1. Radiography of the spines of thirty-three West African patients recently recovered or dead from tetanus revealed vertebral fractures in nineteen. These fractures occurred most frequently in the fourth to eighth thoracic vertebrae.

2. The spines of 111 Nigerians from the same area of West Africa were examined, measurement of the areas and shape of the vertebral bodies carried out, and the proportional incidence of articular shelves and laminar spicules was calculated.

3. The upper mid-thoracic vertebral bodies are relatively long and narrow and have but little greater cross-sectional area than those immediately above them; possessing no neural arch supports to sustain longitudinal compressive forces in flexion, they are at greatest hazard during tetanic spasms.

4. Analyses of these factors and of the clinical features, together with experimental observations drawn from the literature, are used to explain the prevalence of upper mid-thoracic vertebral fractures as a complication of tetanus in West Africans, and in particular the greater degree of compression and higher incidence found in children.

5. Vertebral fracture is not usually an important complication of tetanus; it causes little pain, does not prolong the illness, gives rise to no permanent disability and has no effect on the mortality.