disorder. If the pain occurs (or initially occurred) during sports, consider pars interarticularis fr actures, spondylolytic spondylolisthesis or Scheuermann \200\231s disease (vertebral epiphy seal osteochondritis). \200 Persistent pain, unrelieved by rest and disturbing sleep, req uires consideration of a bone, bone and/or disc infection, or osteoporotic fracture (steroid-rela ted or juvenile idiopathic osteoporosis (JIO)). \200 JIO is rare, occurs between 6 and 13 years of age and is more common in boys. The main differential diagnosis is osteogenesis i mperfecta (see Chapter 16). Although uncommon, neurologic symptoms such as burning pain, paresthesias, and weakness in the legs suggests nerve root irritation. Spinal stiffness in a child (typically between 2 and 6 years of age) associated with irritability and a diffusely tender back may be due to infectious discitis (though organisms are only found in 50%). In an older child or adolescent (typically 10 \200\22315 years of age) and with a less striking history, immobility-related stiffness cou ld represent juvenile enthesitis related arthritis (ERA). If pain is absent \200 Spinal conditions are not always associated with pain. Occasionall y a child may present with back deformity or neurologic symptoms in the legs alone. \200 The history may be nonspeci \201 c and, for example in a very young child, nothing more than a refusal to walk. Scheuermann \200\231s disease commonly presents in teenagers with a painless thoracic kypho sis. Pain is more likely to be present if the chondritis is thoracolumbar rather than thora cic. The condition is often asymptomatic. Spinal dysraphism (bony abnormality \200\224usually spina bi \201 da, associated with neur al anomaly \200\224invariably cord tethering) and spinal cord tumors can often present with neurologic leg symptoms/signs alone without back pain. Symptoms may be mild initially. Scoliosis is usually pain free. Pain with scoliosis usually indicates signi \201 cant underlying pathology. The differential is wide (see Table 2.15). \200 Th e most frequent single cause of a scoliosis in schoolchildren (40%), found from radiographi c screening, is pelvic tilt due to leg length inequality. Past developmental, medical, family, and social history \200 Ask about milestones in musc uloskeletal development. Abnormality or delay might suggest spinal dysraphism or neuromuscu lar conditions. \200 Osteoporosis may be evident from previous fragility fracture \200 \224 axial or appendicular \200\224or may be intimated from risk factors, e.g., steroid use . \200 Previous low back trauma may have been pars interarticularis fractures preceding (the current) vertebral slip or disc prolapse. \200 Irradiation (e.g., of previ ous Wilms \200\231) is a cause of scoliosis. CHAPTER 2 Regional musculoskeletal conditions 86 Table 2.15 Causes of scoliosis in children and adolescents Idiopathic: infantile (0 \200\2233 years); juvenile (3 \200\22310 years); adolescent (> 10 years) Structural scolioses (vertebral rotation, vertebral structural change, and loss of normal s pinal \202 exibility) Neuromuscular Congenital: failure of vertebral formation, segmentation, or both Neuro \201 bromatosis Heritable disorders of connective tissue, e.g., osteogenesis imperfecta Trauma: fracture; surgical (e.g., post- laminectomy); irradiation Spondyloepiphyseal dysplasia Metabolic bone disease Lumbosacral anomalies (e.g., spondylolytic spondylolisthesis) Cervicothoracic anomalies (e.g., cervical fusion (Klippel \200\223Feil)) Rheumatoid arthritis Extraspinal contractures (e.g., postempyema, postburns) Nonstructural scolioses (lateral spinal curvature but no vertebral rotation)* Postural Nerve root irritation associated Abdominal pain associated (e.g., appendicitis, renal pain) Associated with local in \202 ammation Spinal infection Spinal tumors Secondary to leg length discrepancy Related to soft-tissue contractures around the hip Psychogenic It is characteristic of nonstructural scolioses that if the underlying cause is successfull y dealed with, the scoliosis resolves. Ask about previous TB or risk factors for TB in patients you think are at risk of TB osteomyelitis. Torticollis may be associated with chronic squint, previous trauma (which may be associated with a psychogenic component), and neuroleptic drugs. It can be a sign of an underlying ne urologic or in \202 ammatory lesion or occurs because of an underlying structural anomaly. SPINAL DISORDERS IN CHILDREN AND ADOLESCENTS 87 A history of a heritable disease of connective tissue can often be elicited from the family of a child with structural scoliosis. A history of back pain is sometimes elicited from families of children with nonspeci \201 c back pain. Joint dislocation and multiple soft-tissue musculoskeletal injury (especially overuse) in family members raises the possibility of general hypermobility \200\224either j oint hypermobility syndrome or a heritable connective tissue disease, e.g., Marfan syndrome (see Chapter 16). The existence, or child \200\231s perception, of social disharmony at home or school is lik ely to be more important in in \202 uencing the impact of back pain rather than a cause of it. Nevertheless, in children with nonspeci \201 c spinal pain or \201 bromyalgia, soci al con \202 ict resulting in stress and anxiety may be very important in generating sympto ms. Examination It is best, and certainly ultimately more informative, to undertake the examina tion only when the child is comfortable with the situation, with their modesty and dignity preserved, and with consent to go ahead after a reassurance that the examination will be st opped if it is painful. With younger children there may be \200\234an examinable moment \200\235, usually after the child has gained con \201 dence in the surroundings and with t he situation. Observing a young child while playing is a considerate way of starting the ex amination. Age-related variations in biomechanical development and gait patterns \200 Walking while holding a hand or furniture develops by 12 months and normally independent walking by 18 months. Until 3 years the stance is broad-based in relation to pelvic width, the knee may not fully extend, and the ankle may be plantar \202 exed at foot- strike. Climbing stairs is usually done using alternate feet by age of 3 years. \200 Tiptoe walki ng is not abnormal at \201 rst but should disappear by 2 years. If this pattern remains, consider spasticity, tethered cord, or muscle weakness. Flat feet up to age 5 are normal (a consequence of the distribution of fat and paucity of muscle development). Only investigate if symptomatic. Leg alignment often concerns parents. Up until 2 years of age it is normal to have genu varum. From 2 to 5 years, mild genu valgum may occur. Angles of >10 o r asymmetry may be associated with underlying disease. Regression of motor development is a clue to the presence of disease. Observation Observe c hildren unclothed to underwear if possible. Look for weakness, scoliosis, kyphosis, and swe llings. \200 The main cause of spinal asymmetry will be scoliosis (see Table 2.15). \200 Localized soft tissue swelling may denote soft tissue extension of a spinal though an apparent kyphosis associated with scoliosis is usually a result of spinal rotation. CHAPTER 2 Regional musculoskeletal conditions 88 In children with neck pain, look for a short neck (rule out Klippel-Feil) or asymmetric sca pulae (Sprengel \200\231s deformity: a congential abnormality associated with a higher, hyp oplastic scapula). Adolescent kyphosis may be due to Scheuermann \200\231s disease or fractures. Unless there has been steroid use, the former is more likely. \200 Note any sk in markings such as caf -au-lait spots, skin indents (lumbar area) and lumbosacral hair. They may be markers of bony abnormality. Note any muscular weakness. With truncal weakness (e.g., DM, (see Chapter 13)) the child ma y have to roll over before getting up from a supine position. Hip girdle weakness may be pr esent in a child unwilling to squat and unable to stand from squatting without exhibiting G ower \200\231s sign (unable to stand up from the \202 oor without using hands to push off ). Examine the gait pattern \200 Look for asymmetry and a limp. \200 Back or leg pain from any cause can give rise to a limp. Also, limp may be the only feature of a serious underlying neurologic or bony deformity. Asymmetry of shoulder height, transverse posterior skin folds, pelvic tilt, and arm swing may be a clue to spinal pathology. Spinal examination with the child standing Examine the whole spine while the child is stand ing. The immature spine is usually far more \202 exible than an adult \200\231s. \200 A sk about the presence and site of neck or low back pain during forward \202 exion, extension, and lateral \202 exion (and rotation for neck). Experien ced examiners should be able to detect signi \201 cantly limited movements. Palpate along the line of (lumbar) spinous processes. An inward step may be caused by spondylolisthesis. Palpate any swellings. Lipomas are painless. Soft tissue tumors may be, but are not necessarily, tender and \201 xed. Examine the sitting patient Examine the child who is sitting on the couch, legs hanging ove r the side. \200 This is the best way to elicit pain from posterior vertebral structure pathology in thoracic or lumbar segments (e.g., pars osteoid osteoma, pars fracture). Combi ne extension and rotation movements. Ask if the pain is worse on one side than the other. Examine the supine patient Examine the child or adolescent when supine. Look for leg length discrep- ancy, lower leg asymmetry, and do a neurologic examination. \200 Measure and de termine actual or apparent leg length discrepancy. True leg length