The winged scapula is a broad triangular-shaped bone in contact with the posterior surface of the thoracic cage.
Its outer surface is hollow (glenoid fossa) for the joint with the head of the humerus. It also has two important protrusions: the scapula spine that ends up to the acromion and the coracoid process on the front side.
Normal shoulder movements involve lifting and forward tilting movements achieved by the coordinated action of various muscles of the back and shoulder. The pathological activity of one of these muscles causes the shoulder to deviate from its normal position and restricts shoulder movement.
WHAT IS THE NORMAL THORACOSCAPULAR MOVEMENT?
Shoulder movement requires not only the movement of the glenohumeral joint but also of the thoracoscapular joint. The normal movement of the scapula allows the patient to use his shoulder at work and in his daily and sports activities.
WHAT ARE THE PATHOLOGICAL TYPES OF THORACOSCAPULAR MOVEMENT?
The inability of the muscles to control the movement of the scapula results in thoracic malfunction or dyskinesia, as a result of fatigue of the shoulder stabilizing muscles during certain sports or activities.
Indeed, athletes who report shoulder pain often exhibit abnormal shoulder movement and an important part of their recovery is a physiotherapy program. In its most serious clinical manifestation, thoracoscapular dyskinesia is the result of a nerve dysfunction either due to injury or idiopathic (of unknown cause).
The loss of scapula control is often underdiagnosed by physicians. The patient may experience pain with a possible loss of normal range of motion of the shoulder. In some cases, he/she may develop instability of the glenohumeral joint due to the inability of the scapula to move in all directions.
The normal movement of the scapula provides a firm base for the head of the humerus and is achieved thanks to the coordinated action of the muscles of the back and shoulder. The inability of the scapula to move outwards and forward may lead to shoulder instability.
Clinically, the investigation of abnormal shoulder movement begins with an overview of both shoulders. Diagnosis is not difficult as the scapula may be in a lower position than normal and at a distance from the posterior thoracic wall. Some patients report pain that can mimic the rotator cuff pathology. This is due to the impingement of the tendons on the acromion that normally prevent the shoulder muscles from moving the shoulder upwards to effortlessly raise the arm. In particular, due to the weakness of the serratus anterior muscle, the scapula is unable to rotate, resulting in impact and inflammation of the rotator cuff.
CLASSIFICATION – ARE THERE DIFFERENT TYPES OF WINGED SCAPULA?
- Winged scapula with inward dislocation: It is caused by malfunction of the serratus anterior muscle, due to protrusion of the long thoracic nerve, resulting in inward and upward displacement of the inner rim (inner side) of the shoulder.
The serratus anterior muscle is a strong muscle originating from the ribs, which is inserted on the inner side of the scapula. When the muscle malfunctions, it loses the ability to control the scapula. Severe forms of the winged scapula are due to injury to the macro-thoracic nerve that innervates the serratus anterior muscle. It can be injured by high tension or compression in the area of the neck or thorax due to a car accident or other injury. Sometimes, when no clear cause is discovered, it is thought to be due to a viral nerve infection. Diagnosis is usually confirmed with electromyographic studies performed by experienced staff.
- Winged scapula with outward dislocation: It is caused by a malfunction of the trapezoidal muscle, due to accessory nerve palsy, resulting in outward and downward displacement of the outer rim (outer side) of the scapula. The trapezoid is a large triangular muscle, which is innervated by the ancillary nerve, holding the scapula and rotating it outwards and upwards to raise the limb. It is usually caused by an injury to the accessory nerve as a result of a direct injury such as a car accident, an injury caused by a sharp object or medical trauma during a lymph node biopsy operation in the cervical region (neck).
- Some of the rarer causes of winged scapula include paresis of the shoulder stabilizing muscles, brachial plexus palsy and chronic shoulder instability, either due to recurrent dislocation or due to injury of the acromioclavicular joint.
The treatment of the condition is conservative in the majority of cases and includes rest and physiotherapy. However, surgical treatment has specific indications and is applicable to a small number of patients.
In the case of long thoracic palsy, the recovery is slow and can take one to two years.
Newer studies recommend early surgical intervention without clear results. When the nerve palsy is not restored, the most common solution is to have a musculus pectoralis major tendon transfer, with good results in relieving pain and restoring shoulder functionality.
In the case of untreated accessory nerve palsy, patients learn to live with their problem. If, however, it causes severe dysfunction and pain, then Eden-Lange tendon transfer involving several muscles (levator scapulae, rhomboids major and minor) is recommended and provides good results in pain and functionality.
In rare cases of tendon transfer failure, scapulothoracic fusion is performed with the help of a plate and wire, which provides stability to the scapula for shoulder movement.