Nerve Palsies Flashcards
Define Hilton’s Law?
Any nerve supplying a joint will also supply:
- The muscles moving that joint
- Skin over the insertion of those muscles
Infant presents with the classic “Waiters/Porters Tip” position, what is this position?
Shoulder adducted and Internally rotated
Elbow extended and pronated
Wrist flexed
What does the “Waiter’s Tip” position suggest pathologically?
Erb’s palsy, Traction of the brachial plexus (specifically C5/6 aka the superior trunk) e.g. during forceps delivery
Patient presents with a clawed hand, what injury to the brachial plexus could cause this?
Klumpke’s Palsy, i.e. injury to the Inferior trunk (C8/T1). It affects the small hand muscles
Other than Erb’s (sup trunk),Klumpke’s (Inf Trunk) what other common nerve palsies affect the brachial plexus?
Total Brachial Plexus Palsy.
Affecting C5-T1
Patient presents with a wasted deltoid and loss of sensation in their regimental badge area. They also mentioned having had a recent fracture of their arm?
Axillary nerve (C5/6) palsy, commonly associated with surgical neck fractures of the humerus and shoulder dislocation.
It supplies the deltoid, teres minor and regimental badge area
What does the radial nerve arise from and supply?
C5-T1, arising from the post cord
Supplies:
- Triceps
- Brachioradialis
- ECRL & ECRB
- Finger extensors via PIN
- Posterior hand sensation via SRN
How would compression or entrapment of the radial nerve present?
– In axilla: loss of elbow extension, wrist extension and sensory changes forearm and hand
– In arm: loss of wrist extension and sensory loss
– In forearm: loss of finger extension (PIN)
– At wrist: loss of sensation (SRN) eg. handcuffs
From where does the median nerve arise and what does it supply?
C5-T1, arises from medial & Lateral cords
Supplies:
- All forearm flexors except FCU & Medial half of FDP
- LOAF muscles in hand
- Sensation to radial 3.5 digits
What condition comes with median nerve palsy?
Carpal Tunnel Syndrome
What causes carpal tunnel syndrome?
Developmental
Trauma (Distal radial fracture)
Ganglia, fibroma or lipoma swelling
Inflammatory - Gout, rheumatoid, TB or Amyloid
Metabolic - Pregnancy, mucopolysaccharides & Hypothyroidism
How does carpal tunnel syndrome present?
Nocturnal pain Paraesthesia Abductor Pollicis Brevis weakness \+ve Tinnels/Phalen's Signs Thenar wasting scars + deformity
Where does the ulnar nerve arise and what does it supply?
C8/T1, arising from medial cord
Supplies FCU & medial 1/2 of FDP
+ Intrinsic hand muscles except LOAF
Sensation to Ulnar 1.5 digits
What are the LOAF Muscles?
The only intrinsic hand muscles not supplied by the ulna, they’re innervated by the median nerve:
- Lateral 2 Lumbricals
- Oppenens Pollicis
- Abductor Pollicis Brevis
- Flexor Pollicis Brevis
What condition affects the ulnar nerve?
Cubital Tunnel Syndrome
What is the cubital tunnel?
Tunnel between medial epicondyle and olecranon with the FCU fascia forming the roof. Contains the ulnar nerve
How does Cubital Tunnel Syndrome present?
Numbness on ulnar side of hand and fine dexterity loss
Hypothenar and 4th webspace wasting + guttering
Ulnar claw hand
+ve Froment’s Test (Tests Adductor pollicis)
How does Cubital Tunnel syndrome cause a claw hand?
Ulnar claw hand involves hyperextension of the MCPJ and flexion of IPJs
Patient presents with acute foot drop and pain under their knee?
FIbula fracture causing Common Peroneal Nerve Palsy
This presetns with Weakness in Dorsiflexion or “Foot Drop”
Where does the Common Peroneal Nerve arise?
L4-S2
From the Sciatic nerve (L4-S3) which itself arises from the sacral plexus (L4-S4)
Patient experiences altered sensation and pains in their lateral thigh, likely diagnosis?
Meralgia Parasthetica
The Lateral Cutaneous femoral Nerve (a branch of the lumbar plexus) is compressed as it travels under the lateral border of the inguinal ligament
This causes altered sensation and pain in the lateral thigh
What is one of the most common causes of downwards traction injury to the brachial plexus
Falling sideways on neck
What is one of the most common causes of upwards traction injury to the brachial plexus
Breech delivery: bum first
Which are the two most common injuries to nerves?
- Compression
- Entrapment
What different types of Palsies present due to damage to the radial nerve
- Saturday Night Palsy
- Honeymoon Palsy
- Crutch Palsy
What causes damage to median nerve function?
- Wrist laceration
- Carpal tunnel
What is the Ulnar paradox
-A distal lesion has worse clawing than a proximal lesion, due to intact long flexors with a distal lesion
Common cause of damage to sciatic nerve
- Dislocation of hip
- IM injection
- Surgery
