Pelvic Muscles Quiz: Pelvis and Perineum Anatomy

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Questions and Answers

What is the function of the ligaments in the pelvis?

To protect the sacrum

To attach muscles to the pelvis

To support the pelvis (correct)

To provide movement to the pelvis

What type of joints are the sacro-iliac joints?

Plane synovial joints (correct)

Cartilaginous joints

Synovial joints

Fibrous joints

In erect posture, the pelvic brim forms an:

Oblique plane (correct)

Horizontal plane

Inclined plane

Vertical plane

What is the normal position of the pelvis in erect posture?

The ischial spine and upper border of symphysis pubis are in the same horizontal plane Signup and view all the answers

How many bones form the bony pelvis?

4 Signup and view all the answers

What type of joints are the symphysis pubis and sacrococcygeal joints?

Cartilaginous joints Signup and view all the answers

Which muscle forms the pelvic diaphragm along with the coccygeus muscle?

Levator ani Signup and view all the answers

What is the anatomical region below the levator ani muscle?

Perineum Signup and view all the answers

Which nerve is related to the piriformis fascia posteriorly?

Sacral nerves Signup and view all the answers

What is the function of the tendinous arch formed by the obturator fascia?

To give origin to the levator ani muscle Signup and view all the answers

What is the function of the puboprostatic ligaments in males?

To fill the gap between the two levator ani muscles Signup and view all the answers

What is the function of the piriformis muscle in relation to the sacro-iliac ligaments?

To relax the sacro-iliac ligaments Signup and view all the answers

What is the main function of the pelvic floor muscles in the female?

To support the pelvic viscera Signup and view all the answers

What is the origin of the coccygeus muscle?

Ischial spine Signup and view all the answers

What is the nerve supply of the coccygeus muscle?

A branch of the 4th and 5th sacral nerves Signup and view all the answers

What is the function of the puborectalis muscle?

To form a U-shaped sling behind the anorectal junction Signup and view all the answers

What is the insertion of the iliococcygeus muscle?

Into the side of the coccyx and anococcygeal raphe Signup and view all the answers

What is a possible complication of injury to the pelvic floor during childbirth?

All of the above Signup and view all the answers

Study Notes

Posture and Pelvis

Relaxation of sacro-iliac ligaments can lead to "swayback" posture, allowing greater rotation of the pelvis.

Muscles of the Pelvis

Two muscles in the pelvic wall:
- Piriformis
Two muscles in the pelvic floor:
- Levator ani
- Obturator internus
Levator ani and coccygeus form the pelvic diaphragm, which forms the pelvic floor.
The part of the pelvis above levator ani is the pelvic cavity.
The part of the pelvis below levator ani is the perineum.

Pelvic Fascia

Piriformis fascia:
- Part of parietal pelvic fascia
- Anteriorly related to internal iliac vessels
- Posteriorly related to sacral nerves
Obturator fascia:
- Covers the pelvic surface of obturator internus
- Fuses with the periosteum at the margins of the muscle, except at the obturator groove
- Thickens to form the tendinous arch (white line) between the lower border of the pubic body and ischial spine, which gives origin to levator ani muscle.

Muscles of the Pelvic Floor

Puborectalis:
- Passes inferomedially to become continuous with the opposite ones behind the anorectal junction, forming a U-shaped sling
- Inserted into the anococcygeal body
Pubococcygeus proper:
- Passes medially to be attached to the side of the coccyx and anococcygeal body
Iliococcygeus:
- Arises from the posterior half of the white line and ischial spine
- Fibers pass medially inferior to the pubococcygeus proper and have the same insertion into the side of the coccyx and the anococcygeal raphe
Coccygeus muscle:
- Origin: Ischial spine
- Insertion: Lower end of the sacrum and into the coccyx
- Nerve supply: A branch of the 4th and 5th sacral nerves
- Action: Assists the levator ani in supporting the pelvic viscera

Functional Significance of the Pelvic Floor in the Female

Helps in head rotation during the second stage of labor
Injury to the pelvic floor can occur during a difficult childbirth, leading to:
- Uterine and vaginal prolapse
- Herniation of the bladder (cystocele)
- Alteration in the position of the bladder neck and urethra, leading to stress incontinence
- Prolapse of the rectum

Anatomy of the Pelvis

The bony pelvis is formed of 4 bones: Right and left hip bones, the sacrum, and coccyx
The pelvis is united by 4 joints:
- 2 Sacro-iliac joints (plane synovial)
- Symphysis pubis
- Sacrococcygeal joints (cartilaginous joints)
The pelvis is supported by 4 ligaments:
- Iliolumbar
- Lumbosacral
- Sacrotuberous
- Sacrospinous
Normal position of the pelvis:
- In erect posture, the pelvis lies with the anterior superior iliac spine and pubic tubercles in the same vertical plane
- The ischial spine and upper border of symphysis pubis are in the same horizontal plane
The pelvic brim:
- An oblique plane extends from the sacral promontory to the upper margin of symphysis pubis

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Description

This quiz covers the muscles of the pelvis, including those in the pelvic wall and floor, and their roles in maintaining posture and forming the pelvic cavity and floor. Test your knowledge of the pelvic diaphragm, sacro-iliac ligaments, and more.