Week 6 - A - Anatomy 6 - Lateral Pelvic Wall and a Pelvic Mass - Arteries, Veins, Lymphatics

Question 1

Does the uterine or gonadal artery run anterior to one another? What level does the gonadal artery come of the aorta?

Answer 1

The gonadal arteries run anterior to the ureter (water under the bridge) The gonadal arteries leave the aorta at the L2 verterbaral level

Question 2

State what the coloured lines are in reference to The blue line points to a pouch

Answer 2

Blue line - rectovesical pouch (only present in males) (females have the rectouterine and the uterovesical pouches) Black - seminal vesicle/gland Red - epididymyis Green - pubic bone - protects the bladder (when bladder is full it expands beyond the bone)

Question 3

What are important ligaments of the lateral pelvic wall?

Answer 3

The sacrospinous ligament The sacrotuberous ligament The obturator ligament - although not offically called a ligament - it is fibrous in nature

Question 4

What are the attachments of the sacrospinous and sacrotuberous ligaments? What does the obturator membrane span? What is the gap superiorly in the obturator membrane for? What does the canal formed by the obturator internus fascia allow for the passage of?

Answer 4

Sacrospinous ligament - sacrum to the ischial spine Sacotuberous ligament - sacrum to the ischial tuberosity Obturator membrane spans the obturator foramen with a hole superiorly for the passage of the obturator neurovacular bundle in the obturator canal The canal formed by the obtruator internus fascial allows for the passage of the pudendal nerve - known as the pudendal canal (alcock’s canal)

Question 5

Obturator internus muscle covers most of the obturator membrane and crosses out of the pelvis to attach to the greater trochanter of the femur What is the function of the obturator internus?

Answer 5

The function of the obturator internus - one of the deep gluteal musces Laterally rotates the femur and stabilises the hip

Question 6

What is the function of the gluteus maximus, medius and minimus?

Answer 6

Gluteus maximus - main extensor of the thight but also acts to laterally rotates the thigh Gluteu smedius - abducts and medially rotates the thigh Gluteus minmium - abducts and medially rotates the thigh

Question 7

What does the abdominal aorta split into and what does this split into? State the vertebral levels at which each artery splits Random question - when is the coeliac trunk formed and what are its branches?

Answer 7

Abdominal aorta becomes the common iliac artery at the L4 vertebral level

The common iliac artery splits to form the external and internal iliac arteries at the L5/S1 intervertebral disc levels

• Formed at T12 vertebral levels - left gastric, splenic and common hepatic artery

Question 8

What do the majority of arteries in the pelvis and the perineum arise from?

Answer 8

The majority of arteries in the pelvis and perineum arise from the internal iliac artery

Question 9

What are the two exceptions arteries that supply the pelvis/perineum? ie they do not arise from the internal iliac artery and what do they arise from?

Answer 9

This would be: Gonadal arteries - arising at L2 of the abdominal aorta Superior rectal arteries which are continuations of the inferior mesenteric artery (arising at L3) Extensive ansatmoses but this lecture will look at the more important ones

Question 10

Does the abominal aorta or inferior vena cava lie on the left hand side of the body?

Answer 10

The abdominal aorta lies on the left hand side of the inferior vena cava The IVC splits to become the common iliac veins and the abdominal aorta splits to become the common iliac arteries The common iliac veins lie medially to the common iliac arteries

Question 11

The allantois is a hollow sac-like structure filled with clear fluid that forms part of a developing amniote’s conceptus (which consists of all embryonic and extra-embryonic tissues). It helps the embryo exchange gases and handle liquid waste. In mammals, the allantois is part of and forms an axis for the development of the umbilical cord. What is the remnant of the allantois known as?

Answer 11

The remnant of the allantois is known as the urachas

Question 12

The urachus is a fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord. The apex of the bladder stretches and is connected to the umbilicus as a narrow canal. This canal is initially open, but later closes as the urachus goes on to definitively form what ligament?

Answer 12

This urachas goes on to form the median umbilical fold (ligament)

Question 13

Failure of the inside of the urachus to be filled in leaves the urachus open. What is the telltale sign that the urachus is patent?

Answer 13

This would be leakage of urine through the umbilicus

Question 14

What are the other umbilical folds?

Answer 14

The medial umbilcal fold and The lateral umbilical folds Both are paired structures

Question 15

What is the medial umbilical fold a remnant of? Unlike the median and medial umbilical folds, the contents of the lateral umbilical fold remain functional after birth. What runs in the lateral umbilical fold?

Answer 15

The medial umbilical fold is a remnant of the umbilical arteries The lateral umbilical fold contains the inferior epigastric artery and vein

Question 16

What is the inferior epigastric artery a branch of?

Answer 16

The inferior epigastric artery is a branch of the external iliac artery (this along with superior epigastric artery supplies the anterior abdominal wall)

Question 17

Three umbilical folds - lateral, medial and median What does the lateral fold carry? What are the medial and median folds remnants of?

