ORIGINAl ARTIClE The iliopsoas muscle Agust Jorgensson and the lumbar spine The influence of the iliopsoas muscle length on he iliopsoas is the only muscle rotation of the lumbar spine or, in postural and mobility characteristics()f the Tgroup in the body with direct cases of extreme shortening, to draw lumbar spine was investigated in 60 normal attachments to the spine, the the lumbar spine into the opposite male subjects. The passive physiologJcal and pelvis and the femur. Therefore it has movement directions, thus causing a accessory intervertebral movements were the potential to influence, and be scoliosis or a list of the lumbar spine assessed. Measurements which provided influenced by, movements at both the (Kennedy 1978, Michele 1963). estimations of the lumbar lordosis, lumbar spine and the hip joints. Similarly, components of extension and iliopsoas muscle length were The iliopsoas is a postural muscle and compression and of anterior shear also recorded. A difference was found in the has been observed to demonstrate a forces on the lumbar spine have been iliopsoas muscle length with respect to the striking tendency to shorten 0" anda postulated to accompany the basic mobility of the passive physiological and 1978 and 1983). The few studies which actions of the iliopsoas muscle accessory intervertebral movements at the L1- have investigated the length of the (Gracovetsky et aI1977, Nachemson L2 and T12-L 1 segments, and at the L2 and L1 iliopsoas have found that 1968, Troup 1975). These assumptions levels respectively. As the iliopsoas muscle approximately 20-35 per cent of are based on geometry, mathematical shortened, the intervertebral mobility increased. normal individuals show a 5 degrees or calculations and clinical impressions, Furthermore, the iliopsoas muscle length more extension deficit at the hip joint but have not been substantiated by showed a weak tendency toward a correlation attributable to the iliopsoas muscle research. Thus, although a shortening with the lordosis and the lordosis tended to (Barber et al1985, Hellsing etalI987). of the muscle group might be expected increase asthe muscle shortened. No correlation In the two studies listed, the muscle to enhance the accessory compression was found between the iliopsoas muscle length length was tested by a procedure and shear forces, these have not been and the range of lumbar extension. similar to the one recommended by demonstrated experimentally or [Jorgensson A: The iliopsoas muscle and the Janda (1983). clinically. However, many lumbar spine. Australian Journal of When shortened, iliopsoas has been physiotherapists use a regime of Physiotherapy 39: 125-132] described as increasing the lumbar iliopsoas muscle stretching in the lordosis O"anda 1983, Kendall and treatment of lumbar spine disorders in McGreary 1983, Kennedy 1973 and an effort to achieve optimal results. It 1978, Michele 1960 and 1963, Philips is suggested by some practitioners that 1975, Weintraube 1986). However, this may be important, especially in only two studies have investigated this cases of hypermobility of the lumbar relationship, and neither of these . spine, which may be attributed to Key words: Psoas muscles; demonstrated a significant relationship iliopsoas shortening. Lumbar vertebrae; Lordosis; between iliopsoas length and any In view of this knowledge, a study increase in lumbar lordosis (Barber et was devised to examine the nature of Movement al 1985, Toppenberg and Bullock such a potential relationship. 1986). Materials and methods Other authorities have also considered that a shortened iliopsoas A sample of convenience, consisting of muscle acts to limit the available range 60 male students ranging in age from of lumbar extension (Ingber 1986, 17 to 26 years (mean=19.5 years; A Jorgensson BSc(Physio), GradDipAdv Weintraube 1986). However, no S~D.=2.4years) was recruited. ManipTher is a practitioner in Reykjavik. Iceland. reported studies either support or Subjects were excluded if they had: and part-time tutor in the Physiotherapy Faculty dispute these claims. A shortening of of the Icelandic University. a) any marked postural problems the muscle group has also been (for example a scoliosis or leg Correspondence: A Jorgensson, Kleppsveg 40, suggested to limit lateral flexion to the length discrepancy); 105 Reykjavik, Iceland. contralateral side and ipsilateral ORIGINAL ARTICLE right rotation. This order minimised movement of the subject and made recording eaSIer. b) Passive accessory intervertebral movement tests (P AIVM) were conducted manually, commencing at the L5 vertebra and proceeding cephalad to the TIl vertebra. These tests were performed in the following order: central postero-anterior vertebral pressure, right unilateral postero-anterior vertebral pressure, left unilateral postero-anterior vertebral pressure. The passive intervertebral movement tests were graded on an ordinal scale ofone to five such that: l=hypomobile; Figure 1. 