ABDOMINAL CAVITY

the first lecture

Abdominal cavity

Body walls

Rectus sheath

Inguinal canal

Sites of hernias

Arteries and veins of abdominal walls

Planes and regions

Abdominal cavityThe major part of theabdominopelvic cavity

Between the thoracicdiaphragm and thesuperior pelvic aperture(pelvic inlet)

The space which issurrounded by multilayered abdominalwalls

The location of the most digestive organs, thespleen, kidneys and ureters (partially)

Abdominal cavity

Extends superiorly

into the

osteocartilaginous

thoracic cage to the

4th intercostal space

and inferiorly to the

pelvic cavity (pelvic

inlet)

The posterior wall

includes lumbar

vertebrae and

intervertebral discs

Abdominal cavity

The spleen and the liver

are protected by

the thoracic cage

Part of ileum,

cecum and sigmoid

colon are protected

and supported by

the greater pelvis

Abdominal cavity

Part of kidneys

are protected by

the thoracic cage

Subdivision of the abdominal wall

Anterolateral wall:

-anterior wall

-right and left lateral

walls

During physical

examination is inspected,

palpated, percussed and

auscultated

Posterior wall

Abdominal anterolateral wall

Skin

Superficial fascia:

Camper’s (fatty) layer

Scarpa’s (membranous) layer

Muscles

Deep fascia

Transversalis fascia

Endoabdominal

(extraperitoneal) fat

Parietal peritoneum

Muscles of the anterolateral abdominal wall

Flat muscles:

External oblique

Internal oblique

Transverse abdominal

Vertical muscles:

Rectus abdominis

Pyramidalis

External oblique muscle

The largest and the most

superficial of the three

flat muscles

Muscle fibers run

inferomedially and

become aponeurotic,

form a rectus sheath

Extends from external

surfaces of 5th-12th ribs

to linea alba, pubic

tubercle and iliac crest

External oblique muscle

Rotates the trunk to the

opposite side and bends

the trunk to the same

side (unilateral action)

Flexes the trunk and

compresses and

supports abdominal

viscera (bilateral action)

External oblique muscle

Innervation:

thoracoabdominal

nerves (ventral rami

of inferior 5 thoracic

nerves)

subcostal nerve

Internal oblique muscle

Intermediate of the three flat

muscles

Aponeurotic fibers form a

rectus sheath

The superior 2/3 of

aponeurosis splits into two

laminae

Extends from thoracolumbar

fascia, iliac crest and inguinal

ligament to inferior borders of

10th-12th ribs, linea alba and

pecten pubis

Internal oblique muscle

Bends and rotates the trunk to

the same side (unilateral

action)

Flexes the trunk and

compresses and supports

abdominal viscera (bilateral

action)

Internal oblique muscle

Innervation:

thoracoabdominal

nerves (ventral rami of inferior six thoracic nerves)

iliohypogastric and ilioinguinal nerves: terminal branches of the anterior ramus of first spinal lumbar nerve

Transverse abdominal muscle

The innermost muscle

Fibers run more or less

transversomedially and

form the rectus sheath

Extends from internal

surfaces of 7th-12th

costal cartilagines,

thoracolumbar fascia,

iliac crest, inguinal

ligament to linea alba

pubic crest and pecten

pubis

Transverse abdominal muscle

Compresses and supports

abdominal viscera (bilateral

action)

Transverse abdominal muscle

Innervation:

thoracoabdominal nerves (ventral rami of inferior six thoracic)

iliohypogastric and ilioinguinal nerves: terminal branches of the anterior ramus of first spinal lumbar nerve

Rectus abdominis muscle

Principal vertical muscle

Paired rectus muscles-separated

by the linea alba

Enclosed in the rectus sheath

(most of the rectus)

Anchored transversely by

tendinous intersections

Extends from pubic symphysis,

pubic crest to xiphoid process

and 5th-7th costal cartilages

Flexes trunk and compresses

abdominal viscera

Rectus abdominis muscle

Innervation:

thoracoabdominal

nerves (ventral rami of

inferior six thoracic)

Pyramidalis muscle

Absent in approximately 20%

of people

Located in the rectus sheath

anterior to the most inferior

part of the rectus abdominis

muscle

Extends from the pubic crest

of the hip bone to the linea

alba

Draws down on the linea alba

(tenses the linea alba)

