Musculoskeletal / VISUAL EXPLAINER
How Do Fingers Move Sideways?
For finger side-to-side motion, the reference axis passes through the middle finger. The first dorsal interosseous abducts the index away from that axis; its palmar interosseous counterpart adducts it toward the axis.
READ THE IMAGE
What the illustration shows
Two navy panels show dorsal views of a right hand with thumb on the left. A dashed gold line runs through the middle finger. Left, a cyan arrow takes the index away from that axis; the first dorsal interosseous occupies the thumb-index metacarpal space. Right, a gold arrow takes the index toward the axis; the index palmar interosseous is shown as a deeper structure on the ulnar side of the index metacarpal. Lower enlarged views compare radial and ulnar insertion sides with a simplified extensor expansion. Ivory bone, coral muscle, gold branding and a plain navy footer follow the historic palette. Views and sizes are schematic.
How to interpret this poster
- One index-finger example, not all interosseous actions or a universal palmar-muscle count. No little-finger abduction claim.
- Transparent depth, tendon breadth, extensor expansion and muscle proportions are schematic, not a surgical dissection.
- No nerve self-test or injury assessment. University atlas pages were marked unpublished and were corroborated by separate teaching descriptions.
- AI-assisted educational illustration; not physician certification, microscopy, a diagnosis or individualized medical advice.
- Fine annotations need enlargement; the full description provides an accessible text alternative.
- Display the full uncropped illustration; do not trim titles, legends or boundary annotations.
AI-assisted educational illustration, adapted into web-sized images without changing its composition. This is general education, not an individual diagnosis or treatment recommendation.
EVIDENCE / CONTEXT
Sources and what they support
- University of Washington Muscle Atlas: Interosseous muscles, dorsal ↗
Dorsal interosseous origins, insertions and abduction; webpage marked unpublished.
- University of Washington Muscle Atlas: Interosseous muscles, palmar ↗
Palmar interosseous attachments and adduction; webpage marked unpublished.
- Anatomy.app: Palmar interossei ↗
Index palmar-interosseous origin and ulnar insertion.
- Anatomy.app: Dorsal interossei of hand ↗
First dorsal interosseous radial index proximal-phalanx/extensor-expansion attachment.