OUTLINE
INTRODUCTION
BOUNDARIES OF THE ANTEROLATERAL
ABDOMINAL WALL
REGIONS AND PLANES OF THE
ANTEROLATERAL ABDOMINAL WALL
ANATOMICAL LANDMARKS ON THE
ANTEROLATERAL ABDOMINAL WALL
LAYERS OF THE ANTEROLATERAL ABDOMINAL
WALL
FASCIAS OF THE ANTEROLATERAL ABDOMINAL
WALL
MUSCLES OF THE ANTEROLATERAL ABDOMINAL
WALL
RECTUS SHEATH
BLOOD SUPPLY TO THE ANTEROLATERAL
ABDOMINAL WALL
NERVE SUPPLY TO THE ANTEROLATERAL
ABDOMINAL WALL
DERMATOMES OF THE ANTEROLATERAL
ABDOMINAL WALL
LYMPHATIC SUPPLY OF THE ANTEROLATERAL
ABDOMINAL WALL
FUNCTIONS OF ANTEROLATERAL ABDOMINAL
WALL
CLINICAL ANATOMY OF THE ANTEROLATERAL
ABDOMINAL WALL
INTRODUCTION
The wall of the human abdomen is said to be
continuous from anterior to lateral (both right and left) and finally to the
posterior aspect but the absence of a definite boundary between the anterior
and lateral walls of the human abdominal wall makes for the term ANTEROLATERAL
ABDOMINAL WALL especially with the aim of making description easier. The
anterolateral abdominal wall is a musculo-aponeurotic wall i.e it is largely
made up of muscles and their aponeurosis (whitish sheet of fibrous tissue)
BOUNDARIES OF THE ANTEROLATERAL
ABDOMINAL WALL
SUPERIORLY:
the anterolateral abdominal wall is suspended from (Bounded by) the cartilages
of 7th-10th ribs and the Xiphoid process of the sternum
INFERIORLY:
it attaches to the superior free margins of the anterolateral aspects of the
pelvic girdle and the right and left Inguinal ligament; starting from the
right; right Iliac crest; right Inguinal ligament; right public crest; pubis
symphysis (central); left public crest; left Inguinal ligament; and finally the
left public crest
LATERALLY:
it is continuous with the posterior abdominal wall
REGIONS AND PLANES OF THE
ANTEROLATERAL ABDOMINAL WALL
The
anterolateral abdominal wall has been divided into 9 abdominal region and 4
abdominal quadrant mainly for the clinical purposes such as description of
pain; swelling; incision. This regions and quadrants helps the physician to be
able to isolate pain; swelling or any other pathology to the corresponding
tissue or organ in that region or quadrant making clinical diagnosis and more
so treatment more definitive and faster
What
are the nine (9) divisions of the anterolateral abdominal wall?
The
anterolateral abdominal wall is divided into 9 regions by 2 vertical plane and
2 horizontal planes (a plane is a straight line).
The
2 vertical planes are namely;
1. The
Right and (2). the left
Midclavicular planes: which are the clavicular lines; these planes starts
from the midpoint of the clavicle approximately 9cm for the midline on both
sides and cuts through the midinguinal points (the midpoint of an imaginary
line that extends from the Anterior Superior Iliac Spine (ASIS) to the Pubic
tubercle on each side; is completely different from midpoint of Inguinal
ligament; the midpoint of another imaginary line that extends from the ASIS to
the Pubic symphysis; so be careful not to confuse them). The two horizontal
planes are the Transpyloric and intertubercular planes.
3. Transpyloric
plane; is an imaginary tranverse line that cuts through the abdomen midway
between the Jugular notch of the Manubrium of the sternum and Pubic symphysis;
at the level of L1 vertebrae transecting the Pylorus (the distal part of the
stomach) when lying down (supine or prone) as against gravity when standing up;
it also transect other abdominal structures like; the fundus of the gall
bladder; neck of Pancreas; origins of Superior Mesenteric Artery; hepatic
portal vein; root of transverse mesocolon; duodenojejunal junction and the hila
of the kidneys. Some physicians use the Subcostal plane as their transverse
plane which is a little lower and cuts through the inferior margins of the 10th
costal cartilage on both sides.
