Muscles of the Thoracic wall - Dissections

Question 1

Rectus Abdominis:

Orgin?
Insertion?
Innervation?

Answer 1

Pubic Tubercle
between the symphysis

Costal Cartilage 5-7

Intercostal nerves

Question 2

Rectus Abdominis:

Function?

Answer 2

Tenses the anterior wall
Flexion of the lumbar spine
Intrabdominal pressure
Respiration

Question 3

Pyrimidalis:

Origin?
Insertion?
innervation?

Answer 3

Pubic Bone

Linea Alba

Subcostal Nerves/ 12 intercostal nerves

Question 4

External Oblique:

Origin?
Insertion?
innervation?

Answer 4

5-12 ribs
half of the iliac crest
intercostal nerves T7 - T12

Question 5

External Oblique:

Function?

Answer 5

Unilateral contraction; Contralateral rotation

Bilateral contraction:
Flexion of the lumbar spine

Forced Exhalation - increase Intraabdominal pressure

Question 6

Internal Oblique:

Origin?
Insertion?
innervation?

Answer 6

Thoracolumbar fascia
Iliac crest
Inguinal ligament

cranially - ribs 10-12
Linea Alba
In men - spermatic chord

Intercostal nerves T7-T12
Iliohypogastric nerve
Ilinguinal nerve

Question 7

Internal Oblique:

Function?

Answer 7

Unilateral contraction
ipsilateral rotation and
ipsilateral flexion

Bilateral contraction:
flexion of lumbar spine
forced exhalation - increase intrabdominal pressure

Question 8

Transverse Abdominis?