Nerve Palsies in the Limbs Flashcards Preview

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Flashcards in Nerve Palsies in the Limbs Deck (33)
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1
Q

What is a dermatome?

A

A sensory area of skin supplied by a single spinal nerve

2
Q

Is there overlap between adjacent pre- and post-axial dermatomes?

A

No - limb buds grow out from the body wall in axial lines

3
Q

Why are lower limb dermatomes distorted?

A

-Rotation, extension and borrowing of skin from the trunk

4
Q

What is Hilton’s Law?

A
  • “The nerves crossing a joint supply the muscles acting on it and the joint itself”
  • “The motor nerve to a muscle tends to give a branch of supply to the joint that the muscle moves and another to the skin over the joint”
5
Q

Which nerves supply the hip joint?

A
  • Obturator
  • Femoral
  • Lateral femoral cutaneous nerve
6
Q

What is a myotome?

A

A group of muscles supplied by one segment of the spinal cord

7
Q

Give two common anatomical variations of the brachial plexus

A
  • Pre-fixed plexus (C4-8)

- Post-fixed plexus (C6-T2)

8
Q

Name the common brachial plexus lesions

A
  • Downward traction
  • C5 and 6 damage
  • Arm “porter’s tips”
  • Upward traction (breech delivery)
  • T1 damage (intrinsic damage)
  • Klumpke’s paralysis (clawed hand)
9
Q

How can the axillary nerve be damaged and which deficits would be seen?

A
  • As a complication of: fractured humeral neck, shoulder dislocation and saturday night palsy (pressure on posterior cord of brachial plexus)
  • Deficits: loss of shoulder abduction and sensory loss over regimental badge area
10
Q

What are the roots of the radial nerve and where does it travel?

A
  • C5-T1
  • Passes between brachioradialis and brachialis to enter the forearm
  • Posterior interosseous branch passes between 2 planes of supinator
11
Q

At which anatomical locations is the radial nerve most at risk?

A
  • Spiral groove of humerus and lateral intermuscular septum

- Posterior interosseus branch at the radial neck

12
Q

How can the radial nerve be damaged and which deficits would be seen?

A
  • Fractures of humeral shaft, Saturday night palsy and exposure of the proximal radius
  • Deficits: wrist drop (extensors) and sensory deficit in the dorsal 1st web space
13
Q

What are the roots of the median nerve and where does it enter the forearm?

A
  • C7-T1

- Between the two heads of pronator teres

14
Q

At which anatomical locations is the median nerve most at risk?

A

Volar aspect of the wrist and the cubital fossa

15
Q

What can cause damage to the median nerve and which deficits would be seen?

A
  • Carpal tunnel syndrome, wrist lacerations, supracondylar fractures and Struther’s ligament
  • Deficits: thenar wasting , pointing finger and sensory deficit to the volar aspect of the thumb
16
Q

What are the roots of the ulnar nerve and where does it enter the forearm?

A
  • C7-T1

- Passes between the two heads of flexor carpi ulnaris

17
Q

Where is the ulnar nerve most at risk?

A

-Behind the medial epicondyle of the humerus, wrist and canal of Guyon

18
Q

What can cause ulnar nerve damage and which deficits would be seen?

A
  • Fractures of humeral condyles and wrist lacerations

- Deficits: claw hand, hypothenar and 1st dorsal interosseous wasting and sensory deficit to the little finger

19
Q

Where does the lumbar plexus lie?

A

On the surface of quadratus lumborum and within the body of the psoas muscle

20
Q

Which major nerves, that lie around the hip, do not exit the pelvis by the sciatic foramen?

A
  • Genitofemoral
  • Ilioinguinal
  • Femoral
  • Lateral femoral cutaneous
  • Obturator
21
Q

What are the roots of the femoral nerve and which plexus is it a part of?

A
  • L2-4

- Lumbar plexus

22
Q

Describe the route the femoral nerve takes

A
  • Passes through the Psoas major muscle
  • Exits pelvis under the inguinal ligament
  • Lateral to femoral artery, vein and lymphatic channels in the femoral triangle
23
Q

Which structures are supplied by the femoral nerve and where do its terminal branches lie?

A
  • Quadriceps muscles in the anterior thigh

- Long fine sensory branch: saphenous nerve

24
Q

What are the roots of the lateral femoral cutaneous nerve and where does it lie?

A
  • L2-3
  • On the surface of the iliacus muscle
  • Usually exits pelvis under the lateral end of the inguinal ligament
25
Q

What does the lateral cutaneous nerve carry?

A

Sensation to the lateral aspect of the thigh

26
Q

What happens if the lateral femoral cutaneous nerve is compressed?

A

Meralgia paraesthetica

27
Q

What are the roots of the sciatic nerve and which plexus is it a part of?

A
  • L4-S3

- Sacral plexus

28
Q

Where does the sciatic nerve run?

A
  • Exits pelvis through sciatic foramen below piriformis muscle
  • Runs deep to the gluteus maximus muscle
29
Q

Which structures are supplied by the sciatic nerve?

A
  • Hamstring muscles (posterior thigh)
  • Adductor magnus
  • All lower leg and foot muscles via terminal branches (tibial and common fibular nerves)
30
Q

What can cause damage to the sciatic nerve?

A
  • Posterior dislocation of the hip
  • IM injections
  • Surgery
31
Q

What are the roots of the common fibular nerve and which nerve is it a branch of?

A
  • L4-S2

- Sciatic nerve

32
Q

Where is the common fibular nerve at risk and what deficits would be seen?

A
  • As it passes around the lateral aspect of the neck of the fibula
  • Deficits: foot drop and slapping gait
33
Q

Which branches does the common fibular nerve give off?

A
  • Superficial and deep fibular nerves

- Communicating branch to the sural nerve