Lumbar Spine, Sacrum, and Coccyx

The intervertebral foramina of the lumbar spine are located at an angle of _____ in relation to the midsagittal plane

90 degrees

The small section of bone found between the superior and inferior articular processes of the lumbar spine is termed:

Pars interarticularis

The zygapophyseal joints of the upper lumbar vertebrae are ____ in relationship to the midsagittal plane.

50 degrees

The anterior projecting bony process of the sacrum that forms part of the inlet of the true pelvis is the:

sacral promontory

Another term for the sacral horns is the:

sacral cornu

Which specific aspect of the sacrum articulates with the ilium to form the sacroiliac joint?

Auricular surface

What is the term for the superior aspect of the coccyx?

Base

What is the joint classification of the zygapophyseal joints?

Synovial/diarthrodial

The intervertebral joints in the lumbar spine are classified as:

Cartilaginous/amphiarthrodial

What type of joint movement occurs with the zygapophyseal joints?

Plane

The average degree of rotation required to demonstrate the L3-4 zygapophyseal joints is:

45 degrees

Where is the central ray (CR) centered for an AP projection of the lumbar spine with a 14- × 17-inch (35- × 43-cm) IR?

At the iliac crest

An average of ____ segment(s) make up the adult coccyx

Four

What CR angulation should be used for an AP axial projection of the L5-S1 joint space on a male patient?

30 degrees cephalad

A key advantage of a posteroanterior (PA) projection taken during a pediatric scoliosis study as compared with the AP projection is that it reduces:

Breast dose by 90%

Where is the CR centered for an AP axial projection of the sacrum?

2 inches above the symphysis pubis

What type of CR angulation is required for an AP axial projection of the coccyx?

10 degrees caudad

The radiographic appearance on an oblique lumbar spine in which the neck of the Scottie dog appears “broken” suggests the presence of:

spondylolysis

A destructive type of lesion with irregular margins and increased brightness is an indication of possible:

Osteoblastic type of metastases

A fracture through the vertebral body and posterior elements caused by lap seat belts during an auto accident involving sudden deceleration is a ____ fracture

Chance

An anterior wedging of vertebrae with a loss of body height but rarely causing neurologic symptoms is called:

A compression fracture

Sciatic type of pain resulting from a “slipped disk” indicates:

Herniated nucleus pulposus

An abnormal lateral curvature of the spine is a congenital condition termed:

Scoliosis

What CR angle should be used for a lateral sacrum/coccyx projection?

None; CR is perpendicular to the IR

A young female patient comes to radiology for a scoliosis study. The patient has had this series performed frequently. How much will the breast dose be decreased if a PA rather than an AP projection is taken?

90%

For a lateral L5-S1 projection, the CR must be parallel which body plane?

Interiliac plane

How much obliquity of the body is required for posterior oblique (LPO/RPO) positions for the sacroiliac joints?

25 to 30 degrees

Where is the CR centered for posterior oblique projections of the SI joints?

1 inch medial to upside ASIS