3.1 Ankle Block

Question 1

Sensory innervation of foot

Answer 1

1. Saphenous nerve
2. Posterior Tibial Nerve
3. Sural Nerve
4. Deep Peroneal
5. Superficial Peroneal

Question 2

1. Saphenous nerve

Answer 2

1. Term of Femoral N
2. Enters ant. to Medial Malleolus
   adjacent long saphenous vein
3. Supplies Medial border of foot up to ball great toe

Question 3

2. Posterior Tibial Nerve

Answer 3

1. Mixed M + S
   Terminal branch Tibial N
2. Enters Posterior to Med Mall
   Behind Post Tib A.
3. Divides into Medial and lateral plantar nerve
   Sole of Foot

Question 4

3. Sural N

Answer 4

1. Branch Tibial
   Arising below pop fossa
2. Occas receive accessory input from Common Peroneal
3. Supply lat border of foot / 5th Toe
4. Enter foot superficially and posterior to lat Mal

Question 5

4. Deep Peroneal N

Answer 5

1. Branch CPN
   Lies lateral to DP
2. Enters foot as terminal sensory branches
   - underneath extensor retinaculum
   - dividing medial lateral branch
3. Lat branch
   Motor -> Extensor dig brevis
4. Medial branch
   small area over dorsum of foot
   first web space

Question 6

5. Superficial Peroneal N

Answer 6

1. Other branch of CPN
2. Superficial in lower 1/3 calf
   between peroneus tertius and brevis

Dividing into medial and intermed dorsal cutan N.

3. Branch enter foot passing over extensor retinaculum
4. Medial Dorsal cut nerve
   supply medial part dorsum foot
   Supplement 1st and second webspace
5. Intermed dorsal cut nerve
   Lateral dorsum and 3d and 4th webspace

Question 7

Options for blocking N during surgery . Foot surgery

Answer 7

1. Central - SAB / Epidural
2. Nerve Root
   Lumbosacral plexus
3. Nerve trunks
   Sciatic/fem
   pop fossa
4. Ankle block

Question 8

Describe performing an ankle block

Answer 8

Standard preop assessment and procedure consent

SLIMRAG

Sterile equip
Light
IV Access
Monitoring

Resus equip
Assistant trained
GA conversion PRN

Question 9

Nerves in ankle block

Sapnhenous

Answer 9

Saphenous:
Superficial and anterior to Med Mall
Inject LA from Ach tendon s/c anterior to tibia

Question 10

Posterior tibial

Answer 10

Post to med mal
Advance needle onto bone
withdraw 1-2m before inject LA

Question 11

Deep Peroneal

Answer 11

Lat to DP artery
Dorsum foot
3-5ml
Inject deep to fascia

Question 12

Superficial Peroneal

Answer 12

Division of N
vary distances above lateral mall
Single shot difficult

SC infiltration from lateral malleolus
to anterior aspect tibia should block

Question 13

Sural N

Answer 13

Linear blockade s/c from lateral mal to Achilles tendon

Use nerve stim
on benefit mixed nerves

Ultrasound increasing use in single shot techniques rather than linear infiltration