Hemivertebrae, the annoying feature of our Frenchies

We are repeatedly confronted with the flimsy arguments of breeders that the inheritance of hemi vertebrae is not exactly certain. The heritage of hemi vertebrae is a fact! It is also a fact that the breed has massive problems and probably cannot be permanently "cured" of hemi vertebrae without crossbreeding a foreign breed. An abstruse competition is ignited among the breeders, who has the most hemi vertebra-free animals and often one forgets to consider the total package of the dogs. Healthy dogs with valuable hereditary potential are excluded from breeding in a panic because they have few changes in the thoracic spine. This is one of the extremes – affects the dogs but also the thoughts of breeders.


The argument that good spinal columns can also produce bad ones, and vice versa, is also often used by breeders. Here one compares the hemivertebrae problem with the hip dysplasia (HD). These far fetched and scientifically not proven arguments are used as reason for a mating with strongly deformed spinal columns. In some circles one counts only the hemivertebrae and ignores other malformations, others only graduate the spinal columns, ignore however the actual disease value and mate by feel and without large expertise.


The following pictures of tested offsprings show pleasing results - a conscientiously bred Frenchie can also look like a normal dog from the inside!

A healthy back length can significantly reduce the risk of vertebral body deformities.  These differences can be clearly seen in two young dogs of the same age.

Change of vertebral bodies:


The Latin term Hemivertebrae is correctly translated with the term “hemi” (half)vertebra.


From a scientific point of view, wedge vertebrae are distinct deformations of the vertebral bodies that are actually wedge-shaped. Deformations, such as one-sided flattening of the vertebral bodies, which nevertheless mean a loss of stability of the spinal column and can cause subsequent deformations of adjacent vertebrae, are therefore often evaluated as "hemivertebrae-free", depending on the expert or veterinarian.


Given the tedious and often uneducated discussion it is important to show x-rays from good spines but also from abnormalities.

Next will follow a series of moderate French Bulldog spines, with are unlikely to affect the dog. We see the unfortunate typical breed changes in the form of hemivertebrae, but also the possible improvement by good breeding management and the unfortunately much too rarely presented well developed vertebrae in the tail. We have to remember that every dog of every breed can show changes in the spine. The perfect spine does not exist. Genetically induced premature disc changes are a much bigger problem and ultimately leads to more severe neurological symptoms or even surgery. Of course, hemivertebrae in critical places such as the transition area from thorax to loin, the loins itself or in the neck can also have these same symptoms.


Dear puppy buyers, compare the following given x-rays with the evaluations of the parents from your desired puppy! An x-ray made does not mean that the results are satisfactory to your own wishes and standards or will not guarantee a stable spine!


We have several x-rays of medium to highly deformed spines with are given the certificate ‘hemivertebrae free’. And we also see the painful consequences of breeding with these animals. Therefore, we would like to show acceptable  spines with slight changes and urge to point out that this is possible in a heavily abnormal breed. 

Mild hemivertebrae 

We would call this a fairly average bully spine, with significant changes in the thoracic region. This Bully is now healthy 10 years old and has not had any symptoms yet. Nevertheless one should try to improve this wedge vertebra formation by intelligent breeding management!

Another boy with race-typical changes of butterfly vertebrae, which are very common in the thoracic spine, but usually do not cause clinical symptoms.

Spinal images from not so happy French Bulldogs that have other significant problems can be found on our other pages that cover those particular abnormalities.


For a direct comparison to the shown stable spines, the image below shows a short-backed bitch with hemivertebrae, deformations in the transitional area from thoracic to lumbar spine, spondylosis is shown below the vertebra, vertebrae that are shortened, kissing spines, and much more. This is a Dutch dog with an FCI pedigree. Striking in this image is the almost square ribcage, that has adapted over generations, just like the compressed and shortened spine. A wrong way of selection. This dog can not receive surgery due to other reasons and has to motor through her recurrent episodes of pain with appropriate medication and rest. This bitch was sols 2 years after her fist c-section and ‘puppy harvest’. And all this is approved of by the FCI with unrestricted papers for the bitch and her offspring!

X-raying puppies:


Any serious breeder will have all of his puppies x-rayed before being handed over to their new owners. This may be useful for the initial assessment to see if the spine is already deformed by kinks of malformations. However, totally clear from abnormalities can not be given, as the vertebrae are not yet fully developed. An experienced radiologist can advise on the preliminary assessment when it comes to selecting a breeding animal.

Many thanks to our friends to make these images available!


Below is an article written by Dr. Kai Rentmeister, freely translated from German:


Dr. Kai Rentmeister explains the problematic hemivertebrae.

