Extensor Forearm and Hand Flashcards
What is the blood and nerve supply of the posterior (extensor) compartment of the forearm?
Blood: radial and interosseous arteries
Nerve: radial nerve and branches
What are the 6 superficial muscles of the extensor compartment?
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris
What group of muscles is the brachioradialis in, what is its nerve supply, and what is its action?
in superficial group of muscles
supplied by radial nerve
flexes forearm
What group of muscles is the extensor carpi radialis longus in, what is its nerve supply, and what is its action?
Superficial muscles of extensor compartment
supplied by radial nerve
extends and abducts hand at wrist joint
What group of muscles is the extensor carpi radialis brevis in, nerve supply, action?
superficial muscles of extensor compartment
deep branch of radial nerve
extends and abducts hand at wrist joint
Extensor digitorum:
Group of muscles that it is in?
Nerve supply? Action?
superficial muscles of extensor compartment
posterior interosseous branch of radial nerve
extends the fingers, knuckles, and hand at wrist joint
Extensor digiti minimi:
Group of muscles?
Nerve supply?
Action?
Superficial muscles of extensor compartment
Posterior interosseous branch of radial nerve
extends the little finger
Extensor carpi ulnaris:
Group of muscles that it is in?
nerve supply? action?
superficial muscles of extensor compartment
posterior interosseous branch of radial nerve
extends and adducts hand at wrist joint
What are the 5 deep muscles of the extensor compartment?
Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis
Supinator:
what group of muscles in extensor compartment
nerve
action
Deep muscles of extensor
radial nerve
supinates forearm
Abductor pollicis longus
what group of muscles in extensor compartment
nerve
action
deep muscles of extensor compartment
radial nerve
abducts and extends thumb
Extensor pollicis brevis
group of muscles in extensor compartment
nerve
action
deep muscles of extensor
radial nerve
extends thumb, knuckle, wrist
Extensor pollicis longus
group of muscles in extensor compartment
nerve
action
deep muscles of extensor
radial nerve
extends thumb, knuckle, wrist
Extensor indicis
group of muscles in extensor compartment
nerve
action
deep muscles of extensor
radial nerve
extends index finger, knuckle, wrist
What tendon is inflammed in ‘tennis elbow’? What is this medically known as?
Where is the pain in patients?
The common extensor tendon of the lateral epicondyle is inflammed
presents with pain in lateral aspect of elbow
What is the main nerve of the posterior compartment?
What two muscles does it descend between (club sandwich)?
Radial nerve**
Descends between brachialis and brachioradialis
What does the radial nerve branch into, and where?
Radial nerve crosses in front of the lateral epicondyle and divides into superficial branch (sensory) and deep branch (motor)
What branch of the radial nerve pierces the supinator muscle, and what does it emerge as?
The deep branch pierces the supinator
emerges as posterior interosseous nerve (same nerve, new name)
What is the apex and base of the palmar aponeurosis?
Apex = distal border of flexor retinaculum and receives insertion of palmaris longus tendon Base = divides at base of fingers into 4 slips which subdivide into 2 addition slips to attach to fibrous flexor sheath and deep transversal metacarpal ligament
What is Dupuytren’s contracture?
Localized thickening and contracture of palmar aponeurosis
Describe the arrangement of the 4 tendons of the flexor digitorum superficialis and the tendons of the flexor digitorum profundus in the carpal tunnel.
The 4 tendons of the flexor digitorum superficialis are arranged in anterior and posterior rows:
tendons for finger 3 and 4 are superficial, 2 and 5 are deep
Tendons of profundus are in the same plane and are posterior to those of the digitorum superficialis
How does the median nerve pass through the flexor retinaculum?
Passes beneath it in a restricted space
What is housed within the fibrous flexor sheaths?
The sheaths form a tunnel for the long flexor tendons
What are the 3 thenar muscles of the hand? What nerve supplies all 3?
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
All supplied by the recurrent branch of median nerve
What kind of hand muscle is the abductor pollicis brevis, what is its nerve supply and what is its action?
Is one of the thenar muscles
supplied by recurrent branch of median nerve
abducts the thumb
What kind of hand muscle is the flexor pollicis brevis, what is its nerve supply and what is its action?
is one of the thenar muscles
supplied by the recurrent branch of median nerve
flexes thumb
What kind of hand muscle is the opponens pollicis, what is its nerve supply, and what is its action?
is one of the thenar muscles
supplied by recurrent branch of median nerve
opposes thumb
What is the only muscle in the adductor compartment of the hand, what is its nerve supply**, and what is its action?
