The pelvic floor

The pelvic floor is formed by the pelvic diaphragm and, in the anterior midline, the perineal membrane and the muscles in the deep perineal pouch

The pelvic diaphragm is formed by the levator ani and

muscles from both sides

The pelvic floor separates the pelvic cavity, above from the

which is below

Pelvic diaphragm- this is the

part of the pelvic floor. It is shaped like a bowl and attached superiorly to pelvic walls, it consists of the levator ani and coccygeus muscles

Most of the pelvic bone facing the pelvic cavity is covered by the

muscle and its fascia The lumbosacral plexus supplies the lower limbs

Pelvic diaphragm;

The muscle groups are collectively known as levator ani which is very important in determining

The three muscle groups that make up levator ani are:

Iliococcygeus, pubococcygeus and puborectalis

Nerve supply is pudendal and from

Thick fascial sheet called

membrane- occupies anterior part

The structure is weaker in women because of the

The keystone that has to be preserved during surgery is the

Ureters are muscular tubes that transport urine from kidneys to the bladder, they are continuous superiorly with

This is formed from a condensation of 2 or 3 major calices which are formed by condensation of minor calices

The renal pelvis

as it passes inferiorly through the hilum of the kidney and becomes continuous with the ureter at the uteropelvic junction

Inferior to this junction, the ureters descend retroperitoneally on the medial aspect of the

muscle

At the pelvic brim, the ureters cross either the end of the common iliac or the beginning of the external iliac arteries, enter the pelvic cavity and continue their journey to the bladder

Constriction of the ureters can occur at: 1.

junction

2. Where the ureters cross the common iliac vessels at the pelvic brim

3. Where the ureters enter the

As a result kidney stones can become lodged at these areas

In the pelvis, the ureter is crossed by: the

in men and the

in women

In females internal urethral sphincter

well organised, external urethral sphincter is skeletal muscle surrounding the urethra in the deep perineal pouch

There are two extra groups of muscles in females: sphincter uretherovaginalis and compressor urethrae

The bladder:

The apex of the bladder is directed towards the top of the

a structure known as the median umbilical ligament continues from it superiorly up the anterior abdominal wall to the umbilicus

The tetrahedral bladder has a structure at each corner

The bladder is the most

of the pelvic viscera. Despite being part of the pelvic cavity when empty, it expands superiorly when full into abdominal cavity. It is a tetrahedral when empty

Ureters enter at supero-posterior angles and leaves through inferior angle. Superior surface covered in peritoneum. Expands between transversals fascia and lining peritoneum

Look at notes

Intraperitoneal- Structures suspended from abdominal wall by

Retroperitoneal- Structures lying posterior to

e.g.

Retroperitoneal structures - (SAD PUCKER)

suprarenal glands,

Major branches of abdominal aorta:

Coeliac trunk- supplies the

Superior

artery- supplies the

Renal arteries- kidneys

mesenteric artery- supplies the

Foregut-

to the

at the entrance of the

Midgut- Major duodenal

to two thirds along

Hindgut- Distal third of

to

Veins are always

to arteries

Pancreas:

Embryology-

Pancreas develops as a ventral and dorsal bud in the ventral and dorsal

mesenteries respectively and therefore starts

Smaller ventral bud rotates

to become dorsal and associated with the dorsal pancreatic bud

Also superior mesenteric vein becomes trapped between the two and the buds fuse to become secondary peritoneal, except for the tail which lies in the

The original ventral bud is now called the

Furthermore the embryology of the pancreas also explains why there is an accessory pancreatic duct in addition to main one

Superior mesenteric vein and artery are

between the uncinate process and the neck of the

Renal vasculature:

Renal vessels arise at approximately

- the transpyloric plane

Left renal vein is longer than right renal vein and runs posterior to

but anterior to left renal artery. Aneurysms of SMA cause

syndrome

Duodenum:

Tail of pancreas and spleen are

structures

Duodenal arteries:

