L01 General anatomy of the abdomen

Question 1

Upper and lower boundary of thoracic cavity

Answer 1

Upper boundary: thoracic diaphragm

Lower boundary: Pelvic brim/inlet

Question 2

Anatomical separation by thoracic diaphragm

Answer 2

Separates the thoracic cavity (above) from the abdominal cavity (below)

Question 3

Anatomical separation by Pelvic brim

Answer 3

Separates abdominal cavity (above) from pelvic cavity (below)

Question 4

Anatomical separation by pelvic diaphragm

Answer 4

Separates pelvic cavity (above) from perineum (below)

Question 5

Nature of sacroiliac joint

Answer 5

A synovial joint that joins sacrum to hip bone (ilium, ischium, pubis) laterally on wither sides

Question 6

Nature of pubic symphysis

Answer 6

A fibrocartilaginous joint that joins left and right hip bones at the pubis medial anteriorly.

Question 7

Contents of the abdomen (overview)

Answer 7

(i) Most of the gastro-intestinal tract (or G.I.T.) - the last 2 cm of the oesophagus, the stomach, the small and large intestines, the liver and the pancreas,
(ii) Spleen - a large mass of lymphoid tissue
(iii) The organs of excretion - the kidneys with the upper part of their ducts, the ureters,
(iv) Blood vessels and lymphatics supplying/draining these organs
(v) nerves.

Question 8

midclavicular lines

Answer 8

vertical lines are “dropped” from the midpoints of the clavicles

Question 9

transpyloric plane

Answer 9

• horizontal plane
• midway between the xiphoid process of the sternum and the umbilicus (or midpoint of superior border of manubrium of sternum and pubic symphysis)
• passes through the 9th costal cartilage or the body of L1
• transects through pylorus (distal part of stomach) and organs (e.g. Liver, pancreas, duodenum)

Question 10

Subcostal Plane

Answer 10

• horizontal plane
• passes through the inferior border of 10th costal cartilage or the body of L3

Question 11

Transtubercular plane

Answer 11

• horizontal plane
• passes through the iliac tubercles and body of L5

Question 12

Transumbilical plane

Answer 12

• Horizontal plane
• passing through umbilicus (and IV disc between L3 and L4)

Question 13

Median Plane

Answer 13

• Vetical plane
• passing longitudinally through the body, passing thorugh the umbilicus

Question 14

Nine regions of abdominal cavities

Answer 14

Delineated by four planes (2 sagittal / vertical, 2 transverse / horizontal):

• 2 midclavicular planes (left and right sagittal)
• Subcostal plane or transpyloric plane (upper transverse)
• Transtubercular plane (lower transverse)

Producing nine regions:

(right to left, upper to lower)

1. Right hypochondrium
2. Epigastrium
3. Left hypochondrium
4. Right flank/lumbar/lateral
5. Umbilical
6. Left flank/lumbar/lateral
7. Right groin/iliac/inguinal
8. Suprapubic/pubic/hypogastrium
9. Left groin/iliac/inguinal

Question 15

Four quadrants of abdominal cavity

Answer 15

Delineated by two planes (1 sagittal / vertical, 1 transverse / horizontal):

• Median plane (sagittal)
• transumbilical plane (transverse)

Producing four quadrants:

(right to left, upper to lower)

1. Right Upper Quadrant
2. Left Upper Quadrant
3. Right Lower Quadrant
4. Left Lower Quadrant

Question 16

important surface markings of the abdominal viscera

Answer 16

1) liver (Upper margin) - level of 4th intercostals space.
2) Gallbladder - right 9th intercostals space, midclavicular line.
3) Spleen - posteriorly along the 9th to 11th ribs.

Question 17

Muscles of anterolateral abdominal wall

Answer 17

Five (bilaterally paired) muscles; 3 flat muscles and 2 vertical muscles:

• external oblique (flat, outermost)
• internal oblique (flat, middle)
• transversus abdominis (falt, innermost)
• Rectus abdominis (vertical. large)
• Pyramidalis (vertical, small)

Question 18

External oblique muscle

Answer 18

• Flat muscles
• Lateral to rectus abdominis muscles
• Downward forward towards rectus abdominis
• Largest and most superficial muscles of the three flat anterolateral abdominal muscles
• becomes aponeurotic at MCL medially, forming the rectus sheath

