Lecture 15 - Muscles of the Abdominal Wall

Question 1

What muscles make up the anterolateral abdominal wall?

*What functions do they serve when working together?

Answer 1

A) 3 pairs of flat muscles:

• external obliques (most superficial)
• internal obliques
• transversus abdominus (most deep)

B) 1 pair of vertical muscles:
- rectus abdominus

• they compress and support abdominal organs

Question 2

Describe the fibre direction of the external oblique

Answer 2

Antero-inferior

Also known as “hands in pocket”

Question 3

What forms the inguinal ligament?

Answer 3

The inferior edge of the aponeurosis of external oblique

Question 4

Describe the fibre direction of the internal oblique

Answer 4

Anterosuperior; opposite to external oblique

Question 5

Describe the fibre direction of transversus abdominus

Answer 5

Horizontal

Question 6

What is the literal meaning of linea alba?

Answer 6

White line

Question 7

Where do the aponeuroses of the 3 flat muscles meet?

Answer 7

In the midline at the linea alba

Question 8

List the functions of the 3 flat abdominal muscles

Answer 8

• compress and support the abdominal viscera

- trunk rotation and flexion

Question 9

Describe the structure and path of the rectus abdominus

Answer 9

• Bilateral muscle

- runs vertically between the ribs and the pubic symphysis

Question 10

What creates the seperation of the muscle we refer to as 6-pack?

Answer 10

Tendinous intersections

Question 11

The inguinal ligament runs from what point to what point?

Answer 11

ASIS to pubic tubercle

Question 12

What forms the rectus sheath?

Answer 12

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

Question 13

Describe the diaphragm

Answer 13

dome shaped muscle separating the thorax and the abdomen

Question 14

From where to where does the diaphragm attach?

Answer 14

Attaches from the periphery to the margins of the thoracic cage and superior lumbar vertebrae

Question 15

What forms the central tendon? What is its function?

Answer 15

• When muscle fibres of the diaphragm converge

- supports the weight of the heart

Question 16

List the names and locations of the 3 openings in the diaphragm

Answer 16

• caval opening @ T8 for inferior vena cava
• esophageal hiatus @ T10 for esophagus
• aortic hiatus @ T12 for aorta

Question 17

List the ligaments of the diaphragm and muscles they arch over

Answer 17

• Median arcuate ligament : aorta
• 2 Medial arcuate ligament : psoas major
• 2 Lateral arcuate ligament : quadratus lumborum

Question 18

List the muscles located in the posterior abdominal wall

Answer 18

• Psoas major
• Iliacus
• Quadratus Lumborum

Question 19

In animals, psoas is known as?

Answer 19

Tenderloin

Question 20

What happens at the lumbar plexus?

Answer 20

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

Question 21

List the terminal branches in the lumbar plexus

Answer 21

• Femoral nerve
• Obturator nerve
• Lumbosacral trunk