The Sacroiliac Problem: Review of Anatomy, Mechanics, and Diagnosis

Home , Pubic tubercle, Sacroiliac joint, Sacrospinous ligament, Sacrotuberous ligament

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis

MYRON C. BEAL, DD., FAAO East Lansing, Michigan

methods have evolved along with modifications in Studies of the anatomy of the the hypotheses. Unfortunately, definitive analysis sacroiliac joint are reviewed, of the sacroiliac joint problem has yet to be including joint changes associated achieved. with aging and sex. Both descriptive Two excellent reviews of the medical literature and analytical investigations of joint on the sacroiliac joint are by Solonen i and a three- movement are presented, as well as part series by Weisl. clinical hypotheses of sacroiliac joint The present treatise will review the anatomy of motion. The diagnosis of sacroiliac the sacroiliac joint, studies of sacroiliac move- joint dysfunction is described in ment, hypotheses of sacroiliac mechanics, and the detail. diagnosis of sacroiliac dysfunction. Anatomy The formation of the sacroiliac joint begins during the tenth week of intrauterine life, and the joint is fully developed by the seventh month. The joint In recent years it has been generally recognized surfaces remain flat until sometime after puberty; that the sacroiliac joints are capable of movement. smooth surfaces in the adult are the exception. The clinical significance of sacroiliac motion, or The contour of the joint surface continues to lack of motion, is still subject to debate. The role of change with age. 2m In the third and fourth decades the sacroiliac joints in body mechanics can be illus- there is an increase in the number and size of the trated by a mechanical analogy. A 1 to 2 mm. mal- elevations and depressions, which interlock and alignment of a bearing in a machine can cause ab- limit mobility. Schunke 5 reported that a variety of normal wear or a breakdown in function, not only grooves, ridges, eminences, and depressions can of the bearing and adjacent parts, but also of parts occur. After the third decade the opposing carti- remotely related to it through the creation of ab- lages are roughened, furred, and frayed, resem- normal forces. Joints in the body are subject to bling worn, degenerate areas. In the elderly, the similar types of dysfunction, which also may have joint cavity is partly obliterated by fibrous or fibro- local and remote effects. cartilaginous adhesions. 6 Ankylosis is first ob- Low-back pain is often accompanied by marked served in the ventral margins of the cranial part of changes in the soft tissues and in the gross motion the joint. It may be unilateral, occurring predomi- of the lumbar spine. There has been a tendency to nantly on the right. In some males, ankylosis ap- let these changes overshadow those observed at pears as early as the third decade. Holladay re- the sacroiliac joints. The interest of clinical inves- ported a case of unilateral ankylosis at age 25. He tigators has been stimulated by the potential of also observed that ankylosis was usually not de- the sacroiliac joints to cause dysfunction resulting veloped to the same degree on both sides. Brookes in both local and remote effects. Many clinicians reported that 75 percent of 54 sacra in men above believe that slight changes in mobility at the sa- the age of 50 were ankylosed. croiliac joints are responsible for a variety of clini- Wide variations in the structure of the sacroiliac cal conditions. These range from simple strains to joints have been noted. 158-18 The joint surfaces complex problems involving the spine, pelvis, and show divergence in size, shape, contour, facing, lower extremities. and location. They vary from individual to individ- Hypotheses on the nature of sacroiliac function ual, as well as from side to side in the same person. have been advanced to explain clinical problems of The joint is usually described as "L-shaped," the low back and pelvis. These concepts have been with the long arm directed caudally and the short the basis for the development of diagnostic tests arm cranially. Sometimes the arms appear to be and treatment procedures. Refinements in testing nearly equal in length. The joint may also be "V-

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 667/73 shaped," with varying angles between the arms. aspect of the auricular surface is hollowed out pos- The short arm may be absent, and the surface re- terior to the elevations, forming a groove for the semble a rectangle, a triangle, or an intermediate longitudinal ridge, which characterizes the iliac form. The shape of the ventral border is related to surface. the curvature of the sacrum and the shape of the The sacral surface of the joint consists of three a 1 a . parts. Part 1, the cranial segment, is the largest The sacral surface of the joint is longer and nar- and is located on the body of the first sacral verte- rower than that of the ilia. The iliac surfaces of the bra. Part 2 is the narrowest portion and forms an joint are reciprocally shaped but not exactly con- isthmus joining the two facet segments. Part 3, the gruent with the sacral surface. caudad segment, is narrower and shorter than Weisl2 described the sacral joint surfaces in the Part 1 (Fig. 2). Part 3 may end at the junction of young adult as two elevations separated by a sad- the second and third sacral vertebrae, or it can ex- dle-shaped depression (Fig. 1). One elevation is tend to the mid-portion of the third sacral body". found on the cranial part of the lateral aspect of The latter is the most frequent occurrence. Other the first sacral vertebra. The second elevation is on variations have been reported by Peterson and the ventral aspect of the caudad part. The dorsal Solonen l (Table 1). The dimensions on the sacral articular surface have been reported by several investigators. De- scriptions of the method of measurement were given in only two cases (Table 2). The articular surface may be located more forward or backward on the sacrum. Usually the shift is caudal rather than cephalic. The sacral surface is usually covered with hya- line cartilage, and the iliac surface is covered with fibrocartilage. 5 The cartilage layer fills out and partly obliterates the small depressions and ridges of both the sacral and iliac surfaces. The thickness of the cartilage has been estimated at 1-3 mm. on the sacral surface and about 1 mm. on the iliac surface. The thickness of the sacral cartilage surface is such that it resembles an articular disk and, Fig. 1. Auricular surface of sacrum. Adapted from Weisl (+ = thus, can facilitate joint movement." elevations). The planes of the articular surface of the sacroiliac joint vary considerably from outflaring to in- flaring. In addition, the three parts of the sacroiliac joint usually differ in the facing of the facet plane. The right and left sides are commonly dis- similar. Three types of sacral vertebrae have been described on the basis of measurements of the transverse distance of the dorsal and ventral surfaces of the first three sacral segments9 (Fig. 3). Another study demonstrated four different types of sacral wedging based upon measurements of the transverse width of the sacrum. Variations in sacroiliac movement have been related to age and sex. 2 The dimensions and relative proportions of the sacroiliac articular surfaces do not vary significantly for males and females. How- ever, one observer9 reported that the auricular surfaces in females are smaller and smoother than in males. Irregularities in the facet surface that are associated with the aging process are observed earlier and are more pronounced in males. The loss of Fig. 2. Lateral view of sacral vertebra. Sacral segments are num- sacroiliac joint mobility occurs earlier in males, at bered I , 2, 3, 4, and 5. ages 40 to 50 and older; similar changes are not

