Anatomy Lecture 6 - Pelvic Cavity

What is a zygapophysial joint?

A synovial joint between the superior articular process of one vertebra and the inferior articular process of the vertebra directly above it.

Where is the lesser pelvis located?

Between the pelvic inlet and the pelvic outlet.

What type of joints are the sacroiliac joints?

Compound joints consisting of synovial joints anteriorly. Posteriorly they are syndesmosis joints.

What are the superior and inferior pubic ligaments?

Decussating (intersecting) fibers of tendinous attachments of the rectus abdominis and external oblique muscles help strengthen the pubic symphysis anteriorly.

What is endopelvic fascia?

Endopelvic fascia is the fascia that is found between parietal and visceral layers. It is like filler fascia. Some of this fascia is more like loose areolar (fatty) tissue while the rest of it is more ligamentous fascia in nature. These layers are continuous with the parietal and visceral pelvic fascias.

What is the name of the disk between the pubic symphysis?

Fibrocartilaginous interpubic disc. This disc is usually wider in females.

Describe the iliococcygeus muscle.

Iliococcygeus muscle is the posterolateral part of the levator ani, arises from the posterior part of the tendinous arch and ischial spine. It blends with the anococcygeal body/ligament posteriorly.

What is the Inferior hypogastric plexus?

Inferior hypogastric plexus lie lateral to the rectum, bladder, prostate, vagina & uterus. Contains a mix of autonomics. It is made up of sympathetics from the sympathetic chain, lumbar splanchnics and hypogastric nerves; and parasympathetics from the pelvic splanchnic nerves (para/pre and visceral afferents from S2-S4 spinal cord segments).

What is the linea terminalis? What are the six components that compose it?

It bounds the superior boundary and is composed of: 1. Superior margin of the pubic symphysis anteriorly. 2. Posterior border of the pubic crest 3. Pectin pubis. 4. Arcuate line of the ilium. 5. Anterior border of the ala of the sacrum. 6. Sacral promontory.

Describe the median sacral artery.

It branches off near the bifurcation of the aorta and gives off the 5th pair of lumbar arteries.

Describe the ovarian artery.

It branches off the aorta just inferior to the renal artery branches and supplies the ovaries. These are just the gonadal arteries.

Describe the superior rectal artery.

It branches off the inferior mesenteric artery and supplies most of the rectum.

What is the innervation of the bulbourethral glands?

It is from the prostate nerve plexus. Recall this is autonomics.

What is the lateral ligament of the bladder?

It is the anterior part of the hypogastric sheath and it conveys the superior vesical vessels.

What is the lateral rectal ligament?

It is the posterior part of the hypogastric sheath and it conveys the middle rectal vessels.

What does the coccygeal plexus supply?

It supplies the coccygeus muscle, a small part of the levator ani and the sacrococcygeal joint.

What is the paracolpium?

It suspends the vagina between the tendinous arches of the pelvic fascia.

What is the vertebral span of the sacral plexus? What are the two main nerves of the sacral plexus?

L4-S4. Two main nerves: pudendal nerve and the sciatic nerve.

What is the lymph drainage of the ovaries?

Lymph drainage is to the lumbar lymph nodes.

What is the lymphatic drainage of the uterus?

Lymph drainage is to the lumbar, superficial inguinal, external iliac, internal iliac and sacral lymph nodes.

What is the lymph drainage of the rectum?

Lymph drainage is to the pararectal (superior half), sacral (inferior half) and internal iliac lymph nodes (distal ampulla portion).

What is the lymphatic drainage of the urinary bladder?

Lymph drains to the external iliac and internal iliac lymph nodes (M/F).

What is the innervation of the rectum?

Most of the rectum is under autonomic (pelvic nerve plexus) innervation while the distal most portion is innervated by somatics (inferior rectal nerve).

What is the innervation for the female urethra?

Nerves arise from the vesical nerve plexus and the pudendal nerve. Visceral afferents from most of the urethra run in the pelvic splanchnic nerves, but the termination receives somatic afferents from the pudendal nerve.

What is the function and innervation of the obturator internus muscle?

Obturator internus rotates the thigh laterally; assists in holding head of the femur in the acetabulum. It is innervated by the nerve to the obturator internus (L5, S1, S2). Note: obturator nerve is L2-L4. Obturator internus is L5-S2, this makes sense given how low the obturator internus muscle is.

