Cloacal malformations are characterized by the confluence of the lower urinary tract, the female reproductive tract, and the rectum to create a common channel with a single opening on the perineum. The presence of a cloaca is a normal phase of early human embryological development. Between the 4^th and 7^th weeks of gestation, the cloaca undergoes subdivision to form the hindgut and urogenital sinus. Failure of this process results in the congenital anomaly termed persistent cloaca (PC). The term urorectal septum malformation sequence (URSMS) is also used to describe this anomaly. The classic description of this process which is still cited in many standard textbooks dates from the 19^th century. However, this has been increasingly called into question by the findings of studies using modern scientific methodology. Urogenital sinus anomalies are defined by the confluence of the urethra and vagina to form a common channel of varying length with a single perineal opening. In this condition, the anorectal canal opens separately on the perineum. The presence of a urogenital sinus represents a transient phase of the normal development of the lower genital tract in the female fetus. However, the form of urogenital sinus most commonly encountered in the developed world is a feature of disordered sexual differentiation and does not arise simply from the persistence of the anatomical structure which is a feature of normal fetal development.
Cloaca/embryology* ; Female ; Humans ; Urogenital Abnormalities/embryology* ; Vagina/embryology*

No abstract available.

Background: and Purpose High-grade carotid artery stenosis may alter hemodynamics in the ipsilateral hemisphere, but consequences of this effect are poorly understood. Cortical thinning is associated with cognitive impairment in dementia, head trauma, demyelination, and stroke. We hypothesized that hemodynamic impairment, as represented by a relative time-to-peak (TTP) delay on MRI in the hemisphere ipsilateral to the stenosis, would be associated with relative cortical thinning in that hemisphere. Methods: We used baseline MRI data from the NINDS-funded Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis–Hemodynamics (CREST-H) study. Dynamic contrast susceptibility MR perfusion-weighted images were post-processed with quantitative perfusion maps using deconvolution of tissue and arterial signals. The protocol derived a hemispheric TTP delay, calculated by subtraction of voxel values in the hemisphere ipsilateral minus those contralateral to the stenosis. Results: Among 110 consecutive patients enrolled in CREST-H to date, 45 (41%) had TTP delay of at least 0.5 seconds and 9 (8.3%) subjects had TTP delay of at least 2.0 seconds, the maximum delay measured. For every 0.25-second increase in TTP delay above 0.5 seconds, there was a 0.006-mm (6 micron) increase in cortical thickness asymmetry. Across the range of hemodynamic impairment, TTP delay independently predicted relative cortical thinning on the side of stenosis, adjusting for age, sex, hypertension, hemisphere, smoking history, low-density lipoprotein cholesterol, and preexisting infarction (P=0.032). Conclusions Our findings suggest that hemodynamic impairment from high-grade asymptomatic carotid stenosis may structurally alter the cortex supplied by the stenotic carotid artery.