Abdominal Muscles

Question 1

What are the two main groups of muscles in the abdominal wall?

Answer 1

Flat muscles

Vertical muscles

Question 2

Name the flat muscles

Answer 2

External oblique

Internal oblique

Transversus abdominis

Question 3

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

Answer 3

Inferomedially

Question 4

Origin and attachments of the external obliques?

Answer 4

Origins: ribs 5-12

Attachments: linea alba, pubic tubercle, anterior half of iliac crest

Question 5

Innervation of the external oblique?

Answer 5

Thoracoabdominal nerve (T7-11)

Subcostal

Question 6

Action of the external oblique?

Answer 6

Compresses and supports viscera

Flexes and rotates trunk

Question 7

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

Answer 7

Superiormedially

Question 8

Innervation of the internal oblique?

Answer 8

Thoracoabdominal nerves (T6-T12)

First lumbar nerves

Question 9

Action of the internal obliques?

Answer 9

Same as external

Compress and support viscera

Flex and rotate trunk

Question 10

In which direction do the fibres of transversus abdominis run?

Answer 10

Transversely

Question 11

Innervation of the transversus abdominis?

Answer 11

Same as internal oblique

Thoracoabdominal nerves T6-T12

First lumbar nerves

Question 12

Name the vertical muscles

Answer 12

Rectus abdominis

Pyramidalis

Question 13

Attachments of the rectus abdominis?

Answer 13

Origin: pubic symphysis and pubic crest

Attachments: xiphoid process and costal cartilages 5-7

Question 14

Innervation of the rectus abdominis?

Answer 14

Thoracoabdominal nerves (anterior rami of T6-T12)

Question 15

Action of the rectus abdominis?

Answer 15

Flexes trunk

Compresses abdominal viscera

Stabilised and controls tilt of pelvis

Question 16

Where is the pyramidalis found?

Answer 16

Superficially to the rectus abdominis

Question 17

Attachments of the pyramidalis?

Answer 17

Anterior surface of the pubis and anterior pubic ligament

Ends in linea alba

Question 18

Action of the pyramidalis?

Answer 18

Tenses linea alba

(Not present in 20% of population)

Question 19

Name this muscle

Answer 19

External oblique

Question 20

Name this muscle

Answer 20

Rectus abdominis

Question 21

Name this muscle

Answer 21

Intenal oblique

Question 22

Name this muscle

Answer 22

Pyramidalis

Question 23

Name this muscle

Answer 23

Transversus abdominis