MSK Clinical Hand Wrist Elbow Flashcards
What can enlarged axillary lymph nodes be a sign of?
- Lymphedema e.g. caused by infection lymphangitis. Metastases of breast cancer.
How many axillary lymph nodes are there?
5
Pectoral Sub scapular Humeral Central Apical
How can lymph node removal analysis be used clinically? What are two drawbacks of this kind of analysis?
Useful for staging breast cancer
Removal of lymph nodes can lead to lymph oedema (can lead to painful swelling of upper limb)
Risk of damage to long thoracic nerve in this procedure
What can a mid humeral shaft cause injury to?
Radial nerve as runs in the radial groove - Appears as wrist drop
Profunda brachii artery damage
Why does radial nerve injury at the mid-shaft of the humerus result in wrist drop? Why might there be no sensory damage of arm and forearm but sensory damage to the hand? Which part of hand?
Wrist drop is due to the extensors in the posterior forearm being damaged - e.g. extensor carpi radialis longs
Triceps brachia weakened not paralysed
Cutaneous branches to arm and forearm are more proximal.
Cutaneous branch to hand affects the dorsal side lateral 31/2 digits and the associated dorsum of hand.
Why would a stab/laceration to the forearm affecting the radial nerve not lead to wrist drop?
Because the motor branch for extensor carpi radialis longus has already arisen so maintains some extension at the wrist.
Other extensors get wiped.
Which cords does the median nerve arise from in the brachial plexus?
medial and lateral
Which cord does the radial and axillary nerves arise from?
posterior
Which cord does the musculocutaneous nerve arise from?
lateral
Which cord does the ulna nerve arise from?
medial
Which nerve runs through the carpal tunnel?
Median nerve
How could you test for carpal tunnel type pain/sensations? Where might you feel pain/parasthaesia?
Flexion at the wrist for 60secs may produce pain or parasthaesia in the median nerve distribution (lateral 3.5 digits, thenar eminence, tips of fingers, and associated palm)
What is the hand of Benediction?
Median nerve injury at the elbow or wrist may cause this e.g. lacerations.
Thenar muscles paralysed and lateral 2 lumbricals
Sensory loss of lateral 3.5 digits and tips of fingers, thenar eminence and associated palm
Ask to make a fist will make the Hand of benediction
Which nerve supplies the flexors of the anterior compartment of the forearm apart from the flexor carpi ulnaris and medial half of flexor digitorum profundus?
Median
What muscles does the ulnar nerve innervate?
Most of the muscles of the hand except the lateral two lumbricals, the thenar muscles, flexor carpi radialis and the lateral half of the flexor digitorum profundus
Where is the ulnar nerve most susceptible to damage?
Medial epichondyle
What happens with damage to the ulnar nerve at the wrist vs elbow?
Wrist - medial 2 lumbricals paralysed, interossei are paralysed so no flexion or abduction/adduction of those digits gives a claw. Unopposed extension at the MCP, unopposed flexion as DIP from FDP.
At the elbow the flexor carpi ulnaris and medial 1/2 of flexor digitorum profundus are also paralysed so claw looks less severe but more muscles are paralysed - paradox.
Why is brachioradialis an exception of the posterior compartment of the forearm?
It origin and innervation are characteristic of extensors but it is a flexor.
Radial nerve
Flexes elbow in the 1/2 pronated 1/2 supinated position - so assists in pronating/supinating (beer drinking)
What do extensors of the wrist/fingers help with?
Improves grip
What are the 7 superficial extensor muscles of the posterior compartment of the forearm Lateral to medial?
Brachioradialis Extensor carpi radialis longus and brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Anconeus
What is the origin and insertion of the brachioradialis?
Origin is lateral suprachondylar ridge of the humerus
Insertion is the radius just proximal to the radial styloid process
What is the origin insertion and role of extensor carpi radialis longus and brevis and function?
Both abduction at the wrist and extension of the arm at the elbow.
