Ilio- Costalis Lumborum and Longissimus Dorsi
   of the Erector Spinae Group


Common Origin: A broad, thick tendon from the median and lateral sacral crests, the accessory, spinous and transverse processes of the lumbar region (and from the spinous processes of two thoracic vertebrae), part of the lumbar fascia, the inner lip of the iliac crests medially and blends with the posterior ligaments of the sacrum.  These bands "divide" approximately at the level of the last rib.

Insertion of the Ilio-Costalis Lumborum: The inferior angle of the lower seven ribs.

Insertion of the Longissimus Dorsi: The tips of the thoracic transverse processes by long thin tendons and the lower nine ribs, between their tubercles and angles.

Located: The portion of the erector spinae that is valuable for sacral analysis can be located superior to the sacrum.  Using the index and chiropractic index fingers of both hands, begin palpating in the area of the second or third lumbar vertebra, approximately one and a half inches lateral of the spinous processes. Running (partly) in the vertebral groove, lie the ilio-costalis lumborum and longissimus dorsi bands of the erector spinae; these thick bands of muscle converge and descend to insert (anatomical origin) on the sacrum and the crests of the ilium where they become thinner (for this reason the erector spinae is palpated superior to the sacrum).  Place the tips of the fingers on the muscle (in the area of L2 and L3) and palpate slowly back and forth in the horizontal plane (across the direction of the fibers).  Remember, the more lateral you move from the spine, the more the possibility of interpretive error; in this case the student may interpret muscle action due to ilium involvement as he/she palpates the erector spinae too far laterally.

Listing Involvement: The erector spinae, when in combination with other sacral muscles, is working for the superior correction of sacral inferiority and/or ilium inferiority.

Working Sensation: The working erector spinae demonstrates a string-like tension, notable amongst a few fibers tightened in a vertical "thread."