Superior/first part- duodenal cap, common place for

Passes

to bile duct, gastroduodenal artery, portal vein and IVC

Descending/second part- Contains minor and major duodenal

where accessory pancreatic duct and bile duct enter respectively

Inferior/third part- crosses IVC and has SMA anterior to it

Ascending/fourth part- terminates at

Major abdominal lymph nodes and pattern of drainage:

Collectively:

nodes

Lymphatic drainage follows

Inf mesenteric nodes --> Sup mesenteric nodes --> Coeliac nodes --> Cisterna chyli --> Thoracic duct

Unblock resection reduces rates of recurrence in malignancy

Divisions of para-aortic nodes can't be done accurately in vivo

Cisterna chyli is a dilated sac at inferior end of

which empties into junction of left subclavian and left internal jugular veins in the thorax

Rectus sheath:

3 levels: Above costal margin, between costal margin and

line and below arcuate line

Arises from costal cartilages

and the xiphoid process and descends lateral to the

to insert on the public crest and the front of the pubic

Divided into segments by

Rectul abdominis lies deep to the aponeurosis of the external oblique throughout its length. In the upper two thirds of the anterior abdominal wall it lies

to the traverses abdominis aponeurosis while the internal oblique aponeurosis splits to enclose it

Rectus abdominis therefore lies in a fibrous tunnel called the

The anterior wall of the sheath consists of the aponeurosis of the external oblique fused with the anterior leaf of the internal oblique aponeurosis. Similarly the posterior wall comprises the posterior leaf fused with the transverse abdominis aponeurosis

In the lower part of the sheath, all the aponeuroses pass

to the rectus so that this part is backless

The free lower posterior margin of the posterior layer of the rectus sheath is known as the

At the lateral margin of the rectus abdominis, the aponeuroses of the three flat muscles fuse to form the

before enclosing the rectus muscle and fusing again in the midline at the

Contents:

Arteries and veins lying

to the muscle. These are

vessels

There is an anastomosis between the superior epigastric artery and the inferior epigastric.

Nerve supply to the muscles is from

Intercostal nerves are from

and the main trunks of these lie between the internal oblique and

layers

The three sheet muscles from superficial to deep are:

External oblique-

Slips off ribs

and descends antero-inferiorly. Has an important free posterior border which runs from the enter superior iliac spine to the pubic tubercle forming the

Internal oblique-

Originates from

anterior 2/3 of the iliac crest to the lateral 1/3 of the inguinal ligament

Lowest fibres insert on the pubic crest and the pectineal line with the lower part of the internal oblique muscle as the

The arrangement is homologous with the three layers of muscles found in the intercostal spaces. All 3 originate from margins of the

turn into aponeuroses (sheet-like tendons) in the anterior abdominal wall and insert into a tough fibrous band called the

that extends in the mid-lone from the xiphoid process of the sternum to the pubic symphysis

The

pelvis is larger and round, the

pelvis has a wider pubic angle, the

ischial spines project medially

For males, the greater pelvis is

than females

In males, the distance between symphysis pubis to anterior margin of acetabulum is equal to the diameter of the acetabalaum

Parietal peritoneum continues into pelvis cavity but doesn't reach

Pelvic viscera

completely covered by peritoneum

Several folds and pouches are formed

Spaces between pelvic wall and peritoneum isn't occupied by viscera contain pelvic fascia. Pelvic fascial condensations form

supporting viscera like cervix, vagina and prostate

Contents of male pelvic cavity:

Ureter, bladder and urethra

Prostate, ductus deferens, seminal vesicles and bulbourethral glands

Rectum

Some of abdominal GI tract spills into greater pelvis- Caecum, appendix, parts of sigmoid colon and ileum

Vessel, nerves and lymphatics

Prostate glands surrounds 1st part of

Ductus deferent from testis passes through

canal, then over and behind ureter to enter urethra through the prostate

Seminal vesicles on back of bladder open into

between ampulla and ejaculatory duct

The male bladder sits on the

The ductus deferens, seminal vesicles and prostate empty into prostatic urethra to form