discrepancy is a cause o f nonstructural scoliosis. Apparent leg length discrepancy/pelvic tilts can occur to compen sate for scoliosis caused by spinal lesions. Different foot or leg sizes/appearances are a nonspeci \201 c sign of spinal dysraphism. Hip and sacroiliac examination should be done routinely in children with low back pain. Tests for dural irritation and neurologic SPINAL DISORDERS IN CHILDREN AND ADOLESCENTS 89 examination are essential (see section Low Back Pain and Disorders in Adults). Though limb pain, weakness and other neurologic symptoms occur, the majority of children wi th intradural tumors have none of these features. A normal examination does not rule out se rious pathology. Examine the prone patient \200 Palpate over the spinous processes, interspinous spaces, p aracentrally between spinous processes (over facet joints) and in the sacroiliac area. Diffuse tenderness may only be a re \202 ection of muscle spasm and its extensive mechanic al effect. Where there are isolated areas of tenderness, feel for skin warmth, as this may be a site of infection. Diagnostic procedures Radiographs \200 Radiographs have a characteristic appearance in ce rtain cases of bone tumor but may also, in some cases, be normal (see Table 2.16). A normal bone scan rules out most serious pathology. \200 A widened interpedicular distan ce on an AP \201 lm is a sign of meningomyelocele, spinal dysraphism, or an intraspinal m ass. Posterior vertebral scalloping on a lateral radiograph is seen in lumbar or cervical spines, and is most commonly associated with lesions occurring in childhood and most commonly due to spinal tumors, neuro \201 bromatosis, osteogenesis imperfecta, Ehler s \200\223Danlos, and Marfan syndrome. Spondylolysis/pars fractures may be visible on lateral X-rays but are best characterized by oblique \201 lms (see Plate 8). Associated internal disc derangement or radiculopathy is best characterized using MR. \200 Appearances of Scheuermann \200\231s disease (juvenile kyphosis, associated with multiple irregular vertebral endplates, with anterior ring epiphyseal fragmentation an d vertebral wedging) are an occasional incidental X-ray \201 nding. Radiographs of the neck may show a degree of cervical spine fusion (Klippel \200\223Feil syndrome). Suspect hypermobility in nonaffected segments and investig ate C1/C2 with MR if there are high cervical pain or myelopathic symptoms. Bone scan can detect spinal bony abnormalities; a negative test rules out most subtle lesions e.g., osteoid osteomas. Consider SI joint radiographs and MR in patients with prominent immobility-related low back pain and stiffness (commonly due spondyloarthropathy-related conditions). Diagnosing scoliosis \200 The cause of painful scoliosis must be determined. Consider MR or CT of any localized area of pain. Idiopathic scoliosis is asymptomatic and is a diagnosi s of exclusion. Mild idiopathic scoliosis (5 \200\22310 ) can be determined on a posteroanterior thoracolumbar radiograph and is relatively common in the school population (7%). A scoliosis of >20 occurs in 1 in 500 people and is three to four times more common in girls than boys. In 10 \200\22320% of those with a trunk inclination of >5 , the scoliosis progresses at least a further 5 . Most have a nonprogressive scoliosis. CHAPTER 2 Regional musculoskeletal conditions 90 Table 2.16 Radiographic features of spinal tumors in children (see also Table 20.7) Tumor type Notable clinical features and radiological appearances Osteochondroma Has the appearance of an exostosis Osteoid osteoma Radiographs often normal. Bone scan will localize lesion and CT sharply de \201 ne it Osteoblastoma Lytic with central ossi \201 cation on radiograph. Can metastasize Aneurysmal bone cyst Lucent lesion with central trabeculae on radiographs. MR important to document soft-tissue expansion Langerhans cell histiocytosis (eosinophilic granuloma) Either solitary, polyostotic, or associated with systemic illness. Lytic lesion can cause s olitary vertebral collapse, even collapse of adjacent bones. Used to be called histiocytosi s X Myeloma Rare in children. Lytic lesions on radiographs. Distribution of lesions can be shown with b one scan but use as adjunct to radiographs Ewing \200\231s sarcoma Age 5 \200\22320 usually. \200\234Moth-eaten \200\235 destruction of bone on radiograph Lymphoma Sclerotic ( \200\234ivory \200\235) vertebra on \201 lm Osteosarcoma Mixed lytic/sclerotic appearance on radiographs Metastases Most likely are from leukemia or neuroblastoma Intra- and extramedullary tumors Delay in diagnosis common. Up to 50% have abnormal \201 lms: widened spinal canal, pedicl e erosions, scalloping of vertebral bodies. MR usually characterizes the lesion Laboratory tests Laboratory tests should be sought if infection, in \202 ammation, or mali gnancy is considered (see section Low Back Pain and Disorders in Adults). The management of various spinal disorders in adults and children is included in Chapter 20. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 92 Pelvic, groin, and thigh pain Anatomy Anatomy of the pelvis and hip region \200 The bony pelvis consists of two innominate bones (ilium above the acetabulum and ischium below it) t hat articulate with each other at the anterior symphysis pubis and posteriorly with the sac rum at the SI joints. SI joints are initially synovial but become \201 brous with age. A few degrees of rotation can be demonstrated in children and young adults. Strong ligaments stabilize the posterior pelvis through sacroinnominate, lumbo(L5) \200\223sacral, and lumbo(L5) \200\223iliac attachments. The symphysis pubis is a cartilaginous joint and normally does not move. When standing, weight is transferred through the head of the femur. The femoral head is sta bilized in the acetabulum by the acetabular labrum and strong pericapsular ligaments. The ligamentum teres crosses the hip joint and carries blood vessels to the head of the fem ur in children and young adults. In old age, blood supply is largely via vessels that enter the femoral neck. Two bursae are found at the insertion of the gluteus maximus: one separates it from the gre ater trochanter, the other separates it from the vastus lateralis. The ischial bursa separates gluteus maximus from the ischial tuberosity and can become in \202 amed from overuse. Anatomy of pelvic musculature \200 Three groups of muscles move the hip joint: the glutea ls, the \202 exor muscles, and the adductor group. \200 The major gluteal group muscles are: gluteus maximus (L5, S1/2): arises mainly from ilium and sacrum, projects down posterolaterally and inserts into the posterior femur and the lateral tensor fasciae latae. It extends and externally rotates the hip (the hamstrings also extend the hi p). gluteus medius (L4/5, S1): lies deeper and more lateral. It inserts into the lateral greate r trochanter and abducts and internally rotates the hip. piriformis, obturator internus, and quadratus femoris arise deep in the pelvis and insert i nto the posterior greater trochanter. All externally rotate the hip. The major hip \202 exor, the psoas major (L2/3), is a massive muscle that arises from the lateral part of the vertebrae and intervertebral disks (T12 \200\223L5 ) and lateral processes of the lumbar vertebrae. It runs anteriorly over the iliac rim, acr oss the pelvis, under the inguinal ligament, and inserts into the lesser trochanter. The il iacus (L2 \200\223L4) arises from the \200\234inside \200\235 of the iliac blade, passes u nder the inguinal ligament medially to the lesser trochanter. Both \202 ex, but the psoas also internally rotates the hip. PELVIC, GROIN, AND THIGH PAIN 93 The psoas is enveloped in a fascial sheath. Retroperitoneal or spinal infections that track along soft tissue planes sometimes involves the psoas sheath and can cause in \202 ammati on in the psoas bursa, which separates the muscle from the hip joint. All adductor muscles arise from the pubis or ischiopubic rami. The adductor longus and gracilis are the most super \201 cial; they arise from the pubis and i nsert into the femoral shaft and pes anserinus ( \200\234goose \200\231s foot \200\235) bel ow the knee, respectively. The adductor magnus (L4/5) is the largest of the deeper adductor s; it inserts into the medial femoral shaft. Adductors stabilize movement around the hip toward the end of the stance phase of the gait. Body weight is transferred onto one leg during this action; t herefore, adductors need to be strong, especially for running. Functional anatomy of the hip \200 With a \202 exed knee the limit of hip \202 exion is about 135 . \200 Hip extension (at 30 ), internal rotation (at 30 \200\22335 ), and external rotation (at 45 \200\22355 ) is limited by strong, pericapsular ligaments. \200 Abduction is limited to 45 \200\22350 by contact between the greater trochanter and acetabular labrum rim. Adduction is limited to 20 \200\22330 with a \201 xed pelvis (see Plate 9). These are adult ranges. Greater femoral neck anteversion (angle of the neck compared to the distal femur) allows gr eater internal rotation of the hip (and reduced external rotation). Tibial torsion can comp ensate but this and hip anteversion results in a toe-in gait. Femoral neck retroversion (if the angle is posterior to the femoral intercondylar plane) allows greater external rotatio n of the hip, usually resulting in a toe-out gait (see Figure. 