Pelvis, Hips, and Thighs

Ovid: Musculoskeletal Imaging Companion

Editors: Berquist, Thomas H.
Title: Musculoskeletal Imaging Companion, 2nd Edition
> Table of Contents > Chapter 4 – Pelvis, Hips, and Thighs

Chapter 4
Pelvis, Hips, and Thighs
Thomas H. Berquist
Routine radiographs
  • Pelvis
    • Anteroposterior (AP) to include from iliac crest to below lesser trochanters
    • For trauma, use inlet (tube angled 45 degrees to the feet) and outlet (tube angled 45 degrees to the head) AP views
  • Hips
    • AP view, frog-leg oblique, or lateral for screening
    • AP plus Judet (45 degrees anterior and posterior obliques of involved side) views for acetabular trauma
  • Femurs
    • AP and lateral to include hip and knee joints


Computed tomography (CT) (bone and soft tissue windows should be studied)
  • Pelvis
    • Axial 5-mm or 1-cm sections iliac crest to below lesser trochanters for screening
  • Hips
    • Axial 1-mm sections at 0.5-mm intervals
      to be reformatted in coronal, sagittal, or three-dimensional, depending
      on indication (i.e., sagittal reformatting is useful to classify
      acetabular fractures).

Region Pulse Sequence Thickness/Skip Matrix FOV Acquisitions
Pelvis/SI Joints Coronal SE 410/17 6 mm 512 × 512 34–40 2
Axial 580/13 5 mm 512 × 512 34–40 1
Axial FSE 4000/102 6 mm 512 × 512 34–40 2
Coronal STIR 5600/109/165 5 mm 256 × 256 34–40 2
Hips Coronal SE 536/15 4 mm 256 × 256 20–24 1
Axial FSE 4000/102 6 mm 512 × 512 20–24 2
Sagittal SE 536/15 4 mm 256 × 256 20–24 1
Thighs Axial FSE 4000/102 6 mm 512 × 512 30–42 2
Coronal or sagittal SE 536/15 4 mm 256 × 256 30–42 1
Arthrography Axial SE 568/15 4 mm 256 × 256 18 1
Sagittal SE 568/15 4 mm 256 × 256 18 1
Coronal SE 450/15 4 mm 256 × 256 18 1
Coronal FSE 4000/102 4 mm 256 × 256 18 1
Oblique coronal SE 420/15 4 mm 256 × 256 18 1
Oblique sagittal SE 420/15 4 mm 256 × 256 18 1
SI, sacroiliac; FSE, fast-spin echo; SE, spin-echo; STIR, short TI inversion recovery; FOV, field of view.
Additional Options
  • Intravenous gadolinium
    • Neoplasms
    • Early synovial inflammation
    • Infection
    • Early avascular necrosis (AVN)
  • Intra-articular gadolinium (8 to 20 mL of 1 mmol solution)
    • Labral tears
    • Subtle cartilage lesions
    • Loose bodies, synovial chondromatosis


Trauma: Pelvic Fractures—Minor
FIGURE 4-1 Common minor fractures of the pelvis. (A)
Anterior superior iliac spine (1), anterior inferior iliac spine (2),
ischial tuberosity (3), and iliac wing (4). One to three are avulsion
injuries with muscles labeled. (B) Transverse sacral fracture (5), isolated pubic rami fractures (6 and 7).


FIGURE 4-2 (A) AP radiograph of the hip demonstrating an ischial avulsion fracture. (B) CT image of an old ischial avulsion fracture.


FIGURE 4-3 AP radiograph demonstrating an iliac wing fracture (arrow).
Suggested Reading
Young JWR, Resnick C. Fractures of the pelvis: Current concepts in classification. AJR Am J Roentgenol 1990;155:1169–1175.


Trauma: Pelvic Fractures—Single Break In Pelvic Ring
FIGURE 4-4 Anterior Judet view demonstrating pubic rami fractures (arrowheads) resulting in a single break in the pelvic ring.
Suggested Reading
Berquist TH. Imaging of orthopedic trauma. 2nd ed. New York: Raven Press; 1992:207–310.
Mucha P, Farnell MB. Analysis of pelvic fracture management. J Trauma 1984;24:379–386.