Ductus deferens runs

to the ureter

There are 2 seminal vesicles which secrete fluid. Prostate gland has many ducts

The internal urethral sphincter: Smooth muscle, well organised in males and it is closed during ejection by

stimulation

The tip of a urethral catheter can become lodged in the prostatic

There are small openings fir prostatic gland

The internal sphincter is

muscle and the external sphincter is

muscle. During ejaculation, the

sphincter is closed

External iliac artery goes to the

Internal iliac supplies pelvic organs. Anterior division supplies organs and posterior division supplies

muscles

Pudendal supplies perineum and

The perineum is a diamond-shaped area between pubic symphysis, ischial tuberosities and coccyx. It is divided into anterior and posterior

Posterior compartment: there is the ischio-anal fossa- fat-filled spaces separating anal canal and

from the pelvic walls

Anterior triangle divided into superficial and deep parts by perineal membrane

Perineal membrane fills the urogenital triangle. The erectile tissues and associated skeletal muscles are anchored to this

Superior rectal artery is a branch of IMA and joins with inferior rectal artery to form a portal-systemic anamastoses

The rectum receives one pair of arteries from

artery and two from

artery. The venous drainage is similar, there is an important portal-systemic venous anamastoses around the lower rectum and anal canal

Perineal membrane is a thick triangular fascial structure attached to pubic arch. Posteriorly free margin.

Deep perineal space: is

the PM and below fascia of the pelvic diaphragm

Superficial perineal space is below PM and perineal fascia

For male superficial perineum- the

nerve provides all sensory and motor innervation

Median erectile tissue mass- bulb of penis

In females it divides round the vestibule to form vestibular bulbs

Lateral erectile tissue masses attached to ischiopubic rami

Inguinal canal:

A canal formed by the layers of the abdominal wall muscle

Approximately

long, it runs from the deep ring to the

Transmits the spermatic cord in the male and round ligament of the uterus in females

Deep ring- An opening in the back wall of the inguinal canal through which the canals contents

Superficial ring-

shaped slit in the

that allows the contents of the canal to exit e.g. the scrotum

Summary of the borders of the inguinal canal:

Anterior- External oblique aponeurosis and internal oblique

Floor- Inguinal ligament

Roof- Internal oblique arching over

Posterior-

and conjoint tendon medially

General information on hernias:

Hernia- A protrusion of a

through a defect in its containing compartment such that it lies in an abnormal position

-sac returns to containing cavity

-sac can't be returned to containing cavity

Obstructed- sac contains blocked

Strangulated- sac's contents with strangulated blood supply

Children can be born with a defect in the groin

Indirect hernia-

This is the

type of hernia, tends to be in younger adults and children. Due to a lax deep ring or patent processes vaginalis

More common on the

hand side

The deep ring is too large and the

pushes through

Indirect hernia defect is always the deep/internal ring which is always

to the inferior epigastric vessels

Direct:

Groin hernias that occur in the

Acquired defect in the

wall of the inguinal canal

Associated with chronic straining

A direct hernia defect tends to go through

which is always medial to the inferior epigastric vessels

Most often occurs in male babies due to a patent

Processus is required for testicular descent and if it doesn't close properly, the baby can get a direct hernia.

Testes start out at the level of the

and migrate to the scrotum, they descend at the back of the abdomen. There is a finger of

and it acts as a guide for the testes which descend behind it

Factors associated with hernia:

Chronic cough, COPD, asthma, prostatic disease, constipation, muscular effort, previous hernia, obesity and ascites

Treatment is to stitch or clip in a mesh of

Femoral hernia protrudes through the femoral canal, very tight hole which is dangerous because it causes

to lose its blood supply

Below and lateral to pubic tubercle is femoral above and medial is inguinal

Borders of the femoral canal:

Superior- Inguinal ligament

Inferior-

Medial- Lacunar ligament

Lateral- Femoral vein

Femoral hernias can be distinguished from inguinal hernias because they appear below and lateral to the

