be measured for asymmetry The neurologic examination should include inspection of the spine for lumbosacral hair or dimple (indicating possible spinal dysraphism), and testing of strength, sensation, and reflexes The abdomen and external genitalia should be examined for tenderness or masses and the skin for rashes A rectal examination may be indicated if sacral pathology is suspected Finally, wear patterns on the child’s shoes may provide clues to the nature and duration of the limp Laboratory and Imaging Plain radiographs remain a mainstay of the workup of a limping child They provide an excellent means of screening for fracture, effusion, lytic lesions, periosteal reaction, and avascular necrosis In a child with an obvious focus of pain, the radiographs may be obtained with views specific to that area, noting that children with knee pain may have hip pathology The need for comparative views (of the contralateral normal extremity) depends on the experience of the physician interpreting the films Some radiographic findings can be subtle, and comparison with the opposite side may be helpful Although the goal is to focus imaging on areas of greatest concern, in a young child or a child lacking obvious focus for the limp, anteroposterior and lateral tibia/fibula radiographs of both extremities should be ordered If tibia/fibula films are negative, imaging of the pelvis, femur, and ankle/foot may be considered In children in whom hip pathology is suspected, anteroposterior and frog-leg lateral views of the pelvis are required The frog-leg lateral view, obtained with the hips abducted and externally rotated, allows excellent visualization of the femoral heads These radiographs should always include both hips to enable comparison of the femoral heads and width of the joint spaces Radiographs of the spine are necessary if the child has neurologic signs or symptoms In children whose limp is associated with fever or systemic illness, laboratory studies, including a complete blood cell count, C-reactive protein (CRP) level, and an erythrocyte sedimentation rate (ESR), are indicated These studies serve as screens for infection, inflammation, malignancy, and hemoglobinopathy Significant overlap may exist in the clinical and laboratory presentations of infectious and inflammatory arthritis There is currently no single noninvasive test that distinguishes hip septic arthritis from transient synovitis or Lyme disease in the acute setting Algorithms based on variables such as the inability to bear weight, fever, white blood cell count, CRP, and ESR have been created to aid clinicians in their clinical decision making Unfortunately, these algorithms have not been shown to be generalizable across all populations In addition, there is an increasing recognition of Kingella kingae as an etiology for joint infections in