Answer 17

• The lateral fold carries the inferior epigastric artery and vein
• The medial umbilical fold is a remnant of the umbilical arteries
• The median umbilical fold is a remnant of the urachus (a stucture which drained urine from the foetal bladder - the urachus is a remnant of the allantois)

Question 18

The lateral umbilical fold is an important reference site with regards to hernia classification. As it contains the inferior epigastric vessels, it is important in differentiating between a direct and indirect inguinal hernia Which inguinal hernia is lateral and which is medial to the inferior epigastric vessels? Which usually penetrates into the scrotum? What does a femoral hernia travel beneath?

Answer 18

Direct inguinal hernia - medial to inferior epigastric vessels and rarely goes into scortum (old men)

Indirect inguinal hernia - lateral to inferior epigastric vessels and can appear in scortum

Femoral hernia - travels beneath the inguinal ligament

Question 19

How do direct and indirect inguinal hernias occur?

Answer 19

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Question 20

What does the inguinal canal convey in men and women?

Answer 20

Men - conveys the spermatic cord In women - conveys the round ligament of the uterus

Question 21

The internal iliac splits into two major divisions – anterior and posterior division What does the anterior division supply? What does the posterior division supply?

Answer 21

The anterior division of the internal iliac artery supplies the viscera and therefore this is regarded as a visceral division of the internal iliac artery The posterior division is regarded as a parietal division as most of the branches supply the body wall

Question 22

The internal pudendal artery will supply most of the perineum Does this branch arise form the anterior or posterior division of the internal iliac artery?

Answer 22

The internal pudendal artery arises from the anterior division of the internal iliac artery

Question 23

Anterior division will supply the structures within the pelvic cavity themselves Obturator artery – only artery going through obturator foramen so easier to spot – usually a branch of the anterior division What are the main arteries coming off the posterior division of the internal iliac artery?

Answer 23

The main arteries are the gluteal arteries

Question 24

The superior and inferior vesical arteries come off the anterior division in the males Which artery gives a branch known as the prostatic artery? In females, which artery is the inferior vesical artery known as instead?

Answer 24

The prostatic artery is a branch of the inferior vesical artery

The inferior vesical artery in females is the vaginal artery - females only have a superior vesical artery

Question 25

Most branches of the perineum are from internal pudendal What are the end terminations of the internal pudendal artery in the male? The only branch in the male perineum not coming from the internal pudendal artery is what? Where does this artery come from?

Answer 25

* The end terminations are the dorsal artery of the penis * The deep artery of the penis * The posterior artery of the scortum

The only branch in the male perineum not coming from the internal pudendal artery is the anterior scrotal artery which is a branch of the external iliac artery

Question 26

Majority of female pelvis is the same as male but there are a number of important differences. What is the inferior vesical artery in females?

Answer 26

The superior vesical and the uteirne artery are from the anterior division of the internal iliac artery in females The inferior vesical artery in females is the vaginal artery The vaginal artery is a branch of the uterine artery

Question 27

What is the blood supply to the bladder in males and females? What is the uterine artery homologous to in males?

Answer 27

Males - superior and inferior vesical arteries

Females - superior vesical artery and the vaginal artery gives off branches to the bladder inferiorly

The uteirne artery is homologous to the artery to the vas deferns in males

Question 28

An anastomosis occurs between the uterine artery and the vaginal artery What does the vaginal branch of the uterine artery mainly supply?

Answer 28

The vaginal branch mainly supplies the superior vagina and the cervix

Question 29

What is the ansastamosis between the ovarian and the uterine artery?

Answer 29

An anastamoses exists between he tubal and the ovarian branch of the ascending uterine artery to the the ovarian artery

Question 30

Where is the anastomases between the blood supply to the superior and inferior parts of the vagina?

Answer 30

Superior part of the vagina - vaginal artery inferior part of the vagina - internal pudendal artery as this part of the vagina is in the perineum Therefore anastamoses between vaginal artery and internal pudendal artery

Question 31

Describe the anastamoses in the pelvic region in the female

Answer 31

Anastamoses in the pelvis that are important in the female: * Ovarian and uterine artery (connected by tubal an ovarian branch of ascending uterine artery) * Uterine and vaginal artery (connected by vaginal branch of uterine artery) * Vaginal and internal pudendal artery

Question 32

In males, what were the terminations of the internal iliac artery?

What was the artery supplying an area of the perineum that arises from the external iliac artery?

Answer 32

Terminations

• Dorsal artery of the penis
• Deep artery of the penis
• Posterior scrotal artery

Anterior scrotal artery arises from the external iliac artery

Question 33

In females, what is the artery which is the end artery of the internal iliac artery? (homologous to the dorsal artery of the penis in males)

Answer 33

In females this would be the dorsal artery of the clitoris

Question 34

Mostly the venous drainage from the pelvis runs alongside the arterial supply to the pelvis The veins form a plexus around the structures they are draining to eventually join all the plexi branches to form a vein Where do the veins of the pelvis mainly drain into?

