Abdominal Wall Muscles

Question 1

Costal: internal surface of ribs 7-12 and their costal cartilages
Sternal: internal surface of the xiphoid process of the sternum
Lumbar: l1-03 via medial and lateral arcuate ligaments, right and left crura
I: Central tendon (dome) of the diaphragm
A: Increases the volume (expands) of the thoracic cavity via abdominal breathing
Increase the volume of the thoracic cavity via thoracic breathing (reverse action)

Answer 1

Diaphragm

Question 2

O: Pubic Crest and symphysis
I: Xiphoid process in the cartilage of ribs five through seven
A: Flexes the trunk at the spinal joints
Laterally flexes the trunk at the spinal joints
Posteriorly tilts the pelvis at the lumbosacral joints and flexes the lower trunk relative to the upper trunk (at the spinal joints) (reverse action)

Answer 2

Rectus Abdominus

Question 3

O: Anterior part of the iliac crest, pubic Crest and tubercle and the abdominal aponeurosis
I: Inferior border of ribs 5-12
A: Flexes the trunk at the spinal joints
Laterally flexes the trunk of the spinal joints
Contralaterally rotates the trunk at the spinal joints
Posteriorly tilts the pelvis at the lumbosacral joint and flexes the lower trunk relative to the upper trunk (at the spinal joints) (reverse action)

Answer 3

External Obliques

Question 4

O: Lateral 2/3 of the inguinal ligament, iliac crest, and the thoracolumbar fascia
I: Lower three ribs (10-12) and the abdominal aponeurosis
A: Flexes the trunk at the spinal joints
Laterally flexes the trunk at the spinal joints
Ipsilaterally rotates the trunk of the spinal joints
Posteriorly tilt the pelvis at the LS joint and flexes the lower trunk

Answer 4

Internal Obliques

Question 5

O: Lateral 2/3 of the inguinal ligament, the costal cartilage of ribs 7 through 12, iliac crest, and thoracolumbar fascia
I: Abdominal aponeurosis
A: Compresses abdominopelvic cavity

Answer 5

Transverse Abdominus

Question 6

O: Anterolateral aspects of bodies of T12-L5, including intervertebral discs between and anterior aspect of TVP of L1-L5
I: Lesser trochanter of the femur
A: Flexes the trunk at the spinal joints
Posteriorly tilts the pelvis at the LS joint and flexes the lower trunk (reverse action)

Answer 6

Psoas Major

Question 7

O: Upper 2/3 of iliac fossa, and the AIIS and the sacral ala
I: Lesser trochanter of the femur
A: Flexes the thigh at the hip joint
Laterally rotates the thigh at the hip joint
Anteriorly tilts the pelvis at the hip joint

Answer 7

Iliacus