Trunk Muscle Flashcards
External Oblique IO and innervation
Origin:
* Outer surface of the 5th to 12th ribs
Insertion:
* Linea alba
* Pubic crest and tubercle
* Anterior superior iliac spine
* Iliac crest
- Lower intercostal nerves
- Subcostal nerve
External and Internal Oblique Action
Unilateral action:
Ext:* Rotation of the trunk (contralateral)
Int: * Rotation of the trunk (ipsilateral
* Lateral flexion *(ipsilateral)
Bilateral action:
* Compression of abdominal contents
* Flexion of the trunk
Internal Oblique IO and innervation
Origin:
* Deep layer of the thoracolumbar fascia
* Anterior 2/3rd of the iliac crest
* Lateral 2/3rd of the inguinal ligament
* Iliopsoas fascia
Insertion:
* Lower margins of the 10-12th ribs
* Pubic crest
* Anterior and posterior layers of the linea alba
- Lower intercostal nerves
- Subcostal nerve
- 1st lumbar nerve
Rectus abdominis IO and innervation
Origin:
* Pubis
* Pubic symphysis
Insertion:
* Xiphoid process of the sternum
* Costal cartilages of the 5th – 7th ribs
- Lower intercostal nerves
- Subcostal nerve
Action of Rectus abdominis
- Compression of abdominal contents
- Flexion of the trunk
- Stabilization of the pelvis
Transversus abdominis IO and innervation
Origin:
* Inner surface of the 7th-12th cartilages of the ribs
* Deep layer of the thoracolumbar fascia
* Anterior 2/3rd of the iliac crest
* Lateral 1/3rd of the inguinal ligament
Insertion:
* Linea alba
* Xiphoid process
* Pubic crest
* Pecten pubis
- Lower intercostal nerves
- Subcostal nerve
- 1st lumbar nerve
Quadratus lumborum IO and innervation
Origin:
* Posterior part of the iliac crest and iliolumbar ligament
Insertion:
* 12th rib
* Transverse processes of L1-L4 vertebrae
- Subcostal nerve
- L1-L4 spinal nerves
QL action
Unilateral action:
* Lateral flexion of trunk (ipsilateral)
* Elevation of ilium (ipsilateral)
Bilateral action:
* Extension of lumbar vertebral column
* Fixation of 12th rib to stabilize diaphragm during respiration
* Stabilization of lumbar spine and pelvis
Iliacus IO and innervation
Origin:
* Iliac fossa and crest
* Ala of sacrum
Insertion:
* Lesser trochanter of the femur where it joins with and inserts as the iliopsoas muscle
Femoral nerve
Iliacus Action
Unilateral action:
* Flexion of femur at hip
* External rotation of femur at the hip
* Lateral flexion of trunk (ipsilateral)
Bilateral action:
* Flexion of trunk
Psoas major IO and innervation
Origin:
* Anterolateral surfaces of T12-L5 vertebrae and intervertebral discs
Insertion:
* Lesser trochanter of the femur - inserts as iliopsoas tendon
- Anterior rami of lumbar spinal nerves
Psoas Major Action
Unilateral action:
* Flexion of femur at hip
* External rotation of femur at the hip
* Lateral flexion of trunk (ipsilateral)
Bilateral action:
* Flexion of trunk
Psoas minor IO and innervation, action
Origin:
* Bodies of T12 and L1 vertebrae and intervertebral discs
Insertion:
* Pecten pubis
* Iliopubic eminence
* Iliac fascia
Anterior rami of 1st lumbar spinal nerve
- Assists with flexion of spine
Diaphragm IO and innervation, action
Origin:
* Posterior surface of xiphoid process
* Lower 6 costal cartilages and adjoining ribs on each side
* Medial and lateral arcuate ligaments
* Anterolateral aspect of bodies of lumbar vertebrae
Insertion:
* Central tendon
Phrenic nerve
Action:
* Primary muscle of inspiration
* Draws central tendon inferiorly to change the volume and pressure within the thoracic and abdominal cavities
