The Abdominal Cavity
Anatomical and Physiological
Relationships
Clinical Practicum 1
Lecture One
Holdorf
The ability of the sonographer to
understand anatomy as it relates to
the cross-sectional, coronal, oblique,
and sagittal projections is critical in
performing a quality sonogram.
The sonographer must have a
thorough understanding of anatomy
as it relates to the anteroposterior
relationships, as well as the
variations in sectional anatomy
 Gross
anatomy studies the body by
dissection of tissues.
 Histology
studies parts of the tissues
under the microscope.
 Embryology
before birth.

studies the development
Pathology is the study of the disease
process.
 Within
the human body, the basic
unit of structure and function is a
microscopic part called a cell.
 All
cells have tiny parts called
organelles that carry on specific
activities.
 These
organelles are composed of
aggregates of large molecules
(proteins, carbohydrates, lipids, and
nucleic acids).
 Cells
are organized into layers or
masses that have common functions,
known as a tissue.
 Groups
of different tissues form
organs (complex structures with
specialized functions).
A
group of organs is arranged into
organ systems.
 Organ
systems make up an
organism.



A coordinated group of organs are
arranged into organ or body systems.
For example the digestive system consists
of the mouth, esophagus, stomach,
intestines, liver, gallbladder, and pancreas.
Body systems make up the total part or
organism; that is, the human body itself.
Metabolism
 All
of the physical and chemical
changes that occur within the body
are referred to as metabolism.
 The
metabolic process is essential to
digestion, growth, and repair of the
body, and conversion of food energy
into forms useful to the body.
Homeostasis
 Homeostasis
is the ability to
maintain a steady and stable internal
environment.
 Stressful
stimuli, stressors, disrupt
homeostasis.
Vital signs
Vital signs are medical
measurements used to ascertain how
the body is functioning.
These vital signs include measuring
body temperature and blood
pressure and observing rates and
types of pulse and breathing
movements.
Anatomic Directions
The anatomic position implies that
the body is standing erect, the eyes
are looking forward, and the arms
are at the sides with the palms and
toes directed forward.
Superior/inferior
 The
top of the head is the most
superior point of the body.
 The
inferior point of the body is the
bottom of the feet. All anatomic
structures are designated relative to
these two terms.
 The
liver is considered to be superior
to the bladder because the liver is
closer to the head.
 The
gallbladder is inferior to the
diaphragm because it is closer to the
feet.
 Others
terms that are interchanged
with superior are
cephalic and
cranial (toward the head).
 Caudal
(toward the tail) is
sometimes used instead of inferior
Anterior/posterior
The front (belly) surface of the body
is anterior, or ventral.
The back surface of the body is
posterior, or dorsal.
This concept is very important to the
sonographer and their understanding
of sectional anatomy.
Medial/lateral
 The
body axis is an imaginary line
from the center of the top of the
head to the groin.
 Medial
is described as the superior–
inferior body axis as it goes right
through the midline of the body..
 Structures
are said to be medial if
they are closer to the midline of the
body than to another structure (i.e.,
the hepatic artery is medial to the
common duct).
 The
structure is lateral if it is toward
the side of the body.
 The
adnexa are lateral to the uterus
Proximal/distal
 When
a structure is closer to the
body midline or point of attachment
to the trunk, it is described as
proximal .
 Distal
means father from the midline
or point of attachment to the trunk
Superficial/deep
 Structures
located toward the
surface of the body are superficial
 Structures
located farther inward
(away from the body surface) are
deep.
Planes or Body Sections
The body is observed by the
sonographer in several different
planes: transverse, sagittal, and
coronal.
Transverse:
The transverse plane is horizontal to
the body. This plane divides the body
or any of its parts into upper and
lower portions
Sagittal:
The sagittal plane is a lengthwise
plane running from front to back. It
divides the body or any of its parts
into right and left sides, or two equal
halves. This is also known as the
midsagittal plane.
Coronal:
The coronal plane is a lengthwise
plane running from side to side,
dividing the body into anterior and
posterior portions.
Abdominal Quadrants and
Regions
In order to identify specific
abdominal structures or refer to an
area of pain, the abdomen may be
divided into four quadrants or
abdominal regions.
The quadrant is determined by a
midsagittal and a transverse plane that
pass through the umbilicus.
The abdominopelvic cavity is divided into
four quadrants:




the right upper quadrant (RUQ),
left upper quadrant (LUQ),
right lower quadrant (RLQ), and
left lower quadrant (LLQ).
 The
abdomen is commonly divided
into nine regions by two vertical and
two horizontal lines.
 The
surface landmarks of the
anterior abdominal wall help to
define the specific abdominal
regions.
 Each
vertical line passes through the
midinguinal point; that is, the point
that lies on the inguinal ligament
halfway between the pubic
symphysis and anterior superior iliac
spine.



