Muscles of the anterolateral abdominal wall

Question 1

How many large muscles are on either side of the midline of the anterolateral abdominal wall?

Answer 1

Four � external oblique, internal oblique, transversus abdominis, rectus abdominis

Question 2

Name the two small muscles in the anterolateral abdominal wall.

Answer 2

Cremaster and pyramidalis

Question 3

What structure is formed by the decussation of aponeuroses at the midline?

Answer 3

Linea alba

Question 4

What muscle runs vertically on either side of the linea alba?

Answer 4

Rectus abdominis

Question 5

From where does the external oblique muscle originate?

Answer 5

Outer surfaces of the middle of the shaft of the lower eight ribs

Question 6

In what direction do the fibres of the external oblique run?

Answer 6

Downwards, forwards, and medially

Question 7

Where are most of the fibres of the external oblique muscle inserted?

Answer 7

Xiphoid process, linea alba, pubic symphysis, pubic crest, and pectineal line

Question 8

Into which structure are the lower fibres of the external oblique inserted?

Answer 8

Anterior two-thirds of the outer lip of the iliac crest

Question 9

What nerves supply the external oblique muscle?

Answer 9

Lower six thoracic nerves

Question 10

Which muscles interdigitate with the upper and lower slips of the external oblique?

Answer 10

Serratus anterior (upper four), latissimus dorsi (lower four)

Question 11

What forms the inguinal ligament?

Answer 11

The free inferior border of the external oblique aponeurosis folded on itself

Question 12

What does the aponeurosis of the external oblique form between the linea semilunaris and the linea alba?

Answer 12

Anterior wall of the rectus sheath

Question 13

What is the superficial inguinal ring?

Answer 13

A triangular aperture in the external oblique aponeurosis above the pubic crest

Question 14

Where does the internal oblique muscle originate?

Answer 14

Lateral two-thirds of the inguinal ligament, anterior two-thirds of the intermediate iliac crest, and thoracolumbar fascia

Question 15

In what direction do the fibres of the internal oblique run?

Answer 15

Upwards, forwards, and medially

Question 16

Where are the uppermost fibres of the internal oblique inserted?

Answer 16

Lower three or four ribs and their cartilages

Question 17

What nerves supply the internal oblique muscle?

Answer 17

Lower six thoracic nerves and first lumbar nerve

Question 18

How does the internal oblique aponeurosis contribute to the rectus sheath in the upper three-fourths of the wall?

Answer 18

Splits into an anterior and posterior lamina

Question 19

What is the arcuate line?

Answer 19

Free lower margin of the posterior lamina of the internal oblique aponeurosis

Question 20

What does the internal oblique form along with the transversus abdominis?

Answer 20

Conjoint tendon

Question 21

What muscle is formed by fibres of the internal oblique?

Answer 21

Cremaster muscle

Question 22

From where does the transversus abdominis originate?

Answer 22

Lateral one-third of inguinal ligament, anterior two-thirds of inner lip of iliac crest, thoracolumbar fascia, inner surfaces of lower six costal cartilages

Question 23

In what direction do the fibres of the transversus abdominis run?

Answer 23

Horizontally forwards

Question 24

Where is the transversus abdominis inserted?

Answer 24

Xiphoid process, linea alba, pubic crest, and pectineal line

Question 25

What nerves supply the transversus abdominis muscle?

Answer 25

Lower six thoracic nerves and first lumbar nerve

Question 26

Where does the aponeurosis of the transversus abdominis pass in relation to the rectus abdominis above the arcuate line?

Answer 26

Behind the rectus abdominis

Question 27

Where does the aponeurosis of the transversus abdominis pass in relation to the rectus abdominis below the arcuate line?

Answer 27

In front of the rectus abdominis

Question 28

What lies between the internal oblique and transversus abdominis muscles?

Answer 28

Neurovascular plane

Question 29

From where does the rectus abdominis muscle originate?

Answer 29

Lateral and medial parts of the pubic crest and anterior pubic ligament

Question 30

Where is the rectus abdominis inserted?

Answer 30

5th, 6th, and 7th costal cartilages and xiphoid process

Question 31

What nerves supply the rectus abdominis?

Answer 31

Lower six or seven thoracic nerves

Question 32

What are tendinous intersections in the rectus abdominis?

Answer 32

Three transverse fibrous bands dividing the muscle

Question 33

Which muscle is most responsible for flexion of the trunk?

Answer 33

Rectus abdominis

Question 34

Which muscles produce lateral flexion of the trunk?

Answer 34

Oblique muscles

Question 35

Which muscles produce rotation of the trunk?

Answer 35

External oblique + opposite internal oblique

Question 36

Which muscle depresses and compresses the lower part of the thorax for forceful expiration?

Answer 36

External oblique

Question 37

What function do the abdominal muscles have in expulsive acts like vomiting or coughing?

Answer 37

Compress abdominal viscera

Question 38

What forms the anterior wall of the rectus sheath below the arcuate line?

Answer 38

Aponeurosis of the internal oblique and transversus abdominis

Question 39

What forms the conjoint tendon?

Answer 39

Lowest fibres of the internal oblique and transversus abdominis

Question 40

What is the function of the conjoint tendon?

Answer 40

Strengthens the abdominal wall at the superficial inguinal ring

Question 41

Where does the inguinal ligament extend between?

Answer 41

Anterior superior iliac spine to the pubic tubercle

Question 42

What forms the lacunar ligament?

Answer 42

Medial end of the inguinal ligament

Question 43

What does the cremasteric reflex test for?

Answer 43

Integrity of the L1 spinal segment

Question 44

Which nerve is responsible for the cremasteric reflex?

Answer 44

Genital branch of the genitofemoral nerve

Question 45

What lies between the aponeurosis of the external oblique and the inguinal ligament?

Answer 45

Inguinal canal

Question 46

What makes the abdominal wall strong despite being thin?

Answer 46

Interdigitation of the aponeurotic laminae at the linea alba

Question 47

What role do the abdominal muscles play in respiration?

Answer 47

Assist in forceful expiration