ANATOMY OF ABDOMEN

8/7/2019 ANATOMY OF ABDOMEN

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B. ARUN, MPT,CMPT,COHS.

ORTHOPEDIC PHYSIOTHERAPIST 1

ANATOMY OF ABDOMEN


PROFESSOR IN PHYSIOTHERAPY

The abdomen is the lower part of the trunk and lies below

the diaphragm.

It is divided by the plane of the pelvis inlet into a larger

upper part, the abdomen proper and a smaller lower part,

the true pelvis.

The abdomen is bounded to a large extent by muscles,

which can easily adjust themselves to periodic changes in

the capacity of abdominal cavity.

INTRODUCTION

The abdominal wall is made up of the

following six layers

1. Skin

2. Superficial fascia

3. Muscles

4. A continuous layer of fascia

5. Extra peritoneal connective tissue

6. Peritoneum.

MUSCLES OF THE ANTERIOR

ABDOMINAL WALL

The anterior abdominal wall is made up mainly of

muscles.

On either side of the midline there are four large

muscles.

These are

1. External oblique,

2. Internal oblique

3. Transverse abdmonins

4. Rectus abdominis

Introduction

Muscles of the Abdominal Wall


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Apart from it two small muscles also present

1) Cremaster

2) Pyramidalis

The Ext.oblique, Int.oblique, TA are large flat muscles

placed in the antero-lateral part of abdominal wall.

Ends in an extensive aponeuroses that reaches the

midline.

The aponeuroses of the right and left sides decussate to

form a median band called the linea alba.

The rectus abdominis runs vertically on either side of the

linea alba.

It is enclosed in a sheath formed by the

aponeuroses of flat muscles named above.

The various muscles are considered one by one

below.

Origin:

the muscle arises by eight fleshy slips from the lower eight ribs,

The fibres run downwards, forward and medially.

Insertion:

Most of the fibres of the muscles end in a broad aponeuroses

through which they are inserted into the Xiphoid process, the linea

alba, the pubic symphysis, the pubic crest and the pectineal line of

the pubis.

The lower fibres of the muscle are inserted directly into the

anterior two third of the outer lip of the illiac crest.

Nerve supply:

Lower six thoracic nerves

Origin:

Lateral two third of the inguinal ligament

The anterior two third of the intermediate area of illiac crest

The thoracolumbar fascia.

Insertion:

The upper most fibres inserted directly into lower three or

four ribs and cartilages.

Greater part of the muscles ends in an aponeurosis through

which it is inserted into 7th,8th, &9th costal cartilage, Xiphoid,

linea alba, pubic crest and pectineal line of pubis.

Nerve supply:

Lower six thoracic nerves & first lumbars


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Origin:

Lateral two third of the inguinal ligament

The anterior two third of the inner lip of illiac crest

The thoracolumbar fascia.

Inner surfaces of the lower six costal cartilages.

Insertion:

The fibres end in a broad aponeurosis which is inserted into

the xiphiodprocess, linea alba, pubic crest, and pectineal line

of the pubis.

Internal oblique to form co-joined tendon.

Nerve supply:

Lower six thoracic nerves & first lumbars

Origin:

Lateral head from the lateral part of the pubic crest

Medial head from the anterior pubic ligament

The fibres run vertically upward

Insertion:

On the front of the wall of throax, along a horizontal

line passing laterally from xiphoid process and

cutting the 7th ,6th &5th Coastal cartilage.

Nerve supply:

Lower six or seven thoracic nerves

Support for abdominal viscera.

Expulsive acts.

Forceful expiratory acts.

Movement of trunk.

Actions of the main muscles of the

anterior abdominal wall MUSCLES OF THE POSTERIOR

ABDOMINAL WALL


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These are

1. Psoas major

2. Illiacus

3. Quadratus lumborum

Introduction This is a fusiform muscle placed on the side of

the lumbar spine, & along the brim of the

pelvis. The psoas and the illiacus are together

known as iliopsoas, due to their common

insertion and action.

Psoas major

Origin:

From ant. Surfaces and lower border of transverse

process of all lumbar vertebra.