What organs are found in the lesser pelvis?

Pelvic viscera such as the urinary bladder and reproductive organs such as the uterus and ovaries.

What are the periarterial plexuses?

Periarterial plexuses of the superior rectal, ovarian and internal iliac arteries provide sym/post to each of the arteries and its branches.

Describe the pubococcygeus muscle.

Pubococcygeus muscle is the wide but thinner intermediate part of the levator ani, arises from the anterior part of the tendinous arch and passes posteriorly in a nearly horizontal plane.

What is the peritoneal status of the urinary bladder?

Retroperitoneal.

What innervates the coccygeus muscles?

S4 and S5.

What is the vertebral span of the coccygeal plexus?

S4-Co1. This makes sense since the sacral plexus ended at S4.

Is the coccygeal nerve plexus somatic or autonomic nerves?

Somatic!

What is the name of the thickening in the obturator fascia?

Tendinous arch of the levator ani.

What is the vasculature of the ductus deferens?

The artery of the ductus deferens which usually branches off the superior vesical artery.

What is the vasculature of the ejaculatory duct?

The artery to the ductus deferens which usually branches off the superior vesical artery.

What is the pelvic brim?

The bony edge surrounding the pelvic inlet.

What is the pectin pubis?

The continuation of the superior ramus of the pubis which forms a sharp ridge.

What are the names of the os coxae?

The ilium, ischium and pubis.

What is the pelvic diaphragm composed of?

The levator ani and the coccygeus.

What separates the greater and lesser pelvis?

The oblique plane of the pelvic inlet.

What muscle makes up the lateral pelvic walls?

The obturator internus.

What is the innervation of the uterine tubes?

The ovarian & uterine nerve plexuses (autonomic).

What are the lumbosacral and the sacrococcygeal joints directly related to?

The pelvic girdle.

What are the anterior and posterior boundaries of the pelvis?

The pubic symphysis anteriorly and the sacrum/coccyx posteriorly.

What is the puboprostatic ligament? What is the pubovesical ligament?

The puboprostatic ligament (male) and pubovesical ligament (female) are the most anterior part of the pelvic tendinous arch The posterior most portion of the tendinous arch runs as the sacrogenital ligaments from the sacrum around the side of the rectum to attach to the prostate in the male or vagina in the female.

What is the visceral pelvic fascia?

The visceral pelvic fascia includes the membranous fascia that directly ensheathes the pelvic organs, forming the adventitial layer. This layer becomes continuous with the parietal layer where the organs penetrate the pelvic floor.

What are the coccygeus muscles?

These extend from the ischial spines to the inferior sacrum and coccyx.

Describe the structural setup of the uterine tubes.

They extend posterolaterally to the lateral pelvic walls where they ascend and arch over the ovaries.

What is unique about the articular surfaces of the sacroiliac synovial joints?

They have irregular but congruent elevations and depressions that interlock.

What is the ala of the sacrum?

This is the "wing" of the sacrum. So imagine looking at the anterior portion of the sacrum head on. The parts on the top that wing out to make the sacroiliac joint are the ala of the sacrum.

What are uterosacral ligaments?

Uterosacral ligaments/folds are thickened mounds of endopelvic fascia in females that extend from the sacrum to the cervix.

What is the vascular supply for the female urethra?

Vascular supply is by the internal pudendal and vaginal arteries.

Does the sympathetic trunk go all the way down to the sacrum?

Yes. It comes from the base of the skull down to the sacrum. At each side it will meet an end at the GANGLION IMPAR. Note: the function of the sympathetic trunk in the sacrum is to provide sym/post fibers to the sacral plexus for sym innervation of the lower limb.

What is the vascular supply for the urinary bladder?

-superior vesical (M/F) -inferior vesical (M) and vaginal (F) =TQ Blood drains into the vesical venous plexus (M/F) and the prostatic venous plexus (M).

What is the innervation of the uterus?

With the uterovaginal plexus (autonomic).

What is the innervation of the ovaries?

ovarian & uterine nerve plexuses (autonomic).

What are the three types of ligaments associated with the sacroiliac joints?

