Bicornuate uterus

A bicornuate uterus or bicornate uterus (from the Latin cornū, meaning "horn"), is a type of mullerian anomaly in the human uterus, where there is a deep indentation at the fundus (top) of the uterus. A bicornuate uterus develops during embryogenesis. It occurs when the proximal (upper) portions of the paramesonephric ducts do not fuse, but the distal portions that develops into the lower uterine segment, cervix, and upper vagina fuse normally. Diagnosis of bicornuate uterus typically involves imaging of the uterus with 2D or 3D ultrasound, hysterosalpingography, or magnetic resonance imaging (MRI). On imaging, a bicornuate uterus can be distinguished from a septate uterus by the angle between the cornua (intercornual angle): less than 75 degrees in a septate uterus, and greater than 105 degrees in a bicornuate uterus. Measuring the depth of the cleft between the cornua (fundal cleft) may also assist in diagnosis; a cleft of over is indicative of bicornuate uterus. Bicornuate uterus is typically classified based on whether or not the division extends to the external cervical os. Bicornuate uteri with a division above the os are called bicornuate unicollis and those with a divided os are called bicornuate bicollis. There is a continuous range of the degree and location of the fusion of the paramesonephric ducts, and existence of a spectrum, rather than a fixed number of types corresponding to strict medical definitions. Two processes that occur during the embryonic development of the paramesonephric ducts — fusion and reabsorption — can be affected to different degrees. There is also a hybrid bicornuate uterus: External fundal depressions of variable depths associated with a septate uterus can be seen by laparoscopy, indicating the coexistence of the two anomalies. These cases are candidates for hysteroscopic metroplasty under appropriate sonographic and/or laparoscopic monitoring. An obstructed bicornuate uterus showing uni or bilateral obstruction might also be possible.