Trauma: Pelvic Fractures—Complex



FIGURE 4-5 Lateral compression injuries. (A) Type I: force applied posterolaterally (arrow)
resulting in a crush injury to the sacrum, ilium, and sacroiliac joint
(1) and oblique or horizontal pubic rami fractures (2). (B) Type II: force directed anterolaterally (arrow)
resulting in diastasis of the sacroiliac joint (1 and 3) (Type IIA) or
iliac wing fracture (Type IIB) plus oblique or horizontal pubic rami
fractures (2). (C) Type III: force applied anterolaterally (arrow)
with oblique or horizontal pubic rami fractures (2) and involvement of
both sacroiliac joints and ligaments (1, 3, and 4) (Type IIIA) or
sacroiliac joints and ipsilateral iliac wing fracture (Type IIIB).




FIGURE 4-6 AP compression injuries. (A) Type I: force applied anteriorly (arrow) resulting in diastasis of the pubic symphysis or vertical pubic rami fractures. (B)
Type II: wider diastasis of the pubic symphysis or vertical pubic rami
fractures with disruption of the anterior sacroiliac ligaments. (C)
Type III: wider diastasis of the pubic symphysis or displaced vertical
pubic rami fractures with disruption of both the anterior and posterior
sacroiliac ligaments. (D) AP compression
injury with vertical pubic rami fractures. Sacroiliac joints are
normal. Note the elevated bladder resulting from a large pelvic
hematoma. Type I. (E) Type III AP compression injury with wide diastasis of the pubic symphysis, displaced iliac wing fracture (white arrow), widening of the right sacroiliac joint (black arrow), and multiple avulsion fractures (arrowheads).


FIGURE 4-7 Vertical shearing injury. (A) Force is applied vertically (arrow)
with vertical pubic rami fractures (3) or step-off at the pubic
symphysis and disruption of the anterior and posterior sacroiliac
ligaments (1 and 2). (B) Widening and step-off of the right sacroiliac joint (open arrow) and symphysis (arrow). Suprapubic tube in the bladder because of associated urethral injury.
Suggested Reading
Failinger S, McGarrity PL. Unstable fractures of the pelvic ring. J Bone Joint Surg 1992;74A:781–791.
Young JWR, Resnick C. Fractures of the pelvis: current concepts and classification. AJR Am J Roentgenol 1990;155:1169–1175.


Trauma: Acetabular Fractures—Simple
FIGURE 4-8 (A) Judet view of the hip demonstrating and undisplaced central acetabular fracture (curved arrow). (B) CT image demonstrating an uncomplicated central acetabular fracture (arrow).
Suggested Reading
Letournel E. Acetabular fracture classification and management. Clin Orthop 1980;151:81–106.


Trauma: Acetabular Fractures—Complex



FIGURE 4-9 (A) Acetabular margins and the anterior (iliopectineal) and posterior (ilioischial) columns. Three-dimensional CT images (B,C) demonstrating the anterior and posterior columns.


FIGURE 4-10 Fracture patterns (AO classification). (A)
Type A: A1, posterior wall fracture; A2, posterior column fracture;
A3-1, anterior wall fracture; A3-2, anterior column fracture. (B)
Type B1-1, transverse fracture; Type B1-2, transverse with posterior
wall fracture; Type B2-T, fracture; Type B3, anterior column with
posterior transverse fracture. (C) Type
C1, both columns with fracture extending to the iliac crest; Type C2,
both columns extending to anterior inferior iliac spine; Type C3, both
columns with extension to sacroiliac joint. Types A1, B1-1, B1-2, B-2,
and C1 are the most common.



