Anatomy & Function of the “Core” Ellen Casey, MD Assistant Professor Associate Director Sports Medicine Fellowship

Disclosures None

Objectives Define core stability Review the components of the core Discuss the role of coordination vs. strength in achieving a stable core

Functional Spinal Stability Neural Control Spinal Column Spine Stabilit y Muscles Panjabi, 2003

Osseoligamentous Structures Lucas & Bresler, 1961

Thoracolumbar Fascia 7

Core Musculature 8 Hodges 1999

Muscles of the Lumbar Spine Global Rectus abdominus External oblique Internal oblique (ant) Iliocostalis (thoracic) Local Multifidi Psoas Transversus abdominis Quadratus lumborum Internal Oblique (post) Iliocostalis Longisimus Akuthota & Nadler, 2004

Paraspinals

Quadratus Lumborum

Psoas major

Diaphragm “Ceiling” of the Core Respiration –Reciprocal with pelvic floor –Descends with inspiration Spine stability –Increase IA pressure –Pts with LBP and SIJ  abnormal recruitment O’Sullivan, 2002

Pelvic Floor “Floor” of the Core Respiration –Reciprocal with diaphragm Spine Stability –Support lumbopelvis and pelvic organs –Co-activation withTrA (Sapsford 2001) Specialized Functions –Sphincteric control –Sexual function

Abdominal Wall Musculature

Obliques EXTERNAL Increases IAP Trunk rotation Side bending Controls ant pelvic tilt INTERNAL Increases IAP Trunk rotation Side bending

Transversus Abdominis (TrA) 1.Increase Intra-abdominal Pressure  Symmetric  Active in both sagittal flex/ext (Barker 2005) 2.Contributes to control of trunk rotation  Asymmetric  Ipsilateral > Contralateral (Urquhart 2005)  Feed forward/anticipation (Hodges 1996) 3.Different types of activation  Tonic during gait  Phasically active with breathing and heel strike (Saunders 2004)

“Core” Controversy HOLLOWING “Drawing in” Selective recruitment of TrA and multifidi (Urquhart 2004) Incr spine stiffness (Hodges 2003) Early in rehabilitation BRACING EO > TrA, multifidi, IO (Urquhart 2004) Greater spine stiffness than hollowing (Grenier 2007) Incr ability to stabilize against trunk perturbations (Vera-Garcia 2006) More functional 18

Gender & Abd Wall Nm Control Rho 2013 EO IO TrA MALE FEMALE AT REST CONTRACTION

Putting it all together functionally Driver of the kinetic chain Proximal stability  distal mobility Small contraction = big effect (Cholewicki & McGill 1996) –5% MVC for ADLs –10% MVC for vigorous activity Controlled by neural subsystem –Constant feedback –Continued refinement of movement Contribution of each muscle changes based on the demand (Zazulak 2007)

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