Related Experiment Video
Updated: Jul 9, 2026
06:22
Optical Sectioning and Visualization of the Intervertebral Disc from Embryonic Development to Degeneration
Published on: July 8, 2021
When are intervertebral discs stronger than their adjacent vertebrae?
Daniel Skrzypiec1, Maria Tarala, Phillip Pollintine
1Department of Anatomy, University of Bristol, Bristol, United Kingdom.
Spine
|December 20, 2007
Summary
Intervertebral discs are relatively weaker in younger men and stronger in older women, with disc strength correlating to vertebral strength in males. This highlights age and gender differences in spinal tissue vulnerability.
Area of Science:
- Orthopedics
- Biomechanics
- Spinal Research
Background:
- Vertebral bone strength varies with mechanical demands, but intervertebral disc (avascular) adaptation is less understood.
- Limited data exists on the comparative strength of intervertebral discs and vertebrae.
Purpose of the Study:
- To compare the strength of intervertebral discs and vertebrae from the same spinal segments.
- To determine which spinal component is more vulnerable to injury.
- To investigate how age and gender influence the relative vulnerability of discs and vertebrae.
Main Methods:
- Mechanical testing of 47 thoracolumbar motion segments from 30 cadavers (aged 48-91).
- Compression testing of vertebrae to determine yield compressive stress.
- Tensile testing of anulus fibrosus slices to determine ultimate tensile stress.
Main Results:
- Vertebral compressive strength significantly decreased with age in both males and females.
- Anulus fibrosus tensile strength remained largely stable with age, except in the outer region of male discs.
- Disc strength correlated with vertebral strength only in the outer anulus of male spines.
Conclusions:
- The outer anulus fibrosus shows adaptive capacity due to metabolic activity, influencing disc strength.
- Spinal component strength is better matched in males due to less hormonal influence on vertebrae.
- Intervertebral discs exhibit low adaptive potential, leading to relative weakness in younger men and relative strength in elderly women.
Related Concept Videos
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...
01:27Degenerative Disc Disease I: Introduction
Degenerative disc disease is a chronic condition in which intervertebral discs gradually lose structure and function. It is not infectious or autoimmune; rather, it results from age-related biochemical and mechanical changes, influenced by genetic, metabolic, and environmental factors.Structure and Function of DiscsThe spine contains 23 intervertebral discs that absorb load, distribute forces, maintain spacing, and allow flexibility. Each disc consists of a nucleus pulposus, a gel-like core...
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.
01:23Degenerative Disc Disease ll: Pathophysiology
The symptoms of degenerative disc disease arise from a combination of mechanical compression, vascular compromise, and biochemical inflammation, which together disrupt nerve function and produce pain.Mechanical CompressionDisc degeneration reduces height and elasticity, predisposing to herniation of the nucleus pulposus, a major cause of radicular pain. Herniations may be protrusion (bulging with intact annulus), extrusion (nucleus extends beyond disc but remains connected), or sequestration...
01:27Muscles of the Vertebral Column
The back muscles that lie deep into the thoracolumbar fascia are called intrinsic or true back muscles. These muscles are divided into four layers: superficial, intermediate, deep, and deepest layers.
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...
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...