4. Intertubercular
or Transtubercular plane: as the name suggests is also an imaginary
tranverse line that cuts across the right and left tubercle of the Iliac crest
5cm posterior to the ASIS and the body of L5 vertebra. The Transtubercular
plane is midway between the umbilicus and the superior margin of Pubis
Symphisis. Worthy of mentioning is the Interspinous plane the lowest transverse
plane that transect both palpable point of the ASIS.
The
9 regions of the anterolateral abdominal wall are as follows;
(Starting
from right to central to left)
1. Right hypochondrium
2. Epigastric region (central)
3. Left hypochondrium
4. Right lumbar/flank
5. Umbilical region (central)
6. Left lumbar/flank
7. Right Iliac fossa/Inguinal region
8. Hypogastric or suprapubic region
9. Left Iliac fossa/Inguinal
What
are the four (4) quadrants of the anterolateral abdominal wall?
The
anterolateral abdominal wall is divided into 4 quadrants by one vertical plane
and one horizontal plane that intersects at the umbilicus. The vertical plane
is called the Vertical Median plane and the horizontal plane is called
Transumbilical plane
1. Vertical Median plane: is a vertical
imaginary line that separates the two halves of the body but in this context of
the abdomen; it extends from the Xiphoid process cutting through the Linea
alba; the umbilicus to the Pubis Symphisis
2. Transtubercular plane: is a
horizontal imaginary line that transects the umbilicus and the Inter-vertebra
disc between L3 and L4. It divides the body into upper half and lower half
Names
of the four (4) quadrants and their contents
Starting
from right to left;
1.
Right
upper quadrant (RUQ):
§ Liver
(right lobe)
§ Gall bladder
§ Duodenum:
(1-3; superior; descending and inferior parts)
§ Pancreas:
head
§ Right
suprarenal gland
§ Right
kidney
§ Right
colic (hepatic) flexure
§ Ascending
colon: superior part
§ Transverse
colon: right half
2.
Left
upper quadrant (LUQ):
§ Liver;
left lobe
§ Spleen
§ Stomach
§ Jejunum
and proximal Ileum
§ Pancreas;
body and tail
§ Left
kidney
§ Left
suprarenal gland
§ Left
colic (splenic) flexure
§ Transverse
colon; left half
§ Descending
colon: superior part
3.
Right
lower quadrant (RLQ):
§ Cecum
§ Appendix
§ Majority
of Ileum
§ Ascending
colon; inferior part
§ Right
ovary
§ Right
uterine tube
§ Right
ureter: abdominal part
§ Right
spermatic cord; abdominal part
§ Uterus
(If enlarged)
§ Urinary bladder; If fully distended
4.
Left
lower quadrant (LLQ):
§ Sigmoid
colon
§ Descending
colon; inferior part
§ Left
ovary
§ Left
uterine tube
§ Left
ureter; abdominal part
§ Left
spermatic cord; abdominal part
§ Uterus
(If enlarged)
§ Urinary
bladder; If fully distended
LAYERS OF THE ANTEROLATERAL ABDOMINAL
WALL
1.
Skin
2.
Superficial
fascia (of subcutaneous tissue) is a thin single layer above umbilicus and all
over the rest of the boy but divides
below it (umbilicus) into;
§ Superficial fatty layer of
subcutaneous tissue (Campers fascia)
§ Deep membranous layer of subcutaneous
tissue (Scarpa's fascia)
3.
Superficial
investing fascia
4.
External Oblique muscle and it's aponeurosis
5.
Intermediate
Investing fascia
6.
Internal Oblique muscle and it's aponeurosis
7.
Deep
investing fascia
8.
Transversus
abdominis muscle and it's aponeurosis
9.
Extraperitoneal
fat
10.
Peritoneum (Parietal)
FASCIAS OF THE ANTEROLATERAL ABDOMINAL
WALL
1.
Camper’s
fascia: is the outer of layer of the subcutaneous
fascia division below the unmbilicus anterior to Scarpa’s fascia and lies
immediately below the skin. This fascia is generally thicker than Scarpa’s and
its mainly made up of fat. It is continuous as the superficial fascia of the
thigh
2.
