dr al muhtaseb -...
TRANSCRIPT
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عجميّة أبو َمها
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- Dr Al - Muhtaseb
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Refer to Snell for clinical notes (as the doctor said in his first lecture O_O)
and to the slides for illustrations.
This sheet is about abdomen, there are anterior and posterior abdominal
walls
The posterior abdominal wall is formed by the lower five lumbar
vertebrae, bones and muscles originating from the back, but today we will
talk about the anterior abdominal wall.
Let’s have some definitions (you can skip)
- Aponeurosis (many aponeuroses): flattened tendon serves as
attachment to flat muscles -either origin or insertion-.
- Viscera: the internal organs in a body cavity
- the difference between the visceral peritoneum and the
parietal peritoneum?
the parietal peritoneum: covering the abdominal cavity. we
can’t reach any organ in the abdomen without incising the
parietal peritoneum.
the visceral peritoneum: adherent to the viscera (the organs),
the viscera cover the abdominal cavity
(parietal peritoneum is then the membrane which covers the
abdominal viscera While the visceral peritoneum is adherent to
the viscera.
Let’s start…
Abdomen: is the region of the trunk that lies between the diaphragm
above and the inlet of the pelvis below
- ABOVE, it is formed by the diaphragm which separates the
abdominal cavity and the thoracic cavity,
The diaphragm has right and left domes (also known as cupolae).
We should know what is found above the right cupola and what is
below it
Below the right cupola, we find the liver, usually pushes the
right cupola upward until it reaches the 5th intercoastal
space
Above in the chest, the base of right pleura
Above the left cupola, we find the left pleura of lung
Below the left cupola, we find the spleen
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- BELOW, no separation here, the abdominal cavity is continuous
with the pelvic cavity through the pelvic inlet, until reaching the
iliac crest, the line between the left and right iliac tubercles
separates abdomen and pelvis
There are some structures that are found in both the abdomen and
pelvis (such as descending colon, rectum and anal canal, they all
start at abdomen and ends at pelvis)
We conclude that the abdomen is not separated from pelvis, but
then, a boundary between them is formed by the iliac crest
Borders
- Superiorly (Anterior Border):
lower Costal cartilages
(7-12 ribs, remember that both 11 and 12 have no coastal
cartilages)
Xiphoid process (at the end of sternum)
- Inferiorly (Anterior Border):
Pubic bone -symphysis pubis-
iliac crest
(at the Level of L4.)
- Umbilicus:
an important landmark, (Level of intervertebral disc L3-L4)
Areas of the abdomen
There are many organs (viscera) in the abdomen, like those of the
digestive system, in order to locate each organ; the abdominal area
is divided into four quadrants, formed by two intersecting lines
(Vertical & Horizontal Intersect at umbilicus):
1) Upper left
2) Upper right
3) Lower left
4) Lower right
This has a great clinical importance, (doctors usually use these anatomical
terms) let’s have some examples,
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1) if a patient complains of severe pain in his lower right quadrant,
one of the most common, possible diagnoses is acute appendicitis,
because appendix is found there (the right iliac fossa) … and when
doctors make sure by blood tests, surgeons will hence perform
appendectomy to relieve pain.
(differential diagnoses: ascending colon and cecum too)
2) If a 40-year old woman feels pain in the right upper quadrant, her
doctor will think of cholecystitis… because the upper right
quadrant is where the gall bladder exists
(liver too)
But the four quadrants method is outdated, and there is a new, more
accurate method which is known as “the nine areas”.
The abdomen is divided into 9 regions by four imaginary planes/ lines
Two Vertical Planes: (left and right Midclavicular planes)
They extend from the midpoint of each clavicle, to the midpoint between
pubic symphysis and anterior superior iliac spine (midinguinal point)
Two Horizontal Planes:
Upper Subcostal plane:
- this plane lies at the level of L3
- Joins the lower end of costal cartilage on each side, (Below the
costal cartilage, more precisely, below the costal cartilage number
9.)
