Sperm morphology — the size and shape of sperm — is one factor that's examined as part of a semen analysis to evaluate male infertility. Sperm morphology results are reported as the percentage of sperm that appear normal when semen is viewed under a microscope. Normal sperm have an oval head with a long tail. Abnormal sperm have head or tail defects — such as a large or misshapen head or a crooked or double tail.
Sperm Morphology (Size and Shape)
Abnormal sperm morphology: What does it mean? - Mayo Clinic
This article presents an update on the variable prognostic significance of different sperm pathologies in patients with severe male factor infertility due to morphology and motility disorders. Identifying structural causes of sperm immotility was of great concern before the advent of intracytoplasmic sperm injection ICSI , because immotility was the limiting factor in the treatment of these patients. In these cases, in vitro methods are used to identify live spermatozoa or stimulate sperm motility to avoid selection of non-viable cells. With these advances, fertilization and pregnancy results have improved dramatically. The identification of genetic phenotypes in asthenozoospermia is important to adequately inform patients of treatment outcomes and risks. The one sperm characteristic that seriously affects fertility prognosis is teratozoospermia, primarily sperm head and neck anomalies. Defects of chromatin condensation and acrosomal hypoplasia are the two most common abnormalities in severe teratozoospermia.
Assessment of Human Sperm Cells Morphological Parameters
Male infertility is an increasing problem partly due to inherited genetic variations. Mutations in genes involved in formation of the sperm tail cause motility defects and thus male infertility. Therefore, it is crucial to understand the protein networks required for sperm differentiation. Sperm motility is produced through activation of the sperm flagellum, which core structure, the axoneme, resembles motile cilia. In addition to this, cytoskeletal axonemal structure sperm tail motility requires various accessory structures.
An important part of any breeding soundness exam is an evaluation of sperm morphology. In the most fundamental case, the size and shape of the head, midpiece and tail are examined. Additional information can be gained by evaluating integrity of the acrosome and sperm membranes. Sperm from different species vary in size and shape.