- May 6, 2026The palmar interossei adduct the fingers. There are three (some authors count four including the thumb palmar interosseous). They are…
- May 6, 2026The first lumbrical is the most radial and is median-nerve innervated (unlike lumbricals 3 and 4 which are ulnar). Its…
- May 6, 2026The fourth lumbrical is the most ulnar and is ulnar-nerve innervated. Its origin from two FDP tendons (ring and little)…
- May 6, 2026The palmaris brevis is the most superficial intrinsic hand muscle, attaching the palmar aponeurosis to the overlying skin. It is…
- May 6, 2026The medial head of FHB inserts via the medial sesamoid and is primarily responsible for the medial sesamoid position during…
- May 6, 2026The thenar eminence is formed by four intrinsic thumb muscles whose coordinated action produces thumb opposition — the defining human…
- May 6, 2026The hypothenar eminence is formed by ADM, FDM, and ODM. All three receive deep ulnar nerve innervation via the deep…
- May 6, 2026APB is the most superficial thenar muscle and the primary palmar thumb abductor. Its unique insertion onto the extensor expansion…
- May 6, 2026The oblique head provides the primary adduction force for key pinch. Its more proximal origin gives it a greater moment…
- May 6, 2026The transverse head originates from the entire third metacarpal shaft, providing a transverse pull compressing the first metacarpal toward the…