Anatomy of the Core

Question 1

Main roles of core muscles

Answer 1

1. Stabilize the spine in advance of a sudden movement (isometric activation),
2. Create movement (concentric activation), and
3. Provide continuous support throughout a movement (isometric and/or eccentric
   activation).

Question 2

The eight muscles of the core

Answer 2

1. Pelvic Floor
2. Transverse Abdominis (TA)
3. Diaphragm
4. Internal Obliques
5. External Obliques
6. Multifdus
7. Quadratus Lumborum (QL)
8. Psoas

Question 3

Four groups of core muscles

Answer 3

1. The Deep Cylinder of Support: Pelvic Floor, TA and Diaphragm
2. The Abdominals: Internal Obliques, External Obliques
3. The Back Core Muscles: Quadratus Lumborum (QL), Multifdus
4. Hip Flexor: Psoas

Question 4

The deep cylinder of support

Answer 4

1. Pelvic Floor: layers of muscle forming the bottom of the pelvic bowl; squeeze in and up
2. Transverse Abdominis (TA): wraps around the entire abdomen like a corset; squeezes inward
3. Diaphragm: a circular muscle that attaches to the inside of the lower ribs, completely separating the thoracic cavity from the abdomen; compresses down during inhalation, relaxes up during exhalation

Question 5

Core abdominal muscles

Answer 5

1. Internal Obliques: Cross your arms over your abdomen.
   Your fngers are in the direction of the internal obliques;
   bilaterally they fex the trunk and compress abdominal
   contents, unilaterally they laterally fex and rotate
   toward the same side.
2. External Obliques: Reach into your pants pockets. Your
   arms are now assuming the direction of the external
   obliques; bilaterally they fex the trunk and compress
   abdominal contents, unilaterally they laterally fex to
   the same side, rotate to the opposite side.

RA-Rectus Abdominis flexes the trunk and has an important role as a mobilizer of the trunk but is actually not a core muscle by definition

Question 6

Core back muscles

Answer 6

1. Multifdus: Runs along either side of the spine, each
   fber spanning across one or two vertebrae, from the top
   of the sacrum to the base of the skull; bilaterally they
   extend the spine, unilaterally they rotate to the opposite
   side.
2. Quadratus Lumborum (QL): Extends from the top of
   each hip bone to the lumbar vertebrae and 12th rib;
   bilaterally it extends the spine, unilaterally it laterally
   flexes the trunk or raises the hip

Question 7

The psoas

Answer 7

The psoas extends from the lumbar vertebrae to the inside of the upper thigh; it flexes, abducts and laterally rotates the thigh.
The psoas is the strongest hip flexor and the only lower limb muscle that connects to the spine.