FIGURE 4-11 Complex acetabular fractures. (A)
AP radiograph shows a displaced central acetabular fracture with the
femoral head and fragments extending into the pelvis. Note the
coccygeal dislocation (arrow). Three-dimensional reconstructions (B,C) of a complex acetabular fracture (arrows).
Suggested Reading
Brandser E, Marsh JL. Acetabular fractures: Easier classification with a systematic approach. AJR Am J Roentgenol 1998;171:1217–1228.
Saks BJ. Normal acetabular anatomy for acetabular fracture assessment. CT and plain film correlation. Radiology 1986;159:139–145.


Trauma: Fracture/Dislocation—Dislocation of the Hip


FIGURE 4-12 AP radiographs of posterior (A) and anterior (B) dislocations. Note the displaced femoral head fragment (arrow) in (A).


FIGURE 4-13 (A) CT image of a posterior dislocation. Direction of the force (line with arrowhead). Small posterior rim fracture (open arrow). (B) CT image after reduction of an anterior dislocation with fractures of the femoral neck and anterior acetabulum (arrows).


Suggested Reading
P, Young JWR, Porter D. CT detection of cortical fracture of the
femoral head associated with posterior dislocation of the hip. AJR Am J Roentgenol 1990;155:93–94.
Rosenthal RE, Coher WL. Fracture dislocations of the hip: An epidemiological review. J Trauma 1979;19:572–581.


Trauma: Femoral Neck Fractures
FIGURE 4-14 Impacted femoral neck fracture (arrows) with cortical disruption and trabecular compression laterally (curved arrow). The hip was pinned.


FIGURE 4-15 (A) Displaced femoral neck fracture (arrow). (B) Treated with bipolar endoprosthesis.
FIGURE 4-16 Coronal fast spin-echo T2-weighted image demonstrates edema with a central linear low-intensity line (arrow) caused by femoral neck stress fracture.


Suggested Reading
Berquist TH. Imaging atlas of orthopedic appliances and prostheses. New York: Raven Press; 1995:217–352.
Garden RS. Stability and union of subcapital fractures of the femur. J Bone Joint Surg 1964;64B:630–712.
Morgan CG, Wenn RT, Sikand M, et al. Early mortality after hip fracture: Is delay before surgery important. J Bone Joint Surg 2005;87A:483–490.


Trauma: Trochanteric Fractures
FIGURE 4-17 Sites for avulsion fractures in the pelvis and hips with muscle origins labeled.


FIGURE 4-18 AP radiograph of a comminuted intertrochanteric fracture. Trochanters (arrows) and angular deformity (lines).


FIGURE 4-19 AP radiograph of a subtrochanteric fracture with overriding and slight angulation of the fragments.
Suggested Reading
Jensen JS. Classification of trochanteric fractures. Acta Orthop Scand 1980;51:803–810.
Lorich DG, Geller DS, Nelson JH. Osteoporotic peritrochanteric hip fractures. J Bone Joint Surg 2004;86A:398–410.


Trauma: Insufficiency Fractures
  • Insufficiency fractures occur because of normal stress on bone with abnormal elastic resistance.
  • Insufficiency fractures most commonly involve the sacrum, pubic rami, and supra-acetabular regions and femoral necks.
  • Most insufficiency fractures occur in elderly osteopenic patients or patients on steroid therapy.
  • Patients present with back, hip, or groin pain.
  • Because of the patient’s age, metastatic disease often is included in the differential diagnosis.
  • Image features
    • Radiographs: bone sclerosis or condensation, typically linear.
    • Radionuclide scans: increased tracer in area of fracture. Bilateral sacral fractures give “H” appearance (Honda sign).
    • MRI: marrow edema pattern (increased
      signal on T2-weighted images, decreased signal on T1-weighted images)
      with or without visible fracture line.
    • CT: fracture lines clearly defined.


FIGURE 4-20 Radiographs of insufficiency fractures. (A) Radiograph demonstrates subtle bone condensation in the sacrum (arrow) caused by an insufficiency fracture. (B) AP radiograph of the pelvis with linear condensation in the left acetabulum (arrow) caused by an acetabular insufficiency fracture.


