Anatomy study note · Upper limb

Flexor retinaculum and carpal tunnel

A thick band of deep fascia that bridges the front of the carpal arch, turning it into the carpal tunnel for the long flexor tendons and the median nerve.

Key points

• Medial: pisiform + hook of hamate. Lateral: scaphoid tubercle + trapezium.
• In the tunnel: FDS ×4, FDP ×4, FPL, median nerve (FCR in its own split).
• Superficial to it: ulnar nerve and artery, palmaris longus, palmar cutaneous branches.
• Carpal tunnel syndrome: lateral 3½ fingers + thenar weakness, thenar skin spared.
• Connective tissue: from leftover mesenchyme.
• Dense CT: irregular (capsules) or regular (tendons, ligaments).

The full note in the atlas also covers

Features · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 3, PDF pp. 286–289, 294–296
• Inderbir Singh’s Human Embryology, ch. 7, PDF pp. 94–95
• BRS Cell Biology & Histology, 7th ed., ch. 6, PDF p. 110

More from the upper limb

• Humerus
• Hypothenar muscles
• Infraspinatus
• Intercarpal and carpometacarpal joints
• Interossei of the hand
• Latissimus dorsi
• Levator scapulae
• Long thoracic nerve
• Lumbricals of the hand
• Medial cutaneous nerves of arm and forearm
• Median cubital vein
• Median nerve

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