Anatomy study note · Upper limb

Extensor digitorum

The main extensor of the fingers. Its four tendons join the extensor expansions on the backs of the fingers.

Key points

• Lateral epicondyle → extensor expansions of fingers 2–5.
• Deep (posterior interosseous) radial nerve.
• Central slip → middle phalanx; lateral bands → distal phalanx.
• Limb muscles: in situ from limb-bud mesenchyme.
• Upper limb bud C4–T2; lower limb bud L2–S2.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Origin · Insertion · Action · Nerve supply · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 3, PDF pp. 309, 312–314
• Inderbir Singh’s Human Embryology, ch. 7, PDF p. 109; ch. 10, PDF pp. 142–145
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the upper limb

• Extensor indicis
• Extensor pollicis brevis
• Extensor pollicis longus
• Extensor retinaculum of the wrist
• Flexor carpi radialis
• Flexor carpi ulnaris
• Flexor digitorum profundus
• Flexor digitorum superficialis
• Flexor pollicis longus
• Flexor retinaculum and carpal tunnel
• Humerus
• Hypothenar muscles

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