FIGURE 4-21 MRI of insufficiency fractures. Coronal T1- (A) and fast spin-echo T2- (B)
weighted images show abnormal signal intensity in the acetabulum on the
right caused by insufficiency fracture. There is also marrow edema in
the femoral head and neck caused by early AVN. (C) Axial fast spin-echo T2-weighted image of the sacrum with and insufficiency fracture and fluid (arrow) in the fracture line.


Suggested Reading
Pek WCG, Khong PL, Yur Y, et al. Imaging of pelvic insufficiency fractures. Radiographics 1996;16:335–348.


Trauma: Soft Tissue Trauma

Condition Imaging Approach
Muscle/tendon injury MRI
Ligament injury MRI, arthrography, or magnetic resonance (MR) arthrography for hip
Neurovascular injury MRI
Acetabular labral tears MR arthrography
Bursitis Ultrasound or MRI
Snapping tendon syndrome Tendon injection with motion studies, ultrasound
Suggested Reading
Cvtanic O, Henzie G, Skezas DS, et al. MRI diagnosis of tears in the abductor tendons (gluteus medius and gluteus minimus). AJR Am J Roentgenol 2004;182:137–143.
C, Hofmann S, Nenhold A, et al. Lesions of the acetabular labrum:
Accuracy of MR imaging and MR arthrography in detection and staging. Radiology 1999;220:225–230.
DeSmet AA, Fisher DR, Heiner JP, et al. Magnetic resonance imaging of muscle tears. Skel Radiol 1990;19:283–286.
Lonner JH, Van Kleunen JP. Spontaneous rupture of the gluteus medius and minimus tendons. Am J Orthop 2002;31:579–581.


Trauma: Soft Tissue Trauma: Muscle/Tendon Tears
FIGURE 4-22 Axial (A) and sagittal (B) T2-weighted images of a Grade 1–2 strain of the hamstring muscles (arrows).


FIGURE 4-23 Coronal (A) and axial (B) T2-weighted images of an adductor muscle tear (arrows) with a central hematoma.
Suggested Reading
DeSmet AA, Fisher DR, Heiner JP, et al. Magnetic resonance imaging of muscle tears. Skel Radiol 1990;19:283–286.
Koulouris G, Connell D. Evaluation of the hamstring muscle complex following acute injury. Skel Radiol 2003;32:582–589.


Trauma: Soft Tissue Trauma: Bursitis
FIGURE 4-24 Hip arthrogram/injection with filling of the iliopsoas bursa (arrows).


FIGURE 4-25 Coronal fast spin-echo T2-weighted image demonstrating an enlarged iliopsoas bursa (arrows) with low signal intensity filling defects because of chronic synovitis.
FIGURE 4-26 Axial fast spin-echo T2-weighted image of an inflamed trochanteric bursa (arrow).


Suggested Reading
Bencardino JT, Palmer WE. Imaging of hip disorders in athletes. Radiol Clin North Am 2002;40:267–287.
P, White LM, Agur A, et al. Obturator externus bursa: Anatomic origin
and MR imaging features of pathologic involvement. Radiology 2003;228:230–234.
Wunderholdinger P, Bremer C, Schellenberger E, et al. Imaging features of iliopsoas bursitis. Eur Radiol 2002;12:409–415.


Trauma: Soft Tissue Trauma: Greater Trochanteric Pain Syndrome


FIGURE 4-27 (A) Coronal T1-weighted image shows gluteus minimus atrophy (arrows). (B) Fast spin-echo T2-weighted image shows high signal intensity because of a high-grade tear in the minimus tendon (arrow).
Suggested Reading
PA, Oakley SP, Shnier R, et al. Prospective evaluation of magnetic
resonance imaging and physical examination findings in patients with
greater trochanteric pain syndrome. Arthritis Rheum 2001;44:2138–2145.
A, Tirovan PFJ, Feller J, et al. Tendinosis and tears of the gluteus
medius and minimus muscles as a cause of hip pain: MR imaging findings.
AJR Am J Roentgenol 1999;173:1123–1126.


