To investigate whether rostral extension of the hind limbs increases the cranio-caudal
dorsal interlaminar distance between the seventh lumbar vertebra and the sacral bone
(LS distance) in sternally recumbent anesthetized dogs.
Prospective clinical study.
Eighteen dogs (eight neutered males, three intact males, six spayed females, one intact
female) of various breeds, weighing 4–34 kg and ranging in age from 1 to 13 years.
Each dog was grouped by size: small (≤10 kg), medium (15–20 kg) or large (≥25 kg).
Each dog was anesthetized and positioned in sternal recumbency. Computed tomography
(CT) of the lumbosacral area was performed with the hind limbs resting on the stifle
and the feet extended posteriorly, and then with the hind limbs extended rostrally.
LS distance, craniocaudal dorsal interlaminar distance between sixth and seventh lumbar
vertebra (L6–L7 distance), length of L7 vertebral body and lumbosacral angle (LS angle)
were measured on a reconstructed mid-sagittal CT image from the two hind limb positions.
The measurements from the two hind limb positions for the whole dog population and
by size were compared using Student's T tests. Diagnostic interpretation of the CT images was performed.
The length of L7 was taken as the reference value as it was not affected by hind limb
position. LS distance, L6–L7 distance and LS angle were significantly higher when
the hind limbs were extended rostrally in all three size groups. The CT images of
ten dogs showed clinically undetected osteoarthrosis of the ileo- and lumbosacral
Conclusions and clinical relevance Rostral extension of the hind limbs significantly increases LS and L6–L7 distance
and LS angle even in dogs with clinically undetected osteoarthrosis of the ileo- and
lumbosacral area, and may enhance the ease of lumbosacral epidural injection in sternally
recumbent anesthetized dogs.