Longus originates from lateral suprachondylar ridge
Brevis from lateral epicondyle
Both insert at metacarpal bones I II
Where do the extensors of the forearm originate from? (4 from lateral epicondyle, 2 from suprachondylar ridge, 1 other)
Lateral epicondyle - Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris
Suprachondylar ridge -
Extensor carpi radialis longus
Brachioradialis
Other - anconeus - some say extension of triceps brachii
What muscles insert into the extensor hoods of the fingers?
Extensor digitorum of each finger
Also extensor indices
Also extensor digiti minimi
What is the major extensor of the fingers? What joints does it extend at?
Extensor digitorum
Extends at the MCP and IP joints
Which two digits have two extensor muscles?
Index and little fingers
Which digit extensor also contributes to extension at the wrist?
Extensor digiti minimi
Which muscles adducts the wrist?
The extensor carpi ulnaris
What are the 5 deep muscles of the posterior forearm?
Supinator
Abductor pollicis longus
Extensor pollicis longus and bravis
Extensor indices
Which of the extensor pollicis longus and brevis insert at the proximal phalanx of the thumb and which at the distal phalanx
Longus - distal phalanx
Brevis - prox phalanx
What is an important structure in the anatomical snuffbox and what is the relevance of the snuff box clinically?
Radial artery
Pain on palpation may indicate scaphoid fracture
What is the Allen’s test used for?
Check patency of radial and ulna arteries - for radial cannulation
What is most common FOOSH injury? Where can FOOSH injuries occur from?
From clavicle to finger - most common is carpal e.g. scaphoid fracture.
What is a colles vs smiths fracture?
Colles (outward hand)- FOOSH fracture to distal radius
Smiths (inward hand - fall onto flexed wrist - fracture to distal radius
What is the worry with a scaphoid fracture? Why might you also need to re-xray?
- Avascular necrosis of the prox head of broken scaphoid due to damage to the branches of the radial artery that supply it
- May not show up on initial X rays
What is a dinner fork deformity a classic sign of
Colles fracture of distal radius (dorsally displaced and angulation)
What is the commonest elbow fracture? What should you check for following a radial head fracture?
Radial head
NV compromise - radial artery and radial nerve (interosseous branch)
What is a pulled elbow and why is it more common in children? What is the most common age?
Subluxation of the radial head - more common in children as their annular ligament is less strong.
Age 1-4 common
How might you get a dislocated elbow?
FOOSH
What is a Boxers fracture? What is the worry with this type of fracture? How is it examined?
5th metacarpal - can become internally rotated and cause clenched first and grabs abnormalities. Examination involves determining the orientation of the little finger.
What is De Quervain’s Tenosynovitis?
Swelling of flexor tendons - painful on flexion or unable to flex
What does the ulnar nerve travel through in the wrist?
Guyons canal
What could be a cause of one or more fingers that are bent (contracture)?
Dupuytrens contracture - normally genetic build up of scar tissue can cause fingers to bend permanently - unable to wash face etc.
What is the effect of ageing on joints?
Lose calcium Lose mineral content Lose mass Lose fluid and become compressed. Loss of cartilage - e.g. knee Pain, stiffness, deformity
What can two causes of mallet finger be of?
Tendon avulsion - due to ruptured tendon (so bone and tendon both come away from main bone) or avulsion fracture where fragment of bone comes away from tendon.
Which nerve and artery are most at risk of damage with a suprachondylar fracture of the humerus?
Median nerve
Brachial artery
Why would a mid shaft fracture of the humerus not effect extension at the elbow but will cause wrist drop
Because the nerve for the triceps brachii arises before the spiral groove in the shaft of the humerus so will be unaffected. Below the mid shaft is the origins for extensors of the wrist e.g. the ECRL ECRB and ECU so these will be damaged
Where is the most reliable place to test for radial nerve cutaneous damage?
On the dorsum of the hand between the thumb and index finger