Trauma: Soft Tissue Trauma: Acetabular Labral Tears
FIGURE 4-28 Coronal MR arthrogram image demonstrating the normal triangular shape of the superior labrum (arrow) and the transverse ligament inferiorly (open arrow).


FIGURE 4-29 Coronal MR arthrogram image demonstrating a superior labral tear (arrow).
FIGURE 4-30 Coronal MR arthrogram image with superior labral tear and paralabral cyst (arrows).
Suggested Reading
Andingoz U, Ozturk MH. MR imaging of the acetabular labrum: A comparative study of both hips in 180 asymptomatic volunteers. Eur Radiol 2001;11:567–574.
Petersilge CA. MR arthrography for evaluation of the acetabular labrum. Skel Radiol 2001;30:423–430.


Trauma: Soft Tissue Trauma: Femoroacetabular Impingement
FIGURE 4-31 Axial (A) and sagittal (B) MR arthrogram images demonstrate a bony prominence at the head–neck junction (arrow) causing impingement.


Suggested Reading
A, Yoon LS, Belzile E, et al. Triad of MR arthrographic findings in
patients with cam-type femoroacetabular impingement. Radiology 2005;236:588–592.
Siebenrock KA, Schoeniger R, Ganz R. Anterior femoroacetabular impingement due to acetabular retroversion. J Bone Joint Surg 2003;85A:278–286.




FIGURE 4-32 Routine radiograph was normal. (A) Radionuclide scan shows increased signal intensity in the right femoral head and neck. (B) Spin-echo T1-weighted image shows a femoral neck fracture (arrow), low-intensity edema pattern, and AVN (open arrow).
Suggested Reading
Jones JP Jr. Etiology and pathogenesis of osteonecrosis. Semin Arthroplasty 1991;2:160–168.
DG, Rao VM, Dalinka MK, et al. Femoral head avascular necrosis:
Correlation of MR imaging, radiographic staging, radionuclide imaging,
and clinical findings. Radiology 1987;162:709–715.


Osteonecrosis: Avascular Necrosis
Stage Clinical Features Radiographs MRI Features
0 No symptoms Normal Normal or uniform edema pattern (↓ signal T1WI, ↑ T2WI)
I May have pain Usually normal Same as Stage 0
II Pain, stiffness Mixed lucency and sclerosis in subchondral bone Geographic zone of demarcation
III Stiffness, groin and knee pain Crescent sign with cortical collapse, joint space preserved Same as Stage II with cortical collapse
IV Severe limp, pain Stage III plus joint space narrowing Same as Stage III plus joint space narrowing
T1WI, T1-weighted image; T2WI, T2-weighted image.



FIGURE 4-33 MRI of AVN. (A) Coronal T1-weighted image of bilateral AVN with greater articular involvement on the left (lines). (B) Sagittal T1-weighted image demonstrating articular surface involvement. (C) Fat-suppressed T1-weighted postcontrast image shows enhancement at the margin of the necrotic bone (arrows) caused by revascularization. (D) Coronal T1-weighted image demonstrating a simple method to calculate the weight-bearing surface involvement. Angle A (thick black lines)
is formed by lines from the center of the femoral head to the
weight-bearing margins. Angle N is formed by lines from the necrotic
margins to the center of the femoral head. N/A × 100% = % of
weight-bearing involvement. In this case 43/94 = 46% indicating a
poorer prognosis.


Suggested Reading
Ficat RF. Treatment of avascular necrosis of the femoral head. Hip 1983;2:279–295.
Koo KH, Kim R. Quantifying the extent of osteonecrosis of the femoral head. A method using MRI. J Bone Joint Surg 1995;77B:825–830.
Liebermann JR, Berry DJ, Mont MA, et al. Osteonecrosis of the hip. Management in the 21st century. J Bone Joint Surg 2002;84A:834–853.


Osteonecrosis: Bone Infarcts
FIGURE 4-34 Coronal T1-weighted MRI showing AVN of both femoral heads and infarcts (arrows) in the trochanteric regions.
Suggested Reading
Berquist TH. MRI of the musculoskeletal system. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2006:201–302.