Question 19

Internal oblique muscle

Answer 19

• Flat muscles
• Lateral to rectus abdominis muscles
• Upward forward towards rectus abdominis (more accurately fans out anteromedially)
• Between external oblique muscle (superficial) and transversus abdominis muscle (deep)
• Becomes aponeurotic at MCL medially, forming rectus sheath

Question 20

Transversus abdominis muscle

Answer 20

• Flat muscles
• Lateral to rectus abdominis muscles
• Runs transversly
• innermost muscles of the three flat anterolateral abdominal muscles
• becomes aponeurotic at MCL medially, forming the rectus sheath

Question 21

Rectus abdominis muscle

Answer 21

• Principal vertical muscle of anterior abdominal wall
• On either side of the median plane
• From xiphoid process of sternum (and 5-7th costal cartilages) to pubic crest and symphysis
• Encased by a rectus sheath produced from the aponeurosis of the three flat abdominal muscles (external oblique, internal oblique and transversus abdominis)

Question 22

rectus sheath

Answer 22

• Strong, incomplete collagenous fibrous sheets containing rectus abdominis and pyramidalis
• Also contains superior and inferior epigastric A/V, lymphatic vessels, and thoracoabdominal nervrd (T7 - T12)
• Formed from the interweaved medial aponeurosis (wide flat tendon) of flat abdominal muscles
• Aponeurosis of external oblique -> Anterior rectus sheath; aponeurosis of internal oblique -> Anterior & posterior rectus sheath; aponeurosis of transversus abdominis -> posterior rectus sheath
• Inferior to the arcuate line of rectus sheath, the aponeurotic posterior rectus sheath disappear
• Fibers of anterior and posterior rectus sheath interlace in anterior median line to form linea alba

Question 23

Layers of anterior abdominal wall

Answer 23

(Superficial to Innermost)

1) Skin
2) Loose Fatty Superficial Fascia (Fascia of Camper)
3) Membranous (fibrous) fascia (Scarpa’s fascia)
4) Anterior rectus sheath (from aponeurosis of external oblique and internal oblique)
5) Rectus abdominis
6) Posterior rectus sheath (from sponeurosis of internal oblique and transversus abdominis; absent below the arcuate line)

*) Linea Alba persists on the Anterior medial line at level 4-6

7) Transversalis fascia
8) Pre-peritoneal fat
9) Parietal peritoneum

Question 24

Nerves of anterolateral abdominal wall

Answer 24

Source: T7 - T11, T12, L1

1) Thoracoabdominal nerves (T7 - T11; continuation of inferior intercostal nerves)

• Anterior cutaneous branches
• Lateral cutaneous branches

2) Subcostal nerve (anterior ramus of T12)

• Anterior cutaneous branches
• Lateral cutaneous branches

3) Iliohypogastric and ilioinguinal nerves (terminal branches of anterior ramus of L1)

Note: The nerves pass into the muscles from the lateral side. These nerves are actually intercostal nerves - they are nerves from the thorax sweeping down below the costal margin into the anterior abdominal wall. Of the lumbar nerves, only L1 is involved in supplying the antero-lateral wall.

Question 25

Arteries of anterolateral abdominal wall (name and origin)

Answer 25

Internal thoracic artery:

• Musculophrenic artery
• Superior epigastric

Abdominal aorta:

• 10th Posterior Intercostal artery
• 11th posterior intercostal artery
• Subcostal artery
  (lumbar artery for posterior abdominal wall)

External iliac artery:

• Deep circumflex iliac artery
• Inferior epigastric

Femoral Artery:

• Superficial circumflex iliac artery
• Superficial epigastric artery

Question 26

Arteries of anterolateral abdominal wall (Course and distribution)

Answer 26

Advance stuff (read if have time)

Question 27

Veins of anterolateral abdominal wall

Answer 27

Skipped (not covered in lecture, review Moore if necessary)

Question 28

Lymphatics of anterolateral abdominal wall

Answer 28

Superficial lymphatic vessels:

- accompany the subcutaneous veins

• superior to the transumbilical plane drain mainly to the axillary lymph nodes; however, a few drain to the parasternal lymph nodes.
• inferior to the transumbilical plane drain to the superficial inguinal lymph nodes.

Deep lymphatic vessels:

• accompany the deep veins of the abdominal wall
• drain to the external iliac, common iliac, and right and left lumbar (caval and aortic) lymph nodes.

