Rote memorize this info. Then answer the questions at the end. No pain no gain.
- Flexor digitorum superficialis
- Flexes the PIPs and MCPs of the 2nd to 5th fingers (and the wrist).
- Does not flex the DIPs.
- Tendon attaches to middle phalanx.
- Innervated by median nerve.
- Flexor digitorum profundus
- Flexes the DIPs, PIPs, MCPs of the 2nd to 5th fingers (and the wrist).
- Tendon attaches to distal phalanx.
- Lateral two parts (2nd and 3rd fingers) innervated by anterior interosseous nerve (branch of the median nerve).
- Medial two parts (4th and 5th fingers) innervated by ulnar nerve.
- Flexor pollicis longus
- Flexes PIP and MCP of the thumb.
- Tendon attaches to distal phalanx.
- Innervated by anterior interosseous branch of median nerve.
Palsy to the anterior interosseous nerve results in an inability to make the “OK sign” with the fingers.
- Flexor pollicis brevis
- Flexes MCP of the thumb.
- Does not flex the PIP.
- Tendon attaches to proximal phalanx.
- Superficial head innervated by recurrent branch of median nerve.
- Medial head innervated by deep branch of ulnar nerve.
- Flexor digiti minimi brevis
- Flexes MCP of 5th finger (in addition to FDS and FDP).
- There is no flexor digiti minimi longus in humans (rare variant).
- Innervated by deep branch of ulnar nerve.
- Lumbricals
- Flex MCPs of 2nd to 5th fingers.
- (Also act to extend the interphalangeal joints of the fingers).
- Lateral two parts (2nd and 3rd fingers) innervated by median nerve.
- Medial two parts (4th and 5th fingers) innervated by ulnar nerve.
- Flexor carpi ulnaris
- Flexes and adducts the hand.
- Innervated by ulnar nerve.
- Flexor carpi radialis
- Flexes and abducts the hand.
- Innervated by median nerve.
- Palmaris longus
- Absent in ~15% of the population.
- Visible as small tendon between flexor carpi radialis and flexor carpi ulnaris.
- Weak flexion function. May be harvested for tendon grafts.
- Innervated by median nerve.
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