Understanding the Anatomy of Core Exercises

The Core Muscles of Core Exercise (aka…an Anatomy Lecture)

New Years is coming up so you are probably seeing the swarm of advertisements saying “New Year, New You” or “get your body beach ready”. When we talk about core exercises it’s important to remember what exactly makes up that core. When talking about the core a lot of people think about the fancy six-pack muscles but there’s so much more than that. So here it goes…the core is comprised of the following:

Diaphragm

What does it attach to?Lumbar vertebra (1-3)
- Lower 6 ribs
- Back of sternum & xiphoid process
Function?
- Concentrically contracts and lowers on inhalation
- Eccentrically contracts and rises on exhalation
- Helps mobilize the ribs, lumbar spine and thoracic spine

Multifidus

What does it attach to?
- Vertebra from sacrum to skull
Function?
- Important role in stabilizing the joints within the spine
- Supports and protects the spine and pelvis to prepare movement of limbs
- Commonly inhibited in pain

Abdominal Raphe (Linea Alba & Linea Semilunaris)

What does it attach to?
- Runs along anterior abdominal wall connecting xiphoid with pubic symphysis and crest
- Receives attachment of obliques and transverse abdominis
- Extends from cartilage of 9th rib to pubic bone
Function?
- Mostly collagen connective tissue

Rectus Abdominis (the six-pack…actually the eight-pack, but who is counting?)

What does it attach to?
- Arises from pubic symphysis and runs vertical to typhoid and costocartilage of 5th and 7th ribs
- Contained in rectus sheath (which is derived from external obliques, internal obliques and transverse abdominis)
Function?
- Important in forced exhalation
- Helps with strength termination

External Obliques

What does it attach to?
- 5th-12th ribs
- Connects with fibers of serrates anterior and latissimus dorsi
- Connects to iliac crest
- Crosses the pubic symphysis
Function?
- Stabilize the pubic symphysis (with anterior pelvic floor muscles)

Internal Obliques

What does it attach to?
- Connects to thoracolumbar fascia posteriorly (via transverse abdominis tendon)
- Connects to anterior iliac crest and lateral inguinal ligament
- Posterior fibers connect to 11th and 10th ribs
Function?
- Accessory muscle of respiration
- Forms inguinal ligament with transverse abdominis
- Rotates and side-bends the trunk by pulling the rib cage and midline towards the hip and lower back, of the same side with contralateral external oblique

Transverse Abdominis

What does it attach to?
- Connects to thoracolumbar fascia with tendon and iliac crest
- Connects to the lower 6 ribs and lateral aspect of inguinal ligament
- Inserts into linea alba
Function?
- Forms inguinal ligament with internal obliques
- Helps support the spine and internal organs

Psoas

What does it attach to?
- All lumbar vertebra bilaterally
- Lateral edges of vertebra from T12-L4 (and intervertebral discs!)
- Lesser trochanter of femur
Function?
- Stress response shortens the psoas
- Affects structural balance
  - Commonly seen in an anteriorly tilted pelvis and/or rib thrusting

Pelvic Floor

Function?
- During breathing, raises and lowers synergistically with the diaphragm
- Works to control the spine and pelvis by offering support for abdominal and pelvic organs
- Supports the urethral and anal sphincters (what you pee and poop out of)

Superficial Pelvic Floor

Composed of bulbocavernosus, ischiocavernosus, superficial transverse perineal, external anal sphincter
Function?
- In women, it contributes to clitoral erection and orgasm
- Helps empty the canal of the urethra

Deep Urogenital Diaphragm Layer

Composed of deep transverse perineal
Function? Supports central tendon of perineum through perineal body

Pelvic diaphragm

Composed of levator ani (pubocococcygeus, iliococcygeus, coccygeus), piriformis, obturator internus
Function?
- Support pelvic viscera
- Closes back part of pelvic outlet
- Keeps vagina and rectum closed
- Facilitates birth

Up Next? Learn about the The Hows and Whys to Working that Sexy Core!