Nerve Blocks

Question 1

Where is the palmar digital block located?

Answer 1

medial and lateral palmar digital nerve –> between the proximal sesamoid bones and just proximal to the cartilage of the foot

Question 2

What area is desensitized using the palmar digital block?

Answer 2

50-70% of the palmar/plantar aspect of the foot = most of the distal interphalangeal joint except the proximosorsal region

• caudal 1/3 of foot, sole, and navicular apparatus

Question 3

Where is the abaxial sesamoid block located?

Answer 3

medial ad lateral palmar digital nerve –> abaxial surface of the medial and lateral aspect of the proximal sesamoid bones (red arrow)

Question 4

What area is desensitized when using the abaxial sesamoid block?

Answer 4

skin over the palmar pastern and distal dorsal pastern along the foot and proximal interphalangeal joint + partial desensitization of the palmar fetlock

• all structures below the fetlock +/- fetlock itself

Question 5

Where is the low four-point palmar/plantar block located?

Answer 5

medial/lateral metacarpal nerves –> dorsolateral and dorsomedial to the digital flexor tendon (between suspensory ligament and DDFT) at the level of the distal metacarpal bones

• nerves course parallel to the 2nd and 4th metacarpal (splint) bones and can also be anesthetized at the distal end of each
• yellow and purple arrows

Question 6

What area is desensitized by a low four-point palmar/plantar block?

Answer 6

entire metacarpophalangeal (fetlock) joint and structures distal to it

Question 7

Where is a high four-point (subcarpal) block located?

Answer 7

medial/lateral palmar nerves and medial/lateral palmar metacarpal nerves

• between suspensory ligament and DDFT just distal to the carpus
• axial to the splint bones and abaxial to the suspensory ligament and guided to the palmar cortex of the cannon (3rd metacarpal) bone

Question 8

What areas are desensitized with a high four-point (subcarpal) block?

Answer 8

metacarpal region along with the entire metacarpophalangeal (fetlock) joint and structures of the digit

Question 9

You are evaluating a horse with a right front lameness that resolves after performing a low four-point block. The most likely area resulting in the lameness is…

a. proximal metacarpal region or below
b. metacarpophalangeal (fetlock) joint or below
c. proximal P1 and below
d. caudal region of the foot

Answer 9

B

Question 10

Label the following nerve blocks:

Answer 10

a. coffin joint block
b. navicular bursa block
c. palmar digital block
d. abaxial sesamoid block