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Spondylolisthesis is when one spinal vertebra slips out of place compared to another. [1] While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or the sacrum), [2] [3] it is often defined in medical textbooks as displacement in any direction.
The fifth lumbar vertebra is by far the most common site of spondylolysis and spondylolisthesis. [3] Most individuals have five lumbar vertebrae, while some have four or six. Lumbar disorders that normally affect L5 will affect L4 or L6 in these latter individuals.
The Napoleon hat sign (most commonly called "inverted Napoleon hat") is a radiologic sign observed on frontal radiographs of the spine at the level of the fifth lumbar vertebra (L5) and the sacrum (S1) that indicates the presence of severe spondylolisthesis and/or severe lumbar lordosis. When the L5 vertebra becomes severly displaced and ...
These cannot be determined by plain films, as the x-ray passes through the soft tissue. A study by Giles et al., stated that sixteen of the thirty patients (53%) had retrolisthesis of L5 on S1 ranging from 2–9 mm; these patients had either intervertebral disc bulging or protrusion on CT examination ranging from 3–7 mm into the spinal canal.
Sagittal CT of the lumbar spine showing Baastrup's sign. The salient feature of the disorder is the exuberant osteophytosis that occurs at posterior lumbar spinous processes. Osteophytes are coarse calcifications at the edges of bone that form due to repetitive stress and trauma.
Bertolotti's syndrome is characterized by sacralization of the lowest lumbar vertebral body and lumbarization of the uppermost sacral segment. It involves a total or partial unilateral or bilateral fusion of the transverse process of the lowest lumbar vertebra to the sacrum, leading to the formation of a transitional 5th lumbar vertebra.
The bone grafts complete their fusion in 4–8 months following the surgery, securing the spine in the correct position. The procedure is also used to treat spinal instability, fractures in the lumbar spine and, severe degenerative disc disease. The process is relatively non-invasive, performed through small incisions and has a high success ...
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.