Musculoskeletal / VISUAL EXPLAINER
What Is the Fibrous Sheet in the Middle of Your Palm?
The palmar aponeurosis is dense fascia in the central palm, not a muscle belly. Its proximal connections include the flexor retinaculum and, when present, palmaris longus tendon; deeper fibrous partitions help define palmar compartments.
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What the illustration shows
English anatomy poster titled “What Is the Fibrous Sheet in Your Palm?” on a deep navy background. A palm-facing right hand with the thumb on the left is opened to expose a broad ivory triangular palmar aponeurosis between red thenar and hypothenar muscles. Labels identify the fascia, the optional palmaris longus tendon crossing in front of the horizontal flexor retinaculum, and the retinaculum. Two lower close-ups show dense ivory collagen bundles and a simplified fibrous septum descending from the superficial fascial sheet toward a partially shown metacarpal bone. Text distinguishes the sheet from muscle and flexor tendon, and explains its proximal connections and compartment partitions. Gold AllHumanBody.com branding and the complete slogan sit on a plain navy footer. Selected structures, colors and scale are illustrative.
How to interpret this poster
- Absence of palmaris longus does not imply absence of the palmar aponeurosis. Proximal attachments are not asserted invariant.
- Selected oblique cutaway, not complete transverse anatomy or a numbered metacarpal map; collagen is enlarged and stylized.
- No grip-strength prediction, anchoring-force measurement, disease diagnosis or treatment.
- 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
- UAMS Anatomy: Fasciae of the Upper Limb ↗
Dense palmar fascia and distal extensions.
- Texas Tech Anatomy: Hand questions and answers ↗
Triangular fascia, optional palmaris longus, retinacular continuity and compartment septa.
- Complete Anatomy: Palmaris Longus Muscle ↗
Tendon passes superficial to the flexor retinaculum and inserts into palmar aponeurosis/retinaculum.