2.22). Normally, infants have more anteversion than older children or adults (30 \200\22340 at age 2 compared with 8 \200\22315 at age >18). Neuroanatomy \200 The femoral nerve is formed from L2 \200\223L4 nerve roots and supplies mainly muscles of the quadriceps group and some deeper hip adductors. With contributions from L4 \200\223S3 roots, nerves from the plexus converge at the inferio r border of the piriformis to form the sciatic nerve. This is at a foramen formed by the il ium (above and lateral), sacrum (medial), sacrospinous ligament (below), and the sacrotuber ous ligament (posteromedial). In about 10% of people, the sciatic nerve divides before exiting the pelvis. In some, a branch exits above the piriformis muscle. Piriformis syndrome is entrapm ent of the sciatic nerve by the piriformis muscle, and may bene \201 t from physical thera py. CHAPTER 2 Regional musculoskeletal conditions 94 Taking a history Age Age is a risk factor for some conditions: \200 Congenital hip disloc ation is common (prevalence 1:500), more so in girls than boys (8:1). It should be considered in toddlers if there is delay in motor mi lestones or pain on weight bearing. The most common cause of hip pain in children aged 2 \200\22312 years is transient synovitis (which is unilateral and self-limiting). The differential diagnosis inc ludes Legg \200\223Calv \200\223 Perthes disease (osteonecrosis of the femoral head) and Lyme or poststreptococcal arthritis. Legg \200\223Calv \200\223 Perthes disease (age 3 \200\22312 years) is four to \201 ve times more common in boys, and bilateral in 10 \200\22320% of cases. Slipped capital epiphysis is rare in children younger than 8 or older than 16 years old. It is associated with obesity and endocrine disorders (4% are hypothyroi d). Unless there has been previous hip disease (e.g., osteonecrosis, synovitis), trauma, or a l ong-standing biomechanical abnormality (e.g., epiphyseal dysplasia, heritable disease of co nnective tissue), hip osteoarthritis (OA) is uncommon in adults less than 55 years old Paget \200\231s disease of bone is rare in adults over 50 years old. Distribution and type of bone and soft tissue pain \200 All mechanical lesions of the lumbar spine can result i n referred pain around the pelvis and thighs. It is often bilateral, localizes poorly, and is aching in nat ure. Lateral pelvic pain is often referred from the lumbosacral spine. If pain localizes (i.e., the patient points) to the greater trochanter, it may be due to trochanteric bursitis, enth esitis, or meralgia paresthetica (lateral femoral cutaneous nerve syndrome, see Table 2.17) . Hip joint pain is felt in the groin, but it can be located deep in the buttock when ischial bursitis and sacroiliac pain should also be considered. It may be referred distally to the anteromedial thigh and knee. Groin pain on weight-bearing suggests hip pathology such as synovitis, osteonecrosis or OA, but it is not speci \201 c. Tendonitis of the adductor longus, osteitis pubis, a femoral neck stress fracture (4% of all stress fractures), osteoid osteoma, or psoas bursitis can g ive similar symptoms. Bone pathology typically gives unremitting pain. Sleep is often disturbed. \200 Pain from deep musculoskeletal pelvic structures is typically poorly localized, although can be severe. If the pain appears to be \200\234catastrophic, \200\235 consider pelvic bone disease (tumors, infection, Paget \200\231s disease, osteomal acia, osteoporotic fracture) (see Chapters 16 and 17), or an unstable pelvis (chronic ostei tis pubis with diastasis/laxity of the symphysis pubis and sacroiliac joints). Enthesitis and osteitis pubis associated with spondyloarthropathy (SpA) (see Chapter 8) are probably under-recognized. \200 Aching in the back of the legs after standing is found with spondylolisthesis (i.e., anterior displacement of a vertebra). PELVIC, GROIN, AND THIGH PAIN 95 Table 2.17 Patterns of pain around the proximal leg and their major causes Pattern of pain Causes Referred pain from: lumbar spine e.g., facet, OA, spondylolisthesis; SI joint in \202 amma tion; lower lumbar nerve root irritation; sciatic nerve entrapment (piriformis syndrome) Pain in buttock and posterior thighs Localized pain: ischial bursitis/enthesitis or fracture; coccydynia Diffuse muscular pain/stiffness: myositis or PMR Paget \200\231s or other bone lesion of sacrum Lateral pelvic pain Referred from lumbosacral spine Trochanteric bursitis/enthesitis Gluteus medius tear Lateral hip joint pain, e.g., osteophyte Groin pain Hip disease, e.g., OA, osteonecrosis, synovitis Psoas bursitis Adductor tendonitis, osteitis pubis Pelvic enthesitis Paget \200\231s disease (pelvis or femur) Femoral neck or pubic ramus fracture Hernia Anterior or medial pain Referred from: lumbar spine, e.g., facet OA, thigh spondylolisthesis; upper lumbar nerve root; hip joint, femoral neck, psoas bursa Myositis, PMR, diabetic amyotrophy Meralgia paresthetica (anterolateral) Adductor tendonitis, osteitis pubis Ischemia (claudication) Lymph nodes Sacroiliac pain and stiffness radiates to the buttocks and posterior thighs. Pain in a muscular distribution \200 Diffuse pain in the buttocks and thighs occurs in po lymyalgia rheumatica (PMR). It