spine related

What is spondylolisthesis?

The forward slipping of one vertebra on the one below it.

What is spondylolysis?

The breakdown of the pars interarticularis, which may be unilateral or bilateral and results in forward slipping of the involved vertebra—the condition of spondylolisthesis.

What does spondylitis refer to?

Inflammation of one or more vertebrae.

What is spondylosis?

Degenerative changes occurring in the vertebra.

What is the angle of the sacroiliac joints relative to the midsagittal plane?

The sacroiliac joints open anteriorly at an angle of 25 to 30 degrees to the midsagittal plane.

How should the sacroiliac joints be positioned for optimal imaging?

A 25- to 30-degree oblique position places the joints perpendicular to the image receptor (IR).

Which projections can demonstrate the right sacroiliac joint?

The right sacroiliac joint may be demonstrated in the LPO (Left Posterior Oblique) and RAO (Right Anterior Oblique) positions with little magnification variation.

What is demonstrated in a lateral projection of the lumbar spine?

The intervertebral articulations (disk spaces) and intervertebral foramina are well demonstrated.

Why are the intervertebral foramina well visualized in the lateral projection?

The intervertebral foramina, formed by the pedicles, are 90 degrees to the midsagittal plane (MSP), allowing them to be well demonstrated.

At what angle do the articular facets of the lumbar spine lie relative to the MSP?

The articular facets, forming the zygapophyseal joints, lie at an angle of 30 to 50 degrees to the MSP.

How are the zygapophyseal joints visualized?

The zygapophyseal joints are visualized in an oblique position.

What are the key features of the atlas (C1)?

The atlas (C1) is a ring-shaped bone with no body and no spinous process; it has an anterior arch, a posterior arch, two lateral masses, and two transverse processes.

What does the anterior arch of the atlas contain?

The anterior arch of the atlas has a tubercle at its midpoint and a facet on its posterior surface for articulation with the anterior portion of the odontoid process/dens.

What separates the anterior and posterior arches of the atlas?

The anterior and posterior arches of the atlas are separated by the transverse atlantal ligament.

Where do the superior articular processes of the atlas articulate?

The superior articular processes of the atlas articulate with the skull at the atlanto-occipital joint, allowing for flexion and extension.

With which vertebra does the atlas articulate inferiorly?

The lateral masses of the atlas articulate inferiorly with the axis (C2).