Wakuri H, Mori T, Mutoh K
Department of Veterinary Anatomy, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan.
Okajimas Folia Anat Jpn. 1990 Dec;67(5):339-50. doi: 10.2535/ofaj1936.67.5_339.
A full-term female newborn calf of the Japanese black short-horn breed which was two-headed (dicephalus) and had two incomplete necks was carefully dissected. The calf was one of twins, the other being a normal male. There was no record of reproductive problems with the cow. The left and right heads were of almost the same size and shape. Each head had a nose, mouth, eyeballs, and ears. The brains were very congested. That is to say, in both the left and right brains, the longitudinal fissure was unclear, and these was narrower pattern in the cerebral gyri. The surfaces of the two brains displayed poly- or microgyria-like features. The cerebellar gyri ran longitudinally among the occipital lobes of the cerebral hemispheres. The caudal half of the cerebrum, the cerebellum and the brain stem were distorted ventrally at an angle of approximately 80 degrees. Twisting of the brain stem was observed in the right brain. The end of the medulla oblongata and a tongue-like process of the cerebellum extended through the foramen magnum of the skull into each enlarged vertebral canal (Arnold-Chiari malformation). They extended under the arch of the each 2nd cervical vertebra. The 4th ventricle was also displaced and irregularly dilated. The two necks were conjoined in the single 3rd cervical vertebra at an angle of approximately 45 degrees to each other. The one trunk was slightly distorted. The ribs revealed the presence of a left 14th extra tib. In the lumbar region, spina bifida was apparent. The pelvis was distorted asymmetrically. The tail was short. The viscera appeared as one set, but the rectum and anus were duplicated. Although the calf displayed female features, the vagina was undeveloped. The four limbs appeared normal and the joints moved freely.
一头日本黑短角品种的足月雌性新生犊牛，双头（双头畸形）且颈部不完整，被仔细解剖。这头犊牛是双胞胎之一，另一个是正常的雄性。母牛没有繁殖问题的记录。左右头的大小和形状几乎相同。每个头都有鼻子、嘴巴、眼球和耳朵。大脑严重充血。也就是说，在左右大脑中，纵裂不清晰，脑回呈较窄的形态。两个大脑表面呈现多小脑回或微小脑回样特征。小脑回在大脑半球枕叶之间纵向延伸。大脑尾端、小脑和脑干腹侧扭曲约80度。在右脑观察到脑干扭转。延髓末端和小脑的舌状突起通过颅骨大孔延伸到每个扩大的椎管内（阿诺德-奇亚里畸形）。它们延伸到第二颈椎弓下方。第四脑室也移位并不规则扩张。两个颈部在第三颈椎处相连，相互呈约45度角。单一躯干略有扭曲。肋骨显示左侧有第14根额外肋骨。在腰部，脊柱裂明显。骨盆不对称扭曲。尾巴短。内脏看起来是一套，但直肠和肛门是重复的。虽然犊牛表现出雌性特征，但阴道未发育。四肢外观正常，关节活动自如。