By 5 slips one from the bodies of two adjacent

vertebra & IV disk from T12 to L5.

From 4 tendinous arches extending across the

constricted parts of the bodies of lumbar vertebrae,

the origin is continuous from T12 to L5.

The muscle passes behind the inguinal ligament

and in front of the hip joint to entre the thigh.

It ends on a tendon which receives the fibres of

the iliacus on its lateral side.

It is inserted into the tip and medial part of the

anterior surface of the lesser trochanter of the

femur.

Insertion

Branches from L2, L3 & L4

Nerve supply With the iliacus, it acts as a powerful hip flexor

Maintaining stability at hip

Balances trunk when sitting

Lateral flexion of trunk ( act on one side)

Lateral rotator of hip

Action


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This is a small muscle which lies in front of the

psoas major

It is frequently absent.

Psoas minorOrigin:

Sides of the bodies of vertebrae

T12 & L1 and disc between them

The muscle ends in a long, flat tendon which is

inserted into the pecten pubis and the iliopubic

eminence.

Insertion

Branches from L1

Nerve supply

Weak flexors of trunk

Action Triangular Muscle

ILIACUS


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Origin:

Upper two third of illac fossa

Inner lip of the iliac crest and the ventral

sacroliac and iliolumbar ligaments

Upper surface of the lateral part of the sacrum

Lateral part of anterior surface of lesser

trochanter

The insertion extends for 2.5 cms below

trochanter.

Insertion

Branches from femoral nerve

Nerve supply

With Psoas it flexes the hip joint

Action

This is a Quadrate muscle lying in the lumbar

region.

Its origin lies below and insertion above.

QUADRATUS LUMBORUM

Origin:

Transverse process of vertebrae L5

Iliolumbar ligament

Adjoining 2 inches of the inner lip of the iliac

crest


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Medially it is attached to the tips of the lumbar

transverse process and the intertransverse ligament

Laterally it blends with the anterior layer at the

lateral border of the quadratus lumborum

Superiorly it is attached to the lower border of the

12th rib and to the lumbocostal ligament

Inferiorly it is attached to the posterior part of the

intermediate area of the iliac crest.

MIDDLE LAYER Medially it is attached to the vertical ridges on the

anterior surface of the lumbar transverse processes

Laterally it blends with the middle layer at the

lateral border of the Quadratus lumborum

Superiorly it forms the lateral arcurate ligament

extending from the tip of the first lumbar

transverse process to the 12th rib.

Inferiorly it is attached to the inner lip of the iliac

crest and the iliolumbar ligament.

Anterior layer

This is an Aponeurotic sheath covering the

rectus abdominis muscle.

It has two walls, Anterior & Posterior

Rectus sheath

It is complete covering the muscle from end to

end.

Its composition is variable

It firmly adherent to the tendinous

intersection of the rectus muscle.

Anterior Wall

Incomplete, being deficinet above the coastal

margin and below the arcuate line

Its composition is uniform

It is free from Rectus muscle.

Posterior WallAbove the Costal margin.

Anterior wall: External oblique aponeurosis

Posterior wall: It is deficient, the rectus rest directly

on coastal cartilage.

Below the Costal margin & Arcuate line.

Ant: External oblique aponeurosis, Ant. Lamina of

aponeurosis of Internal oblique

Post: Post. Lamina of the aponeurosis of internal

oblique., Aponeurosis of transverse muscle.

Details of walls


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Midway between the umbilicus & the pubic

symphysis, the posterior wall of the rectus sheath

ends in the arcurate line.

Below the arcuate line:

Ant: Aponeuroses of all the three flat muscles of

abdomen, the aponeuroses of the transverses and

internal oblique are fused, but ext oblique is spared.

Post: it is deficient, the rectus muscle rest on the

fascia transversalis.

Muscles:

Rectus Abdominis is the chief & largest content

Pyramidalis lies in front of the lower part of

Rectus

Contents of rectus sheath

Arteries:

Superior Epigastric artery enters the sheath by passing

between the cosatal & xiphoid origin of the diaphragm.

It crosses the upper border of the transverse abdominis

behind the 7th Costal cartilage.

