Section 01 of 20
Introduction
Iliocostalis is the outermost of the three columns of the erector spinae group, beside longissimus and spinalis. It is a long, narrow muscle made of overlapping slips that run from the pelvis up the angles of the ribs to the lower cervical vertebrae. It is divided into three parts named for the region: iliocostalis lumborum, iliocostalis thoracis, and iliocostalis cervicis.
Together with the rest of the erector spinae, it keeps the trunk upright and controls forward bending. Because it attaches to the ribs, it also helps hold the rib cage steady and can pull the ribs downward.
Section 02 of 20
Origin
| Origin | Iliocostalis lumborum: the common erector spinae tendon attached to the sacrum, the iliac crest, and the thoracolumbar fascia. Iliocostalis thoracis: the angles of the lower six ribs, medial to the lumborum insertions. Iliocostalis cervicis: the angles of ribs 3–6. |
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An anatomical image for this section will be added when verified source media becomes available.
Section 03 of 20
Insertion
| Insertion | Iliocostalis lumborum: the angles of the lower six or seven ribs. Iliocostalis thoracis: the angles of the upper six ribs and the transverse process of C7. Iliocostalis cervicis: the transverse processes of C4–C6. |
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An anatomical image for this section will be added when verified source media becomes available.
Section 04 of 20
Actions
No dedicated action video is currently available. This movement is explained below and video will be added when verified source media becomes available.
| Primary action | Extension of the spine. |
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| Secondary actions | Lateral flexion to the same side and depression and control of the ribs. |
| Movement at the joint | Intervertebral joints of the lumbar, thoracic, and lower cervical spine, and the costovertebral joints. |
| Heads / fiber groups | Three parts: iliocostalis lumborum, thoracis, and cervicis. |
| Functional examples | Standing upright; lifting; bending forward and returning upright; walking; carrying loads. |
Spinal extension
Both sides together extend the spine and keep the trunk upright.
Lateral flexion
One side bends the trunk and neck to that side.
Rib depression and control
Pulls the ribs down and steadies them during breathing and trunk movement.
Eccentric control
Lengthens under load to control forward bending and lowering the trunk.
Section 05 of 20
Nerve Innervation
| Nerve | Posterior (dorsal) rami of the spinal nerves at the corresponding levels, from the lower cervical to the lumbar spine. |
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The posterior rami also supply the skin of the back and the deep spinal joints. Pain, numbness, or weakness that spreads down the leg may reflect a nerve root or disc problem, not only muscle tightness.
Section 06 of 20
Blood Supply
| Blood | Posterior branches of the intercostal, subcostal, and lumbar arteries, with the deep cervical and transverse cervical arteries supplying the upper part. |
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Section 07 of 20
Pictures and Visual Anatomy
An anatomical image for this section will be added when verified source media becomes available.
Section 08 of 20
Functional Movement
Iliocostalis is active in standing upright, lifting, bending forward and returning upright, walking, and carrying loads. The lumborum part works continuously to keep the low back steady, especially when the trunk is bent or twisted.
Section 09 of 20
Synergists and Antagonists
Synergists: longissimus and spinalis (the other erector spinae columns), multifidus, quadratus lumborum, and the obliques (lateral flexion). Antagonists: the abdominal muscles (rectus abdominis and obliques) for spinal extension, and the opposite-side muscles for lateral flexion.
Section 10 of 20
Palpation and Location
Client position and technique
Position the client prone with a pillow under the abdomen. Locate the spinous processes, then slide about a hand-width laterally to find the thick vertical columns of the erector spinae. The iliocostalis is the most lateral column, running along the angles of the ribs in the thoracic region and lateral to the longissimus in the low back. Ask the client to gently lift the head or extend the trunk to feel the columns tighten.
Protect nearby structures
Use moderate, broad pressure, avoid pressing directly on the spinous processes and the ribs, and take care over the lower ribs, which are less well protected. Stop if the client reports sharp pain, tingling that travels into the leg, or pain that feels deep in the chest or flank.
Section 11 of 20
Massage Therapy Relevance
The erector spinae, including iliocostalis, is among the muscles most often reported as tight or sore in low and mid back pain. It is worked in most back massage, but pain in this area can come from many other structures.
Section 12 of 20
Dysfunction: What Happens When Movement Goes Wrong
Changes in how a muscle works can change how a joint moves. The points below describe possibilities that may be associated with altered muscle function; they are not diagnoses, and one muscle is never assumed to be the sole cause of a problem.
When the muscle is weak
Weakness may reduce trunk endurance and may be associated with a slumped posture and more load on the discs and joints.
When it is tight or shortened
Tightness may be associated with limited forward bending and a stiff, aching back, especially after long periods of sitting or standing.
