Pelvis and Pelvic Girdle Study Guide

These flashcards cover key concepts related to the pelvis and pelvic girdle, including joint types, movements, pelvic positions, and clinical signs.

What structures form the pelvic girdle?

The pelvic girdle is formed by the right and left innominate bones, fused ilium, ischium, and pubis, along with the sacrum.

What type of joint is the sacroiliac (SI) joint?

The sacroiliac joint is a synovial joint that allows minimal movement and primarily transmits forces between the spine and pelvis.

What is nutation at the SI joint?

Nutation is sacral flexion where the superior portion of the sacrum rotates anteriorly and inferior portion rotates posteriorly, occurring with trunk flexion or hip extension.

What is counternutation at the SI joint?

Counternutation is sacral extension in which the superior portion rotates posteriorly and the inferior rotates anteriorly, occurring with trunk extension or hip flexion.

What type of joint is the pubic symphysis?

The pubic symphysis is a cartilaginous joint between the left and right pubic bones that allows minimal movement and contributes to pelvic stability.

What structures form the lumbosacral joint?

The lumbosacral joint is formed by the articulation between the inferior surface of the fifth lumbar vertebra (L5) and the superior surface of the sacrum (S1).

What movements occur at the lumbosacral joint?

The lumbosacral joint primarily allows flexion and extension in the sagittal plane; lateral bending occurs in the frontal plane, and rotation is minimal.

How is neutral pelvic position defined?

Neutral pelvic position is defined by level iliac crests and alignment of the ASIS and pubic symphysis in the same vertical plane.

What characterizes an anterior pelvic tilt?

An anterior pelvic tilt occurs when the superior portion of the pelvis tilts anteriorly, increasing lumbar lordosis and hip flexion.

What characterizes a posterior pelvic tilt?

A posterior pelvic tilt occurs when the superior portion tilts posteriorly, decreasing lumbar lordosis and increasing hip extension.

What is a lateral pelvic tilt?

A lateral pelvic tilt is identified by the lower side of the pelvis, commonly caused by weakness of hip abductors on the high side.

What is pelvic elevation?

Pelvic elevation, or hip hiking, occurs when one side of the pelvis is raised through the contraction of hip abductors and quadratus lumborum.

What is pelvic rotation?

Pelvic rotation occurs when one side of the pelvis moves forward or backward relative to the opposite side and is named after the forward side.

What is a lateral pelvic shift?

A lateral pelvic shift occurs when the pelvis shifts to one side, often due to compensating for weakness or to improve balance.

What is the normal lumbosacral angle?

The normal lumbosacral angle is approximately 40 degrees, indicating the angle between the superior surface of the sacrum and a horizontal line.

What is a positive Trendelenburg sign?

A positive Trendelenburg sign occurs when the pelvis drops on the unsupported side during a single-leg stance, indicating weakness of hip abductors.