Peritoneal Cavity and Abdomen Wall Muscles

Question 1

What separates the thoracic and abdominal cavity

Answer 1

Diaphragm

Question 2

The peritoneal cavity is lined with what cells?

What is produced?

Answer 2

Lined with mesothelium (flatted simple squamous epithelium)

A lubricating serous fluid is produced (by the mesothelium)

Question 3

Compare Intra- and Retro-Peritoneal Organs

Answer 3

Intra-peritoneal: Organs enveloped by peritoneum

Retroperitoneal: Behind peritoneum (Peritoneum in contact with anterior surface of these organs)

Question 4

Name 3 Intra and 3 Retro Peritoneal Organs

Answer 4

Intra:

• Liver
• Stomach
• Small Intestine

Retro:

• Vertebrae
• Ascending Colon
• Kidney

Question 5

Are Intraperitoneal organs within the peritoneal cavity?

Answer 5

No, but they are enveloped within the cavity

Question 6

Compare the Visceral and Parietal Peritoneum

Answer 6

Visceral: Envelopes viscera
Parietal: Lines cavity wall

Question 7

What is the Mesentery of the GI Tract (A newly classified organ)

What does it allow?

Answer 7

• A double fold of peritoneum that attaches certain viscera to the the posterior abdominal wall (Holds them in place)
• Allows passage of blood and lymph vessels from Retroperitoneal space to organs without breaching peritoneal cavity

Question 8

What is a Peritoneal Ligament?

Answer 8

A double fold of peritoneum that connects two viscera together

Question 9

What is an Aponeurosis?

What is the Linea Alba?

Answer 9

A flattened tendon (thin and sheet like)

A thick, fibrous band that extends from the Xiphoid Process of Sternum to the Pubic Symphysis

Question 10

List the Anterolateral Abdominal Wall Muscles and identify which groups they’re in

Answer 10

Flat;

• External Oblique (Runs Inferiomedially)
• Internal Oblique (Runs Superomedially)
• Transversus Abdominis

Vertical;

• Rectus Abdominis
• Pyramidalis

Question 11

Pyramidalis is a small muscle, superficial to Rectus Abdominis.

State its Origin, Insertion and Action

Answer 11

Origin: Pubic Symphysis and Pubic Crest
Insertion: Linea Alba

Action: Tenses Linea Alba

Question 12

State the Origins and Insertions of External Oblique (It moves Inferomedially)

Explain why this muscle actually forms one of its insertions

Answer 12

O: Ribs 5-12
Ins: Iliac crest, Inguinal Ligament, Linea Alba

The Inguinal Ligament is actually a thickened roll of the External Oblique as it extends from the ASIS to the Pubic Symphysis

Question 13

List the actions of External Oblique

Answer 13

• Compress Abdominal Vicera
• Trunk flexion (Both sides contract)
• Contralateral trunk rotation

Question 14

State the Origins and Insertions of Internal Oblique (Perpendicular to External Oblique)

Answer 14

O: Lateral Inguinal Ligament, Iliac crest, Thoracolumbar Fascia

Ins: Linea Alba, Lower Ribs (10-12), Pubic Crest

Question 15

List the actions of Internal Oblique

Answer 15

• Compress abdominal viscera
• Trunk flexion (Both sides contract)
• Ipsilateral Trunk rotation

Question 16

The Lateral Abdominal muscles have an unusually extensive aponeurosis.

Which parts of the muscles are aponeuroses

Answer 16

Envelop the midline Rectus Abdominis muscles

Question 17

Is Rectus Abdominis or Transversus Abdominis deeper?

Answer 17

Transversus Abdominis

Question 18

State the Origins, Insertions and Actions of Transversus Abdominis

Answer 18

O: Costal cartilages of lower ribs (7-12), Thoracolumbar Fascia, Iliac crest, Inguinal ligament

Ins: Linea Alba, Pubic Crest

A: Compression of viscera + Core stability

Question 19

State the Innervations of the 3 Lateral Abdominal wall muscles

Answer 19

External Oblique- T7 to T12, L1
Internal Oblique- T7 to T12, L1
Transversus Abdominis- T7 to T12

Question 20

What is deep to Transversus Abdominis?

Answer 20

Transversalis Fascia

Question 21

State the origins and insertions of Rectus Abdominis

What do you call the surface marking made by the lateral borders?

Answer 21

O: Pubic crest and Symphysis
Ins: Xiphoid process and Costal cartilages 5-7

Linea semilunaris

Question 22

At several places the Rectus Abdominis is intersected by Fibrous Strips, what are these called?

Answer 22

Tendinous Intersections (These along with the Linea Alba give us the appearance of a 6 pack)

Question 23

List the actions of Rectus Abdominis

Answer 23

• Assists the flat muscles in compression of viscera
• Stabilises pelvis during walking
• Depresses ribs

Question 24

What is the Rectus Sheath

Answer 24

The apouneuroses of the 3 lateral muscles surrounding the Rectus Abdominis (both posteriorly and anteriorly)

Question 25

Identify what make up the Anterior and Posterior walls of the Rectus Sheath

Answer 25

Anterior: Aponeuroses of External Oblique and of half of Internal Oblique

Posterior: Aponeuroses of half of Internal Oblique and Transversus Abdominis

Question 26

Where is the Arcuate Line?

How does the Rectus Sheath change as it crosses this line inferiorly.

Answer 26

Halfway between Umbilicus and Pubic Symphysis

All the aponeuroses of the Rectus Sheath move anterior to Rectus Abdominis

Question 27

Below the Arcuate Line, what lies posterior to Rectus Abdominis

(These were also present above the Arcuate Line)

Answer 27

• Transversalis Fascia

- Parietal Peritoneum

Question 28

List 9 Retroperitoneal organs

Remember: SAD PUCKER

Answer 28

Suprarenal Glands (Adrenal glands)
Aorta + IVC
Duodenum

Pancreas (except tail)
Ureters
Colon (Descending and ascending)
Kidneys 
Esophagus
Rectum