From the Guidelines
The conus medullaris typically ends at the level of the L1-L2 disc space. This is based on the most recent and highest quality study available, which states that by 2 months after birth, the conus medullaris ends most commonly opposite the disc space between the first and second lumbar vertebrae (L1-L2 disc space) 1. The study also notes that the lowest normal level (95% confidence limits) is opposite the L1-L2 disc space, indicating that this is the typical ending point for the conus medullaris.
Some key points to consider when evaluating the level at which the conus medullaris ends include:
- The conus medullaris is the tapered lower end of the spinal cord
- It represents the transition point where the spinal cord proper ends and gives way to the cauda equina
- The level at which the conus medullaris ends is clinically significant for procedures like lumbar punctures
- There is some normal anatomical variation, but the L1-L2 disc space is the most common ending point
The study by 1 provides the most recent and highest quality evidence on this topic, and its findings support the conclusion that the conus medullaris typically ends at the level of the L1-L2 disc space. This knowledge is essential for medical professionals to understand, particularly when performing procedures that involve the spinal cord or lumbar region.
From the Research
Conus Medullaris Levels
The level at which the conus medullaris typically ends is a subject of medical study. According to the provided evidence:
- The conus medullaris terminates at the second lumbar vertebra, as stated in the literature 2.
- However, the termination level can vary, with some studies suggesting that it can end at levels ranging from L1 to L3 2, 3.
- One study found that the conus medullaris ended at the L-1 or L-2 vertebral level in all 13 specimens examined 3.
- Another study suggested that the conus medullaris can be found below the vertebra L3 in infants without recognized spinal pathology 2.
Key Findings
- The level of the conus medullaris can vary between individuals, with a range of normal positions 4, 5.
- The conus medullaris is not always a fixed structure and can move with positional changes 5.
- The presence of a conus medullaris at a normal position does not necessarily rule out the possibility of tethered cord syndrome 4, 6.
Relevant Studies
- A study published in the Journal of Korean Neurosurgical Society found that the conus medullaris terminates at the second lumbar vertebra 2.
- A study published in Neurological Research suggested that the conus medullaris can be tethered even if it is in a normal position 4.
- A study published in Clinical Anatomy found that high lumbar punctures may be safer than previously thought due to the movement of the conus medullaris with positional changes 5.
- A study published in the Journal of Neurosurgery: Pediatrics found that the filum terminale may contain functional neural elements 3.
- A study published in Neurosurgery found that tethered cord syndrome can occur even if the conus medullaris is in a normal position 6.