Toddler born breech who is beginning to walk who was noted to have a left limp

Radiograph of developmental dysplasia of the hip
Frogleg radiograph of the pelvis shows markedly asymmetrical ossification of the femoral epiphyses, with the left femoral epiphysis smaller in size than the right femoral epiphysis. The left acetabulum is also more shallow than the right acetabulum and the left femoral epiphysis appears slightly subluxed laterally and superiorly.

The diagnosis was developmental dysplasia of the left hip.

Preschooler with back pain

MRI of osteomyelitis of the spine
Coronal T1 MRI without contrast of the lumbar spine (left above) shows areas of low signal intensity on the right side of the L4 and L5 vertebral bodies and a right-sided paraspinal mass all of which enhance after the administration of contrast (right above). Axial T2 MRI through the L5 vertebral body (below) shows high signal intensity in the right side of the vertebral body and in the right paraspinal mass. The disk spaces are not involved.

The diagnosis was osteomyelitis.

Toddler with limp who won’t bear weight on right leg

Radiograph and MRI of diskitis / osteomyelitis
Lateral radiograph of the lumbar spine shows loss of height of the L3-L4 intervertebral disc space. Sagittal T2 MRI of the lumbar spine shows (right top) loss of normal bright signal of the L3-L4 intervertebral disc and an epidural mass just posterior to the L4 vertebral body. Axial T1 MRI with contrast at the L4 level shows the epidural mass to be right sided and to also involve the right psoas muscle.

The diagnosis was osteomyelitis / diskitis.