Supplies to Rectus muscle

Anastomoses with inferior epigastric artery

Inferior Epigastric artery enters the sheath by passing in

front of arcurate line.


Veins:

Superior epigastric vein accompanies its artery

& joins the internal thoracic vein.

Inferior epigastric vein also accompanies its

artery & joins the external ilian vein


Nerves:

Lower six thoracic nerves

Including lower 5 intercostal nerves and the

subcostal nerves.



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This is an oblique passage in the lower part of the anterior

abdominal wall, situated just above the medial half of the

inguinal ligament It is about 4cm long

It directed downwards, forward & medially.

Inguinal canal extends from the deep inguinal ring to the

superficial inguinal ring.

The deep inguinal ring is an oval shape opening in thefascia transversalis, situated half an inch above the mid-

inguinal point.

Superficial inguinal ring is a traingular gap in the external

oblique aponeurosis.

It is shaped like an Obtuse angled triangle.

The Base of Triangle is formed by Pubic crest and two

sides from lateral and medial margins of the opening.

These margins are referred to as Curra.

At and beyond, the apex of the triangle the two

crura are united by intercrural fibres.

A) Anterior wall is formed by the following:

a) skin, superficial fascia & external oblique aponeurosis

b) lateral 1/3 the fleshy fibres of the internal oblique muscles

Boundaries

Superficial fascia

Int. Oblique

Ext. Oblique

Posterior wall is formed by the

a)Whole extent Fascia transversalis, Extraperitoneal

tissue & parietal peritoneum

b) Medial 2/3 by cojoint tendon, inguinal ligament

and over its lateral 1/3 by interfoveolar ligament.

Boundaries Formed by arched fibres of the internal

oblique and transverse abdominis muscles

ROOF


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Formed by the grooved upper surface of the

inguinal ligament and at the medial end by the

lacunar ligament

The inguinal canal is larger in males than in

Females.

FLOOR

1) Spermatic cord in males or

round ligament of uterus in females

It enters the inguinal canal through the deep inguinal

ring and passes out through the superficial inguinal ring.

2) Ilioinguinal nerve enters the canal through the interval

between the external and internal oblique muscles and

passes out through the superficial inguinal ring.

STRUCTURES PASSING THROUGH CANAL

Spermatic cord

Round Ligament

Presence of inguinal canal cause weakness in

the lower part of the anterior abdominal wall.

This weakness is compensated by following.

MECHANISM OF INGUINAL CANAL

The two inguinal rings do not lie opposite each

other.

Therefore , when the intra-abdominal pressure

rises the anterior and posterior walls of the

canal are approximated,

Thus obliterating the passage.

This is known as Flap valve mechanism

Obliquity of the inguinal canal Superficial inguinal ring is guarded from behind the cojointtendon and by the reflected part of the inguinal ligament.

Deep inguinal ring is guarded from the front by the fleshy

fibres of the internal oblique.

Shutter mechanism of the internal oblique. This muscle has

triple relation to the inguinal canal. It forms the anterior wall,

the roof, & post wall of the canal. When it contracts roof

approximated to floor, like shutter.

The arching fibres of the transversus also take part in shutter

mechanism.


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Contraction of the cremaster helps the spermatic cord to plug the

superficial inguinal ring.

Contraction of the external oblique results in approximation of the

two crura of the superficial inguinal ring. The integrity of the superficial

inguinal ring is greatly increased by the intercrural fibers.

Hormones play a role in maintaining the tone of the inguinal

musculatures.

When ever there is a rise in intra-abdominal pressure ( coughing,

sneezing, & lifting) all these mechanisms come into play , so that the

inguinal canal is obliterated, its openings are closed, and herniation of

abdominal viscera is prevented.

Abnormal protrusion of abdominal contents into

the inguinal canal is known as inguinal hernia.

This is more likely to occur in persons in whom

intra-abdominal pressure is frequently increased.

(e.g) chronic cough by work involving frequent

lifting of heavy weights ect..

Types Direct or Indirect hernia.

