Anatomy study note · Upper limb

Ulnar nerve

The main branch of the medial cord (C8, T1). It supplies 1½ forearm muscles and most of the small muscles of the hand.

Key points

• Medial cord, C8–T1.
• Behind the medial epicondyle ("funny bone"); between the heads of FCU.
• Forearm: FCU + medial half of FDP only.
• Hand: all interossei, medial 2 lumbricals, hypothenar, adductor pollicis.
• Lesion: claw hand (worse at the wrist), Froment sign.
• Upper limb nerves: C4–T2 segments; lower limb: L2–S2.
• Ventral root: basal-lamina neurons. Dorsal root: neural-crest ganglion cells.
• Nerve: epineurium → perineurium (blood–nerve barrier) → endoneurium.
• Cut nerve: Wallerian degeneration; regrows 0.5–3 mm/day.

The full note in the atlas also covers

Course · Branches · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 3, PDF pp. 347–350, 364–369
• Inderbir Singh’s Human Embryology, ch. 17, PDF pp. 318, 321, 323–325; ch. 10, PDF pp. 143–144
• BRS Cell Biology & Histology, 7th ed., ch. 9, PDF pp. 163–166, 171–172

More from the upper limb

• Veins of the hand
• Wrist joint
• Abductor pollicis longus
• Acromioclavicular joint
• Adductor pollicis
• Anconeus
• Axillary artery
• Axillary lymph nodes
• Axillary nerve
• Axillary vein
• Basilic vein
• Biceps brachii

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