1. Anterior sacroiliac ligament. 2. Interosseous sacroiliac ligament. 3. Posterior sacroiliac ligament.

What are the three laminae of the hypogastric sheath?

1. Anteriorly - lateral ligament of the bladder. 2. Medially - rectovesical septum. 3. Posterior - lateral rectal ligament.

Name the four primary lymph nodes associated with the lymphatic drainage of the pelvis.

1. Common iliac. 2. External iliac. 3. Internal iliac. 4. Sacral.

What are the four components to the pelvic outlet?

1. Inferior margin of the pubic symphysis anteriorly 2. Inferior rami of the pubis and the ischial tuberosities anterolaterally 3. Sacrotuberous ligaments posterolaterally 4. Tip of the coccyx posteriorly

What are the three main arteries in the male that enter the lesser pelvis?

1. Internal iliac. 2. Median sacral. 3. Superior rectal arteries.

What are the four main arteries in the female that enter the lesser pelvis?

1. Internal iliac. 2. Median sacral. 3. Superior rectal arteries. 4. Ovarian.

What are the four parts of the male urethra?

1. Intramural. 2. Prostatic. 3. Intermediate. 4. Spongy. Mnemonic: I PIS.

What are the five nerves that come off of the sacral plexus? Give the vertebral level of each.

1. Lumbosacral trunk (L4-L5) 2. Sciatic nerve (L4-S3) 3. Pudendal nerve (S2-S4) 4. Superior gluteal nerve (L4-S1) 5. Inferior gluteal nerve (L5-S2)

What are the three muscles of the levator ani?

1. Puborectalis muscle. 2. Pubococcygeus muscle. 3. Iliococcygeus muscle.

What are the six ligaments associated with the uterus?

1. ovarian ligament 2. round ligament 3. suspensory ligament 4. broad ligament 5. cardinal ligament 6 uterosacral ligaments

What are the three walls of the uterus?

1. the outer perimetrium 2. middle myometrium 3. inner endometrium.

What type of joint is the sacrococcygeal joint?

A secondary cartilaginous joint with a disk similar to an IV disk between the sacrum and coccyx.

What is the innervation of the prostate?

An abundant supply of autonomics from the prostate nerve plexus.

What is the pelvic pain line?

An imaginary line at the inferior limit of the peritoneum. An organ in the pelvis is said to be "above the pelvic pain line" if it is in contact with the peritoneum, except in the case of the large intestine, where the pelvic pain line is said to be located in the middle of the sigmoid colon. Visceral afferents that transmit pain sensations from the viscera inferior to the pelvic pain line travel with parasympathetic fibers to the spinal ganglia of S2-S4. These fibers also travel alongside with visceral afferents fibers that conduct reflexive sensations. Visceral afferent fibers conducting pain from the viscera superior to the pelvic pain line (except the distal sigmoid colon and rectum) follow the sympathetic fibers retrogradely to inferior thoracic and superior lumbar spinal ganglia.

What is the innervation of the ureter?

Autonomic innervation is from the renal, aortic, superior and inferior hypogastric plexuses.

What is the innervation to the male urethra?

Autonomic nerves arise from the prostatic nerve plexus as well as the dorsal nerve of the penis.

What is the innervation of the ductus deferens?

Autonomic nerves composed mainly of sympathetic fibers derived from the larger pelvic plexus.

What is composition of the greater pelvis?

Bounded by the abdominal wall anteriorly, the alea (wings) of the ilium's laterally and the L5 and S1 vertebrae posteriorly. The greater pelvis is superior to the pelvic inlet.

What is the innervation of the seminal vesicles?

From the prostate nerve plexus Recall this is autonomics.

What is the vascular supply for the ureter?

Inferior vesical and uterine vessels supply the ureters in the pelvic region. It receives blood from renal, gonadal, superior vesical and iliac branches.

What is the innervation of the vagina?

Innervation is with the deep perineal branch of the pudendal nerve (inferior part and somatic). The uterovaginal plexus (autonomic) innervates the rest.

What is the innervation to the levator ani?

Innervation to these muscles is mainly from the nerve to the levator ani (S4), inferior rectal nerve & coccygeal plexus.

Describe the internal iliac artery.

