You probably remember the school nurse checking your spine when you were a kid. She was making sure it didn't curve too far in one direction, a deformity called scoliosis. Kitty can have scoliosis, too.
Kitty's spine has 30 vertebrae, which is five more than you do. Between each of his vertebrae, he has a thick disk of cartilage that functions as a shock absorber. His shoulder blades allow for movement in most directions. Unlike your collarbone, which is anchored and restricts movement, Kitty's is floating. This means it is flexible enough to allow him to fit into tight spaces. This flexible spine is part of what makes your feline pal so agile, allowing him to race up a tree with ease, jump to high places and almost always land on his feet.
If Kitty has scoliosis, this is a type of deformity of his spine. If you look at Kitty's spine from the top down, his spine should be straight from his neck to his tail. If it curves to one side or the other, this lateral deformity is referred to as scoliosis. It can be mild, which you probably won't even notice by looking at him, to severe and obvious. It occurs when one of his vertebrae didn't develop all the way, called a hemivertbrae.
Kyphosis and Lordosis
Malformed hemivertebrae can cause two other forms of spinal deformation. If Kitty's spine resembles the Hunchback of Notre Dame's, it is referred to as kyphosis. If he's spine sags and makes a “U” shape, this deformity is called lordosis. Kyphosis and lordosis can occur at the same time as scoliosis.
The cause of a malformed spine is most likely genetic, meaning he inherited the disorder from his mom or dad. It could also be because of a genetic mutation that occurred while he was in the womb, possibly because his mother was malnourished or exposed to toxins that caused birth defects while she was pregnant. Since it is genetic and he could pass it on to any of his kittens, you should get him neutered as soon as he's old enough.
Diagnosis and Treatment
To find out if your cat has a deformed spine, his vet will take X-rays of his back. To find scoliosis, these X-rays will need to be from the top down. If he's looking for kyphosis or lordosis, the X-rays will be taken of his spine from the side. If the deformity is severe, he may need surgery to correct his spinal alignment. A deformed spine can put pressure on his spinal cord, leading to neurological symptoms. In less severe cases, his vet will want to take X-rays a few times a year to make sure the condition hasn't gotten worse. Physical therapy can be useful in helping Kitty get around easier.