Anatomy of Sacroiliac Joint Ligaments

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Questions and Answers

What is the primary function of the interosseous ligament in the sacroiliac joint?

To facilitate flexion and extension of the sacrococcygeal joint

To increase the anteroposterior diameter of the pelvis

To prevent excessive backward movement (correct)

To prevent anterior movement of the sacral apex

What is the main purpose of the sacrococcygeal joint?

To provide a wide range of motion for the pelvis

To facilitate flexion and extension during labor and defecation (correct)

To absorb shock during weight-bearing activities

To stabilize the sacrum and coccyx

Which ligament transforms the lesser sciatic notch into a foramen?

Deep posterior sacrococcygeal ligament

Sacrospinous ligament (correct)

Sacrotuberous ligament

Anterior sacrococcygeal ligament

What is the function of the sacrotuberous ligament?

To transforms the greater sciatic notch into a foramen Signup and view all the answers

What is the purpose of clinical provocation tests for the SIJ?

To diagnose sacroiliac joint injuries Signup and view all the answers

Which ligament attaches to the margin of the sacral hiatus and the dorsal surface of the coccyx?

Superficial posterior sacrococcygeal ligament Signup and view all the answers

What is the primary function of the sacroiliac joint?

To control and distribute the forces from the upper body into the legs Signup and view all the answers

What is the range of movements at the sacroiliac joint?

2 mm to 4 mm and 2° to 5° Signup and view all the answers

What is the function of the interosseous ligament?

To prevent forward and downward movement of the sacrum Signup and view all the answers

What is the name of the movement where the sacrum rotates in an anterior direction around its transverse axis?

Nutation Signup and view all the answers

What is the type of cartilage that covers the auricular surface of the sacrum?

Hyaline cartilage Signup and view all the answers

What is the name of the ligament that blends with fibers of the joint capsule and is rich in nociceptive fibers?

Anterior Sacroiliac ligament Signup and view all the answers

What is the function of the posterior sacroiliac ligament?

To contribute to SIJ mobility Signup and view all the answers

What is the name of the ligament that overlies the interosseous sacroiliac ligament?

Posterior Sacroiliac ligament Signup and view all the answers

What is the function of the sacrospinous ligament?

Accessory ligament Signup and view all the answers

What is the movement of the sacrum around its transverse axis in a posterior direction called?

Counter-nutation Signup and view all the answers

What is the approximate angle of the lumbo-sacral angle in 95% of cases studied?

30 degrees +/- 10 Signup and view all the answers

Which part of the sacrum articulates with the coccyx?

Sacral apex Signup and view all the answers

What is the function of the anterior sacral foramina?

Both exit point for sacral nerves and entry point for sacral arteries Signup and view all the answers

What is the characteristic of the sacrum posterior surface?

Convex, narrower, and highly irregular Signup and view all the answers

What is the purpose of the sacral canal?

To represent the end of the vertebral canal Signup and view all the answers

How many transverse ridges are present on the middle portion of the sacrum?

4 Signup and view all the answers

Study Notes

Sacroiliac Joint

Located between the auricular surfaces of the sacrum and ilium
Synovial joint with joint capsule and synovial membrane
Some resources describe SI as part synovial on its anterior side and in part a syndesmosis on its posterior side
Functions to control and distribute forces from the upper body into the legs
Acts as a shock absorber for the spine and controls transmission of forces from the lower body into the spine
Allows spinal and thigh movements, and changes in posture or position
Supports the weight of the upper body
Facilitates pregnancy and childbirth in women by widening and becoming more mobile

Ligaments within SI Joint

Three main ligaments:
- Anterior Sacro Iliac ligament
- Posterior Sacro Iliac ligament
- Interosseous ligament
Two accessory ligaments:
- Sacrospinous ligament
- Sacrotuberous ligament
Anterior Sacro Iliac ligament:
- Blends with fibers of the capsule
- Rich innervation of nociceptive fibers, may be a significant source of pain
Posterior Sacroiliac ligament:
- Overlies the interosseous sacroiliac ligament
- Contributes most to SIJ mobility
- Undergoes tension during transmission of forces from the legs to the upper body and vice versa
Interosseous Ligament:
- Strongest ligament in the body
- Consists of short, strong bands that detach from the bone
- Blends with fibers of the capsule
- Prevents forward and downward movement of the sacrum

Sacrococcygeal Joint

Articulation between the apex of the sacrum and the base of the coccyx
A symphysis, the two bones lined by hyaline cartilage and connected by a fibrous disc
Only slight mobility; flexion-extension to increase the anteroposterior diameter of the pelvis during labor and defecation

Ligaments of the Sacrococcygeal Joint

Anterior Sacrococcygeal ligament:
- Extends from the anterior surface of the sacrum to the anterior surface of the apex of the coccyx
Lateral Sacrococcygeal ligament:
- Attaches to the inferolateral angle of the sacrum and the transverse processes of the coccyx
Superficial Posterior Sacrococcygeal ligament:
- Arises from the margin of the sacral hiatus and attaches to the dorsal surface of the coccyx
Deep Posterior Sacrococcygeal ligament:
- Spans from the dorsal surface of the S5 to the dorsal surface of the coccyx

Coccyx Anatomy

Bony Landmark:
- Base (oval)
- Apex (rounded)
- Anterior surface
- Posterior surface
- Lateral surface
- Base
- Cornua
- Rudiments of Spinous process
- The Cornua of Co1 articulates with the Sacral cornua
- Anterior: pelvic surface, concave
- Lateral: thin edges remnant of TVP
- Apex: posterior, convex
- 4 rows of tubercles (rudiments of Spinous process)

Sacrum

Five sacral vertebrae fused to form a triangular or wedge-shaped structure
Base sits at an oblique angle forming the lumbosacral angle that measures 30 degrees +/- 10 in 95% of cases studied
Lumbosacral Articular facets/surface orients posteriorly and articulates with Inferior facets of L5
Sacral apex (formed by the S5 vertebra) articulates with the coccyx
Sacral Alar (wings) articulates with Ilium
Sacral tuberosities articulate with the iliac tuberosity

Sacrum Anterior Surface

Transverse ridges:
- Middle portion has 4 transverse ridges corresponding to 5 sacral bodies
Anterior Sacral foramina:
- Anterior sacral foramina 4 on each side
- First 4 sacral nerves exit here, arteries enter here

Sacrum Posterior Surface

Convex, narrower, highly irregular
Sacral canal runs down the center of the sacrum and represents the end of the vertebral canal

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Description

This quiz covers the ligaments within the sacroiliac joint, including the interosseus ligament, sacrospinous ligament, and sacrotuberous ligament, and their functions.