It delivers most of the blood to the pelvic region. It is divided into an anterior & posterior division with the anterior division giving off most of the distal branches. Note: make sure you know all the branches!

What is the pelvic fascia?

It is a continuation of the transversalis fascia. The pelvic fascia is connective tissue that occupies space between the membranous peritoneum and the muscular pelvic walls and floor not occupied by pelvic organs.

What is the tendinous arch of the pelvic fascia?

It is the location where the parietal and visceral pelvic fascia are continuous with one another. At the point the parietal fascia thickens forming the tendinous arch of the pelvis fascia. This arch runs from the pubic to the sacrum.

What is the rectovesical septum?

It is the medial part of the hypogastric sheath. It is located between the rectum and prostate in the male. Note: In the female, the cardinal ligament (transverse cervical) conveys the uterine vessels and the ureter which passes inferior to the uterine vessels. (This is the notion of water under the bridge).

What are the left and right hypogastric nerves?

Left and right hypogastric nerves are the inferior extensions of the superior hypogastric plexus into the pelvis and the connection to the inferior hypogastric plexus. Contain a combination of autonomic fibers.

What is the lymph drainage of the seminal vesicles?

Lymph drainage is to the external iliac (superior part) and internal iliac (inferior part) lymph nodes.

What is the lymph drainage of the bulbourethral glands?

Lymph drainage is to the external iliac (superior part) and internal iliac (inferior part) lymph nodes. Recall: this is the same as the seminal vesicle.

What is the lymph drainage of the ductus deferens?

Lymph drainage is to the external iliac lymph nodes.

What is the lymph drainage of the ejaculatory duct?

Lymph drainage is to the external iliac lymph nodes.

What is the lymph drainage of the vagina?

Lymph drainage is to the internal and external iliac (superior part); internal iliac (middle part); sacral and common iliac (inferior part); and superficial inguinal lymph nodes (external orifice).

What is the lymph drainage of the prostate?

Lymph drainage is to the internal iliac mainly but also the sacral lymph nodes.

What is the lymph drainage to the male urethra?

Lymph drainage is to the internal iliac, external iliac and deep inguinal lymph nodes.

What is the lymph drainage of the uterine tubes?

Lymph drainage is to the lumbar lymph nodes.

What is the lymphatic drainage of the ureter?

Lymph drains into the lumbar, common iliac, external iliac and internal iliac lymph nodes.

What is the lymphatic drainage for the female urethra?

Lymph drains mainly to the sacral and internal iliac lymph nodes. A few vessels drain to the inguinal lymph nodes.

What is the function of parasympathetics in the pelvic region?

Parasympathetics: -stimulate contraction of the rectum (defecation) and bladder (urination) -supply the erectile bodies of the external genitalia leading to an erection.

What is the function and innervation of the piriformis muscle?

Piriformis rotates thigh laterally; abducts thigh; assists in holding head of the femur in the acetabulum. It is innervated by S1 and S2.

What is the vascular supply to the male urethra?

Prostatic branches of the inferior vesical and middle rectal, internal pudendal and the dorsal artery of the penis.

How much of semen volume is composed of prostatic fluid?

Prostatic fluid provides ~20% of the volume of semen.

Describe the puborectalis muscle.

Puborectalis muscle is the medial most muscle and it forms a U-shaped muscular sling (puborectal sling) that passes posterior to the anorectal junction. This muscle plays a major role in maintaining fecal continence. =TQ.

What is the function of the pelvic diaphragm?

Recall that the pelvic diaphragm is composed of levator ani and coccygeus muscles and the fascias covering the muscles. These muscles function mainly to support the pelvic viscera and resist increases in intra-abdominal pressure.

What type of joint is the pubic symphysis?

Secondary cartilaginous joint. it is formed by the union of the bodies of the pubic bones.

Is the sacral nerve plexus somatic or autonomic nerves?

Somatic! Everything that came off of the plexus (Lumbosacral trunk, Sciatic nerve, Pudendal nerve, Superior gluteal nerve, Inferior gluteal nerve) is also somatic.

What organs are found in the greater pelvis?

Some abdominal viscera such as the sigmoid colon and some loops of the ileum.

What is the superior hypogastric plexus?

Superior hypogastric plexus lies just inferior to the bifurcation of the aorta. Mainly sym/post and visceral sensory fibers.

