Aetiology and pathogenesis of congenital torticollis and head scoliosis in the equine foetus

Abstract

Summary In 214 cases of severe dystocia in mares, of which 141 (66 per cent) were Draught horses, deviation of the head and neck, with or without torticollis, malformed head and limbs were found to be the cause of dystocia. No evidence of a genetic lethal factor was found and torticollis was often combined with scoliosis of the head and, frequently, with malformation of one or more limbs. This is considered evidence of a common aetiology and pathogenesis of the syndrome of malformation. The malformations were found to be associated with an increased incidence of caudal and, particularly, transverse presentations. These findings are presented as evidence to support the hypothesis that, during the second half of pregnancy, the narrow tip of the uterine horns provides only limited space for the developing cranial half of the foetus. The surprisingly rapid and complete anatomical and functional recovery of severe malformations of the bones of the neck, head and limbs of surviving foals, born by caesarian section, is taken as further evidence that these malformations have no genetic basis, but originate from unfavourable intrauterine conditions.

Computed Tomographic Evaluation of Anatomic and Pathologic Variations in the Feline Nasal Septum and Paranasal Sinuses

“…Concurrent facial deformities were not seen in any of our cats. Theories in humans and horses relating to the cause of this developmental anomaly include dystocia with subsequent postnatal maldevelopment or maldevelopment in utero 24,26–28 . The limited available patient data did not allow us to investigate the perinatal history but given the high prevalence of septal deviation in our study, we regard dystocia as an unlikely cause.…”

Congenital Scoliosis in a Quarter Horse Filly

“…In another study of congenital torticollis and head scoliosis it was proposed that the development of head, neck, and limb malformations may be associated with an inappropriate intrauterine environment 8 . For example, during the second half of pregnancy, the narrow tip of the uterine horns may provide limited space for fetal development.…”

“…For example, during the second half of pregnancy, the narrow tip of the uterine horns may provide limited space for fetal development. Consequently, if an abnormal fetal posture is assumed in utero (i.e., torticollis), the limited space of the intrauterine environment may maintain the head and neck in a forced reflected posture resulting in skeletal malformations at birth 8 …”

Surgical Correction of Wry Nose in Four Horses

“…Although wry nose reportedly occurs in many equine breeds, incidence is seemingly highest in Arabian horses, causing speculation that the malformation may be genetic 1 ; however, to our knowledge, inheritance of this abnormality has not been reported. Inability of the uterus, particularly that of a primiparous mare, to distend to accommodate the fetus as it grows has been speculated as one cause of this abnormality 5 …”