Question 29

Dermatome (definition)

Answer 29

• Area of skin which is supplied by general sensation fibers of a simple spinal nerve
• based on somatic sensation; but related to referred pain from visceral afferent fibers

Question 30

Dermatomes of anterolateral abdominal wall

Answer 30

• The map of dermatomes of the anterolateral abdominal wall is almost identical to the map of peripheral nerve distribution
• because the anterior rami of spinal nerves T7–T12 (which supply most of the abdominal wall) do not participate in plexus formation.
• L1 is an exception - L1 anterior ramus bifurcates into Iliohypogastric and ilioinguinal nerves
• Each dermatome begins posteriorly overlying the intervertebral foramen by which the spinal nerve exits the vertebral column and follows the slope of the ribs around the trunk.
• Dermatome T10 includes the umbilicus, dermatome L1 includes the inguinal fold

Question 31

Referred pain

Answer 31

pain perceived at a location other than the site of the painful stimulus

Question 32

Function of strong abdominal muscular wall

Answer 32

(a) For trunk movements
(b) Protection of abdominal viscera
(c) To contain the abdominal viscera. After a large meal, the size of the abdominal cavity increases. The stomach and intestines contain a large amount of smooth muscle in their walls. This smooth muscle not only produces peristalsis but also moves the intestines around in the abdominal cavity. An abdominal wall that is formed only by fibrous tissue would gradually stretch and become loose. A muscular wall is more elastic and stronger and can contain abdominal viscera and prevent hernia. Even so, the intestines will try to push through any point of weakness if they can.
(d) Deep expiration. After exercise, you need to breathe large amounts of air quickly. Contraction of the muscles of the anterior abdominal wall will push against abdominal contents, raise intra-abdominal pressure and force the diaphragm upwards, thus facilitating expiration. Coughing is also performed in this manner.
(e) For muscular effort, supporting the trunk. Raising the pressure inside the trunk helps the vertebral column to keep the trunk straight. Contraction of the muscles of the anterior abdominal wall will push against abdominal contents, raise intra-abdominal pressure. This would normally push the diaphragm up. However, this can be stopped by closing the airway in the larynx (by laryngeal muscles). This raises the pressure inside the thorax too. This supports the trunk.
(f) Aiding defecation, micurition, or parturition. these processes are all helped by increasing intra-abdominal pressure. The organs involved - the last part of the large intestine (sigmoid colon, rectum and anal canal), the bladder and the uterus - all have a lot of smooth muscle, which provides the force to expel their contents, BUT they need help. High intra-abdominal pressure, with a sealed larynx to stop the diaphragm going up, directs extra pressure on these organs to help push. This is called the Valsalva’s maneuver.

Question 33

Reasons why the abdominal wall is clinically important:

Answer 33

1) General surgery is abdominal surgery (Every surgeon needs to know how to incise (cut) the anterior abdominal wall open without weakening it. A surgeon must know the layers of this wall.)
2) Most hernias are formed by intestines pushing out of the abdominal cavity. The most common hernia of all is an inguinal hernia in males and is found in the lower part of the anterior abdominal wall, either side of the midline.
3) Referred pain in the abdomen is common

Question 34

General surgery consideration

Answer 34

• how to incise the anterior abdominal wall open without weakening it.
• A surgeon must know the layers of this wall
• Nerve supply of abdominal muscles are important. If nerves are cut, then muscle stops contracting and the intestines may push the layers of the wall forwards.
• Anterior abdominal wall is often cut via the linea alba as it provides least damage to abdominal musculature (less weakening) and vasculature (less bleeding)
• The position of a surgical incision depends on what the surgeon wishes to approach. The muscle-splitting (gridiron) incision is one of the most common.
• The point of maximum tenderness in appendicitis (McBurney’s point) can be marked as two-thirds of the distance from the umbilicus towards the anterior superior iliac spine.

