Spinal Vertebral Abnormalities In Bulldogs And Fr. Bulldogs

By: Dr. Roy Kraemer |
DVM, Bulldog Specialist Veterinarian

Spinal Vertebral Abnormalities in Bulldogs and Fr. Bulldogs Butterfly hemivertebrae is a congenital (“at birth,”  “born with”) malformation of the vertebrae seen most often in short-faced, screw-tailed breeds like our bulldogs.

French bulldog wedged vertebrae Kyphosis


Most dogs and breeds normally have from 49 to 53 vertebrae, while the screw-tailed bulldog might have 10 to 15 fewer, depending on the tail formation.  In bulldogs, those tail vertebrae are usually deformed.

Normally, the vertebral bodies are differentiated into:

  • 7 Cervical
  • 12 or 13 Thoracic
  • 7 Lumbar
  • 3 Sacral
  • Several coccygeal (tail) vertebrae.

Bulldogs and French bulldogs are predisposed and have a high probability of incomplete development of their vertebrae.

Bulldog Vertebra Schematic

Dr. Kraemer’s Bulldogs Butterfly RULE OF THUMB

Hemivertebrae form when the right and left halves of the developing vertebral body fail to fuse, producing a body that resembles a butterfly when seen from above. The two unfused bulldog vertebral halves often grow unequally, producing a wedge-shaped vertebral body.

bulldog vertebral malformation hemivertebrae butterfly

Depending on which way the broad side of the wedge is directed, this may cause a dorsal (top) curvature (kyphosis) or a lateral (side) curvature (scoliosis).

As the backbone is bent, it can start affecting the spinal cord, compressing it, and/or its blood supply.

If the function of the spinal cord is impaired by direct compression or by vascular problems, the animal may manifest:

  1. PAIN & SENSATION LOSS: Pain and/or loss of sensation are due to the interruption of the sensory circuits.
  2. MOTOR & MOBILITY: If motor nerve circuits in the cord are affected, weakness or paralysis, especially of the hind limbs, will result.

Any body part receiving its nerve supply from the part of the cord posterior to the damaged area may be affected. The vertebrae most often involved are the 9th – 11th thoracic vertebrae. Most times, only a single vertebra is involved, showing no clinical problems. Thus, the malformation is detected only accidentally when back radiographs are taken, if at all.

If more than one vertebra is involved, the probability of clinical problems increases due to the greater degree of curvature. In those rare cases where the dog does show some clinical signs, the outlook is grave

1-Bulldog Wedge Shape Vertebrae

Spinal Vertebral Abnormalities in Bulldogs Butterfly PREVENTION

Most often, symptoms begin at the age of 3-4 months with a sudden onset of hind limb weakness, which is often preceded by a gait abnormality. In bulldog pups who do show such symptoms, hind limb paralysis generally worsens over time, along with muscle wasting and often a loss of bladder and bowel control.


Fortunately, in most cases, any neurological abnormalities related to this condition will plateau at age 9 months as the vertebrae stop growing. Thus, no additional or new clinical problems are expected.

If your beloved bulldog’s condition is stable at their first birthday, the prognosis is favorable. 

French bulldog butterfly wedge-shaped vertebra


Various supplements can be provided to help improve comfort, arthritis, and inflammation:


Bulldog Back Problem COMFORT:

Bulldog Back Problem: ARTHRITIS

Bulldog Back Problem INFLAMMATION: 

  • V4B Bully Fish Oil EFA 
  • Fish Oil EFA immune-joint-skin Therapeutic Chew Fr Bulldog

WEIGHT MANAGEMENT: Keep your bulldog lean

NON-RX THERAPIES: for comfort and healing

Cold Laser Therapy Class 4


Stem Cell Therapy and cryobanking


  • Steroidal
  • Non-Steroidal (NSAID)
  • Analgesics
  • etc.

Spinal Vertebral Abnormalities in Bulldogs TIP & WARNINGS:

Below is a selective, short list of bulldog vertebra tips and warnings courtesy of Dr. Kraemer


The abnormality might be only detectable radiographically.

Most are incidental findings on a radiograph and are not associated with clinical signs.


Due to the curvature of the last few thoracic vertebrae, secondary changes in the rib cage may be produced.


Both the wedge-shaped and butterfly-shaped types are very common in Frenchies, but when only a single one is present, it very rarely causes problems.


The most common area for problematic hemivertebrae is around the upper back at the 8th (out of 13) thoracic vertebrae.


Rest and possibly corticosteroid injections during flare-ups may be adequate to treat a mild case; more severe cases might require surgery.

defected bulldog vertebrae kyphosis


Should abnormal pressure on the spinal cord be present, the following signs can be seen:

  • A weakness of the rear limbs
  • Fecal incontinence
  • Urinary incontinence


It is important to understand that usually the presence of hemivertebrae is of no significance and is just an interesting finding on a radiograph. If they are present in a dog with neurologic deficits, they are still likely to be incidental findings only, and further testing is likely to be needed before assuming the hemivertebra is the cause.

This kind of testing commonly involves special imaging (myelography, MRI, or CT imaging) to see if the spinal cord is compressed by the hemivertebrae.

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The information provided on this platform is for general informational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your veterinarian regarding any medical condition. It's important to always consider professional medical advice promptly and not to delay seeking it based on information you've read on this platform. Any reliance on the information provided here is entirely at your discretion.

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