The upper horizontal line, referred to as
the subcostal plane, joins the lowest
point of the costal margin on each side of
the body.
The lowest horizontal line, the
intertubercular plane, joins the
tubercles on the iliac crests.
The transpyloric plane is a horizontal
plane that passes through the pylorus,
duodenal junction, neck of the pancreas,
and hilum of the kidneys.
The nine abdominal regions include the
following:
1. upper abdomen\right hypochondrium.
2. epigastrium.
3. left hypochondrium.
4. middle abdomen/right lumbar.
5. umbilical.
6. left lumbar.
7. lower abdomen/right iliac fossa.
8. hypogastrium.
9. left iliac fossa.
Body Cavities
 Within
the human body there are
many body cavities.
 These
body cavities contain the
internal organs, or viscera.
 The
two principal body cavities are
the dorsal cavity and the ventral
cavity.
 The
bony dorsal cavity may be
subdivided into the cranial cavity,
which holds the brain, and the
vertebral or spinal canal, which
contains the spinal cord
 The
ventral cavity is located near
the anterior body surface and is
subdivided into the thoracic cavity
and the abdominal cavity.
 The
thoracic and abdominopelvic
cavities are separated by a broad
muscle, the diaphragm, which
forms the floor of the thoracic cavity
 Divisions
of the thoracic cavity are
the pleural sacs, each containing a
lung, with the mediastinum
between them.
 Within
the mediastinum lies the
heart, thymus gland, part of the
esophagus, and trachea.
 The
heart is surrounded by another
cavity called the pericardial sac.
The Abdominal Cavity
The abdominal cavity (excluding the
retroperitoneum and the pelvis) is
bounded superiorly by the
diaphragm; anteriorly by the
abdominal wall muscles; posteriorly
by the vertebral column, ribs, and
iliac fossa; and inferiorly by the
pelvis.
Abdominal Viscera
The abdominal visceral organs: liver,
gallbladder, spleen, pancreas,
kidneys, great vessels, stomach, and
most of the small and large
intestines.
Other Abdominal Structures
Diaphragm
 The diaphragm is a dome-shaped muscle
that separates the thorax from the
abdominal cavity.
 The right crus arises from the sides of
the bodies of the first three lumbar
vertebrae
 The left crus arises from the sides of the
bodies of the first two lumbar vertebrae.
Abdominal Wall
 The
abdominal wall is superiorly
formed by the diaphragm.
 It
is inferiorly continuous with the
pelvic cavity through the pelvic inlet.
 Anteriorly
the wall is formed above
by the lower part of the thoracic cage
and below by several layers of
muscles:
the rectus abdominis
external oblique
internal oblique
transversus abdominis.