Question 35

Definition of the groin

Answer 35

• The region betweem ASIS and pubic tubercle (abdomen and the lower limb)
• Denoted by “inguinal”

Question 36

Inguinal ligament

Answer 36

• A dense band from Inferiormost part of aponeurosis of external oblique muscle
• Insert into pubic tubercle

Question 37

Lacunar ligament

Answer 37

• archingligament
• attached to the superior pubic ramus lateral to the tubercle
• the lower and medial end of the external oblique aponeurosis that reflects backward on the inguinal ligament

Question 38

Pectineal ligament

Answer 38

• from inferiormost, medial part of external oblique aponeurosis
• most lateral of fibers from lacunar ligament that run along the pecten pubis

Question 39

conjoint tendon

Answer 39

• formed by the lower and medial end of the fibers coming from the internal oblique and tranversus abdominis muscles.
• pubic attachments of internal oblique and transversus abdominis aponeuroses frequently merge into this common tendon

Question 40

Inguinal canal (function, position and length)

Answer 40

• an oblique passage ~4cm long
• lies parallel and superior to medial half og inguinal ligament
• Main occupant of inguinal canal is spermatic duct in males and round ligament of uterus in females
• also contains blood and lymphatic vessels, and the ilioinguinal nerve
• is the connection between deep and superficial inguinal rings

Question 41

Inguinal canal boundaries

Answer 41

1) Anterior wall - formed by the external oblique aponeurosis throughout the length of the canal; lateral part reinforced by internal oblique muscle fibres
2) Posterior wall - formed by the transversalis fascia; medial part reinforced by the conjoint tendon (aka inguinal falx) and the reflected inguinal ligament.
3) Roof - laterally by the transversalis fascia, centrally by musculoaponeurotic arches of the internal oblique and transversus abdominis, and medially by the external oblique aponeurosis.
4) Floor - laterally by the iliopubic tract, centrally by infolded inguinal ligament, and medially by the lacunar ligament

Question 42

Inguinal canal openings

Answer 42

1) Deep Inguinal Ring

• lateral end of inguinal canal
• represents the point where the testis first pushed through the wall
• an opening through fascia transversalis
• edges of this ring give rise to the internal spermatic fascia of the spermatic cord.
• lateral to inferior epigastric vessels

2) Superficial Inguinal Ring

• medial end of inguinal canal
• from which the testis appeared
• an opening through the external oblique aponeurosis
• margins give rise to the external spermatic fascia of the spermatic cord.
• SIR can be felt at the upper lateral part of the scrotum.

Question 43

Development of inguinal canal

Answer 43

The male and female genital organs first develop in the embryo high on the posterior abdominal wall just outside (superficial) the peritoneum.

Later on, in the fetus, they start to move downwards, guided by a fibromuscular cord called the gubernaculum.

The female genital organs, the ovaries, move into the pelvis. The male genital organs, the testes, move further and start to descend into a bag of skin called the scrotum.

The final phase of their journey is through the anterior abdominal wall - through the inguinal canal. As the testes pass through the canal, they do not break the layers of the wall, but push them in front in it as coverings. The testis drags its duct (ductus (vas) deferens), blood, lymphatics and nerves with it. In 96% of newborn male infants, the testis has reached the scrotum, so that at birth and afterwards in the normal male, the inguinal canal is filled with duct, vessels and nerves.

Just as the testis reaches the deep inguinal ring, it pushes a loop of peritoneum in front of it through the canal. This loop is called the processus vaginalis and the loop passes right down into the scrotum almost surrounding the testis.

Question 44

gubernaculum

Answer 44

A fibromuscular cord that connects:

in male: Primodial testis with anterolateral abdominal wall (later site of deep inguinal ring)

in female: Ovaries and Primordial uterus to the developing labium majus [represented postnatally by ovarian ligament and round ligament of uterus]

Question 45

processus vaginalis

Answer 45

Just as the testis reaches the deep inguinal ring, it pushes a loop of peritoneum in front of it through the canal. This loop is called the processus vaginalis and the loop passes right down into the scrotum almost surrounding the testis.

• distal stalk of processus vaginalis usually degenerates
• Distal end, however, will form the tunica vaginalis - the serous sheath of testis and epididymus

Question 46

Tunica vaginalis

Answer 46

the serous sheath of testis and epididymus

• derived from distal end of processus vaginalis

Question 47

Spermatic cord position and function

Answer 47

Begins at the deep inguinal ring lateral to inferior epigastric vessels, passes through the inguinal canal, exits through superficial inguinal ring, ends in the scrotum at posterior border of testes

• contains structures running to and from the testis and suspends the testis in the scrotum

Question 48

Spermatic Cord coverings

Answer 48

(superficial to deep)

