Pelvic Floor and Perinea Flashcards
What is the musculature of the floor of the pelvis called?
Pelvic diaphragm
What dorms the boundary between the true pelvis and perineum?
Pelvic diaphragm
Which two muscular structures make up the pelvic diaphragm?
Coccygeus
Levator ani
Which three muscles make up the levator ani?
Puborectalis
Pubococcygeus
Iliococcygeus
What is the function of levator ani?
- Support of abdomen-pelvic viscera
- Urinary and faecal incontinence
Which muscles form the pelvic
- lateral wall
- posterolateral wall
Lateral wall = obturator internus
Posterolateral = piriformis
Where does the piriformis muscle arise from?
Sacrum
What is found on the anterior surface of the piriformis muscle?
Sacral plexus
What does the obturator internus attach to?
Pelvic surfaces of ilium & ischium
Obturator membrane
Greater trochanter of femur
What is the nerve supply to obturator internus?
L5, S1 & S2
What is the action of the obturator internus?
Rotates hip joint laterally
Holds head of femur in acetabulum
What does the piriformis muscle attach to?
Proximally =
S2-S4, greater sciatic notch and sacrotuberous ligament
Distally - greater trochanter of femur
What is the nerve supply to the piriformis?
Anterior rami S1-2
What is the function of the piriformis?
Rotates hip laterally & abducts
Holds head of femur in acetabulum
What are the attachments of the coccygeus muscle?
Proximal = Ischial spine
Distal = Inferior end of sacrum and coccyx
What is the nerve supply to the piriformis muscle?
S4-5
What is the function of the coccygeus?
Pelvic diaphragm (small part)
Flexion of coccyx
What are the attachments of levator ani?
Proximal = body of pubis, obturator fascia, ischial spine
Distal = perineal body, coccyx, an-coccygeal ligament, walls of prostate/vagina, rectum & anal canal
What is the nerve supply to the levator ani?
Levator ani nerve (S3-4 branches) + Inferior anal nerve and coccygeal plexus
What is the function of the levator ani?
Pelvic diaphragm (majority of it) + resists increases in abdominal pressure
What are the three types of pelvic fascia?
Deep pelvic fascia
Endopelvic fascia
Superficial perineal fascia
(Is also superficial fascia which lines the abdominal wall - Camper’s and Scarpa’s)
Where is deep pelvic fascia found?
Covering muscles + organs
Where is endopelvic fascia found?
Between layers of deep pelvic fascia
Where is superficial perineal fascia found?
Only in urogenital triangle - continuous with superficial fascia of abdomen. Comprises subcut fatty & membranous tissue
What are the two types of deep pelvic fascia?
Parietal
Visceral
Where is parietal pelvic fascia found?
Over musculature - continuous with transversalis and iliopsoas fascia
Where is visceral pelvic fascia found?
Makes up adventitia of the viscera in the pelvis
What does endopelvic fascia form?
Ligaments between the parietal and visceral layers of the deep pelvic fascia (not true ligaments)
What is the function of the endopelvic fascia?
To anchor structures/organs in the pelvic cavity
What type of endopelvic fascia is found in men?
Retrovesical septum
What shape is the perineum?
Diamond
Where is the perineum found?
Superior to interior fascia of pelvic diaphragm
What is the perinea superficial to?
The inferior deep pelvic fascia of the pelvic diaphragm
What are the boundaries of the perinea?
Anterior = mons pubis (F) or root of penis (M)
Lateral - medial surface of thigh
Posterior - gluteal fold & inter-gluteal cleft
What are the osteological boundaries of the perinea?
Anterior - pubic symphysis
Anterolateral - ischiopubic rami
Posterolateral - ischial tuberosities and sacrotuberous ligament
Posterior - coccyx
What are the two triangles of the perinea?
The urogenital and anal triangles
What are the two triangles of the perineal separated by?
Transverse line - which travels through the perineal body
What is the difference between the urogenital triangle and the anal triangle?
Urogenital has a perineal membrane - anal does not.
What is the purpose of the perineal membrane?
Attachment for erectile tissue
What are the contents of the urogenital triangle?
Deep perineal pouch
Perineal membrane
Superficial perineal pouch
External genitalia
What is contained in the deep perineal pouch?
