title: Occipito-atlanto-axial malformation with atlanto-axial subluxation in an ataxic calf.
abstract: Occipito-atlanto-axial malformation with atlanto-axial subluxation was diagnosed radiographically in a 4-day-old Holstein calf with a short neck, symmetric ataxia, and tetraparesis, indicative of a cervical spinal cord lesion. Necropsy confirmed the clinical diagnosis and revealed ribs on C-7, with partial fusion of C-7 and T-1. Histologic examination revealed focal degeneration of the spinal cord in the second cervical segment at the level of the atlanto-axial joint and extensive secondary neuronal fiber degeneration possibly caused by spinal cord trauma that occurred in utero.
mesh_terms: D000818:Animals; D001259:Ataxia / Q000473:pathology / Q000662:veterinary*; D001268:Atlanto-Axial Joint / Q000002:abnormalities* / Q000473:pathology; D001269:Atlanto-Occipital Joint / Q000002:abnormalities* / Q000473:pathology; D002417:Cattle; D002418:Cattle Diseases / Q000151:congenital* / Q000473:pathology; D008297:Male