The linea alba is a fibrous band that
stretches from the xiphoid to the
symphysis pubis.
Posteriorly the abdominal wall is formed in
the midline by five lumbar vertebrae and
their disks.
Laterally it is formed by the twelfth ribs,
upper part of the bony pelvis, psoas
muscles, quadratus lumborum muscles,
and the aponeuroses of origin of the
transversus abdominis muscles.
Superficial Inguinal Ring
 The superficial inguinal ring is a
triangular opening in the external
oblique aponeurosis and lies superior
and medial to the pubic tubercle.
 The
spermatic cord or the round
ligament of the uterus passes
through this opening.
Inguinal Ligament
 The inguinal ligament is formed
between the anterior superior iliac
spine and the pubic tubercle, where
the lower border of the aponeurosis
is folded backward on itself.
 The
lateral part of the posterior edge
of the inguinal ligament gives origin
to part of the internal oblique and
transverse abdominal muscles.
The Pelvic Cavity
Pelvis major (false pelvis): Part of
the abdominal cavity proper; lies
between the iliac fossae, superior to
the pelvic brim.
Pelvis minor (true pelvis):
Contains the pelvic cavity; inferior to
the brim of the pelvis.
Perineum
The true pelvis is subdivided by the
pelvic diaphragm into the main pelvic
cavity and the perineum.
Abdominopelvic Membranes and
Ligaments
Peritoneum
The Peritoneum is the serous membrane
lining the walls of the abdominal cavity; it
covers the abdominal viscera.
It is formed by a single layer of cells
called the mesothelium, which rests on a
thin layer of connective tissue.
The peritoneum is divided into two
layers: parietal peritoneum is the
portion that lines the abdominal wall
but does not cover a viscus; the
visceral peritoneum is the portion
that covers an organ.
The peritoneal cavity is the potential
space between the parietal and
visceral peritoneum.
Accumulation of fluid is known as
ascites.
The peritoneal cavity forms a
completely closed sac in the male; in
the female there is a communication
with the retroperitoneal cavity
through the uterine tubes, uterus,
and vagina.
Retroperitoneal organs and vascular
structures remain posterior to the
cavity and are covered anteriorly
with peritoneum: urinary system,
aorta, inferior vena cava, colon,
pancreas, uterus, and bladder.
Mesentery
 The mesentery is a two-layered fold
of peritoneum that attaches part of
the intestines to the posterior
abdominal wall and includes the
mesentery of the small intestine, the
transverse mesocolon, and the
sigmoid mesocolon.
Omentum
Two-layered fold of peritoneum that
attaches the stomach to another viscus
organ.

Greater omentum: This is attached to
the greater curvature of the stomach and
hangs down like an apron in the space
between the small intestine and anterior
abdominal wall. The greater omentum is
folded back on itself and is attached to the
inferior border of the transverse colon.
 Lesser
omentum: This slings the
lesser curvature of the stomach to
the undersurface of the liver. The
gastrosplenic omentum ligament
connects the stomach to the spleen
Ligament
 Peritoneal ligaments are two-layered folds
of peritoneum that attach the less mobile
solid viscera to the abdominal walls.


The liver is attached by the falciform
ligament to the anterior abdominal wall
and to the undersurface of the diaphragm
The ligamentum teres lies in the free
borders of this ligament
Potential Spaces in the Body
Subphrenic Spaces
 The right and left anterior subphrenic
spaces lie between the diaphragm and the
liver, one on each side of the falciform
ligament.

The right posterior subphrenic space lies
between the right lobe of the liver, the
right kidney, and the right colic flexure,
called Morison’s pouch
Paracolic Gutters
The arrangement of the ascending
and descending colon, the
attachments of the transverse
mesocolon, and the mesentery of the
small intestine to the posterior
abdominal wall result in the
formation of four paracolic gutters.
 The
clinical significance of these
gutters is their ability to conduct fluid
materials (abscess, ascites, blood,
pus, bile, or metastases) from one
part of the body to another.
 The
gutters are on the lateral and
medial sides of the ascending and
descending colon.
 The
right medial paracolic gutter is
closed off from the pelvic cavity
inferiorly by the mesentery of the
small intestine.
 The
right lateral paracolic gutter
communicates with the right
posterior subphrenic space.
 The
left lateral gutter is separated
from the area around the spleen by
the phrenicocolic ligament.
Inguinal Canal
 The inguinal canal is an oblique passage
through the lower part of the anterior
abdominal wall.


In the male, it allows structures to pass to
and from the testes to the abdomen.
In the female, it permits the passage of
the round ligament of the uterus from the
uterus to the labium majus.
Retroperitoneal Spaces
The anterior pararenal space:
Located between the anterior surface
of the renal fascia (Gerota’s fascia)
and the posterior area of the
peritoneum (contents: ascending and
descending colon, pancreas, and
duodenum).
The posterior pararenal space:
Found between the posterior renal
fascia and the muscles of the
posterior abdominal wall (contents:
fat and vessels).
 The
perirenal space: Located
directly around the kidney and is
completely enclosed by renal fascia
(contents: kidneys, adrenal glands,
lymph nodes, blood vessels, and
perirenal fat).