04/06/2026
Lumbosacral Transitional Vertebra (LTV)
What is LTV?
LTV is a congenital malformation at the lumbosacral junction (L7-S1), where a vertebra takes on mixed characteristics of both the lumbar spine and the sacrum.
While organizations like the OFA and BVA only note LTV as an "incidental finding" on standard hip X-rays, the Finnish Kennel Club (*Suomen Kennelliitto*) has a strict, highly technical scoring system based on a 0–4 scale:
•LTV0 (Normal) - Ideal morphology. 7 distinct lumbar vertebrae and a symmetrical, fully fused sacrum.
•LTV1 (Divided Median Crest) - The bone bodies are fused normally, but there is a mild structural separation between the spinous processes of S1 and S2. Generally clinically silent.
•LTV2 (Symmetrical LTV) - Structural changes are present, but they are identical on both the right and left sides. While stable, it alters normal spinal flexion.
•LTV3 (Asymmetrical LTV) - One side of the vertebra behaves like a lumbar bone, while the other is fused to the pelvis creating an uneven pelvic tilt
•LTV4 (Numerical Variation) - The dog has a transitional shift in count—either 8 lumbar vertebrae (lumbarization) or 6 (sacralization).
The Biomechanical Impact on Structure & Performance:
- Unexplained one-sided hip dysplasia scores due to uneven joint loading
- Early-onset Cauda Equina Syndrome (nerve compression at the lumbosacral junction)
- Recurrent iliopsoas (groin) strains as the core muscles work overtime to stabilize the pelvic tilt
- Sensitivity, hypertonicity or guarding of the spine, dipping the pelvis, dislike being held underneath (increases spinal flexion), or showing irritation when the lower back or sacrum is touched, toweled off, or groomed, low tail carriage
- Loss of drive & extension because the L7-S1 hinge cannot effectively transfer force generated from the hind legs
- Reduced scapula mobility due to the anatomy changes of having 12 rather than 13 ribs (LTV4). Some dogs may also have an extra pair of ribs!
Standard ventrodorsal (belly-up) hip X-rays frequently crop out the upper lumbar spine, completely missing numerical variations (LTV4) or mild symmetry issues. To truly protect your breeding program or sport prospect, ask your vet for extended spinal views, including a laterolateral (side view), to accurately count from T1 down.
The reason for the post is I think this is currently very under diagnosed and overlooked as "just missing a rib", so let's look past the hips and evaluate the whole spine. 🧬🔬
