The Hand Flashcards by Jodie Murdoch

Name the intrinsic muscles of the hand

Interossei (7; 3 palmar 4 dorsal)
Lumbricals (4)
Thenar eminence (3)
Hypothenar eminence (3)
Adductor pollicis (1)
Palmaris brevis (1)

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What is the function of the interossei?

Flex the straight finger (metacarpophalageal joint)
Adduction
Abduction

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Which interossei adduct and which abduct?

PAD and DAB
Palmar adduct
Dorsal abduct

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What nerve supplies the interossei?

-Ulnar

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How do you test the palmar interossei?

Palm down on a flat surface

- Insert ruler between fingers and try to pull free

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How do you test the dorsal interossei?

-Squeeze the fingers together and get patient to try to resist

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What are the functions of the lumbricals?

Extension of the interphalangeal joints

- Flexion of the metacarpophalangeal joint

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Where do the lumbricals arise from?

-The 4 tendons of FDP

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What nerve serves the lateral to lumbricals?

-median

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What nerve serves the medial two lumbricals?

-Ulnar

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What is the consequence of denervation of the lumbricals?

Ulnar claw (medial two)

- Hand of benediction (lateral two)

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What three muscles make the thenar eminence?

Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis

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What nerve supplies the thenar eminence?

-Median

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What muscles make the hypothenar eminence?

Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi

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Where does abductor digiti minimi arise from?

-The tendon of FCU

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What nerve supplies the hypothenar eminence?

-Ulnar nerve

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What nerve damage is associated with atrophy of the thenar eminence

-Median nerve compression ie carpal tunnel

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Where is palmaris brevis?

-Overlays the hypothenar eminence

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What nerve supplies palmaris brevis?

-Ulnar nerve

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What is the function of palmaris brevis?

Tightens palmar aponeurosis

- Improves grip by pulling skin of ulnar side of hand to centre

What is the function of adductor pollicis?

-Adduct the thumb

What are the two heads of adductor pollicis?

Transverse

- Oblique

What nerve supplies adductor pollicis?

-Ulnar nerve

What passes between the two heads of adductor pollicis?

-Radial artery

List the layers of the hand from superficial to deep

- Skin - Subcutenous tissue - Fascia - Palmar aponeurosis - Muscle compartments - Carpal bones

What is the carpal tunnel?

- A compartment which passes through the wrist - Formed by two layers -> carpal arch from capral bones - Flexor retinaculum forms the roof

What travels through the carpal tunnel?

- 4 tendons of FDS - 4 tendons of FDP - Tendon of Floxor pollicis longus - Median nerve

What is carpal tunnel syndrome?

-Compression of the median nerve within the carpal tunnel

What are the symptoms of carpal tunnel syndrome?

- Aching of the wrist and/or forearm | - Parasthesia of the 1st and second digits

Where does the blood supply to the hand originate from?

-The radial and ulnar arteries

Describe the path of the radial artery after it has passed the wrist

- Crosses the wrist and travels dorsally across the anatomical snuff box - Gives off a branch proximal to the thumb; superficial palmar branch of radial artery

Describe the path of the ulnar artery after it has passed the wrist

-Passes over flexor retinaculum and divides into deep and superficial branches

What forms the superficial palmer arch?

-The superficial branches of the ulnar and radial arteries

What forms the deep palmar arch?

-Deep branch of ulnar artery anastamoses with radial artery as it passes through the two heads of adductor pollicis

What branches arise from the deep palmar arch?

-Palmar metacarpal arteries

What branches arise from the superficial palmer arch?

-Common palmer digital arteries

What forms the digital arteries?

-Anastomoses of common palmar digital arteries and palmar metacarpal arteries

Describe venous supply to the hand

-A dorsal network of veins drains into the superficial cephalic and basilic veins

What does the median nerve supply in the hand? (motor and sensory)

- Innervates Thenar eminance and lateral two lumbricals - Sensory innervation of lateral 3 and a half digits, the associated palm (except for small area over thenar eminence) and the back of the 3 and half finger tips

What does the radial nerve supply in the hand?

- No motor function - Supplies sensory innervation to dorsal lateral 3 and half fingers (except the fingertips) and the associated dorsum - Also supplies an area over the thenar eminence

What does the ulnar nerve supply in the hand? (motor and sensory)

- Medial 1 and a half fingers and associated palmar and dorsal area - Medial two lumbricals - Interossei - Hypothenar eminence - Adductor pollicis - Palmaris brevis

What does the ulnar nerve travel down the forearm with?

-Ulnar artery

How does the ulnar nerve enter the hand?

-Passes over flexor retinaculum through guyons canal

What is the presentation of ulnar claw?

-Hyperextension of the MCP joints and unopposed flexion of the IP joints of the 4th and 5th digits

What causes ulnar claw?

- Long standing ulnar nerve damage at the wrist causing ulnar claw by paralysis of the medial 2 lumbricals (flex MCP + extend IP) - Hyperextension at MCP occurs because of unopposed extension from extensor digitorum - Flexion at IP due to unnopposed flexion from FDP

What is ulnar paradox?

-Ulnar claw but to a lesser extent as damaged occurs at the elbow -> FDP damaged so less unopposed flexion

What is the presentation of hand of benediction?

-On attempting to form a fist, there is inability to flex the 2nd and 3rd didgit

What causes hand of benediction to occur?

- Long-term median nerve damage at the elbow causes paralysis of the long flexors in anterior forearm (except FCU and med half FDP) and the lateral two lumbricals - This results in loss of flexion at the MCP and IP and the inability to make a complete fist producing a claw like shape (4th and 5th digit still work)