118174 June 1082"Jouroal d A0Ahol. 81/no. 10 noted in the female until the end of the fifth de- TABLE 1. VARIATIONS OF THE AURICULAR JOINT SURFACE ON THE cade.22 SACRUM. Accessory auricular facets have been observed Vertebral dorsal to the auricular surface between a rudimen- segments No. of cases tary transverse process of the second sacral verte- Peterson Solonen SI, S2 21 3 bra and the ilium. 5 They range in size from 2 mm. Sl, S2, S3 242 23 to over 1 cm. in diameter and have a fibrocartilag- SI, S2, S3, S4 3 2 inous surface. S2, S3 3 The sacroiliac ligaments have been classified as S2, S3, S4 3 L5, Sl, S2 1 capsular and accessory ligaments (Fig. 4). The L5, Sl, S2, S3 4 ventral, interosseous, and dorsal sacroiliac liga- L6, Sl, S2 2 ments are capsular ligaments, and they play an L6, Sl, S2, S3 1 important part in maintaining the integrity of the Solonen observed two cases with Sl, S2, and S3 on one side, and Sl, sacroiliac joint. The interosseous ligament forms S2, S3, and S4 on the other side. the chief bond between the sacrum and ilia and TABLE 2. MINIMUM AND MAXIMUM DIMENSIONS OF THE SACRAL has cranial and caudal bands. JOINT SURFACE. The iliolumbar, sacrotuberous, and sacrospinous Investigator Length (cm.) Width (cm.) ligaments are described as accessory ligaments. A Schunke 55.3 - 8.0 1.8 - 4.1 striking feature of all the accessory ligaments in Albee 196.0 - 8.0 2.5 - 3.0 the adult is their arrangement into two groups of Weis1 25.1 - 6.9 2.9 - 4.1 Simkens2° 4.0 - 6.5 2.3 - 3.0 fasciculi, one cranial and the other caudal. Sepa- Solonen 4.6 - 8.0 1.6 - 3.3 ration of the iliac bones during movement is resist- Gray 8 5.8 - 6.0 2.4 - 3.5 ed by the sacroiliac and iliolumbar ligaments as well as by the ligaments of the symphysis pubis. Forward rotation or nodding of the sacrum is limited by tension of the sacrotuberous, sacrospinous, u ,, 4.■ . u . o 0 0 " u ° and anterior sacroiliac ligaments. The dorsal and 0 V 0 o o °u . interosseous ligaments may also resist forward CI u :: 0 0 0 0 0 rt .rt 0 bending. Backward bending is limited by tension n. of both the anterior and posterior sacroiliac liga- A B C ments.

Fig. 3. Types of sacra based on transverse width: A, first and Motion second segment > the third; B, first segment < the third; C, Motion in the sacroiliac joint has been investigat- mixed types-A and B on opposite sides. ed by using both living subjects and cadaveric material in descriptive and analytical studies. The descriptive studies measure the distances between of sacroiliac movement. The distance was observed pelvic landmarks on the ilia and sacrum. If a to be greater in the upright standing position as change in body position results in an increase or compared with the forward-bent position. Similar- decrease in the distance between landmarks, an ly, Menne11 24 observed the distance between the inference is made that the relative position of the posterior-superior iliac spines to be greater in the pelvic bones has changed because of sacroiliac upright seated position as compared with the joint motion. prone position. The analytical studies obtain similar types of However, other observers using different meth- data, but their primary objective is to define an ods failed to confirm that the distance between the axis of rotation that describes the motion of the posterior-superior iliac spines changes with body joint. Both types of investigations have proposed position.25,26 similar hypotheses regarding sacroiliac joint mo- Pitkin27 measured the angle of inclination be- tion, and their data provide the major scientific tween the anterior-superior and the posterior-su- evidence supporting earlier anatomic observa- perior iliac spines using an inclinometer. Measure- tions. ments were taken of the right and left ilia in three Ashmore23 was one of the first to report quanti- standing positions: (1) normal standing; (2) right tative data on motion in the sacroiliac joint. She foot on a 1 1/2-inch block; and, (3) left foot on the measured a difference in the distance between the block. He concluded that there were two types of posterior-superior iliac spines as a function of body sacral movement: (1) flexion and extension of the position, and this difference was cited as evidence sacrum in which the ilia are fixed; and, (2) lateral

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 669/75 (2) Extension of the lumbar spine resulted in Ili° - Lumbar Ligament (A) extension of the sacrum relative to the fixed ilium. Posterior S-I Ligaments (C) The free ilium followed the sacrum but the movement was less. (3) Rotation of the lumbar spine resulted in rotation of the sacrum to the same side. There was a Sacrotuberous Ligament (A) simultaneous lateroflexion of the sacrum to the opposite side. Posterior View Of Pelvis (4) Lateroflexion of the lumbar spine resulted in sidebending of the sacrum to the same side. Ro- tation of the sacrum was slight and inconstant as to direction. (5) Traction of the spine resulted in the sacrum Interosseous Ligament (C) moving into extension but compression of the spine resulted in the sacrum moving into flexion. Strachan 14 characterized the movements of the Sacrospinous Ligament (A) sacrum as gliding. He stated that there is greater Sacrotuberous Ligament (A) freedom in flexion and extension, and in upward and downward gliding, than in rotation and lateroflexion. 22 reported a range of rotation movement Lateral View Of Pelvis Siskin between the sacrum and ilium of from 2 degrees to Fig. 4. Sacroiliac ligaments. (A) denotes accessory ligament and (C) capsular ligament. 8 degrees, with an average of 4 degrees. He studied anatomic preparations of persons 29 years of age and under, within 48 hours of death. bending and rotation in which the ilia are moving A number of x-ray studies have been devised to and the sacrum follows passively. attempt to demonstrate sacroiliac movement, to Holladay, using cadaveric material, observed define axes of rotation, and the range of joint that movement at the symphysis pubis also in- movement. cludes movement at the sacroiliac joints. However, Simkins made the assumption that sacral movement of both sacroiliac joints is not accompa- movement consists of rotation in the sagittal plane nied by movement at the symphysis pubis, where- about a transverse axis at the junction of the sec- as unilateral sacroiliac movement involves the ond and third sacral segments. He compared later- symphysis pubis. Halladay reported that forcible al x-rays of subjects in the flexed and extended po- rotation of the sacrum on the fifth lumbar vertebra sitions by erecting vertical and horizontal coordi- takes place midway between the neutral position nates at the transverse axis. He reported a range and hyperextension. The ilia rotate backward on of sacral movement of from 4 degrees to 12 degrees, the side toward which rotation of the sacrum oc- with the average at 8 degrees. curs, and there is an upward and forward gliding Lateral x-rays have also been used to demon- of the symphysis pubis on the same side. The con- strate sacral movement associated with respira- verse movement takes place on the opposite side. tion. X-ray findings of displacement of the pubic Halladay reported that these rotational move- bones observed in pregnancy or post partum have ments may be observed to a slight extent during been offered as evidence of sacroiliac joint move- walking. ment. Strachan immobilized one ilium of a laborato- Sacroiliac movement has been reported when ry specimen in a concrete block. Steel pins were in- motion was introduced through the trunk or serted into the ilia and sacrum. Observations were through the legs. Motion at the joint has been made of sacroiliac motions as movements were in- characterized as angular, that is, rotatory, and troduced through the trunk. Only the quality of translatory. Two studies263° using stereoscopic x- the movement was recorded, since the intensity of ray techniques defined sacroiliac motion in terms the force applied was not controlled. The following of rotation combined with translatory movement. observations were made: The concept of a fixed axis of rotation has been (1) Flexion of the lumbar spine resulted in flex- found to be incompatible with test observations. ion of the sacrum relative to the fixed ilium. The Weis14 found that the axis of rotation moved more free ilium followed the sacrum but the amount of than 5 cm. with changes in position. Reynolds3° movement was less. noted that the axis of sacral rotation changed with

