Implantation

(redirected from nidation)
Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

implantation

[‚im‚plan′tā·shən]
(medicine)
Placement of a tissue transplant in depth in the body.
Placement in the body of a device for mechanical repair, such as for a ventral hernia or a fracture.
Embedding of an embryo into the endometrium.

Implantation

 

the attachment of the embryo to the wall of the uterus in man and in all mammals with intrauterine development.

Three types of implantation are distinguished: superficial implantation, in which the embryo remains in the uterine cavity and attaches itself to the wall either by the entire surface of the trophoblast or by part of it (in Chiroptera and ruminants); eccentric implantation, in which the embryo deeply penetrates a fold of the uterine mucosa (a uterine crypt), the wall of which then grows together over the embryo and forms an implantation chamber that is isolated from the uterine cavity (in rodents); and interstitial implantation, characteristic of higher mammals (primates and man), in which the embryo destroys cells of the uterine mucosa and implants itself within the cavity formed, the uterine defect then healing and the embryo embedding itself totally within the uterine wall, where its subsequent development occurs.