Scarpa’s
fascia: is the membraneous inner layer of the
subcutaneous fascia division below the umbilicus posterior to the Camper’s
fascia and anterior to the superficial investing fascia. It is thinner than
Camper’s fascia and it continues inferiorly as dartos fascia (a superficial
fascia that lies) over the spermatic cord, scrorum and penis; and medially it
attaches to the linea alba and pubic symphysis and blends with the fascia lata
just below the inguinal ligament in the upper thigh region; and finally
posteriorly it continues with as the Colles fascia of the peritoneum
3.
Superficial
investing fascia: is a layer of dense connective tissue that
bounds the anterior aspect of external oblique muscle and lies below the
Scarpa’s fascia
4.
Intermediate
investing fascia: is a layer of dense connective tissue that
bounds the anterior aspect of internal oblique muscle and lies below the
external oblique muscle
5. Deep investing fascia:
is a layer of dense connective tissue that bounds the anterior aspect of tranversus
abdominis muscle and lies below the internal oblique muscle
MUSCLES
OF THE ANTEROLATETRAL ABDOMINAL WALL
There
are two
groups of muslcles present in the anterolateral abdominal wall namel;
1.
Flat
group of muscles:
§ External oblique muscle
§ Internal oblique muscle
§ Transversus abdominis muscle
2.
Vertical
group of muscles:
§ Rectus abdominis muscle
§ Pyramidalis muscle
1.
Flat
group of muscles:
§ External oblique:
v Origin:
external surface of 5-12 ribs
v Insertion:
linea alba; pubic tubercle & anterior half of iliac crest
v Orientation/direction:
fibers run inferomedially
v Nerve supply:
thoracolumbar (T7-T11) and subcostal (T12)
v Blood supply:
superior and inferior epigastric vessels
v Function:
compresses and supports the abdominal visceras; flexes and rotates the trunk
§ Internal oblique:
v
Origin:
thoracolumbar fascia; anterior 2/3rd of iliac crest & lateral half
of inguinal ligament
v
Insertion:
inferior borders of ribs 10-12, linea alba & pubis via conjoint tendon
v
Orientation:
fibers run superomedially but sweeps down medially parallel to the transversus
abdominis aponeurosis in the inguinal region form which they unite to form cojoint
tendon just posterior to the superficial inguinal ring
v
Nerve
supply: thoracolumbar (T7-T11); subcostal (T12)
& iliohypogastric nerve (L1)
v
Blood
supply: superior and inferior epigastric vessels;
deep circumflex iliac vessels
v
Function:
compresses and supports the abdominal visceras; flexes and rotates the trunk
§ Transversus abdominis:
v Origin:
internal surfaces of costal cartilages 7-12, thoracplumbar fascia; iliac crest
& lateral 3rd of inguinal ligament
v Insertion:
linea alba with aponeurosis of internal oblique muscle;pubic crest & pectin
pubis via cojoint tendon
v Orientation:
fibres run transversely but sweeps down
medially parallel to the internal oblique aponeurosis in the inguinal
region from which they unite to form the cojoint tendon just posterior the
superficial inguinal ring
v Nerve supply:
thoracolumbar (T7-T11); subcostal (T12) &iliohypogastric nerve (L1)
v Blood supply:
deep circumflex iliac & inferior epigastric vessels
v Function:
compresses and support abdominal viscera
2.
Vertical
group of muscles
§ Rectus abdominis:
v
Origin:
symphysis and pubic crest
v
Insertion:
xiphoid process and costal cartilages 6-7
v
Orientation:
fibres run superiorly (from distal to
proximal)
v
Nerve
supply: thoracolumbar (T7-T11) and subcostal (T12)
v
Blood
supply: superior and inferior epigastric vessels
v
Function:
flexes the trunk; compresses abdominal viscera & stabilises and control
tilting of the pelvis (antilordosis)
§ Pyramidalis:
v
Origin:
body of pubis and anterior aspect of rectus abdominis
v
Insertion:
linea alba
v
Shape:
triangular
v
Orientation:
apex is attached to linea alba while the base originatesfrom pubis bone
v
Nerve
supply: iliohypogastric nerve (L1)
v
Blood
supply: inferior epigastric artery
v
Function:
tenses the linea alba
RECTUS
SHEATH
OUTLINE
DEFINITION
STRUTURE
BORDERS
CONTENT
ARCUATE LINE OR LINEA SEMICIRCULARIS (OF
DOUGLAS)
LINEA ALBA
LINEA SEMILUNARIS OR SPIGELIAN LINE
TENDINOUS INTERSECTIONS OR INSCRIPTIONS
BLOOD SUPPLY
NERVE SUPPLY
LYMPHATIC DRAINAGE
DEFINITION
The rectus sheath also called rectus fascia is
a fibrous aponeurotic compartment of rectus abdominis and pyramidalis muscle
(vertical muscles of anterolateral abdominal wall) with associated blood
vessels, nerves and lymphatics enclosed by interwoven decussations (or fusion)
of the aponeurosis of external oblique; internal oblique and transversus
abdominis muscle (the flat muscles of the anterolateral abdominal wall)
STRUCTURE
The aponeurosis of the Rectus sheath is divided
above the arcuate line into two walls or layers namely;
1. Anterior
aponeurotic wall or layer
2. Posterior
aponeurotic wall or layer
1.
