Winged scapula
| Winged scapula | |
|---|---|
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| The left side of the thorax. (Winging not illustrated but serratus anterior is labeled at left, and trapezius is labeled at upper right.) | |
| Classification and external resources | |
| ICD-9-CM | 736.89 |
A winged scapula (scapula alata) is a skeletal medical condition in which the shoulder blade, or shoulder bone, protrudes from a person’s back in an abnormal position. In rare conditions it has the potential to lead to limited functional activity in the upper extremity to which it is adjacent. It can affect a person’s ability to lift, pull, and push weighty objects. In some serious cases, the ability to perform activities of daily living such as changing one’s clothes and washing one’s hair may be hindered. The name of this condition comes from its appearance, a wing-like resemblance, due to the medial border of the scapula sticking straight out from the back. Scapular winging has been observed to disrupt scapulohumeral rhythm, contributing to decreased flexion and abduction of the upper extremity, as well as a loss in power and the source of considerable pain. A winged scapula is considered normal posture in young children, but not older children and adults.
The severity and appearance of the winged scapula varies by individuals as well as the muscles and/or nerves that were affected. Pain is not seen in every case. In a study of 13 individuals with facioscapulohumeral muscular dystrophy (FSH), none of the individuals complained of pain. Fatigue, however, was a common characteristic and all had noted that there were limitations in their activities of daily life.
In most cases of winged scapula, damage to the serratus anterior muscle causes the deformation of the back. The serratus anterior muscle attaches to the medial anterior aspect of the scapula (i.e. it attaches on the side closest to the spine and runs along the side of the scapula that faces the ribcage) and normally anchor the scapula against the rib cage. When the serratus anterior contracts, upward rotation, abduction, and weak elevation of the scapula occurs, allowing the arm to be raised above the head. The long thoracic nerve innervates the serratus anterior; therefore, damage to or impingement of this nerve can result in weakening or paralysis of the muscle. If this occurs, the scapula may slip away from the rib cage, giving it the wing-like appearance on the upper back. This characteristic may particularly be seen when the affected person pushes against resistance. The person may also have limited ability to lift their arm above their head.
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Wikipedia