Bone Marrow Edema


FIGURE 4-35 Coronal (A) and sagittal (B) T1-weighted images showing low signal intensity in the right femoral head and neck caused by transient marrow edema.


Suggested Reading
CW, Conway WF, Daniel WW. MR imaging of bone marrow edema pattern:
Transient osteoporosis, transient bone marrow edema, or osteonecrosis. Radiographics 1993;13:1001–1011.
de Berg BC, Malghen JJ, Lecouret FE, et al. Idiopathic bone marrow
edema lesions in the femoral head. Predictive value of MR image
findings. Radiology 1999;212:527–535.


Transient Osteoporosis of the Hip



FIGURE 4-36 Coronal T1- (A) and T2- (B)
weighted images demonstrate abnormal signal intensity in the left
femoral head and neck in a patient with hip pain. Radiographs in a
different patient showing osteopenia in the right hip during the
symptomatic phase (C) and return to normal (D) 6 months later.
Suggested Reading
Guerra JJ, Steinberg MR. Distinguishing transient osteonecrosis from avascular necrosis of the hip. J Bone Joint Surg 1995;77A:616–624.


Bone Tumors No. in Region/Total/% in Region
Chordoma (sacrum) 169/365/46%
Ewing sarcoma 182/512/36%
Chondrosarcoma 312/895/35%
Fibrosarcoma 63/255/25%
Myeloma 185/814/23%
Osteosarcoma 307/1649/19%
Lymphoma 116/694/17%
Benign No. in Region/Total/% in Region
Osteoid osteoma 120/331/36%
Chondroblastoma 26/119/22%
Giant cell tumor 97/568/17%
Osteochondroma 130/872/15%
Chondroma 30/290/10%


Malignant Benign
Liposarcoma Lipoma
Alveolar sarcoma Myxoma
Synovial sarcoma Hemangioma
Epithelioid sarcoma Benign nerve sheath tumors
Malignant fibrous histiocytoma Desmoid tumors*
*Aggressive lesions with high recurrence rate.
FIGURE 4-37 Osteoid osteoma. (A) Routine radiographs demonstrating medial joint space widening (arrow) caused by soft tissue reaction. (B) Axial T2-weighted MR image showing focal increased signal along the femoral neck (arrow). (C) CT clearly demonstrating osteoid osteoma (arrow). Note the anterior soft tissue thickening (open arrow).


FIGURE 4-38 Low-grade liposarcoma. Sagittal T1- (A) and T2- (B)
weighted images demonstrate a large fatty tumor with areas of
low-signal intensity on T1- and high-signal intensity on T2-weighted
sequences (arrows).
Suggested Reading
Berquist TH. MRI of musculoskeletal neoplasms. Clin Orthop 1989;244:101–118.
Unni KK. Dahlin’s bone tumors: General aspects and data on 11,087 cases. Philadelphia, Lippincott-Raven; 1996.
Weiss SW, Goldblum JR. Enzinger and Weiss’s soft tissue tumors. 4th ed. St. Louis: Mosby; 2001.



Systemic Local
Rheumatoid arthritis Posttraumatic arthritis
Seronegative spondyloarthropathies Infection
(Reiter disease, ankylosing spondylitis, psoriatic arthritis) Synovial chondromatosis Pigmented villonodular synovitis
Juvenile chronic arthritis Paget disease
Connective tissue diseases Crystalline arthropathies
Collagen vascular diseases  
Arthropathies: The Hip


Condition Image Features
Rheumatoid arthritis Bilateral symmetric axial joint space narrowing
Small erosions
Cystic changes
Protrusio acetabuli
No osteophytes
Ankylosing spondylitis Bilateral symmetric axial narrowing
Calcium pyrophosphate dihydrate deposition disease Bilateral asymmetric axial narrowing
Cartilage calcification
Degenerative disease with multiple subchondral cysts and osteophytes
Synovial chondromatosis Joint space normal or widened early scalloping at head–neck junction
Joint ossifications
Confirm with conventional or MR arthrography
Pigmented villonodular synovitis Joint space normal or widened early erosive changes
Increased soft tissue density or masses
MRI confirms diagnosis
Septic arthritis Osteopenia
Uniform rapid joint space narrowing with pyogenic infections
Gradual joint space narrowing with tuberculosis or atypical mycobacterial infections


