KIN 100 - Muscles of the Abdominal Wall (lecture 15)

Question 1

What is the abdominal wall subdivided into

Answer 1

• the anterior wall
• right and left lateral walls
• posterior wall

Question 2

Describe the anterolateral wall and what is it’s function

Answer 2

The boundary between anterior and lateral wall
- Muscles work together to compress and support the abdominal organs

Question 3

How many pairs of muscles are located in the anterolateral abdominal wall

Answer 3

4; 3 pairs of flat muscles and 1 pair of vertical muscles

Question 4

What are the three pairs of flat muscles of the anterolateral abdominal wall (from superficial to deep)

Answer 4

1. External oblique
2. Internal oblique
3. Transversus abdominus

Question 5

What is the pair of vertical muscles in the anterolateral abdominal wall

Answer 5

Rectus abdominus

Question 6

Describe the fibre direction of the external oblique

Answer 6

“anteroinferior” and “hands in pocket”

Question 7

What structure forms the inguinal ligament

Answer 7

The inferior edge of the aponeurosis of external oblique

Question 8

Describe the fibre direction of the transversus abdominus

Answer 8

horizontal

Question 9

Describe the fibre direction of the internal oblique

Answer 9

“anterosuperior”

Question 10

Where do all muscles of the anterolateral abdominal wall meet in the midline

Answer 10

linea alba

Question 11

What are the functions of all the muscles of the anterolateral abdominal wall

Answer 11

• compress and support the abdominal viscera
• Flex and rotate the trunk

Question 12

Describe the rectus abdominus

Answer 12

a bilateral muscle that runs vertically between the ribs and the pubic symphysis
- 6 pack
- left and right muscles separated by linea alba

Question 13

Describe how the aponeuroses is formed

Answer 13

aponeuroses of the external oblique crosses the midline and blend with the fibres of the contralateral internal oblique aponeuroses

The aponeuroses form a sheath around the rectus abdominus muscle

Question 14

Describe the diaphragm

Answer 14

A domed muscle that separates the thorax from the abdomen

Question 15

Diaphragm attachment

Answer 15

attached to the periphery to the margins of the thoracic cage and the superior lumbar vertabrae

Question 16

What do the muscle fibers of the diaphragm converge to form

Answer 16

the central tendon (supports the weight of the heart)

Question 17

What are the three openings in the diaphragm

Answer 17

1. Caval opening for the inferior vena cava at the level of T8
2. Esophageal hiatus for the esophagus at the level of T10
3. Aortic hiatus for the aorta at the level of T12

Question 18

How many ligaments can be seen from the inferior view of the diaphragm

Answer 18

5 :
midline median arcuate ligament
bilateral medial arcuate ligaments
bilateral lateral arcuate ligaments

Question 19

Midline median arcuate ligament

Answer 19

arches over the abdominal aorta and forms the aoritc hiatus

Question 20

Bilateral medial arcuate

Answer 20

arch over the psoas major muscles

Question 21

Bilateral lateral arcuate ligaments

Answer 21

arch over the quadratus lumborum muscles

Question 22

What are the 3 pairs of muscles located in the posterior abdominal wall

Answer 22

1. Psoas major
2. Iliacus
3. Quadratus lumborum

Question 23

Psoas major

Answer 23

Proximal attachment: Lateral aspect of lumbar vertebrae

Distal attachment: Lesser trochanter of femur

Actions:
- Thigh flexion
- Trunk flexion (when contracting bilaterally)
- Trunk lateral flexion (when contracting unilaterally)

Question 24

Iliacus

Answer 24

Proximal attachment: iliac fossa

Distal attachment: Lesser trochanter of femur

Action: Thigh flexion

Question 25

Quadratus lumborum

Answer 25

Proximal attachment: 12th rib and transverse process of lumbar vertebrae

Distal attachment: Iliac crest

Actions:
- Trunk extension (when contracting bilaterally)
- Trunk lateral flexion (when contracting unilaterally)

Question 26

Describe how the lumbar plexus is formed

Answer 26

Lumbar spinal nerves (L1-L5) exit the intervertebral foramina and their interior rami of plexus of nerves within the psoas major muscle

Question 27

What are the terminal branches of the lumbar plexus

Answer 27

• Femoral nerve
• Obturator nerve
• Lumbosacral trunk