1) Skin continuous with scrotum

2) External spermatic fascia (derived from external oblique muscle)

3) Cremasteric fascia with loops of cremaster muscles (derived from internal oblique muscle)

4) Internal spermatic fascia (derived from transversalis fascia)

5) Vestige of processus vaginalis

6) Contents of spermatic cords

Note: Transversus abdominis muscle does not contribute to any layers in spermatic cord

Question 49

Spermatic Cord contents

Answer 49

i) Vestige of provessus vaginalis
ii) Ductus deferens
iii) Lymphatic vessels
iv) Blood Vessels

• testicular A/V
• artery to vas deferens
• cremasteric A/V
• Pampiniform venous plexus

v) Nerves

• ANS
• Genital branch of genitofemoral nerve (L1-L2)

Question 50

hernia (definition, common form)

Answer 50

A hernia is a protrusion of a structure from the cavity in which it is normally found.

• Most hernias are formed by intestines pushing out of the abdominal cavity.
• The most common hernia of all is an inguinal hernia in males and is found in the lower part of the anterior abdominal wall, either side of the midline.

Question 51

Clinical significance of inguinal canal

Answer 51

Inguinal canal is a point of weakness in the abdominal wall, which the small intestine can try to push through, leading to inguinal hernia.

There are two kinds of inguinal hernia - direct and indirect.

Question 52

Why is inguinal hernia a clinical emergency?

Answer 52

Inguinal hernia (or any abdominal hernia) is dangerous because:

• as the intestine pushes further out of the abdomen, the blood vessels on the outside of its walls may get squeezed shut (occluded). Once the blood supply of this segment of intestine is lost, it will die. Its wall will gradually decompose and its contents (not sterile) can then leak out into the surrounding cavity, leading to infection. This infection of the cavity, which is called peritonitis, is rapidly fatal unless aggressively treated.

Question 53

Indirect inguinal Hernia

Answer 53

• Indirect inguinal hernia involves abdominal contents pushing down the inguinal canal alongside the spermatic cord through the entire length of the canal - deep ring to superficial ring.
• The hernia lies within the coverings of the cord, and may pass right down into the scrotum.
• typically found in young males. More common in male than female
• Maybe congenital, associated with the failure of close off of the processus vaginalis. Normally, this obliterates at the deep inguinal ring at birth (thus, sealing off the processus from the peritoneum) but, in a fraction of males, it remains open, providing a ready-made path for intestine to pass down.
• May be due to widening and weakening of Deep Inguinal Ring

- Lateral to Inferior epigastric vessels

Question 54

Direct Inguinal Hernia

Answer 54

• Direct inguinal hernia involves a direct push through the posterior wall of the canal through the superficial inguinal ring.
• A hernia may bulge into the superficial inguinal ring, but it lies outside the coverings of the spermatic cord and cannot pass down into the scrotum.
• generally found in older males (who haven’t been doing their abdominal exercises)
• results from weakening of the abdominal wall just lateral to the superficial ring and the margin of the rectus abdominis. Here, the posterior wall of the inguinal canal consists of transversalis fascia and the conjoint tendon.
• Medial to the inferior epigastric vessels
• Common site: Inguinal triangle (Hesselbach triangle)

Question 55

Difference between direct and indirect inguinal Hernia

Answer 55

(indirect vs direct)

• site: [lateral to inferior epigastric vessels] vs [medial to inferior epigastric vessels]
• [may enter scrotum] vs [cannot enter scrotum]
• [Through both deep and superficial inguinal ring] vs [through superficial but not deep inguinsl ring]
• [within scrotal covering
• [affects younger males] vs [affects older males]
• [usually congenital] vs [usually acquired]

Question 56

Inguinal Triangle

Answer 56

• aka Medial Inguinal Fossa or Hesselbach Triangle
• *Medial border:** Lateral margin of the rectus sheat
• *Superolateral border:** Inferior epigastric vessel
• *Inferior border:** Inguinal ligament
• Potential site for less common direct inguinal hernia

Question 57

Femoral canal

Answer 57

• Entry point is femoral ring

anterosuperiorly bounded by the inguinal ligament

posteriorly bounded by the pectineal ligament

medially bounded by the lacunar ligament

laterally bounded by the femoral vein

• through femoral ring bowel can sometimes enter, causing a femoral hernia.