Lower Intertubercular plane: At the level of L5 vertebra, between the two
right and left iliac tubercles of the hip bone.
The names of the regions:
i. First row:
o Right hypochondriac region (below ribs/ the costal cartilage)
you find:
the right lobe of the liver
the gall bladder.
o Left hypochondriac region (below ribs/ the costal cartilage),
you find:
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the spleen. (the spleen is a reservoir of blood, any trauma
can cause bleeding).
o Epigastric region (above the stomach), you find:
the stomach
the left lobe of the liver .
ii. Second row:
o Umbilical region (in the middle, around the umbilicus), the
small intestines are deep to it
o Right lumbar region (ascending colon).
o Left lumbar region (descending colon).
(The kidneys lie in the posterior part of the right and left lateral lumbers)
iii. Third row:
o The suprapubic/ the hypogastric region (below the stomach) :
it is where we find the urinary bladder and urethra.
o Right iliac (inguinal) region (where you find the cecum and the
appendix)
o Left iliac (inguinal) region - Related to the inguinal canal (the
spermatic cord in males and ovaries in females)
NOTES:
you have to be able to differentiate between appendicitis
and menstrual pain in females
The appendicitis` pain starts around the umbilicus, because
there is a dermatome around it, then the pain moves to the
lower right of the abdomen.
Another clinical application: inguinal hernia might take place
here
Anterior abdominal wall
What are the Layers of Anterior Abdominal Wall?
(skin/ superficial fascia -subdermal- / (deep fascia) /transversalis
fascia/ extraperitoneal/ parietal peritoneum -simple squamous
epithelial layer-
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These layers are very important, surgeons!
1. Skin
2. Superficial Fascia :
o Above the umbilicus (one fatty layer). Scarp's fascia.
o Below the umbilicus two layers (fatty and membranous layers)
I. Camper's fascia - fatty superficial layer.
In males’ scrotum, the continuation of this camper’s layer
is a muscle that is called dartos muscle under the skin
meaning that the abdominal wall descends to the
perineum.
II. Scarpa's fascia - deep membranous layer, it attaches to
the fascia lata below the inguinal ligament in the lower
limb. It is continuous into the perineum, it attaches to
the pubic arch at both sides, and posteriorly to the
perineal body.
Attachment of scarpa’s fascia=
Inf: Fascia lata
Sides: Pubic arch
Post: Perineal body
(The membranous fascial layer in the scrotum, has an
extension called COLLE`S FASCIA.)
What is the perineal body?
o It is a fibrous structure anterior to anus (between the anal
orifice and the symphysis pubis anteriorly??).
Clinical point on the scarp`s fascia: rupture of penile urethra leads to
extravasations of urine:
- Around scrotum and penis
- Around perineum
- lower abdomen (below the umbilicus, where membranous layer
is found)
- above the fascia lata. LUCKILY, this happens because of the
continuous scarp’s fascia attachment, if not attached, the urine
would possibly reach the lower limb…
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3. Deep fascia:
- a layer of connective tissue covering the muscles,
- it is very thin, and may be absent in some people, especially in
women, because deep fascia resists the abdomen enlargement,
thus it is absent in women to allow the enlargment of the uterus
forward and upward during pregnancy
Before talking about the muscular layer, let’s talk about linea alba
because it serves as an insertion point to all these abdominal muscles…
األبيض الخط or linea alba: a fibrous connective tissue, it extends along
the midline, from the xiphoid process to symphysis pubis, it is formed
by the fusion of aponeuroses of three abdominal wall (Ex. In, Tran.
Abd. muscles) it has little supply of blood, it is important surgically,
because midline incisions are usually performed there, and this has
some advantages and disadvantages,
- Advantages:
o Good access to both sides of the abdomen, In case of
tumors in the abdomen for example, or any other
purpose that requires wide opening of the abdomen, a
midline incision in the linea alba could be a good option.
o less bleeding, because it is fibrous.
