Where does the spinal cord end in the horse, dog, and cat?

Where does the spinal cord end in the horse, dog, and cat?

• A. Equine: L3; Canine: L5-L6; Feline: Sacrum
• B. Equine: L5-L6; Canine: L3; Feline: L7
• C. Equine: Sacrum; Canine: L3; Feline: L5-L6
• D. Equine: L3; Canine: L5-L6; Feline: Sacrum

Answer: (D)

The level where the spinal cord ends (the conus medullaris) varies by species, while the nerves that continue below form the cauda equina. In the horse, the cord ends around the third lumbar vertebra, so the terminal end is at L3. In the dog, the end sits a bit lower, around L5–L6, with the cauda equina stretching down from there. In the cat, the end is even more caudal, approaching the sacral region, so the cord terminates near the sacrum and the nerve roots extend from there as the cauda equina. This is why the correct pairing is equine L3, canine L5–L6, and feline sacrum: it reflects how far cranially the spinal cord reaches in each species, with the caudal nerve roots continuing beyond that point. Clinically, knowing these endings helps in choosing safe sites for procedures like spinal taps or epidurals, since you want to avoid injuring the spinal cord itself and work with the cauda equina where appropriate.

The level where the spinal cord ends (the conus medullaris) varies by species, while the nerves that continue below form the cauda equina. In the horse, the cord ends around the third lumbar vertebra, so the terminal end is at L3. In the dog, the end sits a bit lower, around L5–L6, with the cauda equina stretching down from there. In the cat, the end is even more caudal, approaching the sacral region, so the cord terminates near the sacrum and the nerve roots extend from there as the cauda equina.

This is why the correct pairing is equine L3, canine L5–L6, and feline sacrum: it reflects how far cranially the spinal cord reaches in each species, with the caudal nerve roots continuing beyond that point. Clinically, knowing these endings helps in choosing safe sites for procedures like spinal taps or epidurals, since you want to avoid injuring the spinal cord itself and work with the cauda equina where appropriate.