"Abnormal formation" refers to something that is not usually formed or structured in the usual or expected way. It signifies something that is different or irregular compared to the norm. Full definition
There are several disorders in the elbow that comprise elbow dysplasia, all involving abnormal formation of the bones of the elbow joint. (www2.vet.cornell.edu)
Exposure to them during early development is associated with increased risk of cancers and abnormal formation of the reproductive tract. (sciencedaily.com)
It has been reported that German Shepherds are predisposed to conditions such as abnormal formation of the hip joint, cancer and degenerative spinal disorders, but the extent to which these conditions are prevalent in the population are unclear. (sciencedaily.com)