- Disadvantages:
o Postsurgical healing process is poor and takes long time,
because of poor blood supply .
In addition to midline incision, there are other types of abdominal
incisions: Rectus sheath/ pararectal (Battle’s incision)/ Transverse and
many others
4. Muscular layer, we have four muscles,
All the abdominal muscles insert themselves in the linea alba, by their
aponeuroses, (from the most superficial to the deepest, 1) external
abdominal oblique 2) Internal abdominal oblique 3) transversus
A) External oblique muscle (external abdominis muscle)
It is a thin, broad muscle that comes from the back and extends in
an oblique fashion -> the fibers run obliquely downward forward
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and medially (analogous to someone’s hands in the pockets of their
pants)
a. Origin: outer surface of lower 8 ribs
b. Insertion:
- Xiphoid process, Linea alba
- Pubic crest and Pubic tubercle, and it reaches Iliac crest
(anterior half)
c. Nerve Supply:
-T7 -T12 (Lower 6 thoracic/intercostal nerves)
-L1 ( iliohypogastric nerve , ilioinguinal nerve).
d. Muscle’s Contributions
The muscular part of External oblique becomes aponeurotic
(aponeurosis) before reaching linea Alba, the aponeurosis of this muscle
contributes to:
i. Inguinal ligament: folding of the lower border of aponeurosis of the
external oblique muscle on itself, extends between anterior superior
iliac spine and pubic tubercle.
ii. Lacunar ligament: reflection of inguinal ligament, it forms the medial
boundary to the femoral canal.
Slides: extension of aponeurosis of external muscle backward and
upward to the pectineal line, on the superior ramus of the pubis, its
sharp, free crecentric edge forms the medial margin of the femoral ring
iii. Pectineal ligament: (aka, Cooper ligament) reflection of inguinal
ligament and it is the continuation of lacunar ligament at pectineal line
and continues with a thickening of the periosteum
iv. Superficial inguinal ring,
- it is a defect in external oblique aponeurosis,
- it lies above and medial to the pubic tubercule
- this ring is triangular in shape and it has medial crus/ lateral crus..
- it transmits structures of the female and male inguinal canal such as
the round ligament of uterus (females) and spermatic cord (males) w
its associated nerves, blood vessels, vas deferens ..
- it contributes in the spermatic cord coverings (external spermatic
fascia)
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v. the anterior layer of rectus sheath
vi. it also contributes to the boundaries of the inguinal canal, which is
found between deep and superficial inguinal rings
ExtraNote: (you can skip)
lat·er·al crus of the su·per·fi·cial in·gui·nal ring (portion of the external oblique aponeurosis that passes lateral to
the superficial inguinal ring blending into the inguinal ligament and forming the lateral boundary of the ring.
me·di·al crus of the su·per·fi·cial in·gui·nal ring : portion of the external oblique aponeurosis that passes medial
to the superficial inguinal ring forming the medial boundary of the ring.
B) Internal oblique muscle (deep to external oblique muscle, its fibers
run upward forward and medially)
a. Origin
Lumbar Fascia, Anterior 2/3 of iliac crest, lateral 2 /3 of inguinal
ligament.
b. Insertion:
Lower three ribs and costal cartilage, Xiphoid process,
Symphysis pubis (Linea alba)
c. Nerve Supply: (like external oblique)
Lower 6 thoracic nerves, and iliohypogastric nerve &ilioinguinal
nerve (L1).
d. Muscle’s Contributions,
i. Cremasteric muscle and fascia,
Internal oblique has free lower border arches over the spermatic cord
or ligament of uterus
The spermatic cord and testes (in males) are covered by cremasteric
fascia.
