Osteomyelitis - femur

Case contributed by Dalia Ibrahim


Severe right thigh pain with pus discharge from its lateral aspect.

Patient Data

Age: 35 years
Gender: Male

An inflammatory process of the right femoral shaft showing a long intramedullary central linear track of fluid signal seen extending from the mid to lower femoral shaft, showing marginal post contrast enhancement and surrounding marrow edema signal. Diffuse cortical thickening is also noted.

A small sequestrum is seen within the mid femoral shaft, eliciting a persistent dark signal.

The track ends by breaching the posterior cortex of the lower femoral shaft by a draining sinus/ostium (cloaca).

A sinus tract extends from the cloaca along the posterior aspect of the thigh, reaching to the skin.

A small abscess collection is seen within the biceps femoris muscle, from which two sinus tracts extend and reach to the skin surface (one passes through the intermuscular fat plane) and the other tract reaches the skin via traversing the rectus femoris muscle).


Plain x-ray shows the sequestrum, involucrum and cloaca

Annotated image

Osteomyelitis. Note the sinus tracts it extends from the cloaca to the skin. Two sinus tracts (yellow arrow) extend from the biceps femoris abscess (red arrow) to reach the skin.

Case Discussion

The case clearly illustrates the pathology and complications of chronic osteomyelitis with formation of sequestrum, involucrum and cloