Pelvis and Perineum

Question 1

Bulbospongiosus

Answer 1

Origin: Male- Median raphe, Bulb of penis, Perineal body
Female- Perineal body
Insertion: Male- Perineal membrane, Corpus cavernosum, Bulb of penis
Female- Dorsum of clitoris, Inferior fascia of urogenital diaphragm, Bulb of vestibule, Pubic arch
Innervation: Deep branch of perineal nerve from pudendal nerve
Function: Male- Compresses bulb of penis, Forces blod into body of penis during eretion, Removes urine from urethra and semen during ejaculation
Female- Contricts vaginal orifice, Assists in expressing secretions of greater vestibular gland, Forces blood into body of clitoris

Question 2

Coccygeus (ischiococcygeus)

Answer 2

Origin: Ischial spine, Sacrospinous ligament
Insertion: Inferior sacrum, Coccyx
Innervation: Ventral rami of lower sacral nerves
Function: Supports pelvic viscera, Draws coccyx forward

Question 3

Compressor Urethrae (female only)

Answer 3

Origin: Ischiopubic Ramus
Insertion: Anterior aspect of urethra
Innervation: Perineal branches of pudendal nerve
Function: Sphincter of urethra

Question 4

Cremaster (male only)

Answer 4

Origin: Lower edge of internal oblique and Middle of inguinal ligament
Insertion: Pubic tubercle, Crest of pubis
Innervation: Genital branch of genitofemoral nerve
Function: Retracts testicle

Question 5

Deep Transverse Perineal

Answer 5

Origin: Inner surface of inferior ischial rami
Insertion: Male- Medial tendinous raphe and perineal body
Female- Sides of the vagina
Innervation: Perineal branches of pudendal nerve
Function: Stabilizes perineal body, Supports prostate/vagina

Question 6

External Anal Sphincter

Answer 6

Origin: Tip of coccyx, Anococcygeal ligament
Insertion: Deeper fibers surround anal canal, Attach posteriorly to coccyx and anteriorly to central point of perineum
Innervation: Perineal and inferior rectal branches of pudendal nerve
Function: Closes anal orifice

Question 7

Iliacus

Answer 7

Origin: Superiour 2/3 of iliac fossa, Ala of sacrum, Anterior sacro-iliac ligaments
Insertion: Lesser trochanter of femur and shaft inferior to it, To psoas major tendon
Peripheral Nerve: Femoral nerve
Nerve Root:
Function: Flexes thigh at hips and Stabilizes hip joint, Acts with psoas major

Question 8

Ischiocavernosus

Answer 8

Origin: Inferior internal surface of ischiopubic ramus, Ischial tuberosity
Insertion: Crus of penis of clitoris
Peripheral Nerve: Deep branch of perineal nerve from pudendal nerve
Nerve Root:
Function: Forces blood into body of penis and clitoris during erection

Question 9

Levator Ani (Iliococcygeus, Pubococcygeus, and Puborectalis)

Answer 9

Origin: Body of pubis, Tendinous arch of obturator fascia, Ischial spine
Insertion: Perineal body, Coccyx, Anococcygeal raphe, Walls of prostate or vagina, Rectum, Anal canal
Peripheral Nerve: Ventral rami of lower sacral nerves, Perineal nerve
Nerve Root:
Function: Supports pelvic viscera, Raises pelvic floor

Question 10

Obturator Internus

Answer 10

Origin: Pelvic surface of obturator membrane and surrounding bone
Insertion: Medial surface of greater trochanter of femur
Peripheral Nerve: Nerve to obturator internus
Nerve Root:
Function: Laterally rotates extended thigh, Abducts flexed thigh at hip

Question 11

Piriformis (somewhere else)

Answer 11

Origin: 
Insertion: 
Peripheral Nerve: 
Nerve Root: 
Function:

Question 12

Sphincter Urethrae

Answer 12

Origin: External fivers from junction of inferior pubic and ischial rami and adjacent fascia; Internal fibers pass medially to surround membranous urethra
Insertion: Male- Median raphe in front and behind urethra
Female- Encloses urethra, attaches to sides of vagina
Peripheral Nerve: Perineal branches of pudendal nerve
Nerve Root:
Function: Compresses urethra at end of micturition; In female also compresses distal vagina

Question 13

Sphincter Urethrovaginalis (female only)

Answer 13

Origin: Perineal body
Insertion: Passes forward and anterior around urethra
Peripheral Nerve: Perineal branches of pudendal nerve
Nerve Root:
Function: Sphincter of urethra and vagina

Question 14

Superficial Transverse Perineal

Answer 14

Origin: Ischial rami and tuberosities
Insertion: Central tendon (perineal body)
Peripheral Nerve: Perineal branches of pudendal nerve
Nerve Root:
Function: Stabilizes central tendon