Question 58

Membrane lining the abdominal cavity

Answer 58

Peritoneum

Question 59

Peritoneum defintion

Answer 59

A continuous, slippery, transparent serous membrane that lines the abdominopelvic cavity and invests the viscera.

Consists of mesothelium, a layer of simple squamous epithelial cells

divided into parietal and visceral layers

Question 60

Visceral peritoneum

Answer 60

Peritoneum that invests viscera such as the stomach and intestines

Question 61

Parietal peritoneum

Answer 61

Peritoneum that lines internal surface of abdominopelvic wall

Question 62

Function of peritoneum

Answer 62

1) Protection of viscera
2) Entry of blood vessels and lymphs and nerves
3) Support the visceral organs
4) Lubrication by secretion of peritoneal fluid

Question 63

Peritoneal fluid

Answer 63

Peritoneal fluid is the thin layer of serous fluid secreted by the peritoneum in the peritoneal cavity that

1) lubricates the peritoneal surfaces, allowing:

• viscera to move over each other without friction
• movements of digestion

2) resists infection (as it contains leukocytes and antibodies)

Usually ~50mL (In Ascites, peritoneal fluid greater than 50mL)

Question 64

Intraperitoneal organs

Answer 64

• Organs almost completely covered with visceral peritoneum
• aka “completely peritonealized”
• All of these organs hang by a double layered band or fold of peritoneum from the posterior abdominal wall (except the liver which has a attachment with the anterior abdominal wall). Mostly, these bands or folds are called mesenteries but some with an attachment to the stomach get the name “omentum” and others may be called “ligaments”. Within these bands lie blood vessels, nerves and lymphatics.

Question 65

Extraperitoneal organs

Answer 65

• organs external to the parietal peritoneum
• only partially covered with parietal peritoneum (usually on one surface only)
• Retroperitoneal organs refers to extraperitoneal organs between parietal peritoneum and posterior abdominal wall (parietal peritoneum covers anterior surfaces)
• Infraperitoneal/ subperitoneal organs are extraperitoneal organs beneath the parietal peritoneum (parietal peritoneum covers superior surfaces)

Question 66

Mesentery

Answer 66

Mesentery is a two-layered fold of peritoneum that attaches part of the intestines to the posterior abdominal wall

e.g. mesentery of the small intestine, transverse mesocolon, sigmoid mesocolon.

Question 67

Omentum

Answer 67

Omentum is a two-layered fold of peritoneum that connects a stomach (and proximal duodenum) to other organs, e.g:

• Greater omentum (stomach to transverse colon)
• Lesser omentum (stomach to porta hepatis of liver)
• Gastrosplenic omentum (stomach to the hilus of spleen)

Question 68

Peritoneal ligaments

Answer 68

Peritoneal ligaments are two layered folds of peritoneum that connects a solid viscera to the anterior abdominal wall, e.g.

• falciform ligament (AAW with liver)
• coronary ligament
• right and left triangular ligaments

Question 69

omental bursa

Answer 69

• An extensive sac-like cavity that lies posterior to the stomach, lesser omentum, and adjacent structures.
• aka lesser sac
• Permits free movement of the stomach on the structures posterior and inferior to it
• Communicates with the greater sac via omental foramen (aka epiploic foramen or foramen of Winslow) situated on the right side, posterior to the free edge of lesser omentum

Question 70

Greater omentum

Answer 70

• A prominent, four-layered peritoneal fold that hangs down from the stomach
• Descends, amd folds back to attach to transverse colon
• contains variable amounts of fat and lymphocytes
• if there is infection or irritation, then this sheet tends to migrate to cover the area
• surgeons opening the abdomen can use the position of the greater omentum to try to discover the site of a clinical problem
• dubbed “policeman of the abdomen”

Question 71

Lesser omentum

Answer 71

A double-layered peritoneal fold that connects stomach (and proximal part of duodenum) to the liver. It contains:

1) Hepatogastric ligament, a membraneous portion (liver to stomach)
2) Hepatoduodenal ligament, the thickened free edge (liver to duodenum), which contains the portal triad or hepatis:

• Hepatic artery
• Bile duct
• Hepatic Portal Vein

Question 72

Labelling Left lateral view of Peritoneal Cavity

Answer 72

Question 73

Autonomic Supply of abdominal cavity

Answer 73

1) Celiac plexus/ ganglion (2 celiac ganglia are located on the abdominal aorta at the origin of the celiac trunk)

