Lecture 15: Muscles of the Abdominal Wall

Question 1

What walls is the abdominal wall subdivided into for descriptive purposes?

Answer 1

Anterior wall, right and left lateral walls, and posterior walls

Question 2

What are the muscles in the anterolateral abdominal wall?

Answer 2

3 pairs of flat muscles
- External oblique
- Internal oblique
- Tranversus abdominus
1 pair of vertical muscles
- Rectus abdominus

Question 3

What is the function of the anterolateral abdominal wall muscles?

Answer 3

• compress and support the abdominal organs

Question 4

What are the fibre direction of the 3 pairs of flat muscles?

Answer 4

External oblique: anteroinferior (“hands in pockets”)
Internal oblique: anterosuperior
Transversus abdominus: horizontal

Question 5

What are the functions of the 3 pairs of flat muscles?

Answer 5

• compress and support the abdominal viscera

- flex and rotate the trunk

Question 6

What’s an aponeurosis?

Answer 6

A thin, flat sheet of tendon

Question 7

What’s linea alba?

Answer 7

a white line

where all 3 flat muscles’ aponeuroses meet in the midline

Question 8

What’s the rectus abdominus and where does it run?

Answer 8

A bilateral muscle that runs vertically between the ribs and the public symphysis

Question 9

What is the rectus abdominus characterized by?

Answer 9

Tendinous intersections that create the separation of the muscle that we often refer to as the “6-pack”

Question 10

The inguinal ligament passes from the _____ to the _____.

Answer 10

ASIS to the public tubercle.

Question 11

What is the diaphragm?

Answer 11

A domed muscle that separated the thorax from the abdomen.

Question 12

What’s the central tendon?

Answer 12

Where the muscle fibres converge and support the weight of the heart

Question 13

What are the 3 openings in the diaphragm?

Answer 13

1) Caval opening at T8 (for the inferior vena cava)
2) Esophageal hiatus at T10 (for the esophagus)
3) Aortic hiatus at T12 (For the aorta)

Question 14

What are the 3 openings in the diaphragm for?

Answer 14

Passage of major structures from the thorax to the abdomen and vice versa

Question 15

What are the 5 ligaments in the diaphragm?

Answer 15

• midline median arcuate ligament (arches over abdominal aorta and forms aortic hiatus)
• bilateral medial arcuate ligament (arches over psoas major)
• bilateral lateral arcuate ligament (arches over quadratus lumborum)

Question 16

What are the three pairs of muscles in the posterior abdominal wall?

Answer 16

• psoas major
• Iliacus
• Quadratus lumborum

Question 17

What is known as tenderloin in animals?

Answer 17

Psoas Major

Question 18

What is the lumbar plexus?

Answer 18

Lumbar spinal nerves (L1 to L5) exit the intervertebral foramina and their anterior rami form a plexus of nerves within the psoas major muscles

Question 19

What are the terminal branches of the lumbar plexus?

Answer 19

• Femoral nerve
• Obturator nerve
• Lumbosacral trunk