2=slightly hypomobile; Figure 3. Measurement of the incline at the S21evel. 3=normal; 4=slightly Measurement of the lumbar extension. hypermobile; 5=hypermobile. Gonnella et al (1982) used a From Page 125 seven point scale to study the therapists in evaluating the b) any previous major trauma or reliability in evaluating passive movements of the lumbar injury affecting their back or lower intervertebral movements, spine in five normal subjects showed intratherapist limbs; oJ.' adding ankylosed (0) and unstable (6) to the scale used reliability to be dependable c) ever experienced problems/pain in while intertherapist reliability their back or lower limbs which in the present study. The performance of five physical was not. Their conclusion was required medical treatment, that in studies where pa~ive limited activities of daily living or intervertebral movements are necessitated absence from school! B":angle recorded at used, the therapist as a source work. of variance should be kept Prior to their inclusion in the study, constant, eg all evaluations each subject was required to answer a x:;d.egree done by the one therapist. questionnaire to ascertain their of 2. To obtain an estimation of the suitability for inclusion. The subject lumbar lumbar lordosis, the standard also provided an indication of the .Iordosis Myrin goniometer, as modified by dominant or preferred leg (eg the one x'!"180~(90~ Grant (1984), was used to measure used for kicking a football). the inclines at the L1 and S2 levels The sequence of testing was x~fl~~~). (see Figure 1). From these values standardised to include: 9ak.B-. .. the angle of lordosis was calculated 1. a) Passive physiological adapting the method proposed by intervertebral movement tests ................... < •• : Cobb (1960) in his measurement (PPIVM) were conducted of the degree of curvature in manually, commencing at the subjects presenting with scoliosis. L5-S1 segment and Figure 2 illustrates the geometry proceeding cephalad to the _~~~~r. appropriate to this calculation. T11-TI2 segment. These Other studies have previously used tests were performed in the Figure 2. Cobb's (1960) method to calculate following order: Extension, Calculation of lumbar lordosis using the the lumbar lordosis (Barber et al right lateral fleJcion, left measured angles of inclination at l1 and 1985, Bullock et al 1987, rotation, left lateral flexion, S2. Toppenberg and Bullock 1986). ORIGINAL ARTICLE figure 4. Figure 5. Performance of the lumbar extension. Test position for measurement of the iliopsoas muscle length. 3. For measurement of the lumbar in the muscle length test. For the asked to hold the flexed knee with extension, a modified lumbar measurement, each subject was both hands and maintain the spondylometer designed by Grant placed supine on the plinth with position. This positioning ensured (1984) was used to monitor the heels supported. Using a plastic that the lower limb to be tested movement between S2 and T12 ruler, a line was marked 5cm hung freely over the edge of the (see Figure 3). A posterior pelvic proximal to the superior edge of plinth, and the subject was asked tilt was performed prior to the each of the patellae. A strap was to relax the free hanging leg as initiation of the movel11ent but applied to the thigh just proximal much as possible (see Figure 5). then perniitted to be lost toward to these lines and a Myrin Following a 20-second period the end of the movement to ensure goniometer was attached to the which allowed for adequate low lumbar extension (see Figure strap by a Velcro fastening. The relaxation, a reading was taken 4). The reason for preceding the examiner then fully extended the from the Myrin goniometer. extension by a posterior pelvic tilt subject's knees to ensure that the This sequence of testing also served was to flatten the lumbar lordosis legs were lying straight on the to make the examiner blind to the and thus stretch the iliopsoas plinth and the goniometer was results of the objective tests of the muscle. That stretch was then calibrated to zero. Next, the lumbar lordosis, lumbar extension and expected to be accentuated by the subject slid down the plinth to iliopsoas muscle length while ensuing extension movement. stand at its edge. The subject was performing the more subjective tests of 4. Estimation of the iliopsoas muscle then asked to lie supine on the PPIVM and PAIVM. length performed first on the right plinth with the coccygeal region just over the end, so that the lower The examination was always carried side and then on the left. As it is out in the afternoon between one and limb to be tested would be free impossible to measure muscle six o'clock, to minimise the possible length in vivo as an absolute value, from any restraints offered by the plinth. While the examiner flexed effects of circadian variations in the length of the iliopsoas was flexibility (Gifford 1987). measured functionally using a the subject's non-tested lower limb method based on the one at the hip and knee, the lumbar Reliability procedures spine was palpated to ensure its recommended by Janda (1983).