Related Experiment Video
Updated: Jun 22, 2026
04:42
Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion
Published on: June 16, 2023
Morphological changes in the cervical intervertebral foramen dimensions with unilateral facet joint dislocation
Nabil A Ebraheim1, Jiayong Liu, Satheesh K Ramineni
1Department of Orthopaedic Surgery, University of Toledo Medical Center, Toledo, OH 43614, USA.
Injury
|June 3, 2009
Summary
Unilateral facet joint dislocation in the cervical spine significantly enlarges the intervertebral foramen. This suggests nerve injury may result from distraction, not direct compression, in these cases.
Area of Science:
- Orthopedic Surgery
- Neurosurgery
- Biomechanics
- Anatomy
Background:
- Unilateral facet joint dislocation (UFD) in the cervical spine is a known injury.
- Previous research has focused on biomechanics, causes, and treatment of UFD.
- Quantitative data on intervertebral foramen (IVF) morphology changes post-UFD is lacking.
Purpose of the Study:
- To quantitatively assess morphological changes in the cervical spine's intervertebral foramen after unilateral facet joint dislocation.
- To provide data crucial for understanding neurological compromise following UFD.
Main Methods:
- Eight human cadaver cervical spine specimens (C1-T1) were utilized.
- Unilateral facet dislocation at C5-C6 was simulated by ligamentous sectioning.
- CT scans were performed pre- and post-simulation, with measurements of IVF dimensions, facet joint space, nerve root size, and vertebral alignment.
Main Results:
- The intervertebral foramen area significantly increased on both the dislocated (41.39 to 113.77 mm²) and non-dislocated sides (50.72 to 67.82 mm²).
- Foraminal height also increased bilaterally.
- Significant anterior displacement of C-5 was observed, while nerve root area showed no significant change.
Conclusions:
- Cervical spine UFD leads to substantial enlargement of the intervertebral foramen.
- The lack of change in nerve root area suggests that neurological injury is likely caused by distraction forces, not direct compression.
Related Concept Videos
01:28Articulations of the Vertebral Column
In addition to being held together by the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called zygapophysial joints (facet joints). These are plane joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the types of motions available in each...
01:17Structural Joints: Cartilaginous Joints
As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but flexible type of connective tissue. Unlike synovial joints, these types of joints lack a joint cavity and involve bones joined together by either hyaline cartilage or fibrocartilage.
There are two types of cartilaginous joints:
Synchondrosis
A synchondrosis ("joined by cartilage") is a cartilaginous joint where bones are connected by hyaline cartilage. Synchondrosis may be temporary or...
There are two types of cartilaginous joints:
Synchondrosis
A synchondrosis ("joined by cartilage") is a cartilaginous joint where bones are connected by hyaline cartilage. Synchondrosis may be temporary or...
01:29Herniated Intervertebral Disc l: Introduction
Intervertebral disc herniation refers to the displacement of the nucleus pulposus (the gel-like inner core of the disc) through a tear or weakened area in the annulus fibrosus (the outer fibrous ring). The displaced disc material extends beyond the normal boundaries of the disc space and may compress or irritate nearby spinal nerve roots or, less commonly, the spinal cord.Etiology and Risk FactorsHerniation commonly results from degeneration, in which aging reduces disc hydration and...
01:30General Structure of a Vertebra
A typical vertebra, with the exception of the sacrum and coccyx, consists of a body, a vertebral arch, and seven different projections termed processes. The anterior portion of the vertebrae, the body, supports about half the body’s weight. The vertebral bodies progressively increase in size and thickness from the cervical region to the lumbar region of the vertebral column. The intervertebral discs present between the bodies of adjacent vertebrae firmly unites them, forming a continuous column.
01:09Functional Classification of Joints
Functional Classification of Joints
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An immobile...
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An immobile...