670/76 June 1982JJournal of AOA/vol. 81/no. 10 different positions of the legs. their resolution. The following is a simplified hy- Weis14 studied x-rays of subjects in four vari- pothetical analysis of pelvic mechanics of a subject ations of three basic positions: standing, lying su- in the upright posture. pine, and lying prone. The four variations were The weight of the trunk is transmitted through with the subject at rest, trunk extension, trunk the pelvis to the lower extremities, and the prom- flexion, and trunk and hip flexion. He reported the ontory of the sacrum rotates forward in response to maximal movement of the sacrum as 5.6 ± 1.4 the trunk weight. The ilia tend to tilt backward as mm. This was the change observed in the move- a result of the location of the hip joints with respect ment of the anterior promontory of the sacrum in to the center of gravity, thus accentuating the for- relation to the symphysis pubis as subjects moved ward bending of the sacrum (Fig. 5). from the recumbent to the standing position. He Forward bending from the erect posture requires found less consistent changes over a shorter range simultaneous rotation of the pelvis about the hip during flexion and extension. The latter sacral mo- joints as the lumbar spine is flexed. The sacrum is tions followed trunk movement. No differences in carried along with lumbar flexion and the ilia tend range of movement could be correlated with to follow the sacrum. In the fully flexed position, height, weight, sacral curve index, or sex, with the the sacrum becomes locked due to the wedging of exception of the puerperal state in the latter in- the sacrum between the ilia and the tautness of stance. All movements were unrestricted in the the capsular and accessory ligaments. The normal adolescent and the young female during pregnan- lumbar spinal lordosis is reversed. If sidebending cy. to one side occurs in the initial stages of flexion, Colachis25 placed Kirschner pins in the posteri- the sacrum tends to follow the lumbar spine. Rota- or-superior iliac spines of subjects and then took tion may be slight but variable. measurements in nine different positions. He ob- Lifting a weight in the flexed position places an served that the greatest motion was in forward additional burden on the neuromusculoskeletal bending from the standing position. Movements of mechanism. The resumption of the typical lumbar several centimeters of the innominate relative to lordosis in the erect posture is accompanied by pel- the sacrum were reported by Frigerio using a vic rotation to a normal position. These move- stereoradiographic technique. ments are dependent upon competent neuromus- Egund26 studied four subjects with a history of cular control. back pain using stereometric x-ray studies. He observed that the sacral promontory moved through a range of approximately 2 degrees about a transverse axis. Reynolds, using a similar procedure, studied a fresh, unembalmed cadaver and reported small rotations of the sacrum in a subject over 70 years of age. Holladay" stated that almost every laboratory case over age 50 had minimal joint movement or complete loss of movement. Brooke observed a compensatory increase in lumbosacral movement when there was ankylosis of the sacroiliac joint. In summary, investigators of the sacroiliac joint have described sacral joint motion as characterized by flexion, extension, rotation, lateroflexion, and upward and downward gliding in relation to the ilia. Movements have been observed to be rotatory, translatory, or a combination of the two. The greatest degree of measured motion occurs in forward bending of the sacrum about a transverse axis.

Theories of pelvic motion It is generally recognized that normal motion at the sacroiliac joint is slight, at best. Hypotheses about sacroiliac function have developed as the result of attempts to explain clinical problems and Fig. 5. Lateral view of the pelvis. Mechanics of upright posture.

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 671/77 Fig. 6. Sacral motion axes in the sagittal plane; a, denotes axial ligament; b, Bonnaires tubercle; c, second sacral segment; and d, anterior sacral position. Fig. 7. Linear displacement of the sacrum.