FIGURE 4-39 Normal AP view of the hip with joint spaces marked (black lines). Narrowing may occur medially (M), axially (A), or superolaterally (SL).
FIGURE 4-40 Degenerative arthritis. AP radiograph of the right hip shows superolateral joint space narrowing, marginal osteophytes (arrows), and subchondral geodes (open arrows). There is bone sclerosis in the femoral head.


FIGURE 4-41 Degenerative arthritis. AP arthrogram shows superolateral joint space narrowing with a large communicating iliopsoas bursa (arrow).
FIGURE 4-42 Pigmented villonodular synovitis. Coronal T1-weighted image demonstrates erosion (arrow) of the head–neck junction with lobulated low signal intensity in the capsule.


Synovial chondromatosis. Axial T2-weighted image demonstrates a
high-signal intensity joint effusion with small low-signal intensity
structures throughout the joint (arrowheads).
Suggested Reading
Brower AC. Arthritis in black and white. 2nd ed. Philadelphia: WB Saunders; 1997:105–122.
D. Patterns of migration of the femoral head in osteoarthritis of the
hip. Roentgenographic-pathologic correlation and comparison with
rheumatoid arthritis. AJR Am J Roentgenol 1975;124:62–74.


Arthropathies: Sacroiliac Joints


FIGURE 4-44 (A) Normal sacroiliac joints. (B) Bilateral sacroiliac ankylosis and spine changes of ankylosing spondylitis.
Suggested Reading
Braunstein EM, Martel W, Moidel R. Ankylosing spondylitis in men and women. A clinical and radiologic comparison. Radiology 1982;144:91–94.
Brower AC. Arthritis in black and white. 2nd ed. Philadelphia: WB Saunders; 1997:155–174.




FIGURE 4-45 Greater trochanteric abscess. (A) Oblique radiograph shows a lucent area in the greater trochanter (arrows). (B)
Coronal fat-suppressed T1-weighted image after gadolinium enhancement
demonstrates an irregular lesion with peripheral enhancement.
Suggested Reading
Gold RH, Hawkins RA, Katz RD. Bacterial osteomyelitis findings on plain radiographs, CT, MR, and scintigraphy. AJR Am J Roentgenol 1991;157:365–370.
Resnick D. Osteomyelitis, septic arthritis, and soft tissue infections: Mechanisms and situations. In: Resnick D, ed. Diagnosis of bone and joint disorders. Philadelphia: WB Saunders; 2002:2377–2480.


Pediatric Hip Disorders: Legg-Calvé-Perthes Disease



FIGURE 4-46 Legg-Calvé-Perthes Disease. (A)
Radiograph shows the right capital epiphysis is 100% involved
(Catterall group IV) with greater than 50% loss of height (Herring
group C). (B) Several years later the epiphysis is still flat and irregular. Fat planes (arrows) are displaced because of a joint effusion. (C) Four years later the physis is closed with flattening and widening of the femoral head and neck on the right.


FIGURE 4-47 Coronal T1- (A) and T2- (B)
weighted images in an older child with Legg-Calvé-Perthes Disease on
the right. There is an effusion on the right and central necrosis of
the epiphysis. Note the uncovered femoral head by the labrum on the
right compared with the left (white lines).


Suggested Reading
Catterall A. Legg-Calvé-Perthes disease. RSNA Instructional Course Lecture. Chicago, Illinois, 1989;9:19–22.
P, Echewall G, Egund N, et al. Femoral head shape in Legg-Calvé-Perthes
disease. Correlation between conventional radiography, arthrography,
and MR imaging. Acta Radiol 1994;35:545–548.
D, Exner GU, Hilfiker PR, et al. Dynamic MR imaging of the hip in
Legg-Calvé-Perthes disease: Comparison with arthrography. AJR Am J Roentgenol 2000;174:1635–1637.


