Nerve Palsies Flashcards

1
Q

Define Hilton’s Law?

A

Any nerve supplying a joint will also supply:

  • The muscles moving that joint
  • Skin over the insertion of those muscles
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2
Q

Example of a nerve following Hilton’s Law?

A

Musculocutaneous nerve supplies the anterior capsule of the elbow, as well as:

  • Muscles biceps, coracobrachialis and brachialis
  • Skin over these muscle insertion

All via the lateral cutaneous nerve of the forearm (one of its terminal branches)

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3
Q

Infant presents with the classic “Waiters Tip” position, what is this position?

A

Shoulder adducted and Internally rotated
Elbow extended and pronated
Wrist flexed

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4
Q

What does the “Waiter’s Tip” position suggest pathologically?

A

Erb’s palsy, Traction of the brachial plexus (specifically C5/6 aka the superior trunk) e.g. during forceps delivery

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5
Q

Patient presents with a clawed hand, what injury to the brachial plexus could cause this?

A

Klumpke’s Palsy, i.e. injury to the Inferior trunk (C8/T1). It affects the small hand muscles

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6
Q

Other than Erb’s (sup trunk) & Klumpke’s (Inf Trunk) what other common nerve palsies affect the brachial plexus?

A

Total Brachial Plexus Palsy.

Affecting C5-T1

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7
Q

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?

A

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

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8
Q

What does the radial nerve arise from and supply?

A

C5-T1, arising from the post cord

Supplies:

  • Triceps
  • Brachioradialis
  • ECRL & ECRB
  • Finger extensors via PIN
  • Posterior hand sensation via SRN
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9
Q

How would compression or entrapment of the radial nerve present?

A

Depends on the level its injured at:

  • Compress SRN at wrist –> lose sensation in hands (e.g. handcuffs)
  • Compress PIN in forearm –> Lose finger extension
  • Compress Radial in arm –> lose above + wrist extension
  • Compress Radial in axilla –> Above + Elbow extension
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10
Q

From where does the median nerve arise and what does it supply?

A

C5-T1, arises from medial & Lateral cords
Supplies:
- All forearm flexors except FCU & Medial half of FDP
- Sensation to radial 3.5 digits

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11
Q

What condition comes with median nerve palsy?

A

Carpal Tunnel Syndrome

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12
Q

What causes carpal tunnel syndrome? [5]

A

Developmental
Trauma (Distal radial fracture)
Ganglia, fibroma or lipoma swelling
Inflammatory - Gout, rheumatoid, TB or Amyloid
Metabolic - Pregnancy, mucopolysaccharides & Hypothyroidism

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13
Q

How does carpal tunnel syndrome present?

A

Nocturnal pain & paraesthesia
Abductor Pollicis Brevis weakness
+ve Tinnels/Phalen’s Signs
Thenar wasting & ~scars + deformity

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14
Q

Where does the ulnar nerve arise and what does it supply?

A

C8/T1, arising from medial cord

Supplies FCU & medial 1/2 of FDP
+ Intrinsic hand muscles except LOAF
Sensation to Ulnar 1.5 digits

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15
Q

What are the LOAF Muscles?

A

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
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16
Q

What condition affects the ulnar nerve?

A

Cubital Tunnel Syndrome

17
Q

What is the cubital tunnel?

What is the ulnar paradox?

A

Tunnel between medial epicondyle & olecranon with the FCU fascia forming the roof. Contains the ulnar nerve

Distal lesion has worse clawing than a proximal lesion due to intact long flexors with distal lesion

18
Q

How does Cubital Tunnel Syndrome present?

A

Numbness on ulnar side of hand and fine dexterity loss
Hypothenar & 1st webspace wasting + guttering
Ulnar claw hand
+ve Froment’s Test (Tests Adductor pollicis)

19
Q

How does Cubital Tunnel syndrome cause a claw hand?

A

Ulnar claw hand involves hyperextension of the MCPJ and flexion of IPJs

20
Q

Patient presents with acute foot drop and pain under their knee?

A

FIbula fracture causing Common Peroneal Nerve Palsy

This presetns with Weakness in Dorsiflexion or “Foot Drop”

21
Q

Where does the Common Peroneal Nerve arise?

A

From the Sciatic nerve (L4-S3) which itself arises from the sacral plexus (L4-S4)

22
Q

Patient experiences altered sensation and pains in their lateral thigh, likely diagnosis?

A

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