Clinical Pilates in Practice: Shoulder Kinematics & Subacromial Impingement (June 2021)
Jun 01, 2021
This literature review examines the relationship between shoulder kinematics and the aetiology of rotator cuff pathology.
Lawrence, Rebekah L., Jonathan P. Braman, and Paula M. Ludewig. "Shoulder kinematics impact subacromial proximities: a review of the literature." Brazilian Journal of Physical Therapy 24, no. 3 (2020), 219-230. doi:10.1016/j.bjpt.2019.07.009.
KEY POINTS: SHOULDER KINEMATICS & SUBACROMIAL IMPINGEMENT
- Subacromial compression is unlikely a contributing factor to rotator cuff pathologies.
- There are limitations to 2D measurements when trying to quantify 3D relationships.
- 3D techniques are not as broadly available.
- There are extreme variations in metrics for quantifying the subacromial space.
- The most common metric is the minimum distance; it quantifies the smallest distance between two structures.
- A ‘‘painful arc’’ of motion between 700 and 1200 humerothoracic elevation is considered a hallmark sign of ‘‘impingement syndrome’’.
- Cadaveric studies show that subacromial contact occurred most frequently between 300 and 900 humeral elevation; however, proximity areas were greatest between 600 and 1200 humeral elevation.
- Beyond 900 humeral elevation, the subacromial space ‘‘no longer accommodated’’ the rotator cuff tendons, therefore it is important to consider tendon location when interpreting subacromial proximities.
- In vivo studies generally report the acromiohumeral distance progressively decreases with increasing humeral elevation until a minimum occurs between approximately750 to 1200 of humerothoracic elevation before increasing again at higher angles.
- The results of in vitro and in vivo studies suggest humeral elevation impacts subacromial distances.
- The smallest proximities occur at a lower angle of humeral elevation.
- The smallest distance between the rotator cuff tendon insertion and coracoacromial arch occurs between 400 and 750 of humerothoracic elevation.
On average, individuals with dyskinesis experience a higher reduction in acromiohumeral distance than individuals without dyskinesis (dyskinesis: 1.9 mm or 21%; without dyskinesis: 1.4 mm or 16%).
- Scapular assistance tests may be used to investigate the effects of scapulothoracic kinematics on subacromial distances.
- The test assesses the effect of altering scapulothoracic kinematics on patient symptoms by manually facilitating upward rotation, posterior tilt, and/or external rotation.
- Scapulothoracic rotations form the basis of movement-based diagnostic classifications (e.g. insufficient scapular upward rotation).
- The relationship between scapulothoracic upward rotation and subacromial proximities is not absolute but depends on the angle of humerothoracic elevation.
- Subacromial proximities appear to be mostly affected by alterations in scapulothoracic upward rotation with or without concurrent alterations in posterior tilt.
- The effect of scapulothoracic kinematics on subacromial proximities is dependent on the angle of humerothoracic elevation.
- Changes in glenohumeral and scapular kinematics are associated with changes in subacromial proximities.
CLINICAL PILATES IN PRACTICE
- Scapular position relative to the thoracic cage, and relative to the humerus, matter:
- Supine Shoulder Mobilisations at the Tower.
- Dart vs Diamond Press vs Baby Swan will all change the ability of the thoracic cage to move underneath the scapulae.
- Mobility and stability at the sternoclavicular and acromioclavicular joint are relevant for impingement syndromes.
- Hug-A-Tree and Ballet Arms supine at various angles will facilitate mobility through different ranges.
- Balance around the upper, middle, and lower trapezius is key for integration with serratus anterior.
- Prone Pulling Straps on the Reformer.
- Windmill and Twist at the Tower.
- Assess glenohumeral joint rotation from a centred position to ensure teres major, lats, and pecs aren't driving: build strength of the long head of triceps and posterior detoid.
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