is often sudden or subacute in onset, associated with stiffness, and m ay give similar symptoms to those caused by sacroiliitis but invariably occurs for the \201 rst time in a much older age group. CHAPTER 2 Regional musculoskeletal conditions 96 Pain is not characteristic of an autoimmune myositis (see Chapter 14). When it does occur, it is unlikely to be con \201 ned to pelvic musculature or to be unilateral, but should be considered where acute or subacute onset diffuse pelvic girdle/thigh pain accompanies weak ness. Quality and distribution of nerve pain \200 Nerve root pain is often clearly de \201 ned and sharp. It may be burning in quality and is often accompanied by numbness or paresthesi as. L5 or S1 lesions generally cause pain below the knee, but can also cause posterior thig h pain. L1 \200\223L3 root lesions can cause pain in the anteromedial thigh. Pain with paresthesias on the anterolateral part of the thigh may be due to entrapment of t he lateral cutaneous nerve of the thigh under the lateral part of the inguinal ligament (i. e., meralgia paresthetica). Symptoms may be referred to this area with L2 or L3 nerve root lesions, since this is where the nerve originates (see Figure 2.12). \200 Diabetics with uncontrolled hyperglycemia are at risk of diabetic amyotrophy. Acute unilateral or bilatera l thigh pain with muscle wasting occurs. It should not be misdiagnosed as PMR (in which wea kness or wasting do not occur) or in \202 ammatory myopathy. \200 Soccer players are at risk of adductor tendonitis (often an adductor apophysitis) and osteitis pubis due to subst antial mechanical forces placed on pelvic structures during running and kicking. Although hip fractures are usually obvious, they can also present subacutely in a patient w ho continues to walk; this is particularly common among the elderly, who may develop stress fractures of the hip. Previous trauma, low back, and musculoskeletal problems \200 Previous trauma or disease c ausing permanent deformity of any lumbosacral or hip joint structure can be considered a risk factor for further trouble (see Table 2.18). Multiparity is a risk factor for osteitis pubis, sacroiliac, and pelvic pain. \200 Trocha nteric bursitis may coexist with referred back pain. \200 Tears of the gluteus medius can occur at its greater trochanter insertion and give similar symptoms to those caused by bur sitis. Historically, tailors were at risk of ischial bursitis because of sitting on the \202 oor continually crossing and uncrossing their legs, which causes friction irritation of soft t issues overlying the ischial tuberosity. Examination The reader is referred to the sequence of examination for the low back, includi ng the sacroiliac and lower limb neurologic examination (see pp. 80 \200\22383). Always con sider lower spinal, muscle, or neurologic pathology when assessing weakness and pain around the pelvis. Observation and palpation For observation and palpation the patient should be supine on a c ouch: \200 Look for leg length discrepancy (hip disease, scoliosis) and a leg resting in external rotation (hip fracture). Psoriasis over the knees may be associated with sacroiliitis. PELVIC, GROIN, AND THIGH PAIN 97 L1 L1 L2 L2 L3 L3 Fig. 2.12 The approximate areas within which sensory changes may be found in lesions of the lateral cutaneous nerve of the thigh (hatched area) and high lumbar radiculopathy (broken line). The shaded areas denote the distribution of sensory symptoms associated with meralgi a paresthetica. Swelling in the groin may be a hernia (reducible, moves with cough), lipoma (soft/nontender /diffuse), a saphenous varix, or lymphadenopathy (hard/rubbery and mobile). A hip joint eff usion cannot be felt. Tenderness over the hip joint in the groin is not speci \201 c for joint pathology: the jo int is deep, muscles and psoas bursa overlie it. \200 If the groin is very tender with sl ight touch, consider hip fracture or infection. Hyperpathia (and allodynia) is consistent w ith complex regional pain syndrome (see Chapter 18). Numbness over the anterolateral thigh suggests meralgia paresthetica (see Figure 2.12). The adductor longus tendon can be palpated at its insertion at the pubic tubercle and dista lly along the upper medial thigh. The pubic tubercle is found by palpating slowly and light ly downwards from umbilicus over the bladder until bone is reached. Pain from osteitis pubis or adductor apophysitis is often signi \201 cant, with abdominal rectus contraction (ask the patient to slowly lift his or CHAPTER 2 Regional musculoskeletal conditions 98 Table 2.18 Risk factors for painful pelvic or hip lesions Risk factor Pelvic/hip pathology Mechanical abnormality of the low back Referred pain Trochanteric bursitis Mechanical abnormality of the hip (e.g., Perthes \200\231, slipped epiphysis, epiphyseal dy splasia, Paget \200\231s) Hip OA Corticosteroid use