The structural integrity of the pelvis is main- sition of the axis may vary from person to person tained by an equilibrium of forces. Strong liga- depending on the type of movement that is carried ments and the wedging mechanism of the sacrum out. between the ilia are important parameters in this A theory of linear displacement has been pro- equilibrium. Standing on one foot, as in walking, posed in which the sacrum slides along a caudal changes the forces in the pelvis so that there is an portion of the joint" (Fig. 7). The terms "upslip" apparent elevation of the hip of the stationary foot, and "downslip"33 have been used clinically to de- and the contralateral hip tends to be pulled down scribe this hypothetical motion. It has been pro- by the weight of the free limb. These loads lead to a posed that this type of movement can combine shearing force at the symphysis pubis, which must with rotatory components either about a horizon- be countered by strong ligaments. tal or a vertical axis. In a similar manner the sacroiliac joints are sub- Another hypothesis of sacroiliac motion as- jected to fairly strong forces in standing and walk- sumes that movement initiated through the trunk ing.32 The promontory of the sacrum tends to ro- to the sacrum will have different test findings from tate forward on the side of the stationary foot. If that introduced through the lower extremities.34 the body moves forward, the ilium moves forward This concept is based on different asymmetries in with the sacrum. As the leg swings forward, the bony landmarks which cannot be explained on the opposite ilium rotates backwards on the contralat- basis of a simple rotatory movement of the sacrum eral side, and the sacrum follows the ilium on that or ilia in the sagittal plane. It is assumed that side. Forces are modified as the pelvis shifts and forces through one lower extremity will result in rotates from side to side. Since the joints of the pel- unilateral changes in the relationship of the ilium vis are subjected to fairly strong forces during nor- and sacrum and that opposing forces through both mal activities, it is logical to find that theories of lower extremities will further accentuate the pelvic mechanics incorporate elements of motion asymmetries observed. involving all of the pelvic joints. The asymmetries of the sacral rotation observed The concept of movement of the sacrum in the by movement introduced through the lower ex- sagittal plane about a horizontal axis has been tremities is contrasted with those created through variously described as rotation, tilting, or nodding the trunk. In the latter instance, the sacrum ro- (nutation). The site of the axis has been described tates about an axis vertical to the promontory of as: (1) the axial ligaments or the interosseous liga- the sacrum and results in converse asymmetries ment, posterior to the auricular joint surface; (2) on opposite sides. It is difficult to reconcile the con- Bonnaires tubercle, a bony prominence on the au- cept that movement from below through the ex- ricular surface located between the cranial and tremities should result in a different set of motions caudal segments of the facet; (3) the second sacral from that of the condition created by a movement segment; and, (4) an anterior sacral position, an- of the trunk from above. It is recognized that a uni- terior and inferior to the articular surface of the lateral movement through one lower extremity sacrum (Fig. 6). Kapandji l° suggested that the po- may differ from a rotation of the sacrum, creating

672/78 June 1982/Journal of AOA/vol. 81/no. 10 bilateral changes. However, the differences be- bis in parturition have been thought to be the pri- tween asymmetrical lower extremity movements mary purpose of sacroiliac joint motion. Limited and bilateral sacral movement can only be ex- motion in the sacroiliac joint has been attributed plained on the basis of possible translatory mo- to the strength of the ligaments, particularly the tions coupled with ilia motion when movement is accessory ligaments. However, during pregnancy introduced through the legs. there is a selective laxity which is noted at the Sacral motion has been thought to occur with symphysis pubis and also at the sacroiliac joint. respiration with the top of the sacrum rotating This starts at the fourth month and lasts for 3 to 5 backward in the sagittal plane with inhalation months post partum. 29 X-rays of the symphysis pu- and forward with exhalation. This concept is sup- bis may show an average increase of 3 mm. in ported by evidence from palpation over the sacrum width. This change is attributed to laxity of the during forced respiration and by one x-ray study.28 pelvic ligaments which is influenced by hormonal Serious questions have been raised as to whether secretions. tissue movement rather than joint movement is Under normal conditions the pelvic ligaments observed on palpation. In view of the magnitude of are designed to prevent excessive or abnormal forces that must be introduced to demonstrate movement. They are stiff and compliant only with- even slight increments of sacroiliac motion, it has in narrow limits. However, cartilage is commonly been questioned whether the forces generated by a more deformable tissue. The irregularities of the respiration are of sufficient degree to deform liga- articular surfaces are covered by cartilage. A de- mentous constraints of the sacrum or whether the formation of the articular cartilage along with whole pelvis flexes and extends. some elasticity of the pelvic ligaments could ac- The concept of counteracting forces acting on the count for the sense of joint motion observed in sa- pelvis has been incorporated into a hypothesis of a croiliac joint motion testing. musculoskeletal stress pattern. 35 It is postulated that the sacrum is a part of a lumbosacral func- Diagnosis tioning unit responding to gravitational forces. Primary dysfunction of the sacroiliac joints occurs The response is an adaptation to posture, habit, oc- as a result of direct injury, strain, childbirth, or cupation, anomalies of development, short leg, in- disease. Examples include falls, lifting, and sacral jury, etc. The result is dependent upon the lumbo- iliitis. Secondary dysfunctions result from malad- sacral facet facings and the integrity of the aptations of the pelvis to extrinsic forces. Exam- supporting structures. The sacrum may be main- ples are gait, posture, occupation, short lower ex- tained in a position of abnormal rotation between tremity, injuries to the lower extremities or spine, the ilia as an adaptation to a torsional stress pat- abnormal spine curvature, and disease of the mus- tern. In this hypothesis the primary response of culoskeletal system. Viscerosomatic reflexes can the pelvis to movement occurs at the lumbosacral also create pelvic dysfunction. facets, and the sacroiliac joints play a secondary or The diagnosis of sacroiliac dysfunction is based negligible role in pelvic mechanics. on the patients history and the physical examina- Although motion in the sacroiliac joint has been tion. Several questions may be raised initially in demonstrated, hypotheses as to its purpose have the diagnostic process. Are the sacroiliac joints in- not received uniform acceptance. Some2° believe volved in the patients dysfunction, or is the local- that sacroiliac motion in man is simply one factor ization just a matter of referred symptoms? Are in a complex evolutionary development which in- the sacroiliac joints primarily or secondarily in- cludes changes from the quadruped to biped volved? If they are primarily involved, are there stance. Thus, the pelvic joints participate in the related secondary mechanical or adaptive transmission of weightbearing forces from the changes? If the sacroiliac joints are secondarily in- trunk to the lower extremities. The sacroiliac volved, where is the primary source of dysfunc- joints are part of the spinal mechanical linkage tion? Is the problem unilateral or bilateral? system involved in body movement. The relative The examination process seeks to: (1) answer the importance of sacroiliac motion in such a concept question, "Is there a problem?" using one or more is not known. The significance of a loss of sacroili- screening tests; (2) locate the problem by palpatory ac motion, such as occurs with aging, is not clearly scanning tests; and, (3) define it by testing the pel- understood nor is it identified as the cause of a spe- vic joints for mobility. The diagnosis of somatic cific change in body mechanics. dysfunction of the sacroiliac joints is based upon a Increases in sacroiliac motion have been noted dysfunction in joint movement, tissue texture during and immediately following pregnancy. changes which usually accompany joint dysfunc- Changes in the sacroiliac joint and symphysis pu- tion, and asymmetry of pelvic landmarks, which