Adductor pollicis
supplied by deep branch of ulnar nerve (it adducts the thumb, and remember that adduct = ulnar)
adducts the thumb
What are the 3 hypothenar muscles of the hand? What nerve supplies all 3?
Abductor digiti minimi
Flexor digiti minimi
opponens digiti minimi
All supplied by deep branch of ulnar nerve
What type of hand muscle is the abductor digiti minimi what is its nerve supply, and what is its action?
Is a hypothenar muscle
deep branch of ulnar nerve
abducts the 5th (pinky) finger
What type of hand muscle is the flexor digiti minimi, what is its nerve supply, and what is its action?
is a hypothenar muscle
deep branch of ulnar nerve
flexes the 5th (pinky) finger
What type of hand muscle is the opponens digiti minimi, what is its nerve supply, and what is its action?
is a hypothenar muscle
deep branch of ulnar nerve
opposes the 5th (little) finger and deepens the palm
What nerve supplies the lumbrical muscles** and what is their action?
1st and 2nd lumbricals are supplied by the median nerve
3rd and 4th by ulnar nerve
Flex metacarpophalngeal joints (the knuckle) and extends the interphalangeal joint
What hand muscles are supplied by the median nerve? What hand muscles are supplied by the ulnar nerve?
Only the 3 thenar muscles and the 1st and 2nd lumbricals are supplied by median nerve
All the rest are supplied by the ulnar nerve
What are the 2 types of interosseous muscles, what are they supplied by, and what are their actions?
There are palmar and dorsal interosseous muscles
They are all supplied by the deep branch of ulnar nerve
Flex metacarpophalangeal joints, extend interphalangeal joints
The palmar interosseous muscles also adduct fingers towards center of 3rd finger (PAD)
The dorsal interosseous muscles also abduct fingers towards center of 3rd finger (DAB)
What tendon passes through the tunnel created by the superficialis tendon?
The tendons of the flexor digitorum profundus
What provides the blood supply for each tendon?
Each tendon has a vincula which provides a route for vessels to reach the tendon
What is formed by the long extensor tendons when they broaden over the knuckles?
forms the dorsal extensor expansion
Which artery makes the superficial palmar arch? Which artery makes the deep palmar arch?**
The superficial palmar arch is made by the ulnar artery
The deep palmar arch is made by the radial artery
Between what 2 muscles does the deep ulnar branch of the ulnar artery pass between?
Passes between the abductor digiti minimi and the flexor digiti minimi
With regard to the pisiform and the ulnar nerve, how does the ulnar artery enter the hand?
It enters superficial to flexor retinaculum
enters lateral to ulnar nerve and pisiform bone (so closer to the thumb)
What is supplied by the superficial palmar arch?**
Supplies branches to all sides of the fingers except the:
thumb
radial side of index finger
What are the two branches given off of the radial artery before it continues as the deep palmar arch?
Radialis indicis artery (supplies lateral side of index finger)
Princeps pollicis artery (supplies two sides of the thumb)
What arteries make up the superficial palmar arch?
What arteries make up the deep palmar arch?
Superficial palmar arch = ulnar artery. completed laterally by the superficial palmar branch of radial artery
Deep palmar arch = radial artery. completed medially by the deep branch of the ulnar artery
What is included in the carpal tunnel?
The 8 flexor tendons of the flexor digitorum superficialis and flexor digitorum profundus
The median nerve also passes through the carpal tunnel
What is the tendon that runs in its own synovial sheath in the carpal tunnel?
The flexor pollicis longus tendon
What is the distribution of the motor fibers of the median nerve in the palm? What is (generally) the distribution for sensory?
Median nerve supplies the thenar muscles and the first 2 lumbrical muscles
Supplies sensory for the lateral palm (and including fingertips/nailbed for thumb, index, middle, adn half of ring finger)
What is the distribution of motor fibers of the ulnar nerve of the palm? What is (generally) the distribution for sensory fibers?
Ulnar nerve supplies motor fibers to: hypothenar muscles 3rd and 4th lumbricals adductor pollicus palmaris brevis all interossei muscle Supplies sensory to the medial palm and medial back of hand
What are the anterior and posterior borders of the anatomical snuff box?
Anterior: abductor pollicis longus and extensor pollicis brevis tendons
Posterior: extensor pollicis longus tendons
What are the contents of the anatomical snuff box?
Terminal parts of the superficial radial nerve (superifical = sensory, so the area on the hand that corresponds to radial cutaneous innervation is right around snuffbox)
Radial artery and branches
Scaphoid bone