INGUINAL HERNIA

INDIRECT INGUINAL HEINIA AND DIRECET

INGUINAL HEINIA

The abdominal aorta begins in the midline at the aortic

opening of the diaphragm, opposite the lower border of

vertebra T12.

It runs downwards & slightly to the left in front of the lumbar

vertebrae, & ends infront of the lower part of the body of

vertebrae L4, about half an inch to the left of the median

plane, by dividing into the right & left common iliac arteries.

Due to forward convexity of the lumbar vertebral column,

aortic pulsation can be felt in the region of the umbilicus,

particularly in slim persons.

Abdominal Aorta

Anteriorly : aorta related to

1) Coeliac & aortic plexus

2) body of the pancreas with the splenic vein

embedded in its posterior surface.

3) Left renal vein clamped to aorta by the

origin of the superior mesenteric artery

4) The uncinate process of the pancreas

5) Third part of the duodenum

6) Parietal peritoneum separating it from

coils of small intestine.

Relation


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Posteriorly : aorta related to

1. The bodies of the upper four lumbar vertebrae & IV

disc

2. Anterior longitudinal ligament

3. Left lumbar veins

4. Beginning of lumbar arteries.

Right side of aorta there are

1) IVC

2) Right crus of the diaphragm which separated aorta

from IVC above the level of the renal veins

3) Cisterna chyil & azygos vein in the upper part

4) Lumbar lymph nodes.

Left side of aorta there are

1) Left crus of the diaphragm

2) Pancreas

3) Fourth part of the duodenum

4) Lumbar lymph nodes.

5) Left sympathetic chain

A ventral braches which develop from ventral

splanchnic arteries and supply the gut, these are.

Coeliac trunk

Superior mesenteric artery

Inferior mesenteric artery

Branches

Lateral braches which develop from lateral splanchnic

arteries and supply the viscera derived from the

intermediate meseoderm these are the right & left.

Inferior phrenic arteries

Middle suprarenal arteries

Renal arteries

Testicular or ovarian arteries

Dorsal braches represent the somatic

intersegmental arteries and are distributed to

the body wall. these are.

Lumbar arteries

Median sacral artery


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Terminal branches are a pair of common iliac

arteries.

They supply the pelvic & lower limbs.

Formed by the union of the right & left common

iliac veins on the right side of the body of the

vertebra L5.

It ascends in front of the vertebral column on the rt

side of the aorta, grooves the posterior surface of

the live pierces the central tendon of the

diaphragm at the level of vertebra T8 & opens into

the lower and posterior part of the rt atrium.

INFERIOR VENA CAVAAnteriorly: from above downwards. It is related to

1. Posterior surface of the liver

2. Epipolic foramen

3. First part of duodenum & portal vein

4. Head of pancreas along with bile duct

5. Third part of duodenum & gonadal vein

6. Posterior parietal peritoneum & root of mesentery

7. Right common iliac artery

Relations

Posteriorly :

Above the right crus of the diaphragm is separated

from the IVC by right renal , middle suprarenal &

inferior phrenic arteries, the right coeliac ganglion,

and the medial part of the right suprarenal gland,

Below, it is related to the right sympathetic chain

and to the medial border of the right psoas.

Common iliac veins

(formed by the union of the external &

internal iliac veins) unite to from the IVC.

Each vein receives an iliolumbar vein, the

medial sacral vein joins the left common

iliac vein.

TRIBUTARIES


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Third & Fourth lumbar veins:

run along with the corresponding arteries and

open into the posterior aspect of the IVC.

The vein of the left side cross behind the aorta

to reach the vena cava.

The 1st & 2nd lumbar veins may end in the 3rd

lumbar vein, the ascending vein, the azygos

vein to the hemiazygos vein.

Right testicular vein,

opens into the IVC just below the entrance

of the renal veins. The left gonadal vein

drains into the left renal vein.

Right Suprerenal vein

is extremely short, it emerges

from the hilum of the

gland and soon opens into

the IVC.

the left suprarenal vein opens

into the left renal vein.

Hepatic veins

Three large and many small opens directly

into the anterior surface of the IVC just

before it pierces the diaphragm.

ANATOMY OF ABDOMEN

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