Trunk Muscles/Abdominals

Question 1

RECTUS ABDOMINIS

Answer 1

O: pubic crest & pubic symphysis
I: xiphoid process, ribs 5-7 & their cartilages
N: intercostal nerve T5-T12
K: 
1) Flexion of the trunk @ spinal joints
2) Lateral flexion " " 
3) Posteriorly tilts the pelvis

Question 2

EXTERNAL ABDOMINAL OBLIQUE

Answer 2

O: *pubic bone: crest & tubercle*, anterior iliac crest, abdominal aponeurosis
I: inferior border of ribs 5-12
N: intercostal nerves T7-T12
K:
1) Flexion of the trunk @ spinal joints
2) Lateral flexion " "
3) Contralateral rotation " "
4) Posteriorly tilts the pelvis

Question 3

INTERNAL ABDOMINAL OBLIQUE

Answer 3

O: inguinal ligament, anterior iliac crest, thoracolumbar fascia
I: ribs 10-12 & abdominal aponeurosis
N: intercostal nerves T7-T12
K:
1) Flexion of the trunk @ spinal joints
2) Lateral flexion " "
3) Ipsilateral rotation " "
4) Posteriorly tilts the pelvis

Question 4

EXTERNAL INTERCOSTALS

Answer 4

Inferior border of ribs 1-11 –> superior border of rib directly inferior (ending with rib 12)
N: Intercostal nerves
K:
1) Elevation of ribs 2-12 at the sternocostal and costospinal joints
2) Contralateral rotation of the trunk
3) Fixation/stabilization of rib cage during other movements

Question 5

INTERNAL INTERCOSTALS

Answer 5

Superior border of ribs 2-12 –> inferior border of the rib directly superior (ending with rib 1)
N: Intercostal nerves
K:
1) Depression of ribs 1-11 at the sternocostal and costospinal joints
2) Ipsilateral rotation of the trunk
3) Fixation/stabilization of the rib cage during other movements

Question 6

DIAPHRAGM

Answer 6

O: internal surface of ribs 7-12 & their cartilages, internal xiphoid process, medial and lateral arcuate ligaments, left & right crura & bodies of L1-L3
I: central tendon
N: phrenic nerve (C3-C5)
K:
1) Increases volume of thoracic cavity

Question 7

TRANSVERSUS ABDOMINIS

Answer 7

O: inguinal ligament, iliac crest, thoracolumbar fascia, and costal cartilages of ribs 7-12
I: abdominal aponeurosis
N: ventral rami of T7-T12
K:
1) Compression of abdominopelvic cavity