Anatomy: Forearm & Hand Flashcards
What connects the radius and ulna? Function?
interosseous membrane
stability, muscle attachment, compartmentalization
What is a Colles’ fracture?
distal radius displaces dorsally after FOOSH
dinner fork deformity
What carpals articulate with the radius?
scaphoid
lunate
What runs through the cubital fossa?
brachial artery
median nerve
What are the two thickenings of the antebrachial fascia?
extensor retinaculum (posterior) Palmar carpal ligament (anterior)
What is the flexor retinaculum?
deeper anterior ligament that forms the roof of the carpal tunnel
Brachioradialis AI
flexor of elbow
radial nerve
Supinator AI
supinates hands
deep radial nerve
What is the action of the anterior forearm muscles?
flexors
pronators
What is the action of the posterior forearm muscles?
extensors
supinators
What are the superficial flexor-pronators?
pronator teres flexor carpi radialis palmaris longus flexor carpi ulnaris flexor digitorum superficialis
Superficial flexor-pronator origin and innervation?
medial epicondyle (common flexor tendon) median nerve (ulnaris - ulnar nerve)
What are the deep flexor-pronators?
flexor digitorum profundus
flexor pollicis longus
pronator quadratus
Deep flexor-pronator innervation?
anterior interosseous nerve
medial FDP - ulnar nerve
What are the pronator muscles?
pronator teres
pronator quadratus
Pronator quadratus innervation?
anterior interosseous nerve
Pronator teres innervation?
median nerve
Flexor digitorum superficialis innervation/action?
flexor of 4 fingers PIP
median nerve
Flexor digitorum profundus innervation/action?
flexor of 4 fingers DIP
medial - ulnar nerve
lateral - AIN
Where do the forearm extensors originate? Innervation?
lateral epicondyle
radial nerve
What are the 3 wrist extensors?
extensor carpi radialis longus/brevis
extensor carpi ulnaris
What are the digit extensors?
extensor digitorum
extensor digiti minimi
extensor indicis (pointer finger)
What is the extensor expansion?
extensor tendons that attach to middle phalanx with one band and distal phalanx with lateral bands
What are the abductors/extensors of the thumb?
abductor pollicis longus
extensor pollicis longus/brevis
What holds the extensor tendons in place at the wrist?
extensor retinaculum
What are the boundaries of the anatomical snuff box? Contents?
thumb extensor tendons
radial artery and scaphoid bone
What is De Quervian’s Tenosynovitis?
snuff box tendonitis, common from lifting/holding babies
What does the superficial radial nerve innervate?
skin on the back of the hand (radial side 3 fingers)
What does the deep radial nerve innervate?
extensors (as posterior interosseous nerve)
What does the ulnar nerve innervate in the forearm?
flexor carpi ulnaris
part of FDP
medial hand sensation
hand muscles
What is the Canal of Guyon?
passage of ulnar nerve through wrist
How can you find the median nerve?
Passes between FDS and FDP
What are the branches of the median nerve?
AIN palmar branch (doesn't pass through flexor retinaculum)
What ligaments stabilize the elbow?
UCL
RCL
annular ligament of radius (radio-ulnar)
What does Tommy John surgery repair?
UCL
What is Nursemaids elbow?
radial head dislocation, easy in kids
What stabilizes metacarpophalangeal joints?
palmar plates and deep transverse metacarpal ligaments
What is Game Keepers Thumb or Skiers Thumb?
UCL tear at the thumb with fracture or dislocation of the thumb base
What are the 6 movements of the thumb?
abduction/adduction (saggital)
flexion/extension (frontal)
opposition/reposition
What are the 8 carpal bones?
scaphoid, lunate, triquetrum, pisiform
trapezium, trapezoid, capitate, hamate
Mnemonic for carpals?
some lovers try positions that they can’t handle
What is the most commonly fractured carpal?
scaphoid (fracture can disrupt blood flow)
What is the most commonly dislocated carpal?
lunate
What is the significance of the 1st carpometacarpal joint?
commonly arthritic (metacarpal-trapezium)
What is a boxer’s fracture?
fracture of 5th metacarpal head
What are the 5 compartments of the hand?
hypothenar central thenar adductor interosseous
What is the fascia called from wrist to finger?
palmar carpal ligament
palmar aponeurosis
longitudinal slips
fibrous digital sheaths
What causes trigger finger?
damaged flexor tendon gets a nodule that gets caught at the fibrous sheath
Hypothenar compartment location and contents?
medial 3 intrinsic muscles: abductor digiti minimi flexor digiti minimi brevis opponens digiti minimi deep branch of ulnar nerve
Thenar compartment location and contents?
lateral 3 intrinsic muscles: abductor pollicis brevis flexor pollicis brevis (with sesamoid) opponens pollicis (opposer) recurrent branch of median nerve
What is ape hand?
thenar atrophy due to loss of recurrent median nerve
Adductor compartment location/contents?
deep to thenar
adductor pollicis
deep branch of ulnar nerve
Central compartment location/contents?
anterior middle
FDS/FDP tendons
lumbrical muscles (originate from FD tendons)
median and ulnar nerves
Lumbrical muscles action and innervation?
flex MCP joints and extend PIP/DIPs (bye-bye muscles)
medial 2: ulnar
lateral 2: median
Interosseous compartment location and contents?
posterior medial
3 palmar interossei muscles (adduct 2,4,5 fingers)
4 dorsal interossei (abduct 2,3,4 fingers)
deep ulnar nerve
What runs through the carpal tunnel?
4 tendons of FDS
4 tendons of FDP
tendon of flexor pollicis longus
median nerve
What does the median nerve innervate?
thenar muscles
2 lumbricals
3.5 fingers sensation
What does the ulnar nerve innervate in the hand?
1.5 fingers sensation
all other intrinsic muscles besides thenar and 2 lumbricals
Where does the ulnar nerve enter the hand?
canal of Guyon
What does the ulnar artery vascularize in the hand?
3.5 fingers via superficial palmar arch
What does the radial artery vascularize in the hand?
1.5 fingers via deep palmar arch
