Atlas of Human Anatomy by Netter

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 box on 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 artery to supply palmar surface and lateral sides of thumb

Anatomical Snuff Box
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Depression on posterolateral wrist

Visible when thumb is fully extended

Bounded anteriorly by tendons of the abductor pollicis longus and extensor pollicis brevis

Bounded posteriorly by tendon 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 may also 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 frequently in elderly women

Healing usually good as the bone has a rich blood supply

Scaphoid Fracture

Scaphoid is the most commonly fractured bone of the carpus

Proximal pole of the bone has a poor blood supply and as a result, fracture may take 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 any patient presenting with a severely

sprained wrist

Dupuytren's Contracture

Progressive fibronodular thickening of the palmar fascia

Leads to fixed flexion deformity of the fingers (most commonly the fourth and fifth digits)

Condition often bilateral and usually affects middle-aged males of Northern European decent, suggesting hereditary predisposition

Risk factors include alcohol, liver disease, and antiepileptic medication

Treatment is surgical

MNEMONICS

Memory Aids

Carpal bones (lateral to medial): Some Lovers Try Positions That They Can't Handle

Table I04-3. PROXIMAL ROW

Some Scaphoid

Lovers Lunate

Try Triquetral

Positions Pisiform

Table I04-4. DISTAL ROW