MSAT Equine

Question 1

What are the forelimb nerve blocks?

Answer 1

• Palmar digital nerve block PDNB
• Abaxial sesamoid nerve block ABSND
• High 2 point block
• Intra-articular blocks (DIP/Fetlock/Carpus)
  –> 19-21 x 1.5” needle. Don’t shape/clip. Iodine scrub

*Start with lowest nerve block and work up the limb. Nerve blocks are used to tell where the source of pain originates from.

Question 2

Landmarks for the PDNB?

Answer 2

Palpate VAN (vein, artery nerve): proximal to collateral cartilages medially and laterally.
On the back of the lower pastern, sensation on most of the foot.

Inject with limb elevated and facing towards tail of the horse.

Inject Subcutaneous and parallel to the VAN
Needle is proximal to distal
25 G 5”
1.5mL x2
Onset 10-15 minutes

Blocks:
- Caudal 1/3 of the foot (heels including the skin)
- Navicular Bone/Bursa
- P3
- Some sole
- DIP Joint
Test: Pricking or prodding heels.

Question 3

How to do ABSND?

Answer 3

• Base of the Proximal sesamoid bone
  Insert SC and parallel to VAN
  3mL
  Onset: 10-20 minutes

Inject with limb elevated and facing head of horse, inject medial side first distal to proximal

Blocks:
- Mid- pastern and distal (entire foot) include skin
- With hindlimb, also need to block dorsal metatarsal nerve at level of dorsal P1

Question 4

How to do a High 2 point block?

Answer 4

• Metacarpus/metatarsus

High 2 point:
Lateral palmar nerve (branch of ulnar + median)
Medial palmer nerve (branch of median)

Lateral Palmer Nerve:
- Lateral aspect’
- Distal to the distal border of the accessory carpal bone
- 22-25 gauge needle, 5mL local
- Pick leg up and flex. Palpate depression between accessory carpal and head of Mc4
Keep finger on landmark and put the leg down.
(Lateral/fourth metacarpal bone)
Inject deep and as needle withdrawn.

Medial palmer nerve:
- Medial aspect
- Elevate contraleteral limb so the limb is weight bearing
- 22-25 G needle 5mL local
- Cranial/caudal to cephalic base of the accessory carpal bone 45 degrees to long axis limb.

Question 5

How to do a DIP Joint Block?

Answer 5

Coffin Joint DIP

Dorsal Approach
- 1.5cm Dorsal to coronet
- 1.5cm off midline
- Insert at 45 degree angle to long axis
- Aim slightly forward

Lateral Approach
- Palpate Notch between palmer P2 and collateral cartilage, angle needle slightly dorsal

20-21 G 1.5”
3-5mL

Blocks:
- DIP Joint
- Sole
-Nbone
(No loss of skin sensation)

Question 6

How to do a Fetlock block?

Answer 6

Low 4 point:
Distal MC: Buttons of splint bones (palmar metacarpal nerves) and palmar nerves between Deep digital flexor and superficial flexor

Low 6 Point:
Buttons of splint bones (palmaer metacarpal nerve) and palmar nerve) between Deep digital flexor and superficial flexor); dorsal metatarsal in hindlimb

2-3mL
15-20 minutes

Blocks:
- Fetlock
- Sesamoids
- SL Br and below

Test: Prick fetlock and below

Question 7

How to do a Navicular Bursa?

Answer 7

Between bulbs at the level of the coronet
- Direct to point midway along the circumference of hoof approx 1cm. distal to coronet with limb in raised wedge block in partial flexion

18G spinal needle
3.5”

Question 8

How to do a PIP Joint nerve block?

Answer 8

Btween palmar P1 cortex & distal eminence & superficial digital flexor tenson branch, partial flexion

• 21 x 1.5” Needle
  5mL

Question 9

How to do a Digital Tendon Sheath block?

Answer 9

• Palmar-plantar axial sesamoid approach
• Flexed fetlock joint
• Midbody lateral to Proximal Sesamoid Bone. Directed 45 degrees medially, angled towards central intersesamoidean region
  Depth of 1.5-2cm

Question 10

Carpal Joint nerve blocks?

Answer 10

Joints:
- Radiocarpal
- Middle carpal
- Carpometacarpal

1. Radiocarpal: Flexed 90 degrees
   - Proximal to radiocarpal bone
   - Medial to extensor carpal radialis
   - Direct slightly caudal
   22G 1” 3m:
2. Middle carpal
   - Head of splint and T4, palpable notch aim towards front fetlock.
   - Needle flatter, medial to extensor carpi radialis
   - Local will diffuse into carpometacarpal joint
   21G 1.5” 3mL