nerves.

2 Advances in Shoulder Surgery

to excellent results [2].

forces on upper arm causing impingement. Internal impingement comprises encroachment of the rotator cuff tendons between the humeral head and the glenoid rim. Anterosuperior and posterosuperior glenoid impingements have been described based on its location.

Introductory Chapter: Shoulder Joint http://dx.doi.org/10.5772/intechopen.76187 5

The posterosuperior impingement consists of the mechanical encroachment of the rotator cuff tendons, particularly the tendon of the supraspinatus and infraspinatus, between the greater tubercle of the humerus and the posterosuperior rim of the glenoid. This friction occurs specifically during the late cocking position of throwing, which is maximal external rotation, horizontal abduction, and, depending on the specific-sport discipline, a certain amount of abduction. Besides the classification of impingement based on the site of encroachment, a very often impingement is classified based on the cause of the problem, dividing it into primary versus secondary impingement. In primary impingement, a structural narrowing of the subacromial space causes pain and dysfunction, such as acromioclavicular arthropathy, type II acromion, or swelling of the soft tissue in the subacromial space. In secondary impingement, there are no structural obstructions causing the encroachment but rather functional

Winging of the scapula is a condition where due to insufficiency of scapular muscles, scapular stability is affected and it moves up like a wing. It can mimic as pseudo-instability of the shoulder. Scapular dyskinesia also has been described in relation to impingement symptoms [4]. This is because during arm elevation, impingement may occur if the scapula insufficiently follows the humeral head movements because of a lack of upward rotation, posterior tilting, and external rotation. Neuromuscular stimulation and scapular muscle strengthening

Tractional damage to the suprascapular nerve leads to suprascapular neuropathy causing an aching or burning pain at the back and/or side of the shoulder joint. Sometimes, a cyst can develop in the region causing symptoms of neural compression and severe shoulder pain. MRI usually diagnoses the condition. It can be treated with arthroscopic

problems, occurring only in specific positions.

improve the condition (**Figure 5**).

decompression.

**Figure 5.** Winging of Scapula.

**Figure 3.** Anteroinferior Glenoid labrum tear.

**Figure 4.** Arthroscopic View of Long head Biceps tear.

of motion and is sometimes followed by associated gains in ER. Other researchers believe that GIRD begins in the early years of overhead throwing with a bony adaptation of the humerus. A third hypothesis regarding the cause of GIRD is muscle hypertony in the external rotators due to frequent eccentric loading.

Shoulder bursitis, impingement, and tendonitis are painful conditions due to the involvement of narrow subacromial space causing pain with overhead activities or compressive forces on upper arm causing impingement. Internal impingement comprises encroachment of the rotator cuff tendons between the humeral head and the glenoid rim. Anterosuperior and posterosuperior glenoid impingements have been described based on its location.

The posterosuperior impingement consists of the mechanical encroachment of the rotator cuff tendons, particularly the tendon of the supraspinatus and infraspinatus, between the greater tubercle of the humerus and the posterosuperior rim of the glenoid. This friction occurs specifically during the late cocking position of throwing, which is maximal external rotation, horizontal abduction, and, depending on the specific-sport discipline, a certain amount of abduction. Besides the classification of impingement based on the site of encroachment, a very often impingement is classified based on the cause of the problem, dividing it into primary versus secondary impingement. In primary impingement, a structural narrowing of the subacromial space causes pain and dysfunction, such as acromioclavicular arthropathy, type II acromion, or swelling of the soft tissue in the subacromial space. In secondary impingement, there are no structural obstructions causing the encroachment but rather functional problems, occurring only in specific positions.

Winging of the scapula is a condition where due to insufficiency of scapular muscles, scapular stability is affected and it moves up like a wing. It can mimic as pseudo-instability of the shoulder. Scapular dyskinesia also has been described in relation to impingement symptoms [4]. This is because during arm elevation, impingement may occur if the scapula insufficiently follows the humeral head movements because of a lack of upward rotation, posterior tilting, and external rotation. Neuromuscular stimulation and scapular muscle strengthening improve the condition (**Figure 5**).

Tractional damage to the suprascapular nerve leads to suprascapular neuropathy causing an aching or burning pain at the back and/or side of the shoulder joint. Sometimes, a cyst can develop in the region causing symptoms of neural compression and severe shoulder pain. MRI usually diagnoses the condition. It can be treated with arthroscopic decompression.

**Figure 5.** Winging of Scapula.

of motion and is sometimes followed by associated gains in ER. Other researchers believe that GIRD begins in the early years of overhead throwing with a bony adaptation of the humerus. A third hypothesis regarding the cause of GIRD is muscle hypertony in the external rotators

Shoulder bursitis, impingement, and tendonitis are painful conditions due to the involvement of narrow subacromial space causing pain with overhead activities or compressive

due to frequent eccentric loading.

**Figure 4.** Arthroscopic View of Long head Biceps tear.

**Figure 3.** Anteroinferior Glenoid labrum tear.

4 Advances in Shoulder Surgery