What is the innervation of the urinary bladder?

Sympathetic fibers that simulate ejaculation simultaneously cause contraction of the internal urethral sphincter to prevent reflux of semen into the bladder. Parasympathetic fibers are motor to the detrusor muscle in the bladder wall and inhibitory to the internal sphincter in males.

What is the function of the sympathetics in the pelvic region?

Sympathetics: -produce vasomotion -inhibit peristaltic contraction of the rectum -stimulate contraction of the genital organs during orgasm (producing ejaculation in the male).

What are lumbosacral joints?

The IV disc of L5 and S1.

Where do the anococcygeal nerves pierce and what do they innervate?

The anococcygeal nerves pierce the sacrotuberous ligament and supply a small area of skin between the tip of the coccyx and the anus.

What are the bulbourethral glands?

The bulbourethral glands lie posterolateral to the intermediate part of the urethra and largely embedded within the external urethral sphincter. Their mucus-like secretion enters the urethra during sexual arousal in the male.

What is the parametrium of the endopelvic fascia?

The cardinal ligament and uterosacral ligament are sometimes together called the parametrium of the endopelvic fascia.

What is the subpubic angle? What are the angles in males and females?

The distance between the right and left ischial tuberosities. In males it should be less than 70 degrees and greater than 80 degrees in females.

Describe the pathway of the ductus deferens.

The ductus deferens is the continuation of the duct of the epididymis. The ductus deferens enlarges to form the ampulla of the ductus deferens just before it terminates along with the seminal vesicle to form the ejaculator duct.

What is the ejaculatory duct?

The ejaculatory duct is a slender tube that arises by the union of the ductus deferens & seminal vesicle.

Describe the passage way of the female urethra.

The female urethra passes anteroinferiorly from the internal urethral orifice of the urinary bladder, posterior and then inferior to the pubic symphysis to the external urethral orifice in the vestibule of the vagina. Lies anterior to the vagina.

What is the sacrum composed of?

The fusion of 5 originally separated sacral vertebrae.

Where do most branches of the sacral plexus leave through?

The greater sciatic foramen.

What is the hypogastric sheath?

The hypogastric sheath is a thick band of condensed pelvic fascia that gives passage to all the neurovasculature passing from the lateral pelvic walls to the pelvic viscera, along with the ureters and in the male, the ductus (vas) deferens. This sheath divides into 3 laminae that pass to or between the pelvic organs conveying the neurovasculature to the pelvic organs.

What is the vasculature of the bulbourethral glands?

The inferior vesical and middle rectal arteries.

What is the vasculature of the seminal vesicles?

The inferior vesical and middle rectal arteries.

What type of surface do the anterior synovial joints have? What makes these synovial joints different than most synovial joints?

The joints have an articular surface. These synovial joints differ from most because they have limited mobility.

What is the anococcygeal body?

The lateral fibers of the pubococcygeus muscle attach posteriorly to the coccyx, and the medial fibers merge with those of the contralateralside to form part of the anococcygeal body/ligament. This causes the formation of the anococcygeal raphe. This ligament spans from the coccyx to the anal canal.

Describe the attachment points of the levator ani muscles.

The levator ani muscles are attached to the pubic bones anteriorly, to the ischial spines posteriorly, and to a thickening in the obturator fascia.

What is the vasculature of the uterine tubes?

The ovarian arteries mainly.

What is the vasculature of the ovaries?

The ovarian arteries.

What are the ovaries?

The ovaries are almond-shaped and are typically located near the attachment of the broad ligament to the lateral pelvic walls. It is associated with the suspensory ligament and ovarian ligaments. The oocyte expelled at ovulation passes into the peritoneal cavity but is usually trapped by the fimbriae of the uterine tube and carried to the ampulla.

What is parietal pelvic fascia?

The parietal pelvic fascia is a membranous layer that lines the internal (deep or pelvic) aspect of the muscles forming the walls and floor of the pelvis. It covers the pelvic surfaces of the obturator internus, piriformis, coccygeus, levator ani and part of the urethral sphincter muscles. It is continuous with the transversalis and iliopsoas fascias.

What is the lesser pelvis limited inferiorly by?

The pelvic diaphragm.

