FACTS & HINTS

HIGH-YIELD FACTS

Anatomic Points

Arterial Arches of the Hand

Superficial palmar arch

Formed from main terminal branch of ulnar artery

Enters hand between hook of hamate and pisiform bone

Superficial to flexor retinaculum

Divides into superficial palmar arch and deep branch of ulnar artery

Gives rise to three common palmar digital arteries

Anatomose with palmar metacarpal arteries

Gives rise to two proper palmar digital arteries to sides of digits 2 through 4 Deep palmar arch

Formed from terminal branch of radial artery

Passes from anatomical snuff boxon dorsum of hand

Runs between heads of first dorsal interosseus muscle to reach palm

Anastomoses with deep branch of ulnar artery

Gives off three palmar metacarpal arteries (anastomose with common palmar digital arteries from superficial arch) Gives off princeps pollicis arteryto supplypalmar surface and lateral sides of thumb

Anatomical Snuff Box

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Depression on posterolateral wrist

Visible when thumb is fullyextended

Bounded anteriorlybytendons of the abductor pollicis longus and extensor pollicis brevis

Bounded posteriorlybytendon of the extensor pollicis longus

Structures in floor of snuff box

Radial artery

Radial styloid process proximally

Base of first metacarpal distally

Scaphoid and trapezium between radial styloid and first metacarpal

Clinical Points

Colles' Fracture

Complete transverse fracture within the distal 2 cm of the radius

Distal fragment displaced dorsally, giving the classic "dinner fork deformity"

Ulnar styloid mayalso be avulsed

Results from forced dorsiflexion of the hand, such as in breaking a fall with an outstretched, pronated hand

Most common fracture in adults older than 50 years old

Seen most frequentlyin elderlywomen

Healing usuallygood as the bone has a rich blood supply

Scaphoid Fracture

Scaphoid is the most commonlyfractured bone of the carpus

Proximal pole of the bone has a poor blood supplyand as a result, fracture maytake several months to heal This increases risk of avascular necrosis and subsequent degenerative joint disease at the wrist

Fracture often difficult to spot on initial radiographs, which should be repeated at 2 to 3 weeks in anypatient presenting with a severely sprained wrist

Dupuytren's Contracture

Progressive fibronodular thickening of the palmar fascia

Leads to fixed flexion deformityof the fingers (most commonlythe fourth and fifth digits)

Condition often bilateral and usuallyaffects middle-aged males of Northern European decent, suggesting hereditarypredisposition Risk factors include alcohol, liver disease, and antiepileptic medication

Treatment is surgical

MNEMONICS

Memory Aids

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Note: If you forget if you're starting at the lateral or medial side of each row, remember that the Scaphoid is in the anatomical snuffbox and the trapez iUM is at the base of the th UMB.

Memory Aids

Flexor carpi superficialis and profundus insertions: Superficialis splits the two, to permit profundus to pass through

Interossei muscles: Palmar interossei ADduct the digits (PAD)

Dorsal interossei ABduct the digits (DAB)

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