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Review
. 2020 May-Jun;24(3):219-230.
doi: 10.1016/j.bjpt.2019.07.009. Epub 2019 Jul 24.

Shoulder kinematics impact subacromial proximities: a review of the literature

Rebekah L Lawrence  1 , Jonathan P Braman  2 , Paula M Ludewig  3
Affiliations
Review

Shoulder kinematics impact subacromial proximities: a review of the literature

Rebekah L Lawrence et al. Braz J Phys Ther. 2020 May-Jun.

Abstract

Background: Alterations in glenohumeral and scapulothoracic kinematics have been theorized to contribute to rotator cuff pathology by impacting the magnitude of the subacromial space.

Objective: The purpose of this review is to summarize what is currently known about the relationship between shoulder kinematics and subacromial proximities.

Conclusions: A variety of methods have been used to quantify subacromial proximities including photographs, MR imaging, ultrasonography, and single- and bi-plane radiographs. Changes in glenohumeral and scapulothoracic kinematics are associated with changes in subacromial proximities. However, the magnitude and direction of a particular motion's impact on subacromial proximities often vary between studies, which likely reflects different methodologies and subject populations. Glenohumeral elevation angle has been consistently found to impact subacromial proximities. Plane of humeral elevation also impacts subacromial proximities but to a lesser degree than the elevation angle. The impact of decreased scapulothoracic upward rotation on subacromial proximities is not absolute, but instead depends on the angle of humerothoracic elevation. The effects of scapular dyskinesis and humeral and scapular axial rotations on subacromial proximities are less clear. Future research is needed to further investigate the relationship between kinematics and subacromial proximities using more homogenous groups, determine the extent to which compression and other factors contribute to rotator cuff pathology, and develop accurate and reliable clinical measures of shoulder motion.

Keywords: Impingement; Kinematics; Rotator cuff; Subacromial space.

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Figures

Figure 1
Figure 1
The spatial relationship between the minimum distance vector (red) and the rotator cuff tendon insertion (black area on humeral surface). (A) At 30° of humerothoracic elevation, the minimum distance vector is located within the rotator cuff tendon insertion, which suggests the rotator cuff may be in a position to become compressed and/or abraded. (B) At 90° of humerothoracic elevation, the minimum distance vector is located lateral to the rotator cuff tendon insertion, which suggests the rotator cuff tendon has already cleared the lateral acromion and is no longer in a position to be compressed and/or abraded.
See this image and copyright information in PMC

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