Layers of the Intrinsic Back Muscles Superficial Layer Both Splenius muscles Intermediate Layer Erector Spinae (bilateral andipsilateral action) Designated by region frommedial to lateral Designated by insertion Deep Layer Interconnect and stabilize thevertebra Small muscles that make fineadjustments to vertebra19
+Divisions of the sacrospinalis (akaErector spinae)30Lateral Column. Intermediate Column. Medial Column.Iliocostalis Longissimus Spinalis.(a) I. lumborum. (a) L. dorsi. (a) S. dorsi.(b) I. dorsi. (b) L. cervicis. (b) S. cervicis.(c) I. cervicis. (c) L. capitis. (c) S. capitis.
Erector Spinae(sacrospinalis) Origin Sacrum, spinous processes oflower two thoracic & alllumbar Insertion Transverse and spinousprocesses as well as ribs andskull Location: Posterior Movements (spine) Extension (C & L) Ipsilateral flexion (C & L)Iliocostalis Longissimus Spinalis
+Erector Spinae Muscle is thickest in S & L regions most movement Controls forward flexion Extension of trunk Posterior stability posture
Rectus AbdominisControls Post pelvic tilt & curvature LS Flattens lower back What effect does this have onerector spinae & hip flexors? more effectiveDefinition 3 depressions area of tendinous connective tissue
External ObliqueOrigin Lateral side of ribs 5-12Insertion Anterior iliac crest, pubic crestLocation: Lateral/AnteriorMovements Flexion (together) Ipsilateral flexion Contralateral rotation(independently)
Internal ObliqueOrigin Anterior iliac crest andinguinal ligamentInsertion Cartilage of ribs 8-10 andlinea albaLocation:anterior/medialMovements Flexion Ipsilateral flexionFiber direction