Peripheral nerve lesions Flashcards
Where are the different dermatomes located?
C3-4; shoulder C5; lat elbow and arm C6; lat forearm and thumb C7; mid finger C8; little finger and med forearm T1; med elbow and arm
Which myotomes cover most of the shoulder?
C5 & C6
Which myotomes cover most of the elbow/wrist?
C5-7
Which myotomes cover most of the hand?
C8 & T1
What causes Erb’s palsy?
Stretching of the neck (delivery)»_space; C5&6 damage
What are symptoms of Erb’s palsy?
Paralysis of arm and shoulder muscles
- adducted shoulder (deltoid)
- med rotated arm (infraspinatus)
- extended elbow (biceps brachii)
- pronated forearm (brachialis)
What cause Klumpke’s palsy?
Damage to inferior trunk (ulnar nerve - C8/T1)
What are symptoms of Klumpke’s palsy?
Paralysis of intrinsic hand muscles;
- claw hand (hyperextended MCP joints, flexed IP joints)
- digits IV & V
Carpal tunnel syndrome has similar symptoms to Klumpke’s. Is it harder or easier to treat?
Normally easier ; anti-inflammatories/ surgery
What may be associated with Klumpke’s?
Horner’s syndrome - sympathetic neruons from T1
ptosis, miosis, anhidrosis, etc
What is radial nerve palsy?
Radial nerve injury in spiral groove»_space; wrist drop (paralysis of forearm extensors)
Why is triceps brachii not completely paralysed with radial nerve palsy?
Long head is supplied by a more proximal branch - mild extension possible.
What causes median nerve injury at the elbow?
- Supracondylar fractures
- Pronator teres syndrome
What causes ‘hand of Benediction’, and what does it lead to?
Median nerve injury
- inability to flex I-III
Damage to which nerve causes thenar atrophy?
Recurrent branch of median nerve
