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
Damage to which nerve causes hypothenar atrophy?
Deep branch of ulnar nerve
Damage to which nerve causes 1st interosseous atrophy?
Deep branch of ulnar nerve
Damage to which nerve causes wrist drop?
Radial nerve
Damage to which nerve causes paraesthesia over lateral deltoid?
Axillary nerve
Damage to which nerve causes weakened finger adduction?
Deep branch of ulnar nerve
Damage to which nerve causes winged scapula?
Long thoracic nerve
