SI joint pain (base of the spine): Trigger Points and Muscles Involved

The primary muscles listed for Iliosacral Pain are Levator Ani, Coccygeus, Gluteus Medius, Quadratus Lumborum, Gluteus Maximus, Multifidi, Iliopsoas, Longissimus Thoracis, Iliocostalis Thoracis, Iliocostalis Lumborum. Trigger points can produce referred pain: discomfort is felt away from the tender muscle. “Muscle knots” is an everyday description, whereas myofascial pain is the clinical term used in the linked references. This is a reference association, not proof that a muscle causes this symptom. A pain map cannot rule out joint, nerve or internal-organ conditions. Match the exact location and circumstances, rather than treating every tender spot as the source.

The primary associations for Iliosacral Pain are Levator Ani, Coccygeus, Gluteus Medius, Quadratus Lumborum, Gluteus Maximus, Multifidi, Iliopsoas, Longissimus Thoracis, Iliocostalis Thoracis, Iliocostalis Lumborum. Primary, secondary and tertiary describe the reference's ordering, not a diagnosis or a measured probability. The following extracts describe each muscle's complete referral pattern; not every area mentioned is necessarily part of your symptom.

Levator Ani — Deep aching pain in the pelvis, rectum, perineum and tailbone; sometimes referred to the low back or sacrum and provoked by prolonged sitting or bowel movements.

Coccygeus — Pain over the coccyx and lower sacrum, sometimes into the buttock, typically aggravated by sitting on hard surfaces and by moving from sitting to standing.

Gluteus Medius — Along the iliac crest, into the buttock, sacrum and posterior thigh — a common 'low back' pain pattern of muscular origin.

Quadratus Lumborum — Iliac crest, sacroiliac joint area, greater trochanter, sometimes lower abdominal pain. Often described as a deep, dull lumbar ache.

Gluteus Maximus — Buttock and sacroiliac region; tail-bone-like pain when sitting.

Multifidi — Local segmental pain, often felt as a 'spot' the patient can point to.

Iliopsoas — Anterior hip and groin, with vertical 'low back' pain along the lumbar spine.

Longissimus Thoracis — Buttock and lateral lower back pain, mimicking 'sciatica' but staying above the knee.

Iliocostalis Thoracis — Upward referral toward the upper back and shoulder blade, downward referral toward the lumbar region, and wrap-around pain over the lateral chest wall.

Iliocostalis Lumborum — Lower back pain along the iliac crest, sometimes wrapping to the lower abdomen.

Record where Iliosacral Pain occurs, which position or activity changes it, and whether it is accompanied by numbness, weakness or another symptom. Compare those observations with the linked muscle maps. A clinician can assess whether palpation reproduces the familiar complaint; tenderness alone does not establish the cause. Do not press deeply into the throat, abdomen or other sensitive areas to test a theory.

For Iliosacral Pain, begin with assessment of the symptom rather than assuming that release is needed. Where a muscular contribution has been assessed, the linked pages for Levator Ani, Coccygeus, Gluteus Medius, Quadratus Lumborum, Gluteus Maximus, Multifidi, Iliopsoas, Longissimus Thoracis, Iliocostalis Thoracis, Iliocostalis Lumborum describe their existing self-care options, loading factors and precautions. Read those precautions before trying an exercise. Dry needling and injections are clinician-only procedures. Do not use a referral map to delay care or to stop an established treatment.

Levator Ani — Pelvic floor overactivity, chronic straining or constipation, childbirth, pelvic surgery or trauma, persistent bracing under stress, chronic urinary or prostatic irritation. Internal vaginal or rectal palpation by a clinician trained in pelvic health; taut bands reproduce the patient's familiar deep pelvic pain. Pelvic floor down-training with diaphragmatic breathing, sitting modification, bowel habit and hydration management, warm baths. Clinically: internal manual release by a pelvic health physiotherapist, with medical work-up of urogenital and colorectal causes.

Coccygeus — Falls onto the tailbone, childbirth, prolonged sitting on hard surfaces, chronic straining or constipation, pelvic floor overactivity. Internal pelvic floor examination by an appropriately trained clinician; externally, tenderness may be provoked at the sacrococcygeal junction and around the coccyx. Cushion modification (wedge or coccyx cut-out), pelvic floor down-training and diaphragmatic breathing, avoiding straining. Clinically: internal manual release by a pelvic health specialist; imaging if trauma is suspected.

Seek medical assessment for Iliosacral Pain when it is new, persistent, worsening or unexplained. Muscle associations are educational information, not a way to exclude other causes. The existing warning signs for this entry are: Inflammatory back pain features — refer for rheumatology workup.

For an appointment about Iliosacral Pain, bring a short record of the symptom rather than only the name of a suspected muscle. Note the activity before it started, whether the location has changed and what has already been tried. These observations help a professional compare the muscular associations with alternative explanations without relying on the atlas alone.