Anterior
aponeurotic wall or layer: above the arcuate line (of douglas)
it consists (made) up of fusion of parallel fibrous sheet of external
aponeurosis and the anterior lamina of internal oblique aponeurosis; below the
arcuate line it unites with the posterior aponeurotic wall or layer (posterior
lamina of internal oblique aponeurosis and transversus abdominis aponeurosis).
2.
Posterior
aponeurotic wall or layer: it is suspended from the margins of
7-9th costal cartilage and terminates at the arcuate line (of
douglas); at this point it unites anteriorly with the anterior aponeurotic wall
or layer to form a single cover above the rectus abdominis muscle. It is formed
by fusion of posterior lamina of internal oblique aponeurosis and transversus
abdominis aponeurosis which forms the posterior border of the rectus abdominis
muscle above the arcuate line (of douglas)
NB:
§ “detailed
studies indicates that aponeurosis of external oblique, internal oblique and
transversus abdominis are each bilaminar giving 6 layers in all; 3 forms the
anterior wall an 3 forms the posterior aponeurotic wall”-Last’s anatomy regional and applied 12th
edition by Chummy S. Sinnatamby
§ “Above
the 7-9th costal margin the anterior aponeuorotic wall or layer of
the sheath consists only of external oblique aponeourosis” -Last’s anatomy regional and applied 12th
edition by Chummy S. Sinnatamby
BORDERS
1.
Superiorly:
7-9th costal cartilages
2.
Inferiorly:
pubis symphysis and pubis crest
3.
Laterally:
curved semilunar or spigelian line on both sides
CONTENTS
1.
MUSCLE
§ Rectus
abdominis
§ Pyramidalis
2.
BLOOD
VESSELS
§ Superior
epigastric arteries and veins
§ Inferior
epigastric arteries and veins
3.
NERVES
§ Anterior
branch of thoracoabdominal nerve (T7-T11)- terminal
§ Anterior
branch of subcostal nerve (T12)- terminal
4.
LYMPHATIC
VESSELS
ARCUATE
LINE OR LINEA SEMICIRCULARIS (OF DOUGLAS)
It is an imaginary horizontal (transverse)
crescent shaped line that cuts across one third (1/3rd) the distance
inferior between the umbilicus (from) and (to) the pubic crest. It marks the
point the point at which the posterior lamina of internal oblique aponeurosis
and aponeurosis of the transversus abdominis (posterior aponeurotic wall)
unites with the anterior aponeurotic wall 3/4
(three quarter) the distance from the origin of the rectus sheath. It
also dermacates the point of transition where the anterior covering of the
superior 3/4 (three quarter) changes from the anterior aponeurotic wall
(anterior lamina of internal oblique aponeurosis) to posterior aponeurotic wall
and where the inferior epigastric vessels perforates the rectus abdominis and
bifurcates resulting in lateral and medial row of perforating vessels
NB: a well defined arcuate line might be
absent or present however there is an increasing reduction of aponeurotic
fibres into a single layer (anterior aponeurotic layer) result in increasing
thickening of transveraslis fascia that runs deep and parallel to the inguinal
ligament and combines with iliac fascia (fascia iliaca) to form the iliopubic
tract an important structure that plays a role in hernioraphy (surgical repair
or hernia)
LINEA
ALBA
It is a vertical white midline structure that
consist of fusion of interlaced fibres of the anterior aponeurotic and
posterior aponeurotic wall. It extends from the xiphoid process of the sternum
to the pubic symphysis. It separates the pairs of the rectus abdominis muscle into
two halves. It forms a visible and palpable groove in skinny individuals and
the width narrows down inferiorly to fit the width of the xiphoid process. The
linea alba has a defect in its middle at the level of transumbilical plane
known as the umbilical ring. It is through this defect that blood vessels
communicate (pass) to and from the umbilical cord and placenta. Around 7-14
days when the atrophic umbilical cord falls off fat begins to accumulate within
the subcutaneous tissue and the surrounding skin overlying this regions becomes
raised around the umbilical ring and the umbilicus becomes gradually depressed
flat or inverted depending on the extent of fat accumulation but in situations
of distended or big or bulgy or everted umbilicus in infants that might still
remain in adulthood is as a result of herniation or protrusion of the
intestine, fats or fluid through the defect in the linea alba (the umbilical
ring which is usually common in many kids at birth). The linea alba also
transmits small blood vessels (arteries and vein) and nerves to the overlying skin.