Question 74

Thoracic splanchnic nerve

Answer 74

Neurons in intermediolateral cell column of spinal levels T5-T12; nerves appear to arise by multiple contributions from sympathetic trunk; sympathetic in nature; divided into:

1) Greater splanchnic nerve (T5-T9)
2) Lesser splanchnic nerve (T10-T11)
3) Least splanchnic nerve (T12)

Greater and Lesser splanchnic nerve runs through celiac plexus, superior mesenteric plexus; Lesser runs through aorticorenal ganglia; least enters renal plexus

Question 75

Aortic plexus

Answer 75

Plexus on top of abdominal aorta

(from superior to inferior)

1) Celiac ganglion/ plexus

• 2 celiac ganglia are located on the abdominal aorta at the origin of the celiac trunk
• [sympathetically supplied by greater splanchnic nerve T5-T9, lesser splanchnic nerve T10-T11; parasympathetically CNX]
• Supplies foregut

2) Superior mesenteric ganglion/ plexus

• ganglia located on the abdominal aorta at the origin of superior mesenteric artery
• [sympathetically supplied by greater splanchnic nerve T5-T9, lesser splanchnic nerve T10-T11; parasympathetically CNX]
• Supplies midgut

3) Intermesenteric plexus

• plexus located on abdominal aorta between origin of superior and inferior mesenteric arteries
• [sympathetically supplied by lesser splanchnic nerve T10-T11, lumbar splanchnic nerve L1-L2; parasympathetically not supplied]
• Communication between superior and inferior mesenteric plexus

4) Inferior mesenteric ganglion/ plexus

• ganglia located on the abdominal aorta at the origin of inferior mesenteric artery
• [sympathetically supplied by lumbar splanchnic nerve L1-L2; parasympathetically supplied by pelvic splanchnic nerve S2-S4]
• Supplies hindgut

Question 76

Foregut overview

Answer 76

Boundary: Lower 1/3 of esophagus to mid part of second segment of duodenum

Blood supply: Celiac trunk, portal vein

Nerve supply: Celiac plexus

Lymph: Celiac node

Question 77

Midgut overview

Answer 77

Boundary: Mid part of second segment of duodenum to proximal 2/3 of transverse colon

Blood supply: Superior mesenteric artery, superior mesenteric vein

Nerve supply: Superior mesenteric plexus

Lymph: Superior mesenteric node

Question 78

Hindgut overview

Answer 78

Boundary: Distal 1/3 of transverse colon to upperhalf of anal canal

Blood supply: Inferior mesenteric artery, inferior mesenteric vein

Nerve supply: Inferior mesenteric plexus

Lymph: Inferior mesenteric node

Question 79

Branches of Celiac trunk

Answer 79

3 Major branches (mneumonic LHS):

A) Left gastric artery

B) Common Hepatic artery, which branches to form:

1) Right gastric artery
2) Gastroduodenal artery, which forms:

i) Right gastroepiploic artery
ii) Superior pancreaticoduodenal artery

3) Hepatic artery proper, which forms:

i) Left hepatic artery
ii) Right hepatic artery

C) Splenic artery, which branches to form:

1) Short gastric arteries
2) Left gastroepiploic artery

Question 80

Branches of Superior mesenteric artery

Answer 80

1) Inferior pancreaticoduodenal artery
2) Middle colic artery
3) Right colic artery
4) Ileocolic artery
5) Jejunal arteries
6) Ileal arteries
7) Appendicular/appendiceal artery
8) Ceacal artery

Question 81

Branches of inferior mesenteric artery

Answer 81

1) Left colic artery
2) Sigmoid artery
3) Superior rectal artery

Question 82

Lymph vessels and nodes of Posterior Abdominal Wall

Answer 82

Yet ot be added

Question 83

Branches of Celiac trunk

Answer 83

3 Major branches (mneumonic LHS):

A) Left gastric artery

B) Common Hepatic artery, which branches to form:

1) Right gastric artery
2) Gastroduodenal artery, which forms:

i) Right gastroepiploic artery
ii) Superior pancreaticoduodenal artery

3) Hepatic artery proper, which forms:

i) Left hepatic artery
ii) Right hepatic artery

C) Splenic artery, which branches to form:

1) Short gastric arteries
2) Left gastroepiploic artery