Related Experiment Video
Updated: Aug 15, 2025
A Mouse Model of Lumbar Spine Instability
Published on: April 23, 2021
The midline interlaminar ligament of the spine: An anatomical study
Alexandra Millhuff1, Hannah Haddad1, M Scott Draper1
1Department of Anatomy, Kansas City University, Kansas City, Missouri, USA.
Introduction:
During routine cadaveric dissection, Simonds et al. in 2019 found a previously undocumented ligament, which they termed the midline interlaminar ligament (MIL), in 24 out of 36 (76.5%) lumbar spinal levels. The MIL is an unpaired ligament located between and distinctly separate from the right and left ligamenta flava (LF). The purpose of this study was to identify the presence or absence of the MIL in the cervical, thoracic, and lumbar spinal regions and obtain detailed measurements of the ligaments' toughness (R) and elastic modulus (E).
Materials And Methods:
Intact preserved cadaveric vertebrae from C2 to the upper sacral region were dissected. Presence or absence of the MIL was documented, and length and width of each MIL were measured in situ. The R and E of the LFs from corresponding spinal segments were found for comparison.
Results:
At least one MIL was observed in 90.3% (28) of specimens. Eighty-eight MIL's were observed out of 186 cervical intervertebral levels (0.5%), 371 thoracic intervertebral levels (5.9%), and 101 lumbar intervertebral levels (63.4%). The mean width and length of the MIL were 1.21 ± 0.36 and 16.37 ± 2.17 mm, respectively. The mean R of the MIL and the LF were 1390.27 and 2068.04 J m-2 , respectively. The mean E of the MILs and LFs was 46.78 ± 16.65 and 51.15 ± 21.68 MPa, respectively.
Conclusions:
Based on our findings, the MIL was present in the majority of vertebrae in our cadaveric population with a predominance for the lumbar region.
Insights
The midline interlaminar ligament (MIL) was found in 90.3% of cadavers, predominantly in the lumbar spine. This study details its prevalence and biomechanical properties compared to the ligamentum flavum.
Area of Science:
- Anatomy
- Biomechanics
- Spinal Research
Background:
- A previously undocumented midline interlaminar ligament (MIL) was identified in prior research.
- The MIL is an unpaired ligament distinct from the paired ligamenta flava (LF).
Purpose of the Study:
- To determine the presence and anatomical distribution of the MIL in cervical, thoracic, and lumbar spine regions.
- To measure the toughness (R) and elastic modulus (E) of the MIL.
- To compare the biomechanical properties of the MIL with the LF.
Main Methods:
- Cadaveric dissection of intact preserved vertebrae from C2 to the upper sacral region.
- Documentation of MIL presence/absence and in situ measurement of its length and width.
- Measurement of toughness (R) and elastic modulus (E) for both MIL and LF for comparative analysis.
Main Results:
- The MIL was observed in 90.3% of specimens across all spinal regions.
- MIL prevalence was highest in the lumbar region (63.4%), followed by thoracic (5.9%) and cervical (0.5%).
- Mean MIL toughness (R) was 1390.27 J/m², and elastic modulus (E) was 46.78 MPa, compared to LF values of 2068.04 J/m² and 51.15 MPa, respectively.
Conclusions:
- The MIL is a prevalent anatomical structure in the human spine, particularly in the lumbar region.
- Findings provide baseline data on MIL biomechanical properties, aiding further research into spinal anatomy and function.
Related Concept Videos
01:27Muscles of the Vertebral Column
Superficial Layer:
The superficial layer consists primarily of the splenius muscles, which include the splenius capitis and splenius cervicis. These muscles are mainly responsible for the head and cervical spine movements, including extension, rotation, and lateral bending. The splenius capitis...
01:16Spinal Cord: Cross-sectional Anatomy
Gray Matter and its Components
Central to the gray matter is...
01:28Articulations of the Vertebral Column