The diagnosis of adenomyosis is feasible on pathological specimen examination, while it is unreliable on clinical findings, biopsy, hysteroscopy, sonohysterography, and routine ultrasound or magnetic resonance imaging. Several patterns of 'abnormality' described on imaging have been linked to adenomyosis, but the correlation is weak and the diagnostic accuracy is low outside of a research context. Nevertheless, thickening or abnormality of the subendometrial myometrium, the outer part of the 'endometrial-subendometrial myometrium unit' (thought to be important in human fertility) has been repeatedly documented on imaging, called 'adenomyosis' and linked to infertility. This paper discusses the value of the physiological endometrial-subendometrial myometrium unit in human fertility, reviews the current criteria for its imaging, and reports on its relationship to fertility. It is proposed that endometrial-subendometrial myometrium unit disruption disease is considered as a new entity (distinguished from adenomyosis), the diagnosis of which is feasible and straightforward on imaging and expressed mainly by pathological thickening or abnormality of the subendometrial myometrium (myometrial halo or junctional zone). The study also reports on the influence of abnormal thickening or disruption on human fertility and outcome of assisted reproduction techniques, and demonstrates that this new entity is epidemiologically different from adenomyosis.