
Anatomy
Anatomy
Infraspinatus
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Historical reference: its only source is the original reference manual, and some of it may be out of date. Not used for AI answers until re-sourced.
See this lesson’s sourcesrotator-cuffsitsshoulderinfraspinatusexternal-rotation
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DefinitionA short reference note, not a full lesson.
Definition
The "I" of SITS; an external rotator of the shoulder also involved in horizontal abduction and extension.
Detail
The infraspinatus is one of the four rotator cuff (SITS) muscles. Its functions are external rotation and involvement in horizontal abduction and extension.
Key facts
- Function 1: external rotation.
- Function 2: also involved in horizontal abduction and extension.
Connections
- Rotator Cuff (SITS) — the SITS group.
- External Rotation — primary function.
- Horizontal Extension (Abduction) — also involved.
- Teres Minor — shares the same functions.
Sources
Historical reference · reference manual (page cited)
p.84
Cited authorities in source: Ellison (1991).
Keep this lesson, or ask how it applies to you.
Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.
Explore related topics
Atlas Connections
External Rotation
Rotation with the axis of the bone turning away from the body (e.g., the humerus turned outward).Horizontal Extension (Abduction)
Returning the humerus from the front-horizontal position back to the side-horizontal position.Rotator Cuff (SITS)Closely related
The four rotator cuff muscles — Supraspinatus, Infraspinatus, Teres minor, Subscapularis (SITS) — that rotate and stabilize the shoulder joint.Teres MinorClosely related
The "T" of SITS; an external rotator of the shoulder also involved in horizontal abduction and extension.