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Type:
Educational Exhibit
Keywords:
Musculoskeletal system, Musculoskeletal bone, Musculoskeletal soft tissue, MR, Education, Motility
Authors:
E. Camuera1, L. Fernandez Rodriguez2, I. Hafeez 3, R. Sharma3, J. Gómez4, J. M. Marin5, J. Beltran3; 1Bilbao/ES, 2Madrid/ES, 3Brooklyn, NY/US, 4León/ES, 5Leganés Madrid/ES
DOI:
10.1594/ecr2016/C-1648
Background
Scapular dyskinesis is an alteration in the normal position or motion of the scapula during coupled scapulohumeral movements.
The scapula is part of the glenohumeral and acromioclavicular joint,
although actually,
there is not a true scapulothoracic joint.
The only connection between scapula and axial skeleton is acromioclavicular joint.
Stability of scapulothoracic joint depends on surrounding musculature such as stabilizing muscles (levator scapulae,
rhomboid,
serratus anterior,
trapezius) and shoulder rotator cuff muscles and acromiclavicular ligaments (Fig.
1-3)
Fig. 1: Scapular stabilizers muscles.
The purpose of the scapula is to provide a stable basis which the glenohumeral mobility occurs.
The main functions of the scapula are:
- Stabilization
- Muscle attachment base
- Force transfer link
Dysfunction of the scapular musculature leads to abnormal biomechanical and position of the scapula.
This results in glenohumeral joint lesions,
decreased neuromuscular performance of shoulder complex and abnormal stress to anterior capsular structures.
Multiples factors may cause scapular diskinesis.
Some of them are (Fig.
5):
- Postural abnormality or anatomical disruption such as cervical lordosis,
thoracic kyphosis,
clavicular fractures or AC joint injurys or inestability.
- Neurological causes: Nerve injury due to trauma,
surgical procedure or traction.
The most known cause is the long thoracic nerve palsy and resulting serratus muscle weakness.
Other affected nerves are spinal accesory nerve with subsequent trapezius fatigue or dorsal scapular nerve with rhomboids weakness.
- Muscle weakness or microtrauma
- Proprioceptive dysfunction
- Lack of capsular or muscular flexibility or contracture
Their main consequences are a loss of stability in the elevation and abduction of the arm,
and shoulder back dysfunction.
This entity is most common in baseball pitchers and swimmers.
Although overhead athletes are prone to this function (Fig.6).