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 673/79 provides supportive data for the diagnosis. example, the PSIS in the standing and seated flex- Tests can be classified according to the catego- ion tests. ries suggested by Dinnar.36 Tests of Classes I and II Anatomical landmarks are the least reliable of are screening tests. Class II and III tests are used criteria for somatic dysfunction. A diagnosis as scanning procedures; Classes III, IV, and V are should never be made on the basis of asymmetry of used to define the problem. position alone. Class I tests are general observational tests used Class IV tests of superficial and deep soft tissue to screen the patient to see if he has a problem. Ob- are used to identify areas of tissue texture abnor- servations are made of stance, posture, spinal mality resulting from inflammation, nerve irrita- curves, attitude, gait, palpation for symmetry of tion, or injury. Light touch palpation is used to ex- landmarks (crests, trochanters, posterior-superior amine the skin and subcutaneous tissue for iliac spines [PSIS], posterior-inferior iliac spines temperature, moisture, edema, contour, rough- [PIIS], anterior-superior iliac spines [ASIS], scapu- ness, etc. The muscles and ligaments are examined lae, shoulders, and pubic symphysis), and regional by deep palpation utilizing pressure and/or shear- palpation for muscle tone, contour, and contraction ing stress. The quality of the tissue is observed— or hypertonus (legs, pelvis, and lumbar spine). relaxed, contracted, hypertonic, irritable, fibrotic, Class II tests are regional motion tests used to etc. Ligaments and tissue attachments may exhib- screen the patient to see if there are asymmetries it an immediate elastic quality to induced force or in gross motion which might be associated with an elastic property coupled with a damping effect pelvic dysfunction. Class II tests conducted in the of viscosity, a viscoelastic type of behavior. Mus- standing position are the standing flexion test, pel- cle and ligamentous tension indicate the site of in- vic rotation test, side to side pelvic translation jury or evidence of secondary changes related to al- test, and standing alternately on one foot. Seated terations in pelvic mechanics. tests are the seated flexion test, the long seated The ligaments commonly examined include the test, trunk sidebending test, and rotation test. Su- posterior sacroiliac, sacrospinous, sacrotuberous, pine tests are straight leg raising test, inversion ilioinguinal, and iliolumbar. The muscle groups and eversion of the foot and leg, leg lengthening evaluated are the erector spinae, gluteals, pirifor- and shortening test, Faber test, and leg swing test. mis, psoas, thigh extensors, adductors, abductors, (A glossary of Class II tests is appended.) and rectus femorae group. Information derived from these screening tests Asymmetries in the soft tissues are associated is utilized by some examiners along with Class I with relative changes in the position of the sacrum tests to determine if a problem exists. Others use and ilia. These may result in the relative decrease Class II tests to obtain definitive information in tension of ligaments and muscles on one side in about the sacroiliac joints. For example, in the contrast to a relative increased tension on the op- standing flexion test, some examiners record the posite side. Soft tissue changes alone can account level of the PSIS in the standing and flexed posi- for some cases of sacroiliac dysfunction. Tension in tion. Others record the palpatory sense of move- the ligaments and muscles may restrict joint mo- ment observed at the joints as the patient bends tion. Several authors have stressed the importance forward. Implications of pelvic joint motion derived of soft tissue evaluation as the most important fac- from this class of tests should not be considered ade- tor in the diagnosis of sacroiliac dysfunction. quate for a diagnosis of sacroiliac dysfunction. Class V tests, which test for local response to Class Ill tests assess positional landmarks and motion demand, are used to identify motion dys- are used to identify asymmetry of position which functions at the sacroiliac joints, for example, suggests an alteration in pelvic or general body when the sacroiliac joint is examined for mobility. mechanics. One side is compared with the other. One hand palpates over the sacroiliac joint while Class III landmark positions examined in the su- the other hand introduces movement into the pine patient are medial malleoli, pubic tubercles, joints. The range and quality of motion of one side ASIS, and iliac crests. Landmark positions com- is compared with that of the other. pared in the prone patient are medial malleoli, Motion can be introduced through the legs or PSIS, PIIS, inferior lateral angle (ILA), sacral sul- trunk. The joints can be palpated during respira- cus, iliac crests, and first sacral spine distance to tion, or the ilia or sacrum may be sprung or rocked PSIS. Some of these landmarks can also be exam- to introduce movement into the joints. Some examined in the seated or standing position as well. The iners evaluate the patients subjective pain as the position of landmarks is also used in certain mo- joint is tested for motion. The quality and range of tion tests. Observations of symmetry are made be- motion are evaluated. The motion at the upper fore and after the introduction of movement, for pole of the joint is compared with that at the lower

674/80 June 1982/Journal of AOA/vol. 8Vno. 10 pole (Fig. 8). The right side is compared with the left side. Motion at the sacroiliac joint can be difficult to perceive. Direct palpation over the joint surface is not possible because of the position of the articular surface on the sacrum. The palpating fingers re- ceive reflected joint movement through the soft tissues over the sacroiliac joint, and it is often difficult to differentiate between tissue movement and the restricted mobility of the joint. Joint motion may be variable; however, for the most part, it is small and perceived as a slight fluctuation in motion. Movement at the upper pole is normally greater than that at the lower pole. Fig. 8. Upper and lower poles of the sacroiliac joint. Restriction in motion can be one-sided and con- fined to the area reflecting involvement of the upper or lower pole of the joint. It may be bilateral, in either the upper or lower pole, or the restriction crum to the left is carried out by a movement an- can be in the upper pole on one side and the lower teriorly along the cranial segment of the joint on pole on the opposite side. Occasionally, there may the right, whereas the movement is dorsally along be loss of motion in both the upper and lower poles the caudal portion of the joint on the left. Mitch- on the same side. ell developed the concept of oblique axis to ex- It is sometimes advisable to use more than one plain torsional patterns of sacroiliac dysfunction. test for sacroiliac motion or to test the subject from He stated that the sacrum does not physiologically opposite sides of the table, especially when the dis- rotate on a vertical axis between the ilia; however, crimination of subtle changes in movement is diffi- he failed to give supporting evidence for his state- cult. The acuteness of pain of a joint is not always ment. The oblique axis hypothesis may be helpful indicative of the site of the trouble. Sometimes a to some to explain clinical observations associated locked joint results in increased motion demands with a concept of torsion of the sacrum, but there is on the opposite side with a resulting inflammation no evidence to confirm its existence. of that joint. The anatomical observations of Holladay are Restrictions in sacroiliac joint motion may occa- cited as evidence for the torsional concept. Yet both sionally occur alone without signs of tissue texture Strachan and Holladay, using anatomical speci- changes. More commonly, tissue changes and mo- mens, reported similar findings resulting from ro- tion restrictions are localized at the same part of tation of the sacrum by a force through the spine. the joint. The sacrum follows the rotation of the lumbar The classic physical signs for a dysfunction of spine. The ilium rotates backward on the side to the sacroiliac joint in which a unilateral rotation which the body of the sacrum rotates. Strachan13 movement of the sacrum or ilium has occurred in also observed a simultaneous sidebending of the the sagittal plane about a transverse axis are list- sacrum to the side opposite the rotation. These ob- ed in Table 3. Although unilateral test findings servations of the effect of the lumbar rotation on predominate, there are often some compensatory the sacrum do not validate the hypothesis of an changes on the opposite side. A classic rotation or oblique axis. torsion dysfunction of the sacrum will demonstrate modified combined findings. Similarly, the Discussion opposing rotations of the ilia, for example, one for- Test results for sacroiliac dysfunction can be ex- ward, one backward, will show the combined find- tremely variable for the following reasons: (1) Po- ings (Fig. 11). sitional findings may be clearly positive or difficult The concepts of rotation of the sacrum both in to evaluate; (2) it is easy for the examiner to make the sagittal plane about a transverse axis and in a the findings conform to his diagnostic hypothesis horizontal plane about a vertical axis give logical, unless he gives critical attention to the testing pro- simplistic explanations for clinical observations of cess; (3) soft tissue findings can be transient or sta- sacroiliac dysfunction. However, Magoun39 pro- ble; (4) transient findings may be altered with re- posed that the sacrum rotates about an oblique peated examinations; (5) the degree of soft tissue axis running from the upper pole on one side to the involvement can vary from marked to minimal; (6) lower pole on the opposite side. Rotation of the sa- acute tissue changes may be superimposed upon