The attachment is a

landmark for an accurate

median abdominal incision

Dermatomes

Function and action of the anterolateral abdominal muscles

Form a strong expandable support for the anterolateral abdominal wall

Protect the abdominal viscera frominjury

Compress the abdominal contents

Help to maintain or increase the intra-abdominal pressure oppose thediaphragm (produce expiration and produce the force required for defecation, vomiting, micturition and parturition-maternal pushing duringchildbirth)

Move the trunk and help to maintainposture

Rectus sheath

Strong, incomplete fibrous

compartment of the rectus

abdominis and pyramidalis

muscles

Formed by the aponeuroses

of the flat muscles

Has anterior and posterior

layers

The arcuate line demarcates

the transition between the

aponeurotic posterior wall of

the sheath and the

transversalis fascia

Rectus sheath above arcuate line

Anterior layer:

-aponeurosis of external oblique muscle

-anterior lamina of the

internal oblique

aponeurosis

Posterior layer:

-posterior lamina of the internal oblique aponeurosis

-aponeurosis of transverse abdominal muscle

Rectus sheath below arcuate line

Anterior layer:

-aponeurosis of external

oblique muscle

-aponeurosis of internal

oblique muscle

-aponeurosis of transverse

abdominal muscle

Posterior layer: ABSENT!!!

Rectus abdominis muscle

lies on transversalis fascia

Linea alba

Fibrous band

Runs vertically the

entire lenght of the

anterior abdominal wall

from the xiphoid

process to the pubic

symphysis

Narrow inferior to the

umbilicus and wide

superior to it

Contains umbilical ring

(the fetal umbilical

vessels pass to and

from the umbilical cord

and placenta)

Linea alba

Formed by the fibers

of the anterior and

posterior layers of the

sheath

peritoneal fold and peritoneal recess

Peritoneal fold- a reflection

of peritoneum that is raised

from the body wall by

underlying blood vessels,

ducts and obliterated fetal

vessels

Peritoneal recess (fossa)-

a pouch of peritoneum that

is formed by a peritoneal

fold

Internal surface of the anterolateral wall:

Internal surface of the anterolateral wall- peritoneal folds

Umbilical peritoneal

folds:

-the median umbilical fold

(covers the median

umbilical ligament- the

remnant of urachus, in

fetus runs within the

umbilical cord)

-two medial umbilical

folds (cover the medial

umbilical ligaments- the

remnants of the

occluded fetal umbilical

arteries)

-two lateral umbilical

folds

(cover the inferior

epigastric vessels)

Internal surface of the anterolateral wall – peritoneal

recessesPeritoneal fossae (depressionslateral to the umbilical folds):

-supravesical fossae

-medial inguinal fossae (calledinguinal triangles)

-lateral inguinal fossae

(include the deep inguinal

rings)

The fossae are potential sites for hernias

The falciform ligament:

a sagittally oriented peritonealreflection in the supraumbilicalpart of the internal surface

Inferior epigastric artery

Inguinal canalOblique, inferomedially

directed passage through

the inferior part of the

anterolateral abdominal

wall

Approximately 4 cm long

Has an opening at each

end:

- the deep (internal)

inguinal ring

- the superficial (external)

inguinal ring

The deep (internal) inguinal ring

The site of an outpouching of the transversalis fascia

The beginning of an evagination in the transversalis fascia

Forming an opening through which spermatic cord or round ligament of the uterus pass to enter the inguinal canal

The transversalis fascia continues into the canal and forms the innermost covering (internal fascia) of the structures traversing the canal

The superficial (external) inguinal ring

An opening between the diagonal fibers of the aponeurosis of the external oblique

Exit from inguinal canal

The margins:

-lateral crus

-medial crus

-intercrural fibers (superior

crus)- form the arch

-reflected inguinal ligament

(posterior and inferior

crus)

The inguinal canalHas two walls and roof and floor

formed by:

aponeurosis of the external

oblique (anterior wall)

transversalis fascia (posterior

wall)

fibers of the internal oblique and

transverse abdominal muscles

(roof)

superior surface of the inguinal

ligament (floor)

The inguinal ligament (Poupart)

Fibrous band

Extends between the anterior

superior iliac spine and the

pubic tubercle

Forms the floor of the inguinal

canal

Some fibers form the

reflected inguinal ligament

(pass upward to cross the

linea alba and blend with the

lower fibers of the

contralateral aponeurosis)

The main contents of the inguinal canal

in the female and the male

The femoral canalThe smallest of the threefemoral sheath compartments

Short, approximately 1.25 cm

The base of its (abdominalend) is directed superiorly and although oval shaped is calledthe femoral ring