This Cremasteric Fascia is Related to the Inguinal Canal
ii. this muscle assists in the formation of the roof of the inguinal canal
iii. Conjoint tendon,
o combined fibers of internal oblique and transversus abdominis
muscles.
o The conjoint tendon is -inserted on- the pubis.
o Attached medially to linea alba supporting the inguinal canal
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o Has lateral free border
It is important to take stitches in herniorrhaphy (in inguinal hernia فتق)
because it is very strong tendon
iv. It contributes to layers of the rectus sheath.
C) Transversus abdominis muscle, as the name implies, its fibers run
transversely (horizontally).
i. Origin: (from back)
lumbar fascia, lower 6 costal cartilage, anterior 2 thirds of the iliac crest,
the lateral one third of the inguinal ligament.
ii. Insertion:
linea alba (the xiphoid process to symphasis pubis.)
iii. Nerve supply :
Lower 6 thoracic nerves, L1 (illiohypogastric and illioinguinal nerves)
iv. Muscle’s contributions,
(with the internal oblique muscle’s fibers, it forms the conjoint tendon.
which attaches to pubic crest and pectineal line) and (contributes to the
layers of rectus sheath)
- NoTE:
The collection of the abdominal muscle fibers (downward, upward,
transverse) make a very strong network, thus the abdominal muscles are
very strong muscles. (protection of the abdominal viscera).
let’s talk about the muscular contents of rectus sheath in detail ..
D) Rectus abdominis muscle
Rectus abdominis is a long strap muscle, it extends along the whole
length of the anterior abdominal wall and it differs from the previously
mentioned muscles in many aspects:
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It is found inside the rectus sheath (between the linea alba
and the semilunaris.)
It has tendinous intersections (they are adherent to rectus
sheath, anteriorly)
No L1 nerve supply
the rectus abdominis is colloquially called abs ("six-pack" :P). (it is divided
into squares according to the record) This is due to tendinous
intersections, which are 3 transverse fibrous bands (can be palpated as a
transverse depressions)
these tendinous intersections divide the rectus abdominis muscle into
distinct segments,
1- at level of xiphoid process 2- at level of umbilicus 3- one half
way between these two In embryos, these tendinous intersections come
from myotome, then continue as a separated myotome because of the
tendons.
v. Origin: (lower part) symphysis pubis and pubic crest
vi. Insertion: upwards in the 5th,6th,7th costal cartilage and
the xiphoid process. (linea alba)
vii. Nerve supply: lower 6 thoracic nerves. (but NOT L1)
E) Pyramidalis muscle:
- It lies in front of the lower part of the rectus abdominis muscle
- May be absent
- Inside the rectus sheath in the lower part ( if present).
- Used surgically as reconstructive muscle (in addition to assisting
abdominal muscles in their actions)
o Origin: from the anterior surface of the pubis.
o Insertion: linea alba .
o Action: pulls linea alba.
o Nerve supply: 12th subcoastal nerve ( the last intercostal N.)
5. Transversalis fascia:
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thin layer of fibrous connective tissue covering the muscles, continues to
diaphragm, iliac muscle and pelvis, Found in the posterior wall of the
rectus sheath , below the anterior superior aliac spine
we’ve talked about this fascia (in the MSS System) we said it forms the
anterior wall of femoral sheath
- remember: posterior wall of femoral sheath is formed by the
fascia iliaca
Transversalis fascia contributions:
- femoral sheath
- the posterior layer of rectus sheath
- deep inguinal ring and thus a fascia that covers the spermatic
cord (internal spermatic fascia)
6. Extraperitoneal fascia
- usually it is in the form of adipose tissue(fat).
- Located above the parietal peritoneum, and below the
transversalis fascia.
7. Parietal peritoneum: It is a thin serous membrane, Continuous
below with the parietal peritoneum lining the pelvis.
It covers the abdominal cavity, we incise it to reach abdominal
viscera
(it is then a lining for the abdomino-pelvic cavity)
So when a doctor wants to make a surgery in the stomach , the layers
that he/she’d face are : skin , superficial fascia , (deep fascia if present) ,
the muscles, transversalis facia , extraperitoneal , parietal peritoneum ,
then the visceral peritoneum (which is adherent to viscera, e.g: stomach).