Clinically umbilical and paraumbilical hernia occur here.
LINEA
SEMILUNARIS OR SPIGELIAN LINE
Semilunar line is a bilateral vertical curved
line structure that forms the lateral border of the rectus sheath (where the
aponeurosis began to fuse) and the medial border of the oblique muscles.
TENDINOUS
INTERSECTIONS OR INSCRIPTIONS
They are pairs of fibrous bands on both halves
of the anterolateral abdominal wall that separates the rectus abdominis muscle
transversely. Depending on anatomical variation this intersections or
inscriptions if you like can range from 2-3 or more dividing the rectus
abdominis muscle on both sides of the linea alba into segments circular
regarded as 6 or 8 packs abs or more as the case maybe.
BLOOD
SUPPLY
1. Superior
epigastric vessels (arteries and veins)
2. Inferior
epigastric vessels (arteries and veins)
NERVE
SUPPLY
1. Anterior
branch of thoracolumbar nerve T7-T11 (terminal aspect)
2. Anterior
branch of subcostal vessels T12 (terminal aspect)
NERVE SUPPLY TO
THE ANTEROLATERAL ABDOMINAL WALL
Brief anatomy of spinal nerve:
In order to have a proper understanding of the nerve supply to the anterolateral
abdominal wall I thought it will be nice to take you through a
brief anatomy of the spinal nerves as the anterolateral abdominal wall is
supplied by the lower six anterior rami of the spinal nerves
(T7-T12 & L1). 31 pairs of spinal nerves exists in the human body; 8
Cervical; 12 Thoraic; 5 Lumbar; 5 Sacral and 1 Coccygeal. Each spinal nerve is
formed by union of the anterior (ventral) and posterior (dorsal) root which
are attached by their corresponding rootlets (anterior and posterior) to
the anterior and posterior horns of grey matter respectively.
This union is formed within the intervertebrae foramen from
which each pair of spinal nerve emerge bilaterally (on both sides of the
vertebra) distal to the swelling of the spinal (posterior) root
ganglion. Each emerging spinal nerve on each side then divides further into
the anterior and posterior ramus. It is worthy of noting that
the anterior root (not rami) carries motor
(efferent) nerve supply to skeletal muscle and some small numbers
of unmyelinated afferent (sensory) pain fibres whose cell
bodies ironically originates from the spinal (posterior) root ganglion but
it enters the spinal cord via the anterior root instead
of the posterior root; so it “doubled back” ( a
quick reminder that the afferent/sensory impulses moves from peripheral
tissues; skin; muscles; organs etc. towards the central nervous system [the
brain and spinal cord] and vice-versa [opposite direction] for afferent/motor
neuron ) while the posterior root carries afferent fibres
whose cell bodies are in the posterior root ganglion. These fibers
are unipolar neurons which have a single nerve process and
bifurcate to supply the central nervous system and peripheral receptors;
they do not have synapse like the autonomic ganglia.