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 875/81 TABLE 3. PHYSICAL SIGNS FOR A DYSFUNCTION OF THE SACROILIAC JOINT IN WHICH A UNILATERAL ROTATION MOVEMENT OF THE SACRUM OR ILIUM HAS OCCURRED IN THE SAGITTAL PLANE ABOUT A TRANSVERSE AXIS. Tests Results Anterior sacrum Posterior sacrum Posterior ilium Anterior ilium Class Name (See Fig. 9) (See Fig. 10) III Sacral sulcus Deeper Shallow PSIS Caudad Cephalad ILA Posterior Anterior Pubic tubercle Cephalad Caudad ASIS Cephalad Caudad IV Posterior sacral ligament Tension Tension below PSIS Sacroiliac joint Upper pole, tender Lower pole, tender Sacrospinous ligament Tension Relaxed Sacrotuberous ligament Tension Relaxed Gluteal muscles Contraction opposite Contraction opposite upper pole lower pole Piriformis muscle Contraction V Sacroiliac joint Restriction upper Restriction lower pole pole

■,\ x , Sacral Sulcus - Deep / ...... /". Sacral Sulcus - Shallow ASIS t }Upper Pole - Tender ASIS— Motion Restriction —PSIS I PSIS 1 Lower Pole - Tender Motion Restriction — ILA - Posterior I /- ...... -•- ....0 -ILA - Anterior Pubic Tubercle— S. Spinous Ligament - Tense Pubic Tubercle — 7-•♦ S. Spinous Ligament - Relaxed — S. Tuberous Ligament - Tense ....".. N. S. Tuberous Ligament - Relaxed

Fig. 9. Diagnostic findings for anterior sacrum or posterior ilium. Fig. 10. Diagnostic findings for posterior sacrum or anterior ilium.

Sacral Sulcus - Shallow Sacral Sulcus - Deep PSIS t Gluteal Muscle - Contracted Lower Pole - Tender Upper Pole - Tender Motion Restriction Motion Restriction Posterior S-I Ligament - Tense Posterior S-I Ligament - Tense Gluteal Muscle - Contracted PSIS

ILA - Posterior ILA - Anterior

Fig. 11. Diagnostic findings for sacral torsion, anterior sacrum right, and posterior sacrum left. chronic changes; (7) joint motion restrictions are tional pelvic tests conducted by experienced clini- not only difficult to test but show marked vari- cians was found to be poor. The tests included vi- ations in the quality and degree of change; and, (8) sual observation of the patient in the standing the degree of joint restriction is apparent in only position, with a check of levels; the standing and some instances after a trial of treatment when a seated flexion tests; assessment of bony land- marked improvement in joint mobility is observed. marks; palpation for tissue texture; and tests for The interexaminer reliability of a set of tradi- sacroiliac joint motion. Good agreement was

676/82 June 1982/Journal of AOA/vol. 8I/no. 10 achieved on such factors as trochanter levels, iliac joints. lnterexaminer agreement on this test was crest levels, lumbar convexity, and certain posi- poor." Several problems were identified. The abil- tional landmarks. The individuality of the exam- ity to locate the PSIS varies from subject to subject iners became apparent in the assessment of tissue according to the anatomical structure as well as texture, motion tests of the sacroiliac joint, and the the amount of adipose tissue overlying the PSIS. standing and seated flexion tests. In some individuals the PSISs are easily identi- Some of the difficulties in obtaining examiner fied; in others, they are not. The inferior slopes of agreement can be illustrated by Class III land- the spine are not always well defined. Some exam- mark tests. Pelvic landmarks are not always easily iners are in the habit of picking up tissue cues as identifiable or accessible. Variations in bone struc- well as motion cues during the forward bending ture and contour make it difficult to obtain exact movement. These subjective observations can in- hand or finger placements. Anomalies and asym- fluence their assessment of the test. Repeated at- metric bone growth may create asymmetries and tempts at defining the test procedure gave equiv- give false results. The inferior lateral angle test is ocal results. A high level of interexaminer agree- an example of how an anomaly can confuse the use ment was not achieved. of positional landmarks. Two examiners inde- The reliability of test results is determined by pendently examined the inferior lateral angle of a the ability of the examiner to achieve consistency subject. Their findings did not agree. Upon reeval- in his testing procedures. Critical attention must uation of the test, it was found that the subject be given to the details of the performance of the had a bony prominence on one side, which gave a test so that there is a uniformity in its conduct. It different test result, depending upon whether the is important that each examiner have a high de- examiners finger was on the ridge or not. gree of intra-rater reliability in his testing process The test for depth of sacral sulcus illustrates an- to provide dependable data for diagnosis. Test data other problem in Class III evaluations; that is, it is should also be significant; that is, the test results difficult to palpate through tissue to ascertain the should be positive and an important component of relative position of a bony prominence. With the a diagnostic hypothesis of pelvic function, such as patient in the prone position, the examiners joint mobility. thumbs press firmly on the base of the sacrum to Significant tests in sacroiliac diagnosis have palpate through the skin, subcutaneous tissue, been ranked by several examiners in order of im- and posterior-sacroiliac ligaments down to the portance (Table 4). firm resistance of bone. The relative depth of pal- Many authors have described the anatomical pation is evaluated for symmetry. A greater depth variability of the sacroiliac joint. However, clinical of sulcus is associated with an assumed forward ro- assessment of pelvic mechanics has not been re- tation of the sacrum. However, tissue resistance fined sufficiently to correlate anatomical variabil- created by fibrous contraction of tissue or in- ity with consistent findings from tests of joint mo- creased tissue fluid can give a false impression of tion. Changes in mobility attributed to age and sex deep resistance before the firm resistance of bone have not been related to clinical dysfunction, ex- is reached. Accurate results from this test are de- cept for disorders associated with pregnancy. At- pendent upon the examiners ability to recognize tempts to measure differences in joint mobility and evaluate the tissue texture change in contrast have either been observed to lack precision or sim- to the resistance attributed to bone. ply have not been attempted. The difficulties of obtaining interexaminer The fact that the range of movement at the lum- agreement can be further illustrated by the stand- bosacral joints is greater than that at the sacroili- ing flexion test. This test has been traditionally ac joints has led some to the conclusion that the used to determine dysfunction of the sacroiliac lumbosacral joints play the primary role in pelvic