Pediatric Hip Disorders: Developmental Dysplasia of the Hip


FIGURE 4-48 AP radiographs (A,B) demonstrating developmental dysplasia on the right. The acetabular angle (line
along acetabulum to Hilgenreiner line [H]) is increased and the hip is
displaced superolaterally with interruption of Shenton line (S) (broken white lines).
The femoral head should lie in the inferomedial (im) quadrant. Four
quadrants (im, inferomedial; il, inferolateral; sl, superolateral; sm,
superomedial) are formed by a line (Perkins line) at the acetabular margin perpendicular to Hilgenreiner line. The femoral head is out of the im quadrant in (B).


FIGURE 4-49 MR image in the frog-leg position shows dislocation of the left hip (arrow).
FIGURE 4-50 Coronal T2-weighted image with developmental hip dysplasia on the right. The medial joint space is widened (open arrow). The labrum is well demonstrated (arrow), and the femoral head is less well covered compared with the left hip.
Suggested Reading
AM, Dormans JP. Evaluation of developmental dysplasia, Perthe’s
disease, and neuromuscular dysplasia of the hip before and after
surgery: An imaging update. AJR Am J Roentgenol 1995;164:1062–1073.
Weinstein SL, Mubarak SJ, Wenger DR. Developmental hip dysplasia and dislocation. J Bone Joint Surg 2003;85A:2024–2035.


Pediatric Hip Disorders: Slipped Capital Femoral Epiphysis


FIGURE 4-51 AP (A) and oblique frog-leg views (B,C) of a slipped capital femoral epiphysis on the left. AP view (A) shows osteopenia and widening of the physis (arrows). Note the line along the lateral neck does not intersect the ossified epiphysis. The right hip (B) is normal. The displacement of the capital epiphysis on the metaphysis (lines) is obvious on the frog-leg oblique view (C).


FIGURE 4-52 Coronal T1-weighted image of a slipped capital femoral epiphysis on the left (arrow).
Suggested Reading
Boles CA, El-Khoury GY. Slipped capital femoral epiphysis. Radiographics 1997;17:809–823.
T, Suzuki S, Seto Y, et al. Sequential magnetic resonance imaging in
slipped capital femoral epiphysis: Assessment of preslip of the
contralateral hip. J Pediatr Orthop 2001;10:298–303.
H, Lieblings MS, Moy L, et al. Slipped capital femoral epiphysis: A
physeal lesion diagnosed by MRI with radiographic and CT correlation. Skel Radiol 1998;27:139–144.


Pediatric Hip Disorders: Rotational/Orientation Abnormalities: Coxa Vara And Coxa Valga
FIGURE 4-53 Normal femoral neck angle (lines) seen on AP radiograph.


Coxa vara. AP view of the hips in a patient with healed slipped capital
femoral epiphyses showing a decreased femoral neck angle (lines).
FIGURE 4-55 Coxa valga. Child with thalassemia and increased femoral neck angle (lines).


Pediatric Hip Disorders: Rotational/Orientation Abnormalities: Femoral Anteversion


FIGURE 4-56 Femoral anteversion measurement. (A) Coronal MR image demonstrating oblique angle for axial images (lines). (B) Axial image of the hips with line through the plane of the neck and horizontal line forming the angle. (C)
Axial image of the knee. A line is drawn along the posterior condyles
and the angle formed by the horizontal line. If the knee is externally
rotated, as in this case, the knee angle is subtracted from the axial
femoral angle. If the knee is internally rotated, the angle is added to
the femoral angle to measure the degree of anteversion.
Suggested Reading
RJ, Guenther DP, Rieber A, et al. MR imaging measurement of the femoral
anteversion angle as a new technique. Comparison with CT in children
and adults. AJR Am J Roentgenol 1997;168:791–794.

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