Blood supply of the Anterior Abdominal Wall (from slides)
- Arterial Supply
Sup. Epigastric artery • Inf. Epigastric artery • Intercostal
arteries • Lumbar arteries • Deep circumflex artery
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Note:
superior epigastric (a branch of internal thoracic artery)
Inferior epigastric and deep circumflex iliac artery
(branches of external iliac artery)
- Venous Supply
Below the umbilicus – Inferior (superficial) Epigastric -
<Femoral vein Superficial , meaning that the superficial
epigastric empties into femoral vein
Above the umbilicus - Lat. Thoracic. vein. –<Axillary vein
Paraumbilica veins - Ligamentum teres –< portal vein(Porto-
systemic anastomosis
- Lymphatic drainage of ant. Abdominal wall (from slides)
• Above the umbilicus: Ant.axillary L.N
•Below the umbilicus: Sup. Inguinal L.N
•Above the iliac crest: Post.axillary.L.N
• Below the iliac crest: Sup.inguinal L.N
Innervation of the Anterior Abdominal Wall
- Thoracoabdominal nerve: Lower 6th thoracic nerves & 12th
subcostal nerve
- Dermatomes (Anterior, lateral cutaneous nerve terminal branches
of Thoracoabdominal nerve – T7 to skin superior to umbilicus
below xiphoid process – T10 to skin surrounding umbilicus – L1 to
skin inferior to umbilicus above sym.pubis
- LI nerve - Iliohypogastric nerve+ ilioinguinal nerve
Note: The lumbar triangle in not required.
Fasciae of the anterior Abdominal wall:
- Rectus sheath
- Transversalis fascia:
- extraparietal fascia:
- Parietal peritoneum
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The Rectus Sheath
The rectus sheath is a long fibrous sheath • Formed mainly by the
aponeuroses of the three lateral abdominal muscles.
The rectus sheath starts from linea semilunaris and fuses (ends)
in the linea alba
Semilunaris: the lateral border of rectus abdominis muscle
This muscle has tendinous intersections attached to the
anterior wall of the rectus sheath (not the posterior, it is
separated from the wall posteriorly). It can be palpated and
it extends from 9th c.c to the pubic tubercle
Extra note: it is a bilateral feature (right&left)
The rectus sheath is formed by the aponeuroses of the transverse
abdominal and the external and internal oblique muscles. but It
contains the rectus abdominis (and pyramidalis muscle if not
absent)
It has anterior and posterior wall
Formed by the aponeurosis of the abdominal muscles (external
and internal oblique muscles and transversus abdominis muscle)
Anteriorly, tendinous intersections of the rectus abdominis
muscle, these intersections are adherent (firmly attached)
to rectus sheath but posteriorly, the posterior wall of the
rectus sheath is not attached to the rectus abdominis
muscle, meaning that you can put your hand between the
muscle and this wall of the sheath
Its Contents
a. Lower six thoracic nerves (The anterior rami of the lower
six thoracic nerves
b. Lymphatic vessels
c. Two muscles: rectus abdominis and pyramidalis.
d. two arteries:
inferior epigastric (a branch from external iliac)
superior epigastric (a branch from internal thoracic artery
which is branch from a subclavian artery which comes
from the brachiocephalic artery ).
There is an anastomosis between these two arteries
inside the rectus sheath around the umbilicus, and
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they separate the rectus abdominis muscle from the
posterior layer .
e. Rectus sheaths, We have one at left and one at right,
separated by linea alba. In other words, linea alba
separates the right and left rectus abdominis muscles.
f.
Description the rectus sheath is considered at three levels but, always the
same contents: (refer to slides 31+32+33)
A) Above costal margin (5th,6th and 7th) and xiphoid process: (look
at figure A)
- The anterior wall: skin, superficial fascia, aponeurosis of
external oblique muscle.
