Anatomy study note · Upper limb

Thenar muscles

The three short muscles forming the ball of the thumb: abductor pollicis brevis, flexor pollicis brevis and opponens pollicis.

Key points

• APB, FPB, opponens pollicis — from the flexor retinaculum.
• Recurrent branch of the median nerve.
• Opponens pollicis = the only opposer.
• Median nerve lesion → thenar wasting, ape hand.
• 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. 315–316, 345–347
• 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

• Thoracodorsal nerve
• Trapezius
• Triceps brachii
• Ulna
• Ulnar artery
• Ulnar nerve
• Veins of the hand
• Wrist joint
• Abductor pollicis longus
• Acromioclavicular joint
• Adductor pollicis
• Anconeus

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