Answer 34

They mainly drain into the internal iliac vein

Question 35

Mostly the venous drainage from the pelvis runs is to the internal iliac vein Some veins will drain into the superior rectal vein and some will drain to the lateral sacral veins Where do both of these veins drain to?

Answer 35

The superior rectal vein drains eventually into the hepatic portal system The lateral sacral veins drain into the internal vertebral venous plexus The lateral sacral veins have connections into the internal veterbral plexuses – therefore there is a pathway for disease to spread from pelvis to vertebral column and potentially to the cranial cavity (ie cancers)

Question 36

How does the superior rectal vein drain into the hepatic portal system?

Answer 36

The superio rectal vein drains into the inferior mesenteric vein (becomes the inferior mesenteric vein) which drains into the splenic vein - the splenic vein joins with the superior mesenteric vein to become the hepatic portal vein

Question 37

Where do the gonadal veins drain to?

Answer 37

The right gonadal vein drains into the IVC The left gonadal vein drains into the left renal vein which drains into the IVC

Question 38

When uterine and ovarian ligation occurs during a hysterectomy, what structure needs to be remembered? (try not to damage this)

Answer 38

This would be the ureter - this runs posterior and under the uterine artery - try not incise

Question 39

Most of the nerves of the lateral wall of the pelvis come from the sacral plexus Which nerve is the exception?

Answer 39

The exception would be the obturator nerve which comes from the lumbar plexus

Question 40

What are the nerve roots of the obturator nerve? What does the obturator nerve innervate?

Answer 40

L2-4 is the obturator nerve roots

Obturator nerve innervates the muscles of the medial compartment of the thigh - the adductor muscles Also supplies sensation to the medial inner thigh

Question 41

What is the great big nerve of the sacral plexus which passes inferior to the piriformis? What notch in the pelvis does it pass through?

Answer 41

The sciatic nerve - passes through the great sciatic foramen and under the piriformis Nerve roots - L4-S3

Question 42

The small pelvic splachnic nerves are parasympathetic nerves (they go back to S2,3,4) Which visceral afferents relaying sensory information follow parasympathetic nerve fibres to the spinal cord?

Answer 42

Visceral afferents from the inferiro aspect of the pelvic organs run alongside parasympathetic nerve fibres to S2,3,4 Pain percieved as perineal

Question 43

How does the superficial inguinal node lymphatic drainage reach the abdominal aorta?

Answer 43

Superficial inguinal lymph nodes - drains to the deep inguinal lymph nodes - drains to the external iliac lymph nodes - drains to the common iliac lymph nodes - drains to the abdominal aorta (para-aortic / lumbar lymph nodes)

Question 44

General rules for lymphatics of the pelvis Superior pelvic viscera – drain to external iliac nodes and then to the common iliac and then where do the finally end? Inferior pelvic viscera all drain to the internal iliac nodes and then common iliac and then where do they finally end? Superficial perineum drains into the superficial inguinal lymph nodes and then where?

Answer 44

Superior pelvic viscera - external iliac then common iliac lymph nodes Inferior pelvic viscera - internal iliac then common iliac After common iliac both drain to aortic lymph nodes then thoracic duct which drains into the left venous angle Superficial perineum drains into the superficial inguinal lymph nodes which drain to the deep inguinal - which drains into external iliac, then common, then aortic, then thoracic duct and finally left venous angle

Question 45

The rules for lymphatic drainage are general as lymph can spread basically anywehere Ovaries and testis are most likely to follow their most normal lymphatic drainage Where is their most normal lymphatic drainage?

Answer 45

The normal lymphatic drainage of the testis and ovaries is to the lumbar lymph nodes (lumbar/para-aortic/aortic - all the same)

Question 46

Trans-peritoneal spread: - disease can penetrate through the peritoneal layer and disseminate into the peritoneal cavity Therefore what is one of the common metastases of ovarian cancer?

Answer 46

Therefore one of the common metastases of ovarian cancer due to the trans-peritoneal spread is the underside of the liver

Question 47

Most arterial blood supply for pelvis/perineum comes from the internal iliac * What are the exceptions? Most veins follow the arteries and are named similarly - theyform clinically important venous plexuses * What veins dont drain into the internal iliac vein?

Answer 47

* Gonadal arteries come from the abdominal aorta * Anterior scortal artery comes from the external iliac artery * Superior rectal artery is a direct continuation of the inferior mesenteric artery The superficial rectal vein - drains back into hepatic portal system The lateral sacral veins drain into the internal vertebral venous plexus The gonadal veins drain into the IVC and left renal vein

Question 48

Important nerves on lateral wall of pelvis * Most supply the lower limb – eg. obturator nerve and sciatic nerve * Pudendal nerve supplies perineum Lymphatic drainage is highly variable * large degree of cross-over * gonadal lymphatic drainage to lumbar (aortic/caval) nodes * What is important about lymphatic drainage of the pelvis and cancer?

Answer 48

Transperitoneal spread can occur where cancer invades the peritoneum and spreads elsewhere in the abdomen eg the underside of the liver