Numerical Variations in Human Vertebral Column

Altered Function of Lumbar Nerve Roots in Patients With Transitional Lumbosacral Vertebrae

“…[1][2][3][4][5][6][7] Several authors have pointed out that, in the presence of this anomaly, the functions of the lumbar nerve roots may be altered. 3,8 This is clinically important because the possibility that the nerve root function is altered in such cases may affect a proper surgical decision-making process, in which we must assure that the level of the lesion matches the clinical symptoms.…”

Segmental innervation in lumbosacral transitional vertebrae (LSTV): a comparative clinical and intraoperative EMG study

“…Most authors use anterioposterior and lateral lumbosacral radiographs, and some combine it with a 30° angled cranially directed anterioposteror view that includes the thoracolumbar junction; the lumbar levels are then counted down from the T12 vertebra, defined as the vertebra from which the lowest rib originates 9 13 74 75. Common misleading features in correct counting of LVB are short 12th ribs and long transverse processes of the first LVB17; therefore, we recommended additional radiographs of the thoracic spine.…”

“…Common misleading features in correct counting of LVB are short 12th ribs and long transverse processes of the first LVB17; therefore, we recommended additional radiographs of the thoracic spine. Other authors base the diagnosis of LSTV on sagittal MRI images on the assumption that there are always seven cervical and 12 thoracic vertebrae; they use a cervicothoracic scout MRI in every patient and count caudally from C2 12 18 74 76. The height of the aorta bifurcation in relationship to the lumbar spine was found to be no valid landmark in case of LSVT 77.…”

The Effect of Vertebral Numerical Variation on Anatomical Stature Estimates

“…Numerical variations are typically due to segmental border shifting, which results in vertebrae at transitional zones assuming the characteristics of the region above or below the border (cephalad or caudad), consequently increasing or decreasing the quantity of that particular vertebral type (2). Incidence of nonmodal vertebral numerical patterns varies among populations (5,6) and ranges from 2% to 24% (7,8). Occurrence may be due to developmental irregularities (2) such as that related to an abnormal number of somites (2) and mutations of Hox, Pax, and POU genes (9,10).…”