NERVE
SUPPLY PROPER
The anterior
rami of the lower six Thoracic spinal nerves (T7-T12
& L1) supplies the anterolateral abdominal wall
1. Thoracoabominal nerve (T7-T11); is
divided into
Anterior
cutaneous branch
Lateral
cutaneous branch (T7-T10 or T11)
Anterior
cutaneous branch (T7-T11); pierces the retus sheath to
supply the subcutaneous tissue adjacent to the middline
Lateral
cutaneous (T7-T10 or T11); is shorter than the anterior branch and
hence supplies the skin of right and left hypochondriac region
NB: the thoracoabdominal
nerve generally supplies the muscles of the anterolateral
abdominal wall and its overlying skin
2. First lumbar spinal nerve (L1); which
has 3 terminal branches
Iliohypogastric
nerve
Ilioinguinal
nerve
Genitofemoral
nerve (only exception)
Only
the first two of these terminal branches supplies the lower
aspects of the anterolateral abdominal wall
Iliohypogastric
nerve (L1); supplies the skin overlies the iliac crest, upper
inguinal and hypogastric region; and the muscles of the internal oblique and
transversus abdominis
Ilioinguinal
nerve (L1); supplies the skin that ovelies the lower inguinal
region; mons pubis; anterior scrotum or labium majus, adjacent medial thigh and
finally inferior aspect of internal oblique and tranversus abdominis muscle
NB: note
that by the general principle of the anatomic neurovascular
planes the spinal nerves are accompanied by their
corresponding segmental vessels (arteries and veins) and they almost
all run beneath the arteries except at the anterior aspect adjacent to
the median plane and posteriorly around the vertebra column where the nerves
crosses over the arteries. The thoracoabdominal branches (T7-T12) runs
beneath the corresponding intercostal nerves and subcostal nerve while
the terminal branches of the first lumbar vertebra (L1) the
iliohypogastric nerve the only exception to this principle on the anterolateral
abdominal wall runs immediately above the deep circumference iliac
artey and ilioguinal nerves runs beneath the deep circumflex iliac artery
DERMATOMAL
MAPS OF THE ANTEROLATERAL ABDOMINAL WALL
What are
dermatomes?
Dermatomes
are area of the skin supplied by the spinal nerves as
in contrast to myotome which are areas of the muscle supplied by
spinal nerve
The
dermatomal map of the anteolateral abdominal wall (T7-T12 and L1) would have
been completely identical to the map of peripheral nerve distribution only that
it’s anterior rami as opposed to other regions of the human body does not
participate in the formation of great plexuses like; the Cervical plexus;
Brachial plexus; Lumbar plexus and Sacral plexus
T7-
supplies the skin around the subcostal angle
T8-
supplies the skin around the costal rib cartilage
T9-
supplies the skin just immediately above the umbilicus
T10-
supplies the skin around the umbilicus
T11-
supplies the skin of just immediately below the umbilicus
T12-
supplies the skin of the lower abdomen & the upper buttocks
L1-
supplies the skin of the Supra pubic region; penis; anterior scrotum
or Labia and upper buttocks
Why
you cannot trust the dermatomal map on the anterolateral abdominal wall?
Note
that adjacent T6 and T8 dermatomes overlap and cover up (i.e. this mix makes
up) T7 which infers that possible loss of afferent nerve function of one spinal
nerve would not generally cause complete loss of sensation but a decreased
sensation might be experienced at this dermatome. Hence this explains why a
anaesthesia of a single division of the intercostal nerve does not generally
give rise to anaesthesia of the trunk>>>
BLOOD SUPPLY TO
THE ANTEROLATERAL ABDOMINAL WALL
Venous drainage:
primarily there are two sets of venous drainage of the anterolateral abdominal
wall namely;
1.
The
Superficial cutaneous vein or Subcutaneous venous plexus and
2.
The
deep veins (of anterolateral abdominal wall)
1.
