Severe skeletal malformation a cause of dystocia
Keywords: dystocia, equine, mare, wryneck, wry-neckA pluriparous mare presented for dystocia of several hours duration. The referring veterinarian reported the presence of "a severely deformed" foal that precluded normal delivery.
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An epidural was given and clenbuterol were administered IV.
The foal was in anterior longitudinally presentation and dorso left-ilial position (arrow). There was an obvious wry-neck. Wry-neck is permanent ossification of the neck in a flexed posture; apparently unique to the horse among domestic animals. The head was also deformed. Initially, one gained the impression that there was also bilateral shoulder flexion with both forelimbs retained.
Using a fetotome, the head was removed uneventfully but when an attempt was made to locate the forelimbs, they appear to be absent. Because of the absence of the forelimbs, uterine tone and an inability to rotate the foal into a dorso-sacral position, the foal was delivered by cesarean section. Her recovery was uneventful.
Radiology showed that both the left and right scapulae were present but only the right forelimb was present. Also, the right forelimb was vestigial, about the thickness of a thumb and it was also rotated on its longitudinal axis, so that the hoof faced backward. There was severe scoliosis and the head of the left femur did not articulate with the acetabulum.
