Hand Flashcards
What is the name for damage to C8/T1 at the brachial plexus?
Klumpke’s paralysis
What muscle groups are affected when there is damage to C5/6 at the brachial plexus?
- Abductors and external rotators (–> waiters tip position)
- This is Erb’s palsy
- Associated with loss of sensation in C5/6 dermatomes
What muscles are affected when C8/T1 is damaged at the brachial plexus?
- Small hand muscles paralysed –> claw hand
- Loss of sensation in C8/T1 dermatomes
What is the name of a nerve injury affecting C5/6 at the brachial plexus?
Erb’s palsy
What is this sign?
Waiter’s tip (Erb’s palsy, C5/6)
What is this sign?
- Claw hand (Klumpke’s palsy, C8/T1 brachial plexus injury)
- Note the extension at MCPs and flexion at IPs
Which spinal nerves does the radial nerve carry fibres from?
C5-T1
What sign would you get if there was a fracture to the posterior interroseous nerve following a fracture around the elbow or forearm?
Finger drop due to loss of extension at CMC joint
No sensory loss
What nerve is at risk in a fracture of the elbow or forearm?
Posterior interosseous nerve- originates from radial nerve
What nerve is at risk if a fracture of the humerus affects the radial groove?
Radial nerve
What sign is this? What is the cause? Give 3 injuries that can cause this presentation
Wrist drop- due to radial nerve palsy after a shaft of humerus fracture or a high radial nerve injury (e.g. Saturday night palsy, crutches)
Associated with loss of sensation to dorsum of thumb root (snuff box)
Triceps function depends on injury site- v. high injury –> paralysis, fractures normally associated with normal triceps function
What spinal nerves supply the ulnar nerve?
C8-T1
What effect does an ulnar nerve lesion have?
- Paralysis of intrinsic muscles of hand –> ulnar claw hand (affecting ring and little finger)
- Weakness finger ab/adduction (due to interossei loss)
- Sensory loss over little finger
How would you test for an ulnar nerve lesion?
- Froment’s sign- flexion of thumb IPJ when trying to hold onto paper between thumb and forefinger
- Indicates weak adductor policis
- Can’t cross fingers (for luck)
What is the ulnar paradox?
- Ulnar nerve lesion at the elbow (i.e. higher up) has less clawing as FDP is paralysed –> decreased flexion of 4th/5th digits vs a lesion lower down where clawing will appear more severe.
- NB Claw hand from ulnar nerve lesion involves extension of MCPs and flexion at IPs at 4th and 5th digit
What spinal nerve fibres supply the median nerve?
C5-T1
What muscles does the median nerve supply?
The LOAF muscles:
- Lateral two lumbricals
- Opponens pollicis
- Abductor pollicis brevis
- Flexor pollicis brevis
+ all muscles of forearm except flexor carpi ulnaris and ulnar half of FDP
What is this sign? What is its cause? (I appreciate it says on the photo)
Ape like hand
- Median nerve damage
- NB wasting of thenar eminence
- Inability to oppose thumb
What is this sign? When would you see it? What is the cause?
- Median nerve injury, inability to flex fingers at IPJ on attempting to make a fist
- Can’t flex terminal thumb phalanx (FPL)
- Loss of sensation in median nerve distribution
Name the carpal bones
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
- Trapezium
- Trapezioid
- Capitate
- Hamate
What makes up the roof of the carpal tunnel?
The flexor retinaculum (rigid tendinous sheath)
What makes up the floor of the carpal tunnel?
The carpal bones
What does the carpal tunnel contain?
- 9 tendons (all flexors!):
- 4 tendons flexor digitorum superficialis
- 4 tendons flexor digitorum profundus
- 1 tendon flexor pollicis longus
- The median nerve (supplies LOAF muscles)
Which of these tendons passes through the carpal tunnel?:
- Opponens pollicis
- Flexor pollicis brevis
- Flexor pollicis longus
- Abductor pollicis longus
3- flexor pollicis longus
Also the 4 tendons of flexor digitorum profundus and the 4 tendons of flexor digitorum superficialis
