Unusual midsagittal defects in vertebrae from McKee Island, Alabama (1Ms32)

• Skeletal remains from protohistorical village site on Tennessee River.
• Thoracic vertebrae of two burials present midsagittal infractions in inferior surfaces.
• Etiological interpretations for midsagittal infractions are discussed.
• Defects may represent seizure-induced partial fractures.
• Defects may be early stages of Schmorl's node formation.

Skeletal remains were excavated at a village site on McKee Island, Alabama in 1937, which were stored and later analyzed at the University of Alabama. During analysis, unusual vertebral defects were observed among the historic-era remains of two mature adults: one male, one female. In each case, the inferior endplates of two thoracic vertebral bodies exhibited midsagittal defects that resemble incomplete fractures with sclerotic reaction. These defects are described here as midsagittal vertebral infractions (MVI). Alternative diagnoses are proposed based on various causal mechanisms, including acute axial trauma in relation to Schmorl's node formation, burst fractures secondary to tonic-clonic seizure, chronic trauma due to repetitive axial stress, as well as other possibilities. Intervertebral disc herniation may have played an important part as an etiological factor, or it may have been a secondary result following traumatic disruption of the vertebral surface. Although a conclusive etiology is not proposed at this time, these antemortem midsagittal vertebral infractions may represent rare examples of burst fractures in skeletal remains or a transitional stage between traumatic episode and full recovery with resultant acute Schmorl's nodes.