Muscles of the Abdomen

Question 1

Diaphragm

Answer 1

O (Costal) : Internal surface of ribs 7-12 and their costal cartilages
O (Sternal) : Internal surface of the xiphoid process
O (Lumbar) : L1-L3 via medial and lateral arcuate ligaments and right and left cura tendons
I : Central tendon (dome) of the diaphragm
A : Increases the volume of (expands) the thoracic cavity via abdominal breathing

Question 2

Rectus Abdominis

Answer 2

O : Pubic crest
I : Xiphoid process and cartilage of ribs 5-7
A :
1. Flex the trunk at the spinal joints
2. Laterally flexes the trunk at the spinal joints

Question 3

External Abdominal Obliques

Answer 3

O : Anterior part of the iliac crest, pubic crest and tubercle and the abdominal aponeurosis
I : Inferior border of ribs 5-12
A :
1. Flexes the trunk at the spinal joints
2. Laterally flexes the trunk at the spinal joints
3. Contralaterally rotates the trunk at the spinal joints

Question 4

Internal Abdominal Obliques

Answer 4

O : Lateral 2/3 inguinal ligament, iliac crest and thoracolumbar aponeurosis
I : Internal surface of lower 3 (10-12) and the abdominal aponeurosis
A :
1. Flexes the trunk at the spinal joints
2. Laterally flexes the trunk at the spinal joints
3. Ipsilaterally rotates the trunk at the spinal joints

Question 5

Transversus Abdominis

Answer 5

O L Lateral 2/3 of the inguinal ligament, iliac crest, thoracolumbar aponeurosis and lower 6 costal cartilages
I : Abdominal aponeurosis
A : Compresses abdominopelvic cavity

Question 6

PSOAS Major

Answer 6

O : Anterolateral aspect of bodies of T12-L5, including intervertebral discs between and anterior aspect of TVPs of L1-L5
I : Lesser trochanter
A :
1. Flex the thigh at the hip joint
2. Laterally rotates the thigh at the hip joint

Question 7

Iliacus

Answer 7

O : Upper 2/3 of the iliac fossa, anterior inferior iliac spine and sacral ala
I : Lesser trochanter of the femur
A :
1. Flex the thigh at the hip joint
2. Laterally rotates the thigh at the hip joint