Pelvic Floor Muscles Quiz: Levator Ani, Coccygeus, and More

Pelvic Floor Muscles: Levator Ani and Coccygeus

Test your knowledge of the pelvic floor muscles, including the levator ani and coccygeus muscles, their origins, insertions, nerve supply, and actions. This quiz covers the anatomy of the pelvic diaphragm and its importance in supporting the body during defecation and labor.

Created by

@DecisiveChalcedony5588

Questions and Answers

What is the primary function of the coccygeus muscle during defecation or labor?

It supports the coccyx.

What is the origin of the levator ani muscle?

Back of the body of the pubis, ischial spine, and tendinous arch.

What is the insertion point of the anterior fibers of the pubo-coccygeus muscle?

Perineal body.

Which nerve branch supplies the coccygeus muscle?

S4, S5. Signup and view all the answers

What is the purpose of the intermediate fibers of the pubo-rectalis muscle?

To form a U-shaped loop behind the ano-rectal junction. Signup and view all the answers

What is the primary function of the levator ani muscle, along with the anterior abdominal wall muscles?

To increase intra-abdominal pressure Signup and view all the answers

Which nerve branch is responsible for supplying the quadratus femoris muscle?

Nerve to quadratus femoris Signup and view all the answers

What is the origin of the sacral plexus?

Anterior rami of L4, 5, & S1, 2, 3, 4 Signup and view all the answers

Which muscle is supported by the anterior fibres of the levator ani in the male?

Prostate Signup and view all the answers

What is the function of the puborectalis muscle?

To act as an additional sphincter to the anal canal Signup and view all the answers

Study Notes

Pelvic Floor Muscles (Pelvic Diaphragm)

The pelvic diaphragm consists of two levator ani and two coccygeus muscles, separating the pelvis from the perineum.

Coccygeus Muscle

Origin: inner surface of ischial spine
Insertion: last piece of sacrum and 1st piece of coccyx
Nerve supply: branches from S4, 5
Action: supports the coccyx during defecation or labor

Levator Ani Muscle

Origin: linear origin from back of the body of the pubis, ischial spine, and tendinous arch
Insertion:
- Anterior fibers (levator prostatae / sphincter vaginae): perineal body
- Intermediate fibers (pubo-rectalis): form a U-shaped loop behind the ano-rectal junction
- Posterior fibers (ilio-coccygeus): last 2 segments of the coccyx and anococcygeal raphe
Nerve supply: S3, 4 (direct from sacral plexus) and inferior rectal nerve
Action: increases intra-abdominal pressure, supports pelvic viscera, and keeps them in position

Sacral Plexus

Site: in the pelvis, in front of the sacrum and piriformis muscle
Formation: by the anterior rami of L4, 5, and S1, 2, 3, 4
Branches:
- To the pelvis: nerve to piriformis, pelvic splanchnic nerve (parasympathetic from S2, 3, 4)
- To the lower limb: posterior cutaneous nerve of the thigh, perforating cutaneous nerve
- To the perineum: pudendal nerve, perineal branch of S4
- Other branches: nerve to quadratus femoris, nerve to obturator internus, sciatic nerve, superior gluteal nerve, inferior gluteal nerve