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External rotation during elevation of the arm.

Inui H, Hashimoto T, Nobuhara K - Acta Orthop (2009)

Bottom Line: External rotation peaked at 122 degrees (SD14) of abduction, then decreased according to the arm movement in the lateral planes, but increased gradually to maximum elevated position in the anterior planes.Mean maximal angles of external rotation (in degrees) during elevation were 27 (SD11), 13 (SD13), 3 (SD9), and 3 (SD5), from laterally to anteriorly.There were differences in rotational patterns, and more external rotation was needed to reach maximum elevation in lateral planes than in anterior planes.

View Article: PubMed Central - PubMed

Affiliation: Nobuhara Hospital and Institute of Biomechanics, Tatsunoshi, Hyogo, Japan. inuhiro123@yahoo.co.jp

ABSTRACT

Background: Knowledge about the pattern of rotation during arm elevation is necessary for a full understanding of shoulder function, and it is also useful for planning of rehabilitation protocols to restore range of motion in shoulders in disorder. However, there are insufficient in vivo data available. METHODS; We investigated dynamic arm rotation during elevation in different planes using 30 shoulders in 15 healthy men (age range 21-33 years). Both arms were moved from neutral dependent position to maximum elevated position in 4 planes from laterally to anteriorly, and each dynamic course of motion was traced using a 3-dimensional motion capture system.

Results: Patterns of rotation were categorized as being one of 2 types, depending on whether or not external rotation peaked before the arm reached the maximum elevated position. External rotation peaked at 122 degrees (SD14) of abduction, then decreased according to the arm movement in the lateral planes, but increased gradually to maximum elevated position in the anterior planes. Mean maximal angles of external rotation (in degrees) during elevation were 27 (SD11), 13 (SD13), 3 (SD9), and 3 (SD5), from laterally to anteriorly.

Interpretation: There were differences in rotational patterns, and more external rotation was needed to reach maximum elevation in lateral planes than in anterior planes.

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A. Rotational angles of the right arm during abduction in the first plane (coronal plane) representing type A. B. Rotational angles of the right arm during abduction in the fourth plane (sagittal plane) representing type B.
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Figure 0002: A. Rotational angles of the right arm during abduction in the first plane (coronal plane) representing type A. B. Rotational angles of the right arm during abduction in the fourth plane (sagittal plane) representing type B.

Mentions: All arms were rotated internally at the beginning, and were then externally rotated. Rotational patterns were divided into 2 types depending on whether external rotation peaked before the arm reached the maximum elevated position. After some degree of internal rotation, type A external rotation started at an average of 53˚ (SD14) of abduction, while type B started at an average of 80˚ (SD13) of abduction. Each wave of type A then peaked at an average of 122˚ (SD14) of abduction and the rotational angle decreased slightly until the arm reached maximum abduction. Waves of type B showed no peak of external rotation. Figure 2 shows rotational patterns during abduction in the first and fourth planes, representing types A and B. Mean rotational angles of types A and B at 60˚, 90˚, and 120˚ of abduction are shown in Table 3. Waves of type A accounted for all participants in the first plane and 8 participants in the second plane, while waves of type B accounted for the other 7 participants in the second plane, and all participants in the third and fourth planes. Both arms of each participant showed the same type in each plane. Maximal angles above 20˚ of abduction during the elevation of each path were compared, avoiding the gimbal-lock problem. These values averaged 27˚ (SD11) in the first plane, 13˚ (SD13) in the second plane, 3˚ (SD9) in the third plane, and 3˚ (SD5) in the fourth plane, showing that the amount of external rotation needed to reach maximum elevation was significantly greater when the arm was elevated along more horizontally abducted paths (Table 4).


External rotation during elevation of the arm.

Inui H, Hashimoto T, Nobuhara K - Acta Orthop (2009)

A. Rotational angles of the right arm during abduction in the first plane (coronal plane) representing type A. B. Rotational angles of the right arm during abduction in the fourth plane (sagittal plane) representing type B.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823194&req=5

Figure 0002: A. Rotational angles of the right arm during abduction in the first plane (coronal plane) representing type A. B. Rotational angles of the right arm during abduction in the fourth plane (sagittal plane) representing type B.
Mentions: All arms were rotated internally at the beginning, and were then externally rotated. Rotational patterns were divided into 2 types depending on whether external rotation peaked before the arm reached the maximum elevated position. After some degree of internal rotation, type A external rotation started at an average of 53˚ (SD14) of abduction, while type B started at an average of 80˚ (SD13) of abduction. Each wave of type A then peaked at an average of 122˚ (SD14) of abduction and the rotational angle decreased slightly until the arm reached maximum abduction. Waves of type B showed no peak of external rotation. Figure 2 shows rotational patterns during abduction in the first and fourth planes, representing types A and B. Mean rotational angles of types A and B at 60˚, 90˚, and 120˚ of abduction are shown in Table 3. Waves of type A accounted for all participants in the first plane and 8 participants in the second plane, while waves of type B accounted for the other 7 participants in the second plane, and all participants in the third and fourth planes. Both arms of each participant showed the same type in each plane. Maximal angles above 20˚ of abduction during the elevation of each path were compared, avoiding the gimbal-lock problem. These values averaged 27˚ (SD11) in the first plane, 13˚ (SD13) in the second plane, 3˚ (SD9) in the third plane, and 3˚ (SD5) in the fourth plane, showing that the amount of external rotation needed to reach maximum elevation was significantly greater when the arm was elevated along more horizontally abducted paths (Table 4).

Bottom Line: External rotation peaked at 122 degrees (SD14) of abduction, then decreased according to the arm movement in the lateral planes, but increased gradually to maximum elevated position in the anterior planes.Mean maximal angles of external rotation (in degrees) during elevation were 27 (SD11), 13 (SD13), 3 (SD9), and 3 (SD5), from laterally to anteriorly.There were differences in rotational patterns, and more external rotation was needed to reach maximum elevation in lateral planes than in anterior planes.

View Article: PubMed Central - PubMed

Affiliation: Nobuhara Hospital and Institute of Biomechanics, Tatsunoshi, Hyogo, Japan. inuhiro123@yahoo.co.jp

ABSTRACT

Background: Knowledge about the pattern of rotation during arm elevation is necessary for a full understanding of shoulder function, and it is also useful for planning of rehabilitation protocols to restore range of motion in shoulders in disorder. However, there are insufficient in vivo data available. METHODS; We investigated dynamic arm rotation during elevation in different planes using 30 shoulders in 15 healthy men (age range 21-33 years). Both arms were moved from neutral dependent position to maximum elevated position in 4 planes from laterally to anteriorly, and each dynamic course of motion was traced using a 3-dimensional motion capture system.

Results: Patterns of rotation were categorized as being one of 2 types, depending on whether or not external rotation peaked before the arm reached the maximum elevated position. External rotation peaked at 122 degrees (SD14) of abduction, then decreased according to the arm movement in the lateral planes, but increased gradually to maximum elevated position in the anterior planes. Mean maximal angles of external rotation (in degrees) during elevation were 27 (SD11), 13 (SD13), 3 (SD9), and 3 (SD5), from laterally to anteriorly.

Interpretation: There were differences in rotational patterns, and more external rotation was needed to reach maximum elevation in lateral planes than in anterior planes.

Show MeSH