Human Movement Science & Functional Anatomy of the:
by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS
Quadratus Lumborum (QL):
- Origin: Iliolumbar ligament, iliac crest, and occasionally from upper borders of the transverse processes of the lower three or four lumbar vertebrae (11).
- Insertion: The inferior border of the last rib and transverse processes of the upper four lumbar vertebrae (11).
- The quadratus lumborum is bordered by the deepest layer of the thoracolumbar fascia and psoas anteriorly and the middle layer of the thoracolumbar fascia and erector spinae posteriorly. The lateral border of the quadratus lumborum may be palpated (easiest in prone) by using your index fingers to find the transverse processes of LI and L5, and your thumbs to find the edge of the 12th rib and posterior crest of ilium. This creates a square that borders the QL. Slide your thumbs toward one another. Use slow firm pressure to sink your thumbs deep and medially and you should feel the edge of the QL. If you are unsure have the person you are palpating hip hike; the QL should pop into your fingers (14).
- Nerve: Lumbar Plexus via nerve roots L1-L3 and sometimes T12.
- Primary lateral flexor of the lumbar spine, this may also result in relative hiking of the ipsilateral pelvis
- Weak extensor of the lumbar spine
- Depresses 12th rib; acting bilaterally during respiration, it fixes the last 2 ribs to improve the efficiency of the diaphragm.
- Although there is some debate over the precise role (intrinsic stabelizer or global mover) of this muscle, studies have shown this muscle to be active during “anti-buckling” activities, such as walking while carrying heavy buckets of water (13).
- Stabilization: Stabilization of the lumbar spine, 12th rip, and sacroiliac joint.
- Eccentrically Decelerates:
- Eccentric deceleration of contralateral flexion of the lumbar spine (anti-buckling)
- Eccentric decelerates of flexion of the spine.
- The QL is the prime mover of lateral flexion, with the internal obliques, external obliques, ipsilateral erector spinae, and to a lesser degree the ipsilateral latissimus dorsi acting synergistically.
- The QL may be a synergist for lumbar extension, although it is likely that it can only assist post initiation of extension and only to a small degree. The primary lumbar extensor is the erector spinae.
- The internal obliques are synergists for lateral flexion of the spine, again likely third in ability to produce force behind the external oblique, and prime mover quadratus lumborum.
- The QL, despite its relatively deep position within the trunk musculature, is likely a global stabilizer of the lumbar spine, acting synergistically with other global stabilizers (rectus abdominis, external obliques, internal obliques, erector spinae) when loads increase beyond what a well functioning intrinsic stabilization subsystem can handle. Further, this muscle plays a role in stabilization of the sacroiliac joint as a stabilizer of the lumbar spine and ilium. Sacroiliac joint dysfunction (SIJD) often results in over-activity, trigger point development, and adaptive shortening of the quadratus lumborum on the dysfunctional side, implying that synergistic dominance of the global stabilization system may be a precursor-to, or result-from SIJD.
- The QL acts to stabilize the 12 rib for diaphragmatic contraction on inhalation, separating itself functionally from anterior trunk musculature which or more active during forceful exhalation. Although resting tone of this muscle may be enough to stabelize the 12 ribs, synergistically this implies that motor patterns may recruit the QL with the scalenes, pec minor, SCM, and iliocostalis during forceful inhalation.
- The quadratus lumborum is part of the Lateral Subsystem (LS). As part of this subsystem the QL contributes to frontal plane stabilization of the LPHC, transfer of force between lower and upper extremities, and plays an active role in all integrated (whole body) frontal plane and single-leg movement patterns.
- The muscle activity and relative length of the quadratus lumborum stands in opposition to the key muscle in the lateral subsystem - the gluteus medius. While the gluteus medius has a propensity toward under-activity, the QL has a propensity toward over-activity. The disjunct behavior of the muscles in this subsystem has led many to not include the lateral subsystem with in the muscular sling/subsystem paradigm. One large difference between this and other subsystems is the lack of fascial continuity, that is – unlike other subsystems there is not a single line that can be drawn through all contributing musculature and a fascial link between them (for example, the way a line can be drawn from latissimus dorsi, through the thoraclumbar fascia to the contralateral glute in the Posterior Oblique Subsystem). When viewed relative to movement impairment/postural dysfunction, the QL is most often released and stretched while the gluteus medius is activated and integrated in functional movement patterns. With this said, the QL and lateral subsystem rarely play a large role in postural impairment, and often seem to act as a victim to the activity of other subsystems – for this reason I have nicknamed the the LS the “victim system.” In Lumbo Pelvic Hip Complex Dysfunction (LPHCD) the lateral subsystem may be impaired, but is hardly a concern relative to the relationship between the Anterior Oblique Subsystem AOS and Posterior Oblique Subsystem (POS), in Lower Leg Dysfunction (LLD) the LS is often impaired; however it is the gluteus medius that requires significant attention and the QL only plays a role during integration with the selection of single leg, frontal plane preferred whole body activities. In Upper Body Dysfunction UBD this subsystem seemingly plays little if any role. The one disfunction that seems to highlight a need for specific attention payed to the QL is Sacroiliac Joint Dysfunction (SIJD). In SIJD the QL on the dysfunctional side may be not only short and tight, but tender and symptomatic. Release and stretching may prove to be beneficial in conjunction with SIJ mobilization.
- This muscle plays a role in the arthrokinematics of the lumbar spine, 12th rib and sacroiliac joints.
