The lumbo-sacral transitional vertebra (LSTV) sacrum with negligible sacral kyphosis: a case report with an evolutionary review

ABSTRACT

Monkey and other hominids species have 5 sacral segments in 10% cases. The similar frequencies for each 6-segmented and 4-segmented sacra in human are known as lumbo-sacral transitional vertebra (LSTV). Achieving the erect posture in human has necessitated much skeletal modification, but these are more apparent in the lumbosacral region. Sacral kyphosis is a distinguishing feature of the human sacrum, which helps to differentiate them from the animal. The monkey has a sacral index near 80, and humans a sacral index is near 100. The sacral index was 88 in six-segmented sacra with negligible sacral kyphosis, having sacralisation of the 5th lumbar vertebra. Therefore, SI is 88 and lack of sacral kyphosis challenge its human origin. On the contrary, gross morphology, actual sacral index, and comparison with apes gave sufficient evidence of human origin. Later excluding 5th Lumbar vertebra, the sacral index is 107.34 and might belong to a male which corresponds with bone bank record

RESUMEN

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