- Posterior Wall : costal cartilage number 5,6 and 7, then
intercostal muscle , and xiphoid process in the front
(Content: rectus abdominis muscle.)
B) Below costal margin, (between the costal margin and anterior
Superior iliac spine ASIS): (important)
Midway between umbilicus&xiphoid and Midway between
umbilicus&symphysis pubis:
As you can see from figure B in the slides, the internal oblique
muscle splits to enclose the rectus abdominis muscle, part of it
contributes to the anterior wall and the other part contributes to
the posterior wall
- Anterior Wall: the aponeurosis of external oblique and one layer
of internal oblique.
- Posterior Wall: one layer of internal oblique aponeurosis and
transversus abdominis aponeurosis.
(Contents: rectus abdominis muscle (it is enclosed by the 2 layers
of internal oblique)).
C) Below ASIS anterior superior Iliac spine
(below Midway between umbilicus and symphysis pubis): (look at
figure c) The inferior epigastric artery enters the rectus sheath
below the arcuate line , and the arcuate line is a very important
landmark, because all the muscles of the rectus sheath below at
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this level, are at the anterior wall , and the posterior wall is only
formed by fascia transversalis ,
- Anterior Wall: aponeuroses of all muscles (external oblique,
internal oblique and transversus).
- Posterior Wall: transversalis fascia and lies below it
extraperitoneal fat and peritoneum.
(Content: rectus abdominis muscle.)
Arcuate line (linea semicircularis):
Is a crescent-shaped line marking the inferior limit of the posterior layer
of the rectus sheath just below the level of the iliac crest. Below it, we can
find the transversalis fascia.
All muscles are anterior at level of this line
- The general action of the anterior abdominal muscles:
a. Increase the intra-abdominal pressure when it is
needed in the following processes: Vomiting,
Coughing, Defecation, Labor, Micturition (urination)
and Bending of the trunk forward
- These muscles protect the viscera when contracted (when you
are playing boxing, the muscles of the abdomen take the role of
the protection when contacted. If contraction didn’t take place
the viscera will be affected and bleeding may occur)
- They help in lifting heavy objects (people who lift heavy objects
usually tie a strap on the abdomen to help the muscles doing
their action, and to avoid hernia).
- These muscles keep viscera in position
Clinical Notes (SLIDES)
- Abdominal stab wounds
• Lateral to rectus sheath
• Ant. To rectus sheath
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• In the midline= Linea alba - Structures in the various layers through
which an abdominal stab wound depends on the anatomical location
- Surgical incision
- The length and direction of surgical incision through the ant.
Abdominal wall to expose the underlying viscera are largely controlled
by
1- position & direction of nerves
2- direction of muscle fibers
3- arrangement of the aponeurosis forming the rectus sheath - The
incision should be made in the direction of the line of cleavage in the
skin so that the scare is produced
Meaning that surgical incision should be parallel to skin cleavage so that
it won’t leave a scar. doctors should also be aware of the pathway of the
nerves. So they pull rectus sheath laterally to protect the nerves which
pass from medial to lateral. And the direction of the muscle fibers is also
important.
- Incision through the rectus sheath
• Widely used • The rectus abdominis muscle and its nerve supply are
kept intact • On closure the ant & post wall of the sheath are sutured
separately and the rectus muscle back into position between the suture
lines
Common types of incisions
• Paramedian incision • Pararectus incision • Midline incision •
Transrectus incision • Transverse incision • Muscle splitting •
Abdominothoracic incision
A note I could not place: L1 nerve passes above inguinal ligament and divides
into 2 branches: iliohypogastric and ilio-inguinal (Ilioinguinal – enters
from deep to superficial ring supplying scrotum and it also serves as
sensory innervation to lower abdomen)
I’ve heard record4+ used slide2 to write this sheet, Sorry if I missed anything, GOOD LUCK!!
Telos is not only about your Ultimate steps, But also your first ones -MahaAbuAja100