TABLE 4. SIGNIFICANT TESTS IN SACROILIAC DIAGNOSIS RANKED IN ORDER OF IMPORTANCE.

Test rank Observer 1 2 3 4

Fryette9 Ligamentous tension Mobility Tenderness Position Schwab Mobility Ligamentous tension Tenderness Beilke" Motion Tissue Position Mitche1149 Position Symphysis pubis Bony landmarks

The sacroiliac problem: Review of anatomy, mechanics, and diagnosis 677/83 mechanics and the sacroiliac joints have a minor Special thanks go to Herbert Reynolds, Ph.D., for his or secondary role. Definitive clinical data are not valuable advice and assistance in preparing this review. available to confirm or deny this hypothesis. In Thanks also go to William Johnston, D.O., David Patri- many instances of somatic dysfunction, both joints quin, D.O., and Robert Hubbard, Ph.D., for their helpful critique of the article. The author also wishes to express are involved, and it is often difficult to state which appreciation for the help of Bruce Miles, Ph.D., with the is primary. In other instances the degree of tissue drawings, and to Ms. Ann Eschtruth for her help in the reaction and motion restriction is more localized at preparation of the manuscript. one joint than the other. Treatment of the clinically determined primary site often results in an improvement of the secondary site without applying 1. Solonen, K.A.: The sacroiliac joint in the light of anatomical, roent- genological and clinical studies. Acta Orthop Scand, Suppl. 27:1-115, specific treatment to it. May 57 Several authors have developed their hypoth- 2. Weisl, H.: Articular surfaces of sacro-iliac joint and their relation to eses of pelvic mechanics on the basis of a fixed axis movements of sacrum. Acta Anat 22:1.14, 1954 3. Weisl, H.: Ligaments of sacro-iliac joint examined with particular ref- of motion. Investigations have shown that there is erence to their function. Acta Anat 20:201-13, 1954 no stationary pelvic axis; rather, the axis shifts 4. Weisl, H.: Movements of sacro-iliac joint. Acta Anat 23:80-91, 1955 with the introduction of movement. The number of 5. Schunke, G.B.: Anatomy and development of sacroiliac joint in man. Anat Rec 72:313-31, 25 Nov 38 potential axes for pelvic motion tend to confuse 6. Bowen, V. and Cassidy, J.D.: Macroscopic and microscopic anatomy and complicate the subject of pelvic mechanics. of the sacroiliac joint from embryonic life until the eighth decade. Spine Hypotheses based on a stable axis of movement 6:620-8, Nov-Dec 81 7. Halladay, RV.: Applied anatomy of the spine. J.F. Janisch, Kirks- have little quantitative support and serve only as ville, Missouri, 1920 convenient explanations for certain concepts of 8. Brooke, R.: Sacro-iliac joint. J Anat 58:299-305, Jul 24 pelvic motion. 9. Fryette, H.H.: Principles of osteopathic technic. Academy of Applied Osteopathy, Cannel, California, 1954 10. Kapandji, I.A.: The physiology ofjoints. The trunk and the vertebral Conclusion column. Vol. 3. Churchill Livingstone, London, 1974 The study of pelvic mechanics has led to an exami- 11. Robuck, S.V.: Sacral structure determines function. American Acad- emy of Osteopathy Yearbook, Colorado Springs, Colorado, pp. 1-5, 1966 nation of the importance of the sacroiliac joint in 12. Strachan, W.F.: Applied anatomy of the pelvis and lower extremities. general body performance as well as its relation- JAOA 40:85-6, Oct 40 ship to pelvic dysfunction. Investigations have 13. Strachan, W.F., et al.: A study of the mechanics of the sacroiliac joint. JAOA 37:576-8, Aug 38 shown that motion exists at the sacroiliac joint but 14. Strachan, W.F.: Applied anatomy of the pelvis and perineum. JAOA that it is variable and limited. The importance of 38:359-60, Apr 39 sacroiliac joint movement for body function has 15. Stoddard, A.: Manual of osteopathic technique. Hutchinson, Lon- don, 1959 not been determined. Variations in anatomy of the 16. Beilke, M.C.: Sacro-iliac diagnosis. JAOA 34:415-7, May 35 joints surface have been well documented, but re- 17. Bellew, H.: More aacro-iliac truth (to say nothing about the symphi- lationship to clinical dysfunction is not known. sis pubis). JAOA 27:31-4, Sep 27 The concept that the thick cartilage surface acts 18. Gray, H.: Sacro-iliac joint pain. Finer anatomy; mobility and axes of rotation; etiology; diagnosis and treatment by manipulation. Int Clin as an articular disk promoting gliding motions 2:64-96, Jun 38 helps to explain joint mobility. The young and the 19. Albee, F.H.: A study of the anatomy and the clinical importance of young pregnant female demonstrate the greatest the sacro-iliac joint. JAMA 53:1273-6, Oct 09 20. Simkins, C.S.: Anatomy and significance of the sacroiliac joint. joint movement. However, only in the latter case American Academy of Osteopathy Yearbook, Colorado Springs, Colora- are clinical problems regularly associated with do, pp. 64-9, 1952 21. Peterson, A.M.: The human sacrum. In Scientific transactions of the joint dysfunction. There is a progressive loss of mo- Royal Dublin Society, Vol. II, University Press, London, 1893 bility and evidence of joint disintegration with 22. Siskin, D.: A critical analysis of the anatomy and the pathological age, leading to ankylosis of the joints; yet, corre- changes of the sacro-iliac joints. J Bone Joint Surg 12:891-910, Oct 30 23. Ashmore, E.: Osteopathic mechanics. Journal Printing Co., Kirks- sponding clinical symptoms have not been regu- ville, Missouri, 1915 larly identified. 24. Mennell, J.: The science and art of joint manipulation. In The spinal Sacroiliac diagnosis utilizes palpatory skills in column, Vol. II. Blakiston Co., Philadelphia, 1952 25. Colachis, S.C., Jr., et al.: Movement of the sacroiliac joints in the testing joint motion, analyzing tissue texture, and adult male. A preliminary report. Arch Phys Med Rehabil 44:490-98, assessing asymmetry of pelvic landmarks. Im- Sep 63 proved clinical diagnosis should result from more 28. Egund, N., et al.: Movements in the sacroiliac joints demonstrated with roentgen stereophotogrammetry. Acta Radiol (Diagn) (Stockh) clearly defined relationships between test findings 19:833-46, 1978 and joint dysfunction. The evaluation of the qual- 27. Pitkin, H.C., and Pheasant, H.C.: Sacrarthrogenetic telalgia. A ity and degree of joint mobility requires precision study of sacral mobility. J Bone Joint Surg 18:365-74, Apr 36 28. Mitchell, FL., Jr., and Pruzzo, N.A.: Investigation of voluntary and in testing. Accurate correlation between motion primary respiratory mechanisms. JAOA 70:149-53, Jun 71 and joint dysfunction should lead to a better un- 29. Young, J.: Relaxation of the pelvic joints in pregnancy. Pelvic ar- derstanding of the sacroiliac problem and its treat- thropathy of pregnancy. J Obst Gynaec Brit Emp 47:493-524, Oct 40 30. Reynolds, H.M.: Three-dimensional kinematics in the pelvic girdle. ment. JAOA 80:277-80, Dec 80