When it is overused
Repeated lifting, bending, and prolonged posture may overload the muscle and may contribute to low and mid back ache.
When it is strained
A strain may cause a sharp or aching band of pain along the spine with bending and twisting; disc and joint problems can look similar.
When it is inhibited or others compensate
Reduced activation may be associated with more work by the multifidus, the quadratus lumborum, and the hip muscles.
When it does not coordinate well with synergists and antagonists
Poor coordination with the abdominals, the multifidus, and the gluteals may alter trunk control and may be associated with back symptoms.
Section 13 of 20
Conditions, Pathologies, and Pain Relationships
Low back strain and muscle spasm
Lifting, twisting, and prolonged bending may strain the muscles and cause a tight, painful band along the spine that is worse with movement.
Postural overload
Prolonged sitting or standing with a rounded or swayed back may keep the muscles working hard and may be associated with a chronic ache.
Trigger point referral
Tender points in the muscle may refer pain to the mid back, ribs, flank, buttock, and lateral hip, but disc, joint, and visceral problems can look the same.
Differential considerations
Disc herniation, facet joint pain, rib dysfunction, scoliosis, kidney problems, and referred visceral pain can all cause back pain.
Section 14 of 20
Example Clinical Relationship
A client who lifts boxes at work reports a tight ache along one side of the low back that worsens with bending and eases when lying down. The erector spinae, including iliocostalis, may be involved, and the pattern may be associated with strain or overuse, but disc, joint, and kidney problems can look similar. Gentle, broad work along the muscle may support comfort, while fever, saddle numbness, or progressive leg weakness needs referral.
Section 15 of 20
Massage and Treatment Approaches
For healthy, non-acute tissue, position the client prone with the abdomen supported. Begin with broad effleurage along the back, then use kneading, compression, and slow longitudinal strokes along the lateral column, working within comfortable pressure and the client's breathing.
| Movement | Use gentle pelvic tilts and comfortable trunk side-bending within comfort; do not force stretch. |
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| Regional work | Consider longissimus, spinalis, multifidus, quadratus lumborum, the thoracolumbar fascia, and the gluteals when assessment supports it. |
| Avoid | Deep pressure on the spinous processes, over the lower ribs and the flank, over an acute injury, or at any point that reproduces leg symptoms. |
Section 16 of 20
Precautions and Contraindications
Precautions and contraindications
- Acute back injury, suspected fracture, or recent spinal or thoracic surgery.
- Use caution with severe osteoporosis, anticoagulant use, or easy bruising.
- Avoid deep pressure over the flank and the lower ribs.
- Stop if pressure causes sharp pain, nausea, or tingling in the leg.
Section 17 of 20
Red Flags and When to Refer
Red flags and referral
- Back pain with fever, unexplained weight loss, or night pain.
- New numbness in the saddle area, or bladder, bowel, or sexual changes with back pain (possible cauda equina syndrome).
- Progressive leg weakness, back pain after trauma, or flank pain with blood in the urine.
- Chest pain, shortness of breath, or pain that spreads to the jaw or arm.
Section 18 of 20
Study Summary
Attachments
Origin: sacrum, iliac crest, and rib angles. Insertion: rib angles and the transverse processes of C4–C7.
Actions
Spinal extension, lateral flexion, and rib control.
Supply
Posterior rami of the spinal nerves; posterior intercostal, subcostal, lumbar, and cervical arteries.
Section 19 of 20
Instructor Narration
Open narration transcript
Iliocostalis is the lateral column of the erector spinae. It runs from the pelvis up the ribs to the lower neck and is divided into lumborum, thoracis, and cervicis parts.
The lumborum part arises from the common erector spinae tendon on the sacrum and iliac crest and inserts on the angles of the lower ribs. The thoracis part links the lower and upper ribs, and the cervicis part reaches the transverse processes of C4 to C6.
Both sides together extend the spine, one side bends the trunk to that side, and the muscle helps steady the ribs. Longissimus and spinalis help it, and the abdominal muscles oppose it.
The posterior rami of the spinal nerves supply it, and the intercostal, subcostal, lumbar, and cervical arteries provide its blood.
Palpate with the client prone, about a hand-width lateral to the spine, and find the most lateral column. Use broad moderate pressure and avoid the spinous processes and lower ribs.
Strain, spasm, postural overload, and trigger points are common, and disc, joint, rib, and kidney problems can overlap. Refer back pain with fever or weight loss, saddle numbness with bladder or bowel changes, progressive leg weakness, or chest pain.
Remember: sacrum, iliac crest, and rib angles to the rib angles and lower cervical transverse processes; extension and lateral flexion; posterior rami.
Section 20 of 20