The
Superficial vein or subcutaneous venous plexus
drains in the;
§ Superomedial
direction: drains from the superior epigastric vein into the internal
thoracic vein (superficial epigastric vein>>>internal thoracic
vein>>> brachiocephalic vein>>>superior vena cava>>>right
atrium{heart}; on the respective sides right or left)
§ Inferiorly:
drains from the inferior epigastric and
superficial epigastric veins into the tributaries of external iliac and
femoral vein respectively (superficial epigastric and inferior
epigastric veins >>>respectively into femoral and external iliac
veins>>>common iliac vein>>>inferior vena
cava>>>right atrium{heart})
§ Laterally:
drains
from the lateral thoracic vein into the axillary veins (lateral
thoracic vein>>>axilliary vein>>>subclavian vein>>>
brachiocephalic vein>>>superior vena cava>>>right
atrium{heart}; on the respective sides right or left)
§ Umbilicus:
drains
from the paraumbilical vein into the hepatic portal vein which is
parallel to round ligament of the liver an obliterated umbilical vein (paraumbilical veins>>>hepatic
portal vein>>> inferior vena cava>>>right atrium{heart})
Anastomosis of
the superficial cutaneous veins or subcutaneous venous plexus on anterolateral
abdominal wall: it’s
worthy of noting that other superficial cutaneous veins anastomose with the
paraumbilical veins at the umbilicus; this flow is considered to cause focal or
diffuse hepatic steatosis (fatty liver) when there is obstruction to systemic
venous flow. A lateral anastomostic
channel the thoraco-epigastric may also exist between superficial epigastric
vein and lateral vein in healthy people or when the venous flow is also altered
in the obstruction of the inferior vena cava. In similar fashion during portal
hypertention the paraumblical veins also communicates with the
thoraco-epigastric veins thus forming one of the 5 areas of porto-systemic venous anastomosis (a
collateral circulation between the hepatic portal vein and the systemic veins
{mainly by the tributaries of superior
and inferior vena cava that finally empties into the right atrium} when there
is an hepatic blockage or hypertension) in the paraumbilical region forming the
characteristic group of distended called caput medusae.
NB:
the superficial veins are also called the subcutaneous veins
2. Deep veins
(of the anterolateral abdominal wall): accompanies their corresponding arteries
and bear the
same name
Deep venous anastomosis:
may exist between the superior epigastric/internal thoracic veins and inferior
epigastric vein in other words this anastomosis is between the tributaries of
the subclavian and external iliac veins respectively; hence provides a
collateral (alternate) pathway of venous drainage during obstruction of the
vena cava; superior or inferior
Arterial
supply: there are 9 primary arterial vessels that
supplies the anterolateral abdominal wall along with their corresponding deep
venous drainage and they bear the same name as follows;
1. Superior
epigastric vessels
2. Muscilophrenic
vessels
3. Inferior
egigastric vessels
4. 10th
posterior intercostals vessels
5. 11th
posterior intercostals vessels
6. Anterior
branch of Subostal vessels
7. Superficial
epigastric vessels
8. Deep
circumflex iliac vessels
9. Superficial
circumflex iliac vessels
1.
Superior
epigastric artery: one of
the branches (the other Musculophrenic artery) and continuum of Internal thoracic artery (Superior epigastric artery<<<internal
thoracic artery<<<subclavian artery<<<brachiocehpalic artery
on the right side unlike the left subclavian artery that taps it’s source
directly from<<<arch of aorta<<<ascending aorta<<<left
ventricle{heart})
Orientation: inferomedially
(adjacent on both sides of the midline)
Supplies: restus abdominis muscle; superficial and deep
aspects of the epigastric region of the anterolateral abdominal wall and upper
umbilical region; it also anastomosis inferiorly at the umbilical region with
inferior epigastric artery; all on both sides
2.
Muscilophrenic
vessels: the other
branch of internal thoracic artery (Superior epigastric artery<<<internalthoracic
artery<<<subclavian artery<<<brachiocehpalic artery on the
right side unlike the left subclavian artery that taps it’s source directly
from<<<arch of aorta<<<ascending aorta<<<left
ventricle{heart})
Orientation:
inferolaterally (on both sides)
Supplies:
the superficial and deep region of the hypochondriac abdominal wall and
anterolateral aspect of the diagpragm; all on both sides
3. Inferior epigastric artery:
a branch
of external iliac artery ( inferior epigastric artery<<<external
iliac artery<<<common iliac artery<<<abdominal
aorta<<<thoracic aorta<<<descending aorta<<<arch of
aorta<<<ascending aorta<<<left ventricle{heart})
Orientation:
superomedially (on both sides)
Supplies:
rectus abdominis muscle and abdominal walls of the pubic and inguinal region
4.