What is the pelvic girdle? What it is composed of?

The pelvic girdle is a basin/bowl-shaped ring of bones that connects the vertebral column to the two femurs of the thighs. The pelvic girdle is composed to the left and right hip bones and the sacrum.

What is the superior boundary of the pelvis called?

The pelvic inlet or the superior pelvic aperture. Just say pelvic inlet.

What is the inferior boundary of the pelvis called?

The pelvic outlet or the inferior pelvic aperture. Just say pelvic outlet.

What is the lesser pelvis bounded by?

The pelvic surfaces of the os coxae, sacrum and coccyx.

What muscle makes up the posterior pelvic walls?

The piriformis muscle.

What is the prostate?

The prostate is a walnut-sized gland the surrounds the prostatic urethra. It is 2/3 glandular and 1/3 fibromuscular. It has a dense fibrous capsule that incorporates the prostatic nerve plexus & veins.

What is the vasculature of the prostate?

The prostatic arteries from the inferior vesical but also from the internal pudendal and middle rectal arteries. The prostatic venous plexus drains the deep dorsal vein of the penis.

What is the rectum?

The rectum has a rectosigmoid junction at the S3 vertebral level. The rectum follows the curvature of the sacrum and coccyx forming the sacral flexure of the rectum. Note: Dr. Wiki expects that you know many details of the rectum from the text and the anal triangle lecture!!!

What are the two primary joints of the pelvis?

The sacroiliac and the pubic symphysis.

What are the seminal vesicles?

The seminal vesicles are elongated structures that lie between the fundus of the bladder and the rectum. They do not store sperm but produce a thick alkaline fluid that mixes with sperm as they pass into the ejaculatory ducts and urethra.

What is the function of the pelvic girdle?

The strong pelvic girdle functions to transfer the weight of the upper body from the axial to the lower appendicular skeleton for standing and walking as well as to withstand compression and other forces resulting from its support of body weight.

What glands does the superior part of the urethra contain? What are these glands homologous to?

The superior part of the urethra contains paraurethral glands that are homologous to the prostate.

What is the vasculature of the rectum?

The superior rectal (from inferior mesenteric), middle rectal (from internal iliac) and the inferior rectal arteries (from the internal pudendal).

What is the vasculature of the vagina?

The upper portion is supplied by vaginal arteries that branched off the uterine arteries. The middle and inferior portions are supplied by vaginal arteries that branched off the internal pudendal artery. Note: vaginal arteries can come off of the uterine arteries or the internal pudendal.

What are the uterine tubes?

The uterine (fallopian) tubes extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries. They lie in the mesosalpinx in the free edge of the broad ligament.

What is the vascular supply of the uterus?

The uterine arteries with a potential collateral supply from the ovarian arteries.

What do the uterosacral ligaments contain?

The uterosacral ligaments contain the uterovaginal (this is another word for cervix) autonomic plexus and the ureter as it travels towards the bladder.

What is the uterus?

The uterus (or womb) is a thick walled, pear-shaped, hollow muscular organ that generally lies up against the urinary bladder that sits just anterior to it. It is made up of a body, fundus, isthmus and uterine horns. It terminates as the cervix of the uterus.

What is the function of the sacrotuberous and the sacrospinous ligaments?

The weight of the body is transmitted through the sacrum anterior to the rotation axis, tending to push the superior sacrum inferiorly, thereby causing the inferior sacrum to rotate superiorly. The sacrotuberous and sacrospinous ligaments resist these rotations. These ligaments allow only limited upward movement of the inferior end of the sacrum. This provides resilience to the sacroiliac region when the vertebral column sustains sudden weight increases.

What are the retropubic (prevesical) and retrorectal (presacral) spaces?

These are POTENTIAL spaces that may for for the endopelvic fascia.

What are the anterior and posterior sacrococcygeal ligaments?

These are long strands that reinforce the joint, much like the anterior/posterior longitudinal ligaments do for superior vertebrae.

What are pelvirectal spaces?

These are potential spaces that are divided into anterior and posterior spaces by the lateral rectal ligaments. These spaces are surgically important.

What do iliolumbar ligaments do?

These unite the transverse processes of L5 to the ilia.

What is the peritoneal status of the ureters?

They are retroperitoneal.