- The QL will ipsilaterally compress the intervertebral disks – potentially shifting the nucleus pulposus to the contralateral side, and compress the ipsilateral facet joint and vertebral foramen. It is interesting to note that this could contribute to dysfunction, damage to the disk, and/or nerve root compression on either side (For example, long-term unilateral over-activity may compress the ipsilateral facet and vertebral foramen impinging on the nerve, while simultaneously shifting the nucleus pulposus to the contralateral side resulting in a posterolateral disk protrusion that compresses the nerve root on the contralateral side.) Bilateral over activity may create compression of the disk that results in herniation over time, and although it may be less likely to compress facet joints and vertebral foramen directly, degeneration of the disk over time may lead to herniation, internal nerve root compression, and a loss of disk space height.
- Over-activity of the QL may result in dysfunction of the costovertebral and constotransverse joints of the 12th rib (inferior glide of the rib on both joints, or inferior glide of the rib at the costrotransverse joint and superior glide at the costovertebral joint. Costovertebral joint pain can be quite debilitating and resulting in transversospinalis muscle spasm and pain in the case of the 12th rib, pain during inhalation or exhalation.
- Although the QL does not directly attach to the sacrum it may affect sacroiliac joint mechanic by elevating the ilium – relative inferior glide of the sacrum on the ilium. This is often referred to as an up-slip; although it should be noted that it is the ilium moving superiorly. This is a component of Sacroiliac Joint Dysfunction (SIJD), and it has been my experience that over-activity of the QL is often the result of dyskinesis of the SIJ on the side of dysfunction.
My Fascial Hypothesis: Large fascial sheaths not only play a role in the transmission of mechanical force, but may also play a role in dictating the function of muscular synergies. This is likely caused by reducing or increasing tone of invested musculature via reflex arcs formed between mechanoreceptors imbedded in the connective tissue and the attached musculature. In this way my view of fascia differs slightly from noted expert on the subject Tom Myers. I think of these large fascial sheaths (specifically the thoracolumbar fascia, iliotibial band, and abdominal fascial sheath) as natures “mother board.” A place for mechanical information to be communicated to the nervous system for more efficient recruitment of the muscular system. Despite having a slightly different philosophy it does not change the fact that fascia plays an important communicative role in the human body and we have Tom Myers to thank for his work.
Fascial Integration of the External Obliques:
- QL to Iliacus: There seems to be fascial continuity between the QL and iliacus, as the anterior thoracolumbar fascia blends with the anterior fascia of the iliacus. This may be part of a fascial synergy that results in pelvic elevation and hip flexion during the swing phase of gait. Both muscles have a propensity toward over activity, and although not easily reached using self-administered techniques it manual therapist may consider assessing the iliacus as well as the QL in patients who exhibit LPHCD and/or SIJD
- QL to Diaphragm: It is mentioned in Kendal et al. (11) that the QL stabilizers the 12th rib for contraction of the diaphragm during inhalation. Could this be assisted by a fascial congruity between the two muscles that either mechanically links these two structures or results in receptor activity mediating tone? Although only conjecture it is an interesting relationship to consider. Further, could changes in QL length and activity lead to changes in diaphragm tone and activity? Although this may sound ominous, consider how LPHCD and SIJD often result in synergistic dominance of the global stabilizers and the need to “bear down (valsalva)” during functional activities that would normally be easily stabilized by the ISS.
Behavior in Postural Dysfunction:
This muscle may be prone to adaptive shortening and over-activity.
The quadratus lumborum is prone to adaptive shortening and over-activity, although not often a key player in postural dysfunction. Generally speaking, this muscle only becomes relevant and in need of specific attention when lumbosacral dysfunction is the result of, or resulting in pain. As with all exercise selection, the only way to ensure effective exercise selection is to carefully deduce the movement impairment most responsible for dysfunction, and address the muscle according to the movement impairment observed.
In Upper Body Dysfunction (UBD) the QL may be over-active with little or no change in length, becoming synergistically dominant with the global stabilizers of the lumbar spine in the presence of an under-active/inhibited Intrinsic Stabilization Subsystem (ISS).
In Lumbo Pelvic Hip Complex Dysfunction (LPHCD) the QL may be short and over-active, but is a far larger contributor to dysfunction when combined with Sacroiliac Joint Dysfunction (SIJD). It is in this case that specific techniques may be used to address the QL, although self-administered techniques are not easily implemented.
In short, I often do not address the quadratus lumborum specifically. Although trigger point release and stretching is effective for addressing short/over-active muscles the QL is so deep (much like the psoas), manual work is often necessary if the muscle is a considerable contributor to dysfunction. Further, returning this muscle to optimal length and activity may require lumbar, sacroiliac or rib mobilization and once again, self-administered techniques are not easily implemented.
- Lumbar spine pain
- Costovertebral/costotransverse joint pain (pain often felt during breathing)
- Sacroiliac joint pain and dysfunction
- Hip hike
- Lateral shift of lumbar
Signs of Altered Length/Tension and Tone:
- Overhead Squat:
- Anterior Pelvic Tilt: Short/Over-active
- Asymmetrical Weight Shift: Short/Over-active on side of dysfunction
- Goniometric Assessment
- Decreased Spine Contralateral flexion
- Decreased Spine Flexion
- Decreased Spine Rotation
- Palpation of the Quadratus Lumborum:
- See image below for common trigger point locations and referral pain pattern for active trigger points.
Exercises involving the Quadratus Lumborum:
Self-administered Static Release and Stretch for the Quadratus Lumborum:
Self-administered Spine Mobilization:
Lateral Subsystem Integration (Side Step and Step Up to Curl and Press):
Lateral Subsystem Integration (Lateral Lunge to Curl and Press):
Lateral Subsystem Integration (Single Touchdown to Scaption or PNF Carry Away):
Lateral Subsystem Integration (Standing Cobra to Balance to Calve Raise):
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© 2013 Brent Brookbush
Questions, comments, and criticisms are welcome and encouraged.