Moment arms of the anatomical subregions of the rotator cuff muscles during shoulder rotation.
Biomechanics
Experimental
Moment arm
Rotation
Rotator cuff muscle
Subregion
Journal
Clinical biomechanics (Bristol, Avon)
ISSN: 1879-1271
Titre abrégé: Clin Biomech (Bristol, Avon)
Pays: England
ID NLM: 8611877
Informations de publication
Date de publication:
07 2023
07 2023
Historique:
received:
21
03
2023
revised:
28
06
2023
accepted:
03
07
2023
medline:
21
7
2023
pubmed:
10
7
2023
entrez:
10
7
2023
Statut:
ppublish
Résumé
Rotator cuff muscles are responsible for humeral rotation. Moment arms of different regions of these muscles during humeral rotation were analyzed in neutral and abducted positions. In eight cadaveric shoulders, subregions of the rotator cuff muscles were identified and their excursion during humeral rotation was measured in neutral and abducted positions from an internal rotation of 30° to an external rotation of 45°, with 15° increments, using a 3-D digitizing system. Statistical tests were used to assess differences between subregions within a single muscle. The posterior-deep subregion of the supraspinatus muscle had greater moment arms compared to the anterior-superficial and anterior-middle subregions in both positions (p < 0.001). The middle and inferior subregions of the infraspinatus muscle and the teres minor muscle showed differences in moment arms compared to the superior region in an abducted position (p < 0.042). The superior subregion of the subscapularis muscle showed differences in moment arms compared to the middle and inferior subregions in an abducted position (p < 0.001). The posterior-deep subregion of the supraspinatus muscle behaved similar to the infraspinatus muscle, as an external rotator. The anterior-superficial and anterior-middle subregions of the supraspinatus muscle showed a biphasic behavior during rotation at a neutral position, but acted as pure external rotators during rotation at an abducted position. Inferior subregions of the infraspinatus and subscapularis muscles showed the largest moment arms compared to superior subregions. These findings support distinct functional roles of the rotator cuff muscle subregions.
Sections du résumé
BACKGROUND
Rotator cuff muscles are responsible for humeral rotation. Moment arms of different regions of these muscles during humeral rotation were analyzed in neutral and abducted positions.
METHODS
In eight cadaveric shoulders, subregions of the rotator cuff muscles were identified and their excursion during humeral rotation was measured in neutral and abducted positions from an internal rotation of 30° to an external rotation of 45°, with 15° increments, using a 3-D digitizing system. Statistical tests were used to assess differences between subregions within a single muscle.
FINDINGS
The posterior-deep subregion of the supraspinatus muscle had greater moment arms compared to the anterior-superficial and anterior-middle subregions in both positions (p < 0.001). The middle and inferior subregions of the infraspinatus muscle and the teres minor muscle showed differences in moment arms compared to the superior region in an abducted position (p < 0.042). The superior subregion of the subscapularis muscle showed differences in moment arms compared to the middle and inferior subregions in an abducted position (p < 0.001).
INTERPRETATION
The posterior-deep subregion of the supraspinatus muscle behaved similar to the infraspinatus muscle, as an external rotator. The anterior-superficial and anterior-middle subregions of the supraspinatus muscle showed a biphasic behavior during rotation at a neutral position, but acted as pure external rotators during rotation at an abducted position. Inferior subregions of the infraspinatus and subscapularis muscles showed the largest moment arms compared to superior subregions. These findings support distinct functional roles of the rotator cuff muscle subregions.
Identifiants
pubmed: 37429101
pii: S0268-0033(23)00171-7
doi: 10.1016/j.clinbiomech.2023.106040
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Research Support, N.I.H., Extramural
Langues
eng
Sous-ensembles de citation
IM
Pagination
106040Subventions
Organisme : NIGMS NIH HHS
ID : R25 GM060655
Pays : United States
Informations de copyright
Copyright © 2023 Elsevier Ltd. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of Competing Interest All authors declare that there are no conflicts of interest.