Inguinal hernias are

to the pubic tubercle

The superficial fascia of the abdominal wall is a layer of fatty connective tissue. It is usually a

similar to and continuous with other superficial fascia throughout the body. However in the lower region of the anterior part of the abdominal wall, it forms

superficial fatty and deeper membranous

Superficial fatty layer-

Contains fat and varies in thickness, is also known as

In men, this layer continues over the penis and after losing its fat and fusing with the deeper layer of superficial fascia, continues into the scrotum where it forms a specialised fascial layer containing smooth muscle fibres-

IN women, this superficial layer retains some fat and is a component of the

Deeper layer:

Also known as

is thin and membranous and contains little or no fat. Inferiorly it continues into the thigh but just below the inguinal ligament, it rises with the

of the thigh

In the mid-line, it's firmly attached to the linea alba and the symphysis pubis. It continues into the anterior part of the

where it's firmly attached to the isciopubic rami and to the posterior margin of the perineal membrane. Here it is referred to as the

In men, the deeper membranous layer if the superficial fascia blends withe superficial layer as they pass over the penis, forming the

of the penis before they continue into the scrotum where they form the

Also in men, extensions of the deeper membranous layer of superficial fascia attached to the pubic symphysis pass inferiorly over the dorm and sides of the penis to form the

of penis

In women, the membranous layer of the superficial fascia continues into the

and the anterior part of the perineum

Female pelvic organs:

Ovary, uterine tubes, uterus, cervix, vagina, ureter, bladder, urethra, rectum, caecum, appendix, parts of sigmoid colon and ileum, vessels, nerves and lymphatics

Parietal peritoneum continues into pelvic cavity and

reach the pelvic floor

Uterine tubes are completely enveloped by peritoneum- the

ligament

Ovaries: Suspend by

from posterior of broad ligament (not fully enveloped)

Pelvic fascial condensations form

supporting viscera e.g. cervix and vagina

Important pouches in female pelvis which can be palpated

Ovaries are enveloped on

or else eggs can't get released

Broad ligaments are

joining the uterus to the pelvic walls

Their important contents are the

and uterine arteries

The ovary is suspended by the suspensory ligament of the ovary. Ovary looks like an acorn. The recto-uterine pouch is known as pouch of

and some uterine vessels can be palpated

Peritoneum covers

surface of the uterus

External os of uterus opens into

Fimbriae are finger like projections that guard the

of the uterine tube

One uterine tube opens into peritoneal cavity

Ligament of ovary is part of the

ligament

Arterial supply of female pelvis: Internal iliac artery:

Main branches to pelvic viscera are superior vesicle, uterine and

The walls of the pelvis are supplied by sacral, gluteal and obturator branches

The

artery supplies perineum and recto-anal region

The main blood supply to the uterus is the

It enlarges during pregnancy and runs medially towards cervix. It crosses the

about 1cm from the cervix

The uterine branch runs close to uterus in broad ligament

The ascending branch supplies uterine tubes and ovary, descending branch supplies the

The uterine artery runs

to the ureter

The ovaries lie close to the openings of the

into the peritoneal cavity. Ovaries and adjacent tubes receive an ovarian artery from the upper abdominal aorta

Females get

urinary infections because their

is shorter

Nerves of pelvis:

Pelvic contents are supplied by

nerves only

They receive sympathetic from lower thoracic and upper lumbar via hypogastric plexus

Parasympathetic is from

outflow

Pelvic sensation is visceral and poorly localised, pain is referred to suprapubic region and perineum

Lymphatic drainage of pelvis and perineum:

Pelvic organs drain mainly to external and internal

nodes

The ovary and testis drain to

nodes

Perineum (including anal canal) and external genitalia drain to superficial

nodes

3 sets of fibrous bands- cervical ligaments- anchor the cervix in position within the pelvis. These prevent the uterus from prolapsing through the vagina

The cervix can herniate through the vaginal wall after multiple

Ligaments stabilise uterus

The

ligament is the most important

Uterus and uterine tube:

Consists of fundus, body, lower segment and cervix

Uterine tubes consist of infundibulum, ampulla, isthmus and uterine parts

There is potential communication between

and exterior via the reproductive passage- abdominal osmium of uterine tube and vaginal opening

Fimbriae grab the egg and bring it into the uterus

Ectopic pregnancy is rare but is when the egg is fertilised in the

Cervix:

Fibro-muscular cylinder with internal and external

The cervical canal is lined by mucus secreting simple

Anatomical and functional lobes of liver:

Anatomical- dived into lobes by the

Functional- Divided into lobes dependent on

to portal triads, also defined by fossa for gall bladder and inferior vena cava

Liver-

Largest organ in the body and takes

of cardiac output

Divided into two main lobes- use a line that goes through falciform ligament- Right lobe of liver lies between ribs

Right lobe lies between ribs

Whereas left lobe is 6-7

Portal triad:

area of liver containing a

,hepatic artery and portal vein

Porta hepatis is area on under surface of liver at which the structures in the free edge of the lesser

enter/leave the liver

Bare area of the liver enlarges slightly out go the peritoneum directly in contact with the

The quadrate lobe is functionally part of the

The

lobe is functionally independent of both lobes

Basic diagram of biliary tree- see notes

Common bile duct runs in free edge of lesser momentum

Bile duct is 8cm long and wide

Ampulla of Vater opens into 2nd part of

on posteromedual wall, 10cm from

Also known as major duodenal papilla and marks the start of

The sphincter of Oddi controls pancreatic

Spleen:

Lies

and can't be felt unless it i incredibly enlarged, it is an incredibly vascular organ

Lies behind ribs

Tense organ therefore ruptures

Fibrotic liver disease- causes

which means that when portal and systemic are joined, nutrients and bacteria etc will move to systemic circulation without processing which is bad

3 main sites of porto-systemic anastomoses:

1.

- superficial veins on abdominal veins

2. Superior

3.

tributaries of azygos vein- clinically most important

Mesenteries associated with the liver and spleen

Mesentery-

of peritoneum that are

to each other

conduit for arteries, veins, nerves and lymphatic supplying viscera

Bag metaphor

Ligament- piece of

that attaches to viscera

Lesser omentum=

+ hepato-duodenal ligaments

1. Gastro-hepatic: Contains right and left gastric arteries

2. Hepato-duodenal ligament- Contains the portal triad-portal vein, hepatic artery and

Runs from 1st part of duodenum to

3. Falciform ligament- runs from liver to

4. Ligament teres- Free thickens edge of falciform ligament and contains remnant of umbilical vein which is obliterated

5. Gastro-splenic ligament- Contains short gastric vessels and left gastro-omental vessels

6. Spleno-renal ligament- Contains tail of

and splenic artery and vein

Vascular supply/drainage of liver, spleen and gallbladder:

Liver:

Blood supply- coeliac axis:

gastric

Splenic

Common hepatic

triangle- cholecystectomy- needs to be careful when you clip off artery that you don't clip common bile duct

Borders are:

cystic duct, common and right hepatic ducts and inferior edge of liver

Splenic artery reaches spleen by travelling in

Portal vein is formed from superior mesenteric vein and splenic vein posterior to neck of pancreas at

It filters bacteria from GI tract, metabolises everything

Transport of amino acids straight to brain causes

/encephalopathy due to

Left gastric vein drains

of stomach. Blood drains from liver directly into

via 3 short hepatic veins

Normally elements of GI tract and its derivatives completely fill the abdominal cavity, making the peritoneal cavity a potential space and visceral peritoneum on organs and

peritoneum in adjacent abdominal wall slide freely against each other.

Peritoneum is

-like single layer of cells together with a supportive layer of connective tissue. Peritoneum is similar to the pleura and serous pericardium in the

The peritoneum reflects off the abdominal wall to become a component of the

that suspend the viscera

Components of GI tract are suspended in peritoneal reflections called

Parietal peritoneum

Visceral peritoneum

covers suspended organs

GI tract is suspended from the

aspect

Peritoneal folds attach viscera to abdominal wall

Filled with peritoneal fluid secreted by

Epithelial layer secretes fluid and circulates into lymphatic vessels especially at

surface of the diaphragm

Intraperitoneal- structures e.g. most of

suspended from the abdominal wall by mesenteries

Retroperitoneal- structures e.g.