Osteoporotic fracture Osteonecrosis of the femoral head Autoimmune rheumatic disease (e.g., RA, JIA, AS) Synovitis hip Secondary OA of the hip Pyogenic arthritis of the hip Osteoporotic fracture Maternal history of hip fracture; low body mass index; low bone mass; falls Osteoporotic hip fracture Multiple pregnancies Osteitis pubis ( pelvic instability) Soccer players Adductor tendonitis/apophysitis Osteitis pubis her head and shoulders off the couch, keeping your \201 nger on the pubic tubercle). Hip examination The hip should be examined while the patient is supine. Tests gener- ally h elp to discriminate articular and extra-articular disease, but not the causes of articular disease: \200 Measure and determine actual or apparent leg length discrepancy: measure fr om the anterior superior iliac spine to the medial tibial malleolus; by \202 exing hips a nd knees, the site of shortening should become apparent. A \201 xed loss of extension is a sign of intra-articular hip disease. The patient \202 exes the hip and knee on one side until normal lumbar lordosis \202 attens out (con \201 rmed by feeling pressure on your hand placed under their lumbar spine during the maneu ver). If the other hip \202 exes simultaneously, it suggests hip extension loss on that s ide (Thomas \200\231 test). Using the patella or tibial tubercle as pointers, test the rotational hip range in extensio n by rotating the straightened legs by holding the heels. Rotational movements are also tested by lifting the leg, \202 exed 90 at the knee, and swinging the foot out (internal rotation) or in (external rotation). Hip \202 exion can b e tested in this position too (see Plate 9). Patients without intra-articular pathology sho uld have a pain-free range of movement. PELVIC, GROIN, AND THIGH PAIN 99 Rotational ranges in hip \202 exion and extension may differ between left and right in an individual. Also, variations in femoral neck anteversion contribute to variations in rotat ion range. To test hip abduction/adduction, \201 x the pelvis to avoid pelvic tilt by placing one hand \201 rmly over the iliac crest (see Plate 9). Occasionally, pain at the end of abduction or internal rotation occurs with a bony block (solid \200\234end-feel \200\235). In an older patient this might suggest impingement of a marginal joint osteophyt e. Barlow \200\231s maneuver checks for congenital dislocation of the hips in babies. Flex and adduct the hips exerting an axial force into the posterior acetabulum t o demonstrate posterior dislocation. Greater retroversion (allowing excessive hip external rotation) usually occurs in cases of slipped femoral epiphysis. External rotation is accentuated when the hip is \202 exed. The slip (usually inferoposterior) is thought to occur in association with a period of rapid growth. Muscle activation tests Speci \201 c muscle activation against resistance can be used to e licit pain, but results need to be interpreted cautiously in the context of known hip disea se: \200 Hip adduction against resistance (sliding their leg inward toward the other against your hand) reproducing pain is a sensitive test for adductor longus tendo nitis, but may be positive in osteitis pubis, hip joint lesions, and other soft tissue lesi ons in the adductor muscles. \200 Test the psoas by resisted hip \202 exion while in sl ight internal rotation. Psoas bursitis or infection tracking along the psoas sheath is like ly to give intense pain with minimal resistance. Hip abduction (sliding the leg outwards against your hand) may be particularly painful in c ases of gluteus medius tears but also in trochanteric bursitis or intra-articular pathology . Palpate posterolateral structures Ask the patient to lie on their side and palpate the post erolateral struc- tures (see Figure 2.13): \200 Tenderness over the greater trochanter is usually well-localized although it may be anterior or posterolateral to the trochanter and refers a small way down the leg. The ischial tuberosity and its overlying bursa lie at the apex of the buttock. The soft tissues overlying the point where the sciatic nerve exits the pelvis is found midway between the ischial spine and the greater trochanter. There may be tenderness as a result of soft tissue lesions or trauma causing sciatic nerve entrapment (piriformis syndrome), which can lead to foot drop. A tender coccyx (coccydynia) can be palpated in this position. It can also be palpated (and the sacrococcygeal joint moved) from a bidigital examination, though this requires the index \201 nger to be placed inside the rectum, the thumb outside, the two digits then holding the joint. CHAPTER 2 Regional musculoskeletal conditions 100 Diagnostic procedures Radiographs An AP radiograph of the pelvis is a good initial screenin g test in patients with pelvic, hip, or thigh pain. AP and lateral lumbar spine \201 lms may be warranted. \200 The pelvis