10th
posterior intercostal artery: a branch of the thoracic aorta ( 10th
posterior intercostals artery<<<thoracic aorta<<<descending
aorta<<<arch of aorta<<<ascending aorta<<<left
ventricle{heart})
Orientation:
lateral and inferiorly (on both sides)
Supplies:
superficial and deep lateral abdominal walls of the lumbar region
5.
11th
posterior intercostal artery: same as the 10th
posterior interostal artery
6.
Anterior
branch of Subcostal artey: same as the 10th
posterior interostal artery
7.
Superficial
epigastric artery: a branch of femoral artery ( femoral
artery<<< external iliac artery<<<common iliac
artery<<<abdominal aorta<<<thoracic
aorta<<<descending aorta<<<arch of aorta<<<ascending
aorta<<<left ventricle{heart})
Orientation:
superomedially (on both sides)
Supplies:
superficial aspects of the pubic and lower portion of the umbilical region
8.
Deep
circumflex iliac artery: a branch
of external iliac artery ( Deep circumflex iliac artery<<<external
iliac artery<<<common iliac artery<<<abdominal
aorta<<<thoracic aorta<<<descending aorta<<<arch of
aorta<<<ascending aorta<<<left ventricle{heart})
Orientation:
superolaterally parallel to the inguinal ligament (on both sides)
Supplies:
iliac muscle and deep abdominal wall of iliac fossa and inguinal region
NB:
the superior branch of this artery pose a risk to gridiron incision (during
appecdectomy)
9.
Superficial
circumflex iliac artery: a
branch of femoral artery (
femoral artery<<< external iliac artery<<<common iliac
artery<<<abdominal aorta<<<thoracic
aorta<<<descending aorta<<<arch of aorta<<<ascending
aorta<<<left ventricle{heart})
Orientation:
superolaterally (on both sides)
Supplies:
superficial aspects of the abdominal wall of the inguinal region and adjacent
anterior thigh
LYMPHATIC
SUPPLY TO THE ANTEROLATERAL ABDOMINAL WALL
There are two groups of lymphatic
drainage of the anterolateral abdominal wall namely:
1. Superficial
lymphatic vessel
2. Deep
lymphatic vessel
1.
Superficial
lymphatic vessel: accompanies their corresponding subcutaneous
veins; superficial lypmphaticvessel superior to the transumbilical plane drains
majorly into the Axillary group of lymph nodes and a few drains into the Parasternal
lymph nodes while below the transumbilical plane they drain into the Inguinal
lymph nodes
2. Deep lymphatic vessel:
accompanies their corresponding deep veins in the anterolateral abdominal wall and
drains into the external iliac; common iliac; right and left lumbar (cava &
aortic) lymph nodes
FUNCTIONS AND ACTIONS OF ANTEROLATERAL
ABDOMINAL WALL AND IT’S MUSCLES
1. Protect
abdominal viscera from physical insult
2. Maintain
posture
3. Move
the trunk
4. Helps
to increase intrabdominal pressure which fascilitates expiration when the
diaphragm is relaxed by compressing and squeezing the abdominal visceral the
upward and can at the same time fascilitates sneezing and expulsion of fecal
matter through the anus (defecation) and
or product of conception during parturition(child birth)
5. It
also provides flexibility and also
relaxes or distend to accommodate the downward squeezing of the
abdominal visceral when the diaphragm contracts during inspiration; moreso the
anterolateral abdominal walls and its muscles distended appropriately to create
room for the growing fetus or rising uterus into the abdominal cavity
6. It
supports abdominal viscera; intestine only
CLINICAL
CORRELATES OF THE ANTEROLATERAL ABDOMINAL WALL TO BE DISCUSSED IN THE NEXT
ARTICLE (POST)
REFERENCES
§ Moore
clinically oriented anatomy 7th edition by Keith L. Moore; Arthur F.
Dalley & Anne M.R. Argur
§ Last’s
anatomy regional and applied 12th edition by Chummy S. Sinnatamby
§ Atlas
of human anatomy 7th edition by Frank H. Netter, MD
§ Wikipedia
§ radiopaedia.org
§ ncbi.nlm.nih.gov
§ some
other internet sources that I can’t remember (pardon me)
