26.5.1: Diagnostic anaesthesia Flashcards
Which local anesthetic is typically used for nerve blocks in horses?
a) Lignocaine
b) Procaine
c) Mepivicaine
d) Bupivicaine
c) Mepivicaine
What is the first nerve block you would start with on a horse which is forelimb lame with no localising signs?
a) High 4 point
b) Low 4 point
c) Abaxial sesamoid nerve block
d) Palmar digital nerve block
e) Median and ulnar nerve block
d) Palmar digital nerve block
You have been asked to re-examine a horse which previously had interphalangeal (pastern) joint pain. This resolved, but the horse is now lame again. What response to nerve blocks would you expect if the proximal interphalangeal joint was still painful?
a) the lameness would completely resolve with a palmar digital nerve block
b) the lameness would improve with a palmar digital nerve block
c) the lameness would improve with an abaxial sesamoid nerve block and completely resolve with a low 4 point nerve block
d) the lameness would improve with a low 4 point nerve block and completely resolve with a high 4 point nerve block
c) the lameness would improve with an abaxial sesamoid nerve block and completely resolve with a low 4 point nerve block
The palmar digital nerve block removes sensation to…
the palmar foot
The abaxial sesamoid nerve block removes sensation to…
the foot, pastern, and palmar fetlock
The low 4 point nerve block removes sensation to…
the fetlock and below
What nerve block is indicated by 1?
Palmar digital nerve block
What nerve block is indicated by 2?
Abaxial sesamoid nerve block
What nerve block is indicated by 3?
Low 4 point
Working from distal to proximal, what nerve blocks can you do in the forelimb?
- Palmar digital nerve block
- Abaxial sesamoid nerve block
- Low 4 point (fetlock and below)
- High 4 point (metacarpal region and below)
- Lateral palmar nerve block (proximal suspensory ligament)
- Median and ulnar nerve block (carpus and below)
When should you not perform nerve blocks?
- Suspected fractures -> if in doubt, radiograph!
- Severe soft tissue injuries e.g. DDFT -> catastrophic consequences of weight bearing once pain removed
- Risk of infection e.g. existing skin disease such as mud fever, or environment/ leg that cannot be cleaned adequately
- Risk to handler/ self/ horse
Which nerves are indicated by 1 and which nerve block will block them?
- Palmar digital nerves in the pastern region
- Palmar digital nerve block
Which nerves are indicated by 2 and which nerve block will block them?
- Palmar digital nerves on the abaxial surface of the proximal sesamoid
- Abaxial seasmoid nerve block
Which nerves are indicated by 3 and which nerve block will block them?
- Palmar metacarpal and palmar nerves in distal metacarpus
- Low 4 point nerve block
You are nerve blocking a horse with hindlimb lameness. You suspect the lameness originates from the proximal suspensory ligament. Which nerve block will confirm your suspicions?
Deep branch of lateral palmar nerve block will block the proximal suspensory ligament
Which block is pictured here and why might you do this?
Coffin joint block
Do this if specific concern in the coffin joint e.g. osteoarthritis
Which nerve block is pictured here and what are your landmarks?
Palmar digital nerve block
Depression beside collateral cartilages
Which structures does the palmar digital nerve block numb?
- Sole
- Heel bulbs
- Palmar & distal P3
- Navicular bone
- Navicular bursa
- Distal DDFT
- Impar ligament
- Palmar DIP joint
Which structures does the palmar digital nerve block sometimes numb?
- Dorsal P3
- Dorsal laminae
- Dorsal DIP joint
- Collateral ligaments of coffin joint
- Distal P2
- Collateral cartilages
Which nerve block is pictured here and what does it block?
Abaxial sesamoid nerve block
* Window = top and bottom of the sesamoid bone; needle points distally
* Removes sensation to foot, pastern and palmar fetlock
If the hoof is squared off as pictured, what might this indicate?
The foot has been dragging along the ground