Urethra + external sphincter for urethra
Neurovasculature to genitals
Deep transverse perineal muscles (M) (DTP)
Bulbo-urethral glands (M) - Cowper’s
Smooth muscle (F)
Where are the deep and superficial perineal pouches contained?
Deep = deep to perineal membrane
Superficial = superficial to perineal membrane but deep to superficial perineal fascia
What are the contents of the superficial perineal pouch?
Superficial transverse perineal muscles (STPs)
Neurovasculature (deep perineal branches)
Root of penis (bulb & crura) + musculature (M)
Spongy urethra (M)
Clitoris & musculature (F)
Greater vestibular gland (F)
Bulbs of vestibule & musculature (F)
What overlays the corpus cavernosum?
The ischiocavernous muscle
What contains the corpus spongiosum?
The bulbospongious muscle
What are the bulbs of the vestibule in F homologue to?
The bulb of the penis
Is erectile tissue but has no urethra passing through it.
What is another name for the greater vestibular glands?
Bartolins glands
What is the muscle that contracts the anal canal?
External anal sphincter
Which muscle compresses urethra to maintain urinary continence?
External urethral sphincter
Which muscle supports perineal body & pelvic floor - and compresses bulb of penis to expel last drops?
Bulbospongiosus
Which muscle supports the pelvic body, assists in erection of clitoris & is sphincter of vagina?
Bulbospongiosus
Which muscle maintains erection of penis or clitoris by compressing outflow veins?
Ischiocavernous
Which muscles support the pelvic body and pelvic floor - in turn supporting abdominopelvic viscera?
Superficial & Deep Transverse Perineal Muscles
What is the homologue of the clitoris?
Penis
What do the crura of the clitoris follow?
The ischiopubic ramus
What is bulb of vestibule homologue to?
Bulb of the penis
How can you tell difference between labia majora and labia minora?
What is the function of both?
Labia majora -outer - fatty, subcutaneous tissue - hair covered. Contain sebaceous glands.
Labia minora - inner, thinner, not fat filled, no hair
Both protect external genitalia
What is the opening of the vagina called?
Vestibule of the vagina
What is the function of mons pubis?
Cushioning
What is the bulb of vestibule?
Erectile tissue 3m long - side of vagina opening - superficial to perineal membrane
What is the function of the bulb of vestibule?
Erectile tissue
What is another name for the (1) greater vestibular and (2) lesser vestibular glands?
(1). Bartholin glands
(2). Scene or para-urethral glands
What is the function of the greater and lesser vestibular glands?
Mucous secretion on sexual arousal
What does the scrotum contain?
The testis, associated ducts and neurovasculature
What does spermatic fascia cover?
Where does it arise from?
Spermatic cord and testes
Anterior abdominal lateral wall
What is the homologue of the scrotum?
Labia majora
What are the two features of the anal triangle?
Anus
Ischio-anal fossae
What is the perineal body?
What is it made of?
The site of convergence of the muscles of the pelvis & perineum = a central tendon in the perineum.
Made of collagen and elastic fibres + smooth & skeletal muscle fibres
Which muscles converge at the perineal body?
Bulbospongiosis
DTPs abd STPs. (deep and superficial transverse perineal muscle)
External
Which muscles converge at the perineal body?
Bulbospongiosis
DTPs abd STPs. (deep and superficial transverse perineal muscle)
External anal sphincter
Levator ani
What can damage to the perineal body cause?
Incontinence (both)
Prolapse
Sexual dysfunction
At what level does the abdominal aorta bifurcate and what does it form?
L4 - bifurcates into the common iliac
What does the common iliac bifurcate into?
Internal and external iliac arteries
Which are the two main arteries of the perineum?
Internal iliac artery (anterior and posterior)
Gonadal artery (ovarian / testes)
What are the main branches of the anterior internal iliac artery?
Umbilical a.
Obturator a.
Uterine a.
Vaginal a.
Inferior vesicle a (M)
Internal pudendal a.
Middle rectal a.
Inferior gluteal a.
What are the branches of the internal pudendal artery?
Inferior rectal
Dorsal a. of clitoris / penis
Perineal a.
How do the veins of the pelvis drain?
Drain into plexi –> named veins –> internal iliac vein –> IVC @ L5
Which nerves provide somatic sensation to the pelvis?
Obturator nerve (L2-4)
Lumbosacral trunk (L4-5)
Sacral plexus
Which spinal level does the obturator nerve arise at?
L2-4
Which spinal level does the lumbosacral trunk arise at?
L4-5
What does the obturator nerve travel with?
The obturator artery (through the obturator foramen)
What arises on the surface of the piriformis muscle?
Sacral plexus
What are the main branches of the sacral plexus?
Superior gluteal
Inferior gluteal
Posterior cutaneous of thigh
Perforating cutaneous
Pudendal
Sciatic
What spinal levels do the following nerves arise from?
1). Superior gluteal
2). Inferior gluteal
3). Posterior cutaneous of thigh
4) Perforating cutaneous
5). Pudendal
6) Sciatic
1). L4-S1
2). L5-S2
3). S2-3
4). S2-3
5). S2-4
6). L4-S3
Which vertebral levels does the sacral plexus arise from?
L4 - S4
Which are the autonomic nerves of the pelvis?
Hypogastric nerve
Inferior hypogastric plexus (ANS and visceral afferents)
Pelvic splanchnic nerves
Which nerves innervate the perineum?
Ilio-inguinal n.
Genital branch of genitofemoral n.
Pudendal n.
What are the branches of the pudendal nerve?
Inferior rectal n.
Dorsal n. of clitoris / penis
Perineal n.
What are the boundaries of the greater sciatic foramen?
Greater sciatic notch
Sacrotuberous ligament
Sacrospinous ligament
Ischial spine
What are the boundaries of the lesser sciatic foramen?
Lesser sciatic notch
Sacrotuberous ligament
Sacrospinous ligament
Ischial spine
Ischial tuberosity
What are the boundaries of the obturator foramen?
Ischiopubic ramus
Superior pubic ramus
Obturator membrane
What are the key features for sex differentiation of male and female pelvises?
- Pubic arch - ischiopubic rami - wider in F then M
- Subpubic angle - 80-85° F, 50-60° M
- Pelvic inlet / pelvic brim - round in F, heart in M
- Sacral promontory projection - sticks out further in M
- Ischial spine projection - sticks out further in M
Which aponeurotic structure attaches to the ASIS?
Inguinal ligament
Which bones form the pelvic girdle?
Innominate bones
Sacrum
Coccyx
What is the function of the pelvis and pelvic girdle?
Weight bearing
Protection of pelvic viscera
Muscle attachment of pelvis & lower limb
Attachment of erectile tissue of perineum
What is the name of the site of convergence of the 3 bones that form the innominate bone?
Acetabulum
Where does the sacrospinous ligament attach?
To the lateral surface of the sacrum, coccyx & ischial spine
Where does the sacrotuberous ligament attach?
To the lateral surface of the sacrum, posterior surface of ilium, coccyx and ischial tuberosity
What are the boundaries of the pelvic inlet?
Sacral promontory
Arcuate line
Pecten pubis
Pubic crest
Pubic symphysis
What are the boundaries of the pelvic outlet?
Coccyx
Sacrotuberous ligaments
Ischial tuberosities
Ischiopubic rami
Pubic symphysis
Where is the greater (false) pelvis found?
Superior to pelvic inlet
Where is the lesser (true) pelvis found?
Pelvic inlet to pelvic outlet
Which osteological features form the linea terminalis?
Pecten pubis, pubic crest & arcuate line
What type of fascia invests the pelvic diaphragm?
Parietal layer of deep pelvic fascia
What does the deep pelvic fascia form the roof of?
Roof of perineum
Which structures form the pelvic floor?
Pelvic diaphragm & fascia
Deep perineal pouch
Perineal membrane
Which structures are located within the deep perineal pouch?
Deep transverse perineal muscles (skeletal muscle – male, smooth muscle – female),
External urethral sphincter,
Urethra
Neurovasculature to penis or clitoris,
Bulbo-urethral glands (Cowper’s)
What are the endopelvic fascia ligaments in the female called?
Cardinal (transverse), uterosacral, pubocervical
Which tendinous structure lies in the transverse plane between the two triangles of the perineum?
Perineal body
What are the three types of endopelvic fascia found in women?
Uterosacral
Cardinal (transverse)
Pubocervical