Introduction and causes:

Hemivertebrae belong to the congenital malformations of the spine. They do not arise by wrong or excessive movement in the (young) dog. Among other inherited malformations such as block vertebrae, butterfly vertebrae and transitional vertebrae, they are the most common form of spinal abnormalities in dogs


It is argued that wedge vertebrae develop during the fetal stage due to a genetically caused deficient supply of blood to the vertebrae core or and insufficient perfusion of the ossification. cousing the vertebrae to not be able to develop like normal.


Affected breeds:

  • -Dog breeds with corkscrew-like tail (so-called "screw-tailed breeds") are regularly affected, with the deformed tail itself consisting of hemivertebrae (and other vertebral malformations).
  • The following breeds very often present with hemivertebrae:
  • Pug
  • English bulldog
  • French bulldog
  • Pekingese
  • Boston Terrier
  • In individual case reports, hemivertebrae have also been described in other breeds of dogs (e.g., Rottweiler, West Highland White Terrier, Fox Terrier, Yorkshire Terrier, Beagle, German Shorthair). 


Hemivertebrae can occur as one single vertebrae or in multiple vertebrae together. Often several hemivertebrae are found directly next to each other. Typically, hemivertebrae are found in the middle of the thoracic area (T7-9) and somewhat less often in the posterior thoracic area (T10-13). However, there are no comprehensive studies on the percentage frequency of individual breeds.



The abbreviation ’T’ means thoracic vertebra, a healthy dog has 13 thoracic vertebrae.



While most patients with hemivertebrae do not show any clinical symptoms, an above-average number of hemivertebrae affected dogs develop neurological symptoms, at least in comparison to other vertebral body abnormalities.


These are characterized by pain, progressive loss of strength in the back legs, ataxia (staggering gait) and paralysis, with in the advanced stage also bladder and rectum paralysis (incontinence). The neurological symptoms are typically seen starting at the age of 6 months to one and a half 

years old and usually slowly and progressively deteriorate over several months or even years.


Causes of neurological failing are:

  • Progressive spinal deformity (kinking), such as kyphosis, more rarely also lordosis or scoliosis.
  • Primarily narrowing of the spinal canal due to progressive spinal deformations cause spinal cord compression. 
  • Secondary narrowing of the spinal canal comes from instability in the area of the hemivertebrae. The body tries to compensate for the instability with leads to a thickening of the band structures of the spine and the spinal canal, as well as to a thickening of the small vertebral joints. These thickenings lead to a progressive narrowing of the spinal canal with compression of the spinal cord. In chronic patients, the spinal cord is often only 50% of it’s normal diameter.
  • Rare: Luxation (displacement) of a vertebra due to a sudden trauma like jumping or falling.



Hemivertebrae can be easily detected by x-rays in lateral and supine position. As a rule, no anesthesia or sedation is necessary to perform these x-rays. In patients with neurological disorders , however, further examinations must be performed under general anesthesia such as pyelography (x-ray with contrast imaging of the spinal cord) CT scan of MRI scan. These examinations are necessary to determine the severity, type and location of the spinal cord injury.

IMPORTANT: If patients show any signs of paralysis they should be thoroughly examined as soon as possible. The longer the paralysis, the worse the chances of recovery are.



The treatment depends on the result os the diagnostic tests. Patients with only mild neurological deficits can only be considered conservative in the early stages (!) be treated with medication. If there is no improvement or the signs of paralysis deteriorate, an operation is necessary as soon as possible.

The type of surgical intervention depends on the cause of the spinal cord compression. This can either be static or dynamic)

-In a static spinal cord compression the patient still has a stable spine. Relief of the spinal cord through the limited opening of the spinal canal can be successful. For this purpose, a part of the vertebral roof is removed to make room for the spinal cord.

-In dynamic pesions the spine has to be stabilized with screws, with is a very complex surgical procedure in the area of the spine.



Prognosis depends on the duration and the severity of the symptoms. In general, the longer the symptoms persist and the more severe the signs of paralysis, the worse the chances of success.



In terms of breedhealth and animal welfare reasons (preventing suffering and pain in individual animals) breedingethicswould be desirable. X-ray examinations should be carried out on breeding animals in order to identify patients with vertebral abnormalitiesand to exclude them from breeding if necessary.


Only this measure can permanently prevent certain breedsfrom being "overwhelmed" by a disease and given a bad reputation. Breeders and breed societies are required to act for the benefit and survival of their breeds.


We thank the author:


Dr. Kai Rentmeister

Veterinarian, DiplECVN

Mainfrankenpark 16b

97337 Dettelbach

09302 – 93 22 10 (Tel)

09302 – 93 22 15 (Fax)