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The interactive dog atlas · Skeleton · Vertebral column

Sacrum os sacrum

The sacrum is the bone under the croup, between the lumbar vertebrae and the tail. It is made of three vertebrae fused into a single bone.

Open in the interactive atlas Guide: Skeleton Worksheet

Educational material, not a diagnostic tool. Written by the Mantrailing România team from veterinary sources we read. Updated 14.11.2026.

Dog in left lateral view — exterior, muscles, skeleton and organs Vector study after the Ellenberger, Baum and Dittrich plates: a standing dog, head to the left, deep chest and digitigrade limbs. The four layers use the same contour: exterior with body regions, superficial muscles, skeleton and organs.
  1. Sacrum
  2. Lumbar vertebrae
  3. Caudal vertebrae
  4. Pelvis (hip bone)
Sacrum on the atlas drawing, "Skeleton" layer, with the neighbouring structures. Left lateral view, after the Ellenberger, Baum and Dittrich plates.

Where it is

Between the lumbar vertebrae and the tail, under the croup.

System
Axial skeleton
Region
Vertebral column

What it is and what it does

The sacrum is made of the three sacral vertebrae, fused into a single bone. The pelvis attaches to it through the sacroiliac joint: this is the bony link through which the force of the hindlimbs reaches the spine and pushes the body forward. The sacrum continues with the tail vertebrae.

Worth remembering

The pelvis attaches to it; through this bony link the force of the hind legs reaches the spine and pushes the body forward.

Names

  • Also called: sacral bone, sacral vertebrae.
  • Latin term: os sacrum.
  • In Romanian: Sacrul (Romanian page).

Guides it appears in

From the same region: Vertebral column

All structures, in the atlas · Flashcards: skeleton