that lie between parietal peritoneum and posterior abdominal wall

Foregut- Distal 3rd of oesophagus to 2nd part of

at entrance of bile duct

Midgut- 2nd part of duodenum to two thirds along

Hindgut- Distal 3rd of transverse colon to

rectum

Gut originates from endoderm and

mesoderm

It's suspended from the posterior abdominal wall by a peritoneal fold-

Blood supply, lymphatics and nerve supply all run through the mesentery

Entire gut tube is suspended from a dorsal mesentery, in addition the foregut has a

mesentery

The foregut has a ventral mesentery containing the liver which splits into the

and the

Formation of the Omental Bursa: (lesser sac)

Secondary fusion of the duodenum to the body wall, massive growth of the liver in the ventral mesentery and fusion of the surface of the liver to the

restrict the opening of the space enclosed by the ballooned dorsal mesentery associated with the stomach. The restricted opening is the

The part of the abdominal cavity enclosed by the expanded dorsal mesentery and posterior to the stomach is the

Access through the omental foramen to this space from the rest of the peritoneal cavity is inferior to the free edge of the

Part of the dorsal mesentery that initially forms part of the lesser sac greatly enlarges in an inferior direction and two opposing surfaces of the mesentery fuse to form an apron like structure-

This is suspended from the greater

of the stomach lines every other viscera in the abdominal cavity and this is the first structure observed when the abdominal cavity is opened anteriorly

THE TWO GREATERS GO TOGETHER

As the liver grows it moves to the

while the dorsal mesentery and spleen move to the

The original right side of the peritoneal cavity is now posterior

Lower part of dorsal foregut mesentery extends down as a double fold called the

to the intestine

The lesser momentum is part of the

Functions of greater omentum:

i. fat deposition ii. immune contribution and iii.

Boundaries of lesser sac and epiploic foramen:

The portal vein, hepatic arter and bile duct run between the

and

within the lesser momentum near its free edge. This free edge is present because the ventral mesentery ends at the start of the

The greater and lesser sac of the peritoneal cavity communicate through a narrow opening called the

This lies just below liver posterior to the free edge of the lesser omentum

The lesser omentum is the double layer of

that extends from the liver to the

of the stomach and start of duodenum

Lesser sac (omental bursa) is the cavity in the abdomen that is formed by lesser and greater momentum. Usually found in mammals it is connected with the greater sac via the

Sympathetic nervous system- arises from T1-L2 spinal cord segments

Parasympathetic nervous system- arises from

nerves III, VII IX and X (oculomotor, facial, glossopharyngeal and vagis) and spinal cord segments s2-S4

Efferent: Motor to smooth muscle, secretomotor to glands

Afferent: Sympathetic pain and parasympathetic: specific functional sensation

Vagus travels along

in the abdominal region. Ganglia are named according to the

supplying the GI tract

Parasympathetic- Vagus nerve and

outflow are the main supplies of the viscera

Peripheral vessels and skin- Nerves run with somatic nerves to same region

Autonomic plexuses and ganglia:

The autonomic nerves to the abdomen are routed via

surrounding the aorta and its branches. Sympathetic nerves synapse at

associated with these plexuses

Plexuses and ganglia are named according to the associated

Plexus- interconnecting network of nerves

The brain cannot localise pain sensation from structures for which there is no map in the

These structures are visceral organs and the

In these cases pain is referred to the regions of skin supplied by nerves with the same segmental supply-

IN the abdomen, the nerve supply to the organ is

Dermatome- Area of skin supplied by a single spinal

Adjacent dermatomes overlap so that on the trunk, at least 3 spinal nerves would have to be blocked to produce a region of complete anaesthesia.

There is no

dermatome

When inflammation of the appendix spreads to surrounding peritoneum the pain becomes localised and constant at the right inguinal region. Movement of hip joint and coughing elicits pain

Foregut structures:

Epigastric pain- pain from foregut structures is referred to this region. Structures involved: Stomach, proximal duodenum, pancreas, liver, gall bladder T7/T*

Hindgut structures- suprapubic pain: pain from descending colon to anal canal is referred here