Anatomy of the Piriformis Muscle Quiz
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Questions and Answers

What is the main function of the superior gluteal artery?

  • Supply muscles in the buttocks (correct)
  • Drain venous blood from the pelvis
  • Supply muscles in the lower limb
  • Supply muscles in the pelvic floor
  • Which of the following structures receives most of the venous blood from the pelvis?

  • Internal iliac vein (correct)
  • Hepatic portal system
  • Superior mesenteric vein
  • Inferior mesenteric vein
  • What nerve structure contributes to the sacral plexus?

  • Autonomic pelvic nerves
  • Lumbosacral trunk (correct)
  • Sacral plexus
  • Coccygeal plexus
  • Which nerve structure supplies the muscles of the pelvic floor and perineum?

    <p>Sacral plexus</p> Signup and view all the answers

    What structures unite to form the coccygeal plexus?

    <p>Anterior rami of S1-S4</p> Signup and view all the answers

    Through which opening does the superior gluteal artery leave the pelvis?

    <p>Greater sciatic foramen</p> Signup and view all the answers

    What is the main action of the piriformis muscle?

    <p>Abduction of the thigh</p> Signup and view all the answers

    Which nerve innervates the piriformis muscle?

    <p>Nerve to piriformis (S1-S2 spinal nerve roots)</p> Signup and view all the answers

    Where does the piriformis muscle attach in the lower limb?

    <p>Superior border of the greater trochanter of the femur</p> Signup and view all the answers

    Which artery supplies the piriformis muscle?

    <p>Superior gluteal artery</p> Signup and view all the answers

    Through which foramen does the piriformis muscle leave the lesser pelvis?

    <p>Greater sciatic foramen</p> Signup and view all the answers

    Which vertebrae contribute to the origin of the piriformis muscle?

    <p>S2-S4</p> Signup and view all the answers

    Which nerves provide sympathetic innervation to the pelvis?

    <p>Lumbar and sacral splanchnic nerves</p> Signup and view all the answers

    What is the function of the pelvic diaphragm?

    <p>To support the pelvic organs and prevent prolapse</p> Signup and view all the answers

    Which muscle forms a U-turn around the anorectal junction and creates the urogenital hiatus?

    <p>Puborectalis muscle</p> Signup and view all the answers

    Which nerve provides parasympathetic supply to the pelvis?

    <p>Pelvic splanchnic nerves</p> Signup and view all the answers

    What is the source for subsequent plexuses that innervate the pelvic viscera?

    <p>Inferior hypogastric plexus</p> Signup and view all the answers

    What structures form the pelvic diaphragm?

    <p>Levator ani muscle and coccygeus muscle</p> Signup and view all the answers

    What is the main function of the levator ani muscle?

    <p>Flexes the anorectal canal during defecation</p> Signup and view all the answers

    Where does the levator ani muscle originate from?

    <p>Pubic bones</p> Signup and view all the answers

    What nerve innervates the levator ani muscle?

    <p>Nerve to levator ani (S2-S4)</p> Signup and view all the answers

    What is the function of the coccygeus muscle?

    <p>Supports pelvic viscera</p> Signup and view all the answers

    How does the pelvic diaphragm contribute during childbirth (parturition)?

    <p>By supporting the head of the fetus</p> Signup and view all the answers

    Which part of the levator ani muscle is often torn during childbirth?

    <p>Puborectalis</p> Signup and view all the answers

    What structures are supported by the levator ani muscle?

    <p>Urethra, vagina, and anal canal</p> Signup and view all the answers

    What condition may arise due to weakening of the levator ani muscle and pelvic fascia during childbirth?

    <p>Urinary stress incontinence</p> Signup and view all the answers

    Which type of prolapse is characterized by the descent of the uterus into the vagina?

    <p>Uterine prolapse</p> Signup and view all the answers

    What is the clinical term for the prolapse of both the urethra and bladder into the vagina?

    <p>Urethrocystocele</p> Signup and view all the answers

    In 3rd degree uterine prolapse (Procidentia uteri), what protrudes out of the vaginal opening?

    <p>The whole length of the uterus and cervix</p> Signup and view all the answers

    Which condition results from alterations in the position of the bladder neck and urethra due to weakening of pelvic structures?

    <p>Urinary stress incontinence</p> Signup and view all the answers

    Study Notes

    Piriformis Muscle

    • Located on either side of the pelvic cavity, passing laterally and attaching to the superior border of the greater trochanter of the femur
    • Forms part of the posterolateral wall of the pelvic cavity
    • Arises from the superior aspect of the sacrum (from S2 to S4 vertebrae), lateral to the sacral foramina
    • Innervated by the Nerve to piriformis (S1-S2 spinal nerve roots)
    • Supplied by superior and inferior gluteal arteries, gemellar branches of the internal pudendal artery
    • Actions: external rotation of the thigh, abduction of the thigh when the hip joint is flexed, stabilizes head of femur in acetabulum

    Pelvic Diaphragm

    • Comprises of two paired muscles and their fasciae: levator ani muscle and coccygeus muscle
    • Supports the pelvic organs and prevents them from prolapse
    • Forms the pelvic floor and supports all of the pelvic viscera
    • Levator ani muscle consists of three parts: puborectalis, pubococcygeus, and iliococcygeus
    • Puborectalis part makes a U-turn around the anorectal junction (puborectal sling), forming the urogenital hiatus
    • Urogenital hiatus transmits the rectum, urethra, and vagina in females

    Clinical Significance of Pelvic Diaphragm

    • Weakening of the levator ani and pelvic fascia from stretching or tearing during childbirth may decrease support for the vagina, bladder, uterus, or rectum
    • May cause urinary stress incontinence, characterized by dribbling of urine when intra-abdominal pressure is raised during coughing and lifting
    • May lead to the prolapse of one or more pelvic organs, such as:
      • Cystocele (prolapse of bladder into the vagina)
      • Urethrocystocele (prolapse of both urethra and bladder into the vagina)
      • Uterine prolapse (descent of uterus into vagina), classified into three degrees: 1st degree, 2nd degree, or 3rd degree (procidentia uteri)

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    Description

    Test your knowledge on the anatomy of the piriformis muscle, a muscle located on either side of the pelvic cavity which plays a crucial role in hip movement. Learn about its origin, attachments, and functions.

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