Articulations of the Trunk

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Anatomy > Gray's Anatomy of the Human Body > III. Syndesmology > 5. Articulations of the Trunk > a. Articulations of the Vertebral Column

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

Part I: General Overview and Vertebral Body Articulations

The articulations of the vertebral column consist of two primary groups:

• Amphiarthrodial joints between the vertebral bodies
• Diarthrodial (synovial) joints between the vertebral arches

1. Articulations of the Vertebral Bodies

These joints are classified as amphiarthroses, allowing limited motion between adjacent vertebrae, but collectively providing significant mobility to the spine.

The primary ligaments associated with these joints include:

• Anterior longitudinal ligament
• Posterior longitudinal ligament
• Intervertebral fibrocartilages

Anterior Longitudinal Ligament

(ligamentum longitudinale anterius)

This strong, broad ligament runs along the anterior surfaces of the vertebral bodies, from the axis (C2) to the sacrum. It is widest and thickest in the thoracic region, adherent to the intervertebral discs, and composed of longitudinally arranged fibers of varying lengths.

Median sagittal section of lumbar vertebrae showing ligaments (Gray's Fig. 301)

Posterior Longitudinal Ligament

(ligamentum longitudinale posterius)

Located within the vertebral canal, this ligament extends from the body of the axis to the sacrum. It is narrower than the anterior ligament, broader in the cervical and thoracic regions, and composed of compact longitudinal fibers. It presents a dentated appearance in the thoracic region and is narrower over vertebral bodies due to the basivertebral veins.

Posterior longitudinal ligament in thoracic region (Gray's Fig. 302)

Intervertebral Fibrocartilages

(disci intervertebrales)

These discs lie between adjacent vertebral bodies, from the axis to the sacrum, and form the primary connection between the vertebrae. Each consists of:

• Annulus fibrosus – concentric layers of fibrocartilage with crossed fibers
• Nucleus pulposus – central, gelatinous remnant of the notochord

They are thicker anteriorly in the cervical and lumbar regions, contributing to the natural spinal curvatures. Discs account for about one-fourth of spinal length.

Part II: Vertebral Arch Articulations and Movements

2. Articulations of the Vertebral Arches

These synovial joints (zygapophyseal joints) between the articular processes are reinforced by fibrous articular capsules and several supporting ligaments:

• Ligamenta flava
• Interspinal ligaments
• Supraspinal ligament
• Ligamentum nuchae
• Intertransverse ligaments

Articular Capsules

These enclose the zygapophyseal joints and are more lax in the cervical region, allowing greater mobility.

Ligamenta Flava

These elastic ligaments unite the laminae of adjacent vertebrae, contributing to the posterior wall of the vertebral canal and aiding in spinal recoil after flexion.

Ligamenta flava viewed anteriorly (Gray's Fig. 303)

Supraspinal Ligament

(ligamentum supraspinale)

This strong ligament connects the apices of the spinous processes from C7 to the sacrum. It is continuous superiorly with the ligamentum nuchae.

Ligamentum Nuchae

A fibrous septum running from the external occipital protuberance to C7. It supports the head and provides muscular attachment.

Interspinal Ligaments

These lie between adjacent spinous processes, meeting the ligamenta flava anteriorly and the supraspinal ligament posteriorly.

Intertransverse Ligaments

Situated between the transverse processes, these vary in density across spinal regions.

Movements of the Vertebral Column

Permitted movements include:

• Flexion – greatest in cervical and lumbar regions
• Extension – limited by spinous process contact
• Lateral flexion – most free in cervical and lumbar regions
• Rotation – most free in the thoracic region
• Circumduction – limited and a composite of other movements

These movements depend on the orientation of articular facets and the elasticity of intervertebral discs and ligaments.

Muscles Involved

• Flexion: Longus colli, sternocleidomastoideus, abdominal muscles
• Extension: Erector spinae, semispinalis, splenius
• Lateral flexion: Quadratus lumborum, intertransversarii
• Rotation: Multifidus, rotatores, obliquus capitis inferior

Gray's Anatomy

• Gray's Anatomy Contents
• Gray's Anatomy Subject Index
• About Classic Gray's Anatomy
• Glossary of anatomy terms

Anatomy atlases (external)

[1] - Anatomy Atlases

Adapted from the Classic Grays Anatomy of the Human Body 1918 edition (public domain)