678/84 June 1982/Journal of AOA/vol. 81/no. 10 31. Frigerio, N.A., Stowe, R.R., and Howe, J.W.: Movement of the sacro- 39. Magoun, H.I.: A method of sacroiliac correction. JAOA 39:455-7, iliac joint. Clin Orthop 100:370-7, May 74 Jun 40 32. Goel, V.K., and Svensson, N.L.: Forces on the pelvis. J Biomech 40. Mitchell, FL.: Structural pelvic function. American Academy of Os- 10:195-200, 1977 teopathy Yearbook, Colorado Springs, Colorado, pp. 71-90, 1958 33. Schwab, WA.: Principles of manipulative treatment. The low back problem. JAOA 32:223-7, Feb 33 34. Beckwith, C.G.: Pelvic mechanics. JAOA 43:549-52, Aug 44 Accepted for publication in January 1982. 35. Dunnington, WP: A musculoskeletal stress pattern. Observations from over 50 years' clinical experience. JAOA 64:366-71, Dec 64 Dr. Beal is a professor in the Department of Family Medicine, 36. Dinner, U., et al.: Classification of diagnostic tests used with osteopathic manipulation. JAOA 79:451-5, Mar 80 Michigan State University, College of Osteopathic Medicine, East Lansing, Michigan. 37. Beal, M.C.: Unpublished data from the Biomechanics Clinical Re- search Group. Dr. Beal, Department of Family Medicine, Fee Hall, Michigan 38. Karni, Z., et al.: Mechanical and material descriptors for sacroiliac State University, College of Osteopathic Medicine, East Lan- treatments. JAOA 78:378, Jan 79 sing, Michigan 48824.

Glossary of diagnostic tests malleolus indicates an anterior rotated ilium. Class H - Regional motion tests 7. Trunk sidebending and rotation test Subject seated. Subjects trunk is passively side- 1. Standing flexion test bent to the right and left to ascertain asymmetry; Subject standing. The levels of PSIS are com- likewise, rotation is passively tested to the right pared. The subject bends forward. The PSIS are re- and left. checked for symmetry. On a positive test, one PSIS is cephalad on forward bending, indicating a lock- 8. Straight leg raising test ing of that sacroiliac joint. Subject supine. One leg at a time, with the knee 2. Pelvic rotation test fully extended, is passively flexed at the hip. The Subject standing. The pelvis is passively rotated range, resistance, discomfort, and asymmetry be- to the right and left to ascertain asymmetry of tween the legs is noted. Asymmetry may indicate movement. An asymmetry may indicate pelvic dys- pelvic dysfunction. function. 9. Inversion and eversion of the leg 3. Side to side pelvic translation test Subject supine. The subjects heels are grasped, Subject standing. The pelvis is passively moved in and the legs are passively rotated in the acetabu- a translatory direction from right to left to ascertain lum internally and externally. Asymmetries of mo- asymmetry. Asymmetry of motion may indicate pel- tion may indicate pelvic dysfunction. vic dysfunction. [Ref.: Johnston, W.L.: Hip shift; 10. Leg lengthening and shortening test testing a basic postural dysfunction. JAOA 63:923- Subject supine. The level of the medial malleoli is 930, June 64.] tested. One leg is passively flexed on the abdomen 4. Standing alternately on one foot and then abducted and externally rotated and ex- Subject stands alternately on one leg. Body insta- tended. Normally, the leg should lengthen. If the bility may indicate pelvic dysfunction. leg is flexed on the abdomen and then adducted, internally rotated, and extended, the leg should nor- 5. Seated flexion test mally shorten. Asymmetries may indicate pelvic Subject seated. The levels of the PSIS are com- dysfunction. pared. Subject bends forward. PSIS are rechecked for symmetry. If one PSIS is cephalad on forward 11. Faber test bending, the test is positive, indicating a locking of Subject supine. One leg is passively flexed. The that sacroiliac joint. heel is placed on the opposite knee. The leg is abducted and externally rotated. The knee is sprung 6. Long seated test to externally rotate the hip. Pain or restriction may Subject supine. Level of medial malleoli checked. indicate pelvic dysfunction. Subject asked to sit with knees extended. Malleoli rechecked for symmetry. Caudad position of mal- 12. Leg swing test leoli may indicate posterior rotation of ilium. If the Subject supine. The legs are grasped at the heels standing flexion test is positive on the same side and gently swung to the right and left to test sym- then this test is positive. Conversely, a cephalad metry. Asymmetry may indicate pelvic dysfunction.

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