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Hand & wrist for FRCS (Tr & Orth)
Hand covers compression neuropathy and nerve injury, osteoarthritis and the rheumatoid hand, Dupuytren’s disease, tendon disorders and infection. Wrist and brachial plexus covers carpal instability and scaphoid non-union, the distal radioulnar joint and triangular fibrocartilage complex, Kienböck’s disease, brachial plexus injury and the principles of tendon transfer. It is the domain where anatomy is examined most directly: almost every question can be answered from knowing what runs where and what each muscle does.
Topics in this domain
- Hand75
- Wrist & brachial plexus50
What the paper tends to test
- Nerve questions ask you to localise a lesion: anterior interosseous or posterior interosseous nerve palsy without sensory loss, high against low ulnar nerve lesions, carpal tunnel syndrome against pronator syndrome.
- Dupuytren’s questions test the cords and the joints they contract, and the way a spiral cord displaces the digital neurovascular bundle.
- Carpal instability questions describe a lateral radiograph — the scapholunate angle and the tilt of the lunate — and ask for the pattern and the ligament that has failed.
- Scaphoid questions rest on its retrograde blood supply, and on the predictable sequence of arthritis after non-union or scapholunate dissociation.
- Rheumatoid hand questions ask for the cause of a sudden loss of finger or thumb movement: tendon rupture, nerve compression or joint subluxation.
- Brachial plexus questions separate preganglionic from postganglionic injury, and tendon transfer questions test the principles and the standard sets.
Classic traps and discriminators
- A spiral cord in Dupuytren’s disease displaces the neurovascular bundle superficially and towards the midline of the finger, so the bundle lies directly under the skin incision at the base of the finger.
- The palmar cutaneous branch of the median nerve arises proximal to the carpal tunnel, so numbness over the thenar eminence points to a lesion proximal to the wrist rather than to carpal tunnel syndrome.
- In posterior interosseous nerve palsy the wrist still extends, with radial deviation, because extensor carpi radialis longus is supplied by the radial nerve proper; there is no sensory loss.
- In a dorsal intercalated segment instability pattern the lunate is extended and the scapholunate angle is greater than 60°; in a volar pattern the lunate is flexed and the angle is less than 30°.
- In scapholunate advanced collapse and scaphoid non-union advanced collapse the radiolunate joint is characteristically spared, which is why the lunate can be kept in a four-corner fusion or the proximal row excised.
Interactive 3D: Wrist cross-section
Drag to rotate, tap the hotspots, press play.
Also in this domain: Brachial plexus, Carpal bones & ligaments (coming soon), Flexor tendon sheath & pulleys (coming soon)
Hand & wrist questions, answered
How do you tell a preganglionic from a postganglionic brachial plexus injury?
A preganglionic injury is a root avulsion proximal to the dorsal root ganglion. The clues are Horner’s syndrome, a winged scapula and rhomboid weakness from loss of the root-level branches, a raised hemidiaphragm, and preserved sensory nerve action potentials in an anaesthetic limb. It cannot be repaired directly, so reconstruction relies on nerve transfers.
What are the principles of tendon transfer?
Supple joints with a full passive range and a stable soft-tissue bed; a donor that is expendable, of adequate strength — expect to lose one grade of power — and of similar excursion to the tendon it replaces; a straight line of pull; one tendon for one function; and, ideally, a donor that is synergistic with the function being restored.
Drill hand & wrist tonight
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