is a common site of involvement in myeloma, metastatic malignancy, and Paget \200\231s disease of bone (see Chapter 16). Established, but not early, sacroiliitis can be ruled out. The main differential diagnoses of the causes of sacroiliitis are: AS, psoriatic or reactive arthrit is, enteric arthropathy including Whipple \200\231s disease, brucellosis and other infectio ns, hyperparathyroidism and osteitis condensans ilii (sclerosis of the SI joint on the lowe r iliac side). \200 Widening of the symphysis in children may be a sign of congenital dis orders of development (e.g., epispadias, achondrogenesis, chondrodysplasias, hypophosphatas ia), trauma and hyperparathyroidism (see Chapter 16). Widening of the symphysis pubis, osteitis pubis (bone resorption and sclerosis) and osteiti s condensans ilii are signs associated with chronic pelvic pain in multiparous women. General osteopenia is a risk factor for general low bone mass measured by densitometry; however, it is not a sensitive or speci \201 c indicator of oste oporosis (i.e., may be osteomalacia or rickets). \200 Regional osteoporosis con \201 ned to the femur is nonspeci \201 c but may re \202 ect hip synovitis, infection, or transie nt osteoporosis of the hip (rare). Greater trochanter and site of overlying bursa Sacrum Coccyx Ishial tuberosity and site of overlying bursa Fig. 2.13 Bony anatomy of the posterior hip and pelvis, showing the position in which lesio ns around the greater trochanter and ischial bursa can be palpated. PELVIC, GROIN, AND THIGH PAIN 101 Early synovitis and infection may be demonstrated through subtle radiological signs such as joint space widening and change in soft tissue fat planes. A \200\234frog leg \200\235 (lateral) view of the hip shows the anterior and posterior femoral head more clearly than an AP view (useful in early osteonecrosis/Perthes \200\231, slipped epiphysis). The acetabulae are best visualized on 45 oblique views (acetabular fractures can be missed on a conventional AP view). \200\234Stork \200\235 views of the symphysis pubis (standing on one leg) are useful for con \201 rming diastasis of the joint. Diagnostic ultrasound \200 US is a sensitive and simple way of con \201 rming a hip join t effusion. Using US, \202 uid can be aspirated for culture and an assessment of the extent of synovi al thickening can be made. Tendon damage in the groin area should be identi \201 able with US alone (guided steroid i njection can then be done if necessary) but MR may be needed either to characterize patholo gy further or rule out joint pathology. Bone scan Bone scan is a useful screening test, but it is nonspeci \201 c: \200 Characte ristic, though nonspeci \201 c, patterns of bone scan abnormality are recognized in the hi p/pelvic area. The following conditions can be recognized: sacroiliitis, bone malignancy, m yeloma, Paget \200\231s disease, hip fracture, femoral head osteonecrosis (see Plate 10), o steoid osteoma, OA and synovitis of the hip, osteitis pubis/adductor apophysitis (requires special seated \200\234ring \200\235 view), and bursitis/enthesitis at the greater trochan ter. Bone scan is a useful investigation in children and adolescents as a screening investigation if other radiology tests are normal. CT and MR \200 CT/MR of the high lumbar region should be considered to con \201 rm a nerve root lesion, causing groin or thigh pain. Speci \201 c patterns of X-ray attenuation or signal change around the SI joints occur in sacroiliitis with CT/MR, although active and previous in \202 ammation cannot easily be di stinguished. A suspicion of bony malignancy from radiographs of the pelvis requires further characterization. CT is the technique of choice for characterizing bone le sions around the hip such as femoral neck stress fracture, osteoid osteoma, or other bone t umors. CT may give more information about the lesion (and is valuable for \200\234guided b iopsy \200\235) but MR is useful in checking for pelvic visceral lesions. MR is the technique of choice if hip infection or osteonecrosis is suspected. In adults, patterns of signal change have been correlated with prognosis. CHAPTER 2 Regional musculoskeletal conditions 102 During a single examination the pattern of hip synovitis (vascularity and thickness), carti lage loss, and subchondral bone erosion can be documented. This is particularly useful in c hildren with JIA. Laboratory tests \200 ESR and CRP may be normal in in \202 ammatory SI joints, lumbar vertebral disc, and pelvic enthesis disorders. PMR is almost always associated with an elevated ESR/CRP. \200 Myeloma is unlikely if the ESR is normal. \200 A high alkaline phosphatase is typically associated with an acute ph ase response, although in the elderly, it might suggest Paget \200\231s disease. ANA and RF are unlikely to help diagnostically. \200 Major metabolic bone disease such as osteomalacia and