Abdominals

Question 1

External Obliques

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 1

Origin: External surfaces of fifth to twelfth ribs.

Insertion:

1. Anterior part of the iliac crest,
2. rectus sheath to linea alba

Action:

  Unilaterally: 
          1. Laterally flex vertebral column to the same side
          2. Rotate vertebral column to the opposite side
   Bilaterally:
          2. Flex the vertebral column
          3. Compress abdominal contents

Innervation: (T5,6), T7-11, T12 spinal nerves.

Lower six thoracic nerves
Subcostal nerve

Question 2

Internal Obliques

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 2

Origin:

1. Lateral inguinal ligament
2. iliac crest
3. thoracolumbar fascia

Insertion:

1. Internal surface of lower three ribs
2. rectus sheath to linea alba

Action:

Unilaterally:
1. Laterally flex vertebral column to the same side
2. Rotate vertebral column to the same side

Bilaterally:
1. Flex the vertebral column
2. compress abdominal contents

Innervation:
T7,8,T9-12, L1. iliohypogastric and ilioinguinal, ventral rami

Question 3

Rectus Abdominis

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 3

Origin:

1. Pubic crest
2. pubic symphysis

Insertion:

1. Cartilage of 5th, 6th, and 7th ribs
2. xiphoid process

Action:

Flex the vertebral column
Tilt pelvis posteriorly

Innervation:

T5, 6. T7-11, T12, ventral rami

Question 4

Transverse Abdominis

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 4

Origin:

1. Lateral inguinal ligament
2. iliac crest
3. thoracolumbar fascia
4. internal surface of lower 6 ribs

Insertion:

Rectus sheath to linea alba

Action:

Compress abdominal contents

Innervation:

T7-12, L1, iliohypogastric and ilioinguinal, ventral divisions.

Question 5

Erector Spinae

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 5

Origin:

1. Common tendon (thoracolumbar fascia) that attaches to the posterior surface of the sacrum
2. Iliac crest
3. Spinous processes of the lumbar
4. T11-T12

Insertion:

1. Various attachments at the posterior ribs
2. spinous and transverse processes of the thoracic and cervical vertebrae
3. mastoid process of temporal bone

Action:

Unilaterally:
Laterally flex vertebral column to the same side

Bilaterally: Extend the vertebral column

Innervation: Spinal (Dorsal rami of spinal nerves)

Question 6

Quadratus Lumborum

1. Origin
2. Insertion
3. Action
4. Innervation

Answer 6

Origin:

1. Posterior iliac crest

Insertion:

1. Last rib
2. transverse processes of the L1-L4 vertebrae.

Action:

Unilaterally:
1. Laterally tilt (elevate) the pelvis
2. Laterally flex the vertebral column to the same side
3. Assist to extend the vertebral column

Bilaterally:
1. Fix the last rib during forced inhalation and exhalation

Innervation:

Lumbar plexus T12, L1, L2, L3 spinal nerves.