Question

The number of lumbar vertebrae present in dog are

• A. Five
• B. Six
• C. Seven
• D. Eight

Hint:

Remember that carnivores (dogs and cats) and small ruminants (sheep and goats) have exactly 7 lumbar vertebrae ($L_7$).
In contrast, horses and cattle typically have 6 ($L_6$), and pigs can have 5 to 7 depending on the breed.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The vertebral column of domestic mammals is divided into five regions: cervical, thoracic, lumbar, sacral, and caudal (coccygeal).
Each species has a highly characteristic vertebral formula.

Step 2: Detailed Explanation:
The standard vertebral formula for the dog (Canis lupus familiaris) is:
\[ C_7 T_{13} L_7 S_3 Cd_{20-23} \]
Let us break this down:
- Cervical (C): 7 vertebrae (constant across almost all mammals).
- Thoracic (T): 13 vertebrae (articulating with the 13 pairs of ribs).
- Lumbar (L): 7 vertebrae. These are large, robust vertebrae with prominent transverse processes directed cranioventrally, designed to support the abdominal viscera and transfer power from the hindlimbs during locomotion.
- Sacral (S): 3 fused vertebrae forming the sacrum.
- Caudal (Cd): Typically 20 to 23 vertebrae forming the tail.
Thus, the dog has exactly 7 lumbar vertebrae.

Step 3: Final Answer:
The correct option is (C), which stands for Seven.