Extends distally to the level of the proximal edge of thesaphenous opening

Allows the femoral vein to expand

Contains loose connectivetissue, fat, lymphatic vesselsand a deep inguinal lymphnode

Abdominal herniasHernia= „rupture”

The result from increasedintra-abdominal pressure inthe presence of weakness

The protrusion of parietalperitoneum through an anatomical opening or a secondary defect

Hernial opening- the orifice ordefect

The hernial sac- the pouch, generally lined by parietalperitoneum

Hernial contents- usuallyconsist of greater omentumor loops of small bowel

Indirect inguinal hernias

Pass through the deep inguinal

ring (it is lateral to the inferior

epigastric artery) with the sac

following the course of the

spermatic cord

Strikes the pad of the finger

Direct inguinal hernias

Bulge directly through the

abdominal wall, medial to

the inferior epigastric artery

Strikes the distal tip of the

finger during palpation from

the scrotum

The „three finger rule”

Usefull to appreciate

the topographic

anatomy of inguinal or

femoral hernias and

differentiate among

direct and indirect

inguinal hernias and

femoral hernias

The examiner places

thenar eminence on the

anterior superior iliac

spine- fingers point to

hernias

Posterior abdominal wall

Five lumbar vertebrae and IV discs

Posterior abdominal wall muscles

Lumbar plexus

Fascia, including thoracolumbar fascia

Diaphragm

Fat, nerves, vessels and lymph nodes

Thoracolumbar fascia

The lumbar part is

extending between

the 12th rib and the

iliac crest

Attaches laterally to

the internal oblique

and transverse

abdominal muscles

Main muscles of the posterior abdominal wall

Psoas major

Iliacus

Quadratus lumborum

Quadratus lumborum muscle

Extends from the medialhalf of the inferior border of 12th rib and tips of lumbartransverse processes

to the iliolumbar ligament

and internal lip of iliac crest

Extends and laterally flexesvertebral column, fixes 12th rib during inspiration

Quadratus lumborum muscle

The subcostal nerve

runs inferolaterally on it

Branches of the lumbar

plexus run inferiorly on

the anterior surface

Ventral branches of

T12 and L1-L4 nerves

supply it

Arteries of the anterolateral abdominal wall

Superior epigastrics from the

internal thoracic arteries

Inferior epigastrics and deep

circumflex iliacs from external

iliac arteries

Superficial circumflex iliacs

and superficial epigastrics

from the femoral artery

Branches of the posterior

intercostal arteries

Branches of the

musculophrenic arteries

(from internal thoracic

arteries)

Inferior epigastric artery

Regions and quadrants of the abdomen

Useful for describing

the location of

abdominal organs

or pain

Regions and planes of abdomen

Four quadrants are

defined by two planes:

Horizontal

(transumbilical)

passing through the

umbilicus and the IV disc

between L3 and L4

vertebrae

Vertical (median)

passing longitudinally

through the body

Regions and planes of the abdomen

Nine regions are

defined by four planes:

Subcostal

passing through the inferior

border of the 10th costal

cartilage on each side

Transtubercular

passing through the iliac

tubercules and the body of

L5 vertebra

Two midclavicular

passing from midpoint of the

clavicles to the midinguinal points

Abdominal regions

Right hypochondriac

Epigastric

Left hypochondriac

Right lateral

Umbilical

Left lateral

Right inguinal

Hypogastric (pubic)

Left inguinal

Transpyloric plane:

- midway between the jugular notch of the sternum and the superior borderof the pubic symphysis

- at the level of the L1 vertebra

- the pylorus is generally locatedslightly below this plane

Semilunar line

Tip of 9th

costal cartilage

to the pubic

tubercle

The digestive tract

Extends from the lips to

the anus.

Consists of oral cavity,

pharynx, esophagus,

stomach, small

intestine and large

intestine.

Associated organs:

liver and pancreas

(major glands of the

digestive tract)

The viscera of the abdomen in situ

The viscera of the abdomen in situ

Projection of anatomical structures onto vertebral column

T7 superior border of the liver

T12 aortic hiatus

L1 transpyloric plane

gallblader (fundus)

renal hilum of left kidney

superior part of duodenum

pancreas (neck)

origin of celiac trunk and SMA

transverse mesocolon (attachment)

L1/L2 origin of the renal arteries

L2 duodenojejunal flexure

renal hilum of right kidney

L3 origin of the inferior mesenteric artery

L3/L4 umbilicus

L4 aortic bifurcation

L5 origin of the inferior vena cava from the

common iliac veins

S3 upper (cranial) border of the rectum

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