The Sacroiliac Joint [Part 2] | Factors Affecting Stabilization

The video explores the stability of the sacroiliac (SI) joint, emphasizing its crucial role in supporting the body's weight. It explains the concepts of form and force closure, which contribute to the joint's stability, and compares the SI joint's interlocking mechanism to Legos. The video also covers the limited mobility of the SI joint, highlighting movements like nutation and counter nutation, and the ligaments that restrict these movements. The importance of maintaining stability to prevent dislocation and dysfunction is underscored.

What is the primary function of the sacrum in the SI joint?

• To support the weight of the upper body

• To provide mobility to the lower back

• To allow for extensive movement in the pelvis

• To connect the femur to the pelvis

Why is the mobility of the SI joint considered negligible?

• Because it allows for extensive movement

• Because it only moves about 2 degrees

• Because it is not connected to any ligaments

• Because it is primarily a muscle joint

What is the role of form closure in the SI joint?

• To increase joint mobility

• To provide vertical support

• To allow for joint flexibility

• To provide horizontal support

How does the Lego analogy explain the SI joint's stability?

• The sacrum and ilium have interlocking surfaces

• The sacrum and ilium are held by rubber bands

• The sacrum and ilium are connected by magnets

• The sacrum and ilium are glued together

What is nutation in the context of the SI joint?

• A twisting motion of the lumbar spine

• A forward rotation of the sacrum

• A backward rotation of the ilium

• A sideways movement of the pelvis

Which ligament primarily restricts nutation?

• Sacrotuberous ligament

• Long dorsal sacroiliac ligament

• Anterior sacroiliac ligament

• Iliolumbar ligament

What is counter-nutation?

• A rotation of the lumbar spine

• A forward tilt of the superior sacrum

• A lateral tilt of the pelvis

• A backward tilt of the superior sacrum

Which ligament restricts counter-nutation?

• Sacrotuberous ligament

• Anterior sacroiliac ligament

• Long dorsal sacroiliac ligament

• Iliolumbar ligament

What could happen if the sacrotuberous ligament is disrupted?

• Improved load transfer through the joint

• No change in joint function

• Increased stability of the SI joint

• Increased mobility leading to dysfunction

Why is it important for the SI joint to have low mobility?

• To increase range of motion

• To allow for greater flexibility

• To prevent dislocations

• To enhance muscle strength