Pelvis 2

Relationship btw Colles' Fascia and Scarpa's fascia

"Colles's fascia of the perineum and Scarpa's fascia of the abdominal wall are continuous." "Scarpa's and Colles's fascias are firmly attached to the fascia lata of the thigh and perineal membrane thereby preventing extravasation of fluid into the thigh from the superficial perineal space" pg 63 slide 4-5

Effects of Sympathetic Innervation in male pelvis Effects of parasympathetic innervation in male pelvis

"Major effects of sympathetic innervation in the male: mediate vessel diameter; cause contraction of smooth muscle in the ductus (vas) deferens, seminal vesicles, ejaculatory ducts and prostate for emission of semen into the prostatic urethra; cause contraction of the internal urethral sphincter during ejaculation to prevent retrograde movement of sperm into the bladder; cause contraction of the internal anal sphincter Major effects of parasympathetic innervation in the male: cause contraction of the detrusor muscle and relaxation of the internal urethral sphincter during micturition; cause peristalsis in the rectum and relaxation of the internal anal sphincter during defecation; cause erection of the penis by dilating the vessels that supply these tissues (branches of internal pudendal artery), thus allowing the erectile tissue to fill with blood"

The anorectal junction forms an 80-degree angle that has great significance in rectal continence. The angle is maintained by the U-shaped sling of the ........

"The anorectal junction forms an 80-degree angle that has great significance in rectal continence. The angle is maintained by the U-shaped sling of the ..... puborectalis portion of the levator ani muscle.

Lymphatics of testis/ovaries

"travel with the gonadal veins, and therefore drain directly to the lateral aortic (lumbar) nodes in the posterior abdominal region"

The labia minora overlie the ____________ which are masses of erectile tissue on either side of the vaginal and urethral orifice

bulbs of the vestibule

The pelvic diaphragm is comprised of two striated muscles.....

coccygeus and levator ani

"Most of the blood supply to the pelvis and perineum is from the ________.

internal iliac artery The external iliac artery supplies the lower extremity.

Describe the pelvic plexuses?

pelvic plexuses are located lateral to the rectum and are associated with branches of the internal iliac artery The pelvic plexuses give off 'subsidiary plexuses' that accompany vessels of the same name to the viscera (e.g. vesical plexus, prostatic plexus, uterovaginal plexus, etc.).

Male superficial perineal space

pg 63 slide 8 READ

"After branching from the common iliac artery, the internal iliac courses inferiorly into the pelvic cavity where it divides into ....

posterior and anterior divisions.

Levator ani has three parts that support the pelvic organs like a hammock. Name the 3 parts.

pubococcygeus, iliococcygeus and puborectalis.

Muscles in the Male and Female Urogenital Triangle (the urogenital triangle is formed by the pubis symphysis and ischial tuberosities laterally)

superficial transverse perineal (2) ischiocavernosus (2) bulbospongiosus

What are some variations in females in the anterior division of the common iliac artery?

-uterine artery is typically the third branch of the anterior division (recall it was inferior vesical in males). -vaginal artery branches from the uterine artery or independently from the anterior division; it supplies the vagina, inferior surface of the bladder, and rectum. -In females the inferior vesical artery is typically a branch of the middle rectal artery. -Note close relationship of the uterine artery and the ureter. This relationship is clinically important as the ureter is at risk during a hysterectomy.

2 muscles found on wall of pelvic cavity 2 muscles found on floor of pelvic cavity

-wall: obterator internus, piriformis -floor: levator ani, coccygeus

Pelvic viscera receive innervation from autonomic nerves. Autnomic nerves form plexuses associated w vessels in that region. The prevertebral (aortic) plexus from the abdomen travels anterior to the aortic bifurcation as the... What does this plexus bifurcate into?

...superior hypogastric plexus. This plexus bifurcates into two hypogastric 'nerves' (they are really plexuses) which extend inferiorly into the pelvis to form the inferior hypogastric (pelvic) plexuses.

Branches of lumbar plexus that innervate Pelvis

1. Ilioinguinal nerve 2. Genitofemoral nerve

5 branches of the sacral plexus supply the pelvis or perineum. Name 3.

1. Pupendal Nerve (S2-S4). Major nerve of perineum. 2. The sacral plexus supplies the muscles of the wall and floor via branches that are named by the nerve (e.g. nerve to levator ani) 3. Posterior femoral cutaneous nerve exits the pelvis inferior to piriformis and gives off a perineal branch (to lateral skin of perineum); its main role is to provide cutaneous innervation to the posterior thigh (it is not shown in the diagram).

Describe collateral circulation between the rectum veins.

Anastamoses do exist btw these veins. Portal hypertension can lead to reversal of normal drainage. Blood from superior rectal vein may pass into middle and inferior rectal veins. This causes them to dilate (hemorrhoids)

Arterial blood supply to anal canal.

Arterial blood supply to the anal canal superior to the pectinate line comes from the superior rectal artery (branch of IMA). The inferior rectal arteries (branches of internal pudendal) supply the lower portion of the anal canal inferior to the pectinate line.

Whats the importance of the longitudinal muscle?

Attaches to skin. Important for retraction of skin after anus protrudes during defecation.

What is the deep fascia of the penis called?

Buck's Fascia

Compare the following: cephalic vs caudal to pectinate line 1. Epithelium 2. Nerve Supply 3. Artery 4. Vein 5. Lympathics

Cephalic/Caudal 1. Epithelium: Columnar/Squamous 2. Nerve Supply Autonomic/Somatic 3. Artery IMA/Int. Pupendal 4. Vein Portal Vein/Internal Iliac 5. Lympathics Preaortic nodes/Inguinal Nodes

Layers of UG triangle (from deep to superficial)

Deep Perineal Space (or pouch) Perineal Membrane Superficial Perineal Space (or pouch) Skin and Subcutaneous tissue

Which specific nerves influence erection, emission, and ejaculation?

Erection (arousal): Pelvic Splanchnic Nerves (S2-S4) -parasympathetic Emission: lumbar splanchnic nerves (L1-L2) -sympathetic Ejaculation: pudendal nerves (S2-S4) -somatic

Lymphatics of pelvic organs generally drain to x, y, and z.

External iliac, internal iliac, and sacral lymph nodes. Perineal structures: external pupendal veins to superficial and deep inguinal nodes. A few deep structures of perineum send lymph to internal iliac nodes.

What are the branches of the anterior division of the common iliac artery?

Highly variable. Umbilical artery usually first branch. Travels along lateral wall of true pelvis, gives off ductus deferns artery, superior vesical arteries, then becomes fibrous. Superior vesical artery: supplies superior surface of bladder Inferior vesical artery (male!): supplies inferior aspect of urinary bladder, prostate, seminal vesicles. Obturator artery: anterior along lateral pelvic wall, exits pelvic cavity thru obturator foramen (it does not supply anything in pelvis!) In 20% of ppl, obturator arises from external iliac. Middle rectal artery: enters rectum above pelvic floor and supplies its muscular wall Internal pupendal artery: courses inferiorly on anterior surface of piriformis. Passes through lesser sciatic foramen to enter the pupendal canal. Blood supply to perineum. Inferior gluteal artery: exits pelvic cavity via greater sciatic foramen and into gluteal region.

What is the clinical importance of ischioanal fossa recesses?

Infections involving ischioanal fossa may spread to these recesses

Which one is voluntary: -Internal Anal Sphincter -External Anal Sphincter

Internal Anal Sphincter is involuntary. External Anal Sphincter is voluntary

What is pupendal (Alcock's) canal?

It is a pocket in the ischioanal fossa , on the medial side of obterator internus. It encloses internal pupendal vessels and pupendal nerve while they travel through ischioanal fossa.

Perineal Membrane

Located inferior to the pelvic diaphragm Supports the "U" shaped opening in the anterior portion of the pelvic diaphragm through which the urethra and vagina pass.

What seperates the internal and external anal sphincters?

Longitudinal muscle. Created by fibers of puborectalis and iliococcygeus.

Effects of Sympathetic Innervation in Female pelvis Effects of parasympathetic innervation in female pelvis

Major effects of sympathetic innervation in the female: mediate vessel diameter; cause contraction of the internal urethral sphincter; cause contraction of the internal anal sphincter Major effects of parasympathetic innervation in the female: cause contraction of the detrusor muscle and relaxation of the internal urethral sphincter during micturition; cause peristalsis in the rectum and relaxation of the internal anal sphincter during defecation; cause erection of the clitoris by dilating the vessels that supply these tissues (branches of internal pudendal artery), thus allowing the erectile tissue to fill with blood"

What is the lateral boundary of the ischioanal fossa? What is the medial wall of the ischioanal fossa?

Obteratur internus = lateral boundary of each fossa Levator ani + coccygeus. It is a slanting medial wall.

Piriformis

On Posterior Wall Origin: anterior aspect of sacrum Insertion: exits greater sciatic foramen to reach greater trochanter of femur Innervation: sacral plexus Action: laterally rotates thigh

Coccygeus

Origin: ischial spine and sacrospinous ligament Insertion: sacrum and coccyx Innervation: sacral plexus Action: supports pelvic viscera

Obterator Internus

Origin: obturator membrane Insertion: exits pelvis thru lesser sciatic foramen to reach greater trochanter of femur Innervation: branches of sacral plexus Action: laterally rotates thigh

Levator Ani (origin, insertion, innervation, action)

Origin: pubis, tendinous arch, ischial spine Insertion: blends with fibers from opposite side Innervation: branches of sacral plexus Action: supports pelvic viscera, puborectalis provides anorectal angle (great pic pg 43 last slide)

An erection requires parasympathetic, sympathetic, and autonomous innervation. Explain the sequence of these.

Parasympathetic: inc arterial blood flow into erectile tissues, decrease in venous return = erection Sympathetic: smooth muscle contraction in the vas deferens, seminal vesicles and prostrate produce emission of semen into prostatic urethra. -internal sphincter of bladder constricts to prevent retrograde ejaculation into the bladder Somatic: ejaculation under control bulbospongiosum muscles under control of somatic pudendal nervces

However, where do perineal structures send their lymphatics?

Perineal structures: external pupendal veins to superficial and deep inguinal nodes. A few deep structures of perineum send lymph to internal iliac nodes.

Rectum ends at level of...

S3

Lateral Sacral Veins communicate w the vertebral venous plexus (in epidural space) through the...

Sacral foramina. This is a possible route for the spread of infection from the pelvis to the vertebral canal.

Describe the sacral plexus

Sacral plexus is confluence of lumbosacral trunk: Ventral Rami of L4/L5 + Ventral Rami of S1-S4. The plexus is located on the anterior surface of the piriformis muscle. Moves through greater sciatic foramen. 5 branches supply the pelvis or perineum

Innervation of Pelvis: somatic vs visceral

Somatic Structures: lumbar plexus sacral plexus Visceral Structures: sympathetics parasympathetics visceral afferents

Why are the veins of the rectum unique?

Superior rectal vein --> Inferior Mesenteric Vein --> Portal Vein Middle + Inferior rectal veins --> Internal Iliac Vein Anastamoses do exist btw these veins. Portal

How about superior rectum lymph?

Superior rectum: inferior mesenteric vein. Drain to the inferior mesenteric nodes on the abdominal aorta.

Blood drainage of anal canal

Superior to the pectinate line blood drains primarily into the portal system: the superior rectal vein drains into the inferior mesenteric vein. Inferior to the pectinate line, the inferior rectal veins are tributaries of the systemic circulation that ultimately drain to the IVC (via the internal pudendal --> internal iliac --> common iliac veins). The middle rectal veins, also caval tributaries, form anastomoses with the superior and inferior rectal veins.

Describe the changes in epithelium at the pectinate line.

Superior to the pectinate line: simple columnar epithelium. This will first transition to stratified columnar epithelium, then non-keratinized stratified squamous epithelium, until it final becomes skin (keratinized, stratified squamous epithelium with sweat and sebaceous glands). .

The anal canal begins when...

The anal canal begins when the rectal ampulla suddenly narrows. This occurs where the rectum pierces the pelvic diaphragm.

What does the pelvic floor separate?

The pelvic floor or diaphragm is a funnel-shaped structure that separates the true pelvic cavity from the perineum.

What is the perineal body?

The perineal body is the central tendinous point of the perineum. It is located in the midline anterior to the anus. It consists of fibrous tissue that serves as the anchoring point for several muscles. pg 59

What are the branches of the posterior division of the common iliac artery?

The posterior division has three branches (mnemonic is "PILS", P=posterior). - iliolumbar artery courses superiorly and laterally to supply muscles of the posterior abdominal wall. -lateral sacral artery courses inferiorly on the anterior surface of piriformis and the sacrum. It supplies the piriformis and sends branches through the anterior sacral foramina that supply the contents of the sacral canal. -The superior gluteal artery exits the pelvic cavity through the greater sciatic foramen in a position superior to piriformis. It enters the gluteal region and supplies muscles in that area.

What are the recesses of the ischioanal fossa?

There are anterior and posterior recesses of ischioanal fossa. -Anterior recess: btw pelvic diaphragm + perineal membrane -Posterior recess: btw gluteus maximus and pelvic diaphragm

Visceral Afferents of Pelvis

Travel w Splanchnics Mediate sensations such as distension, cramps or pain. Unlike other areas of the body, pain afferents from pelvic viscera travel with both sympathetics and parasympathetics.

Venous drainage of pelvic organs

Venous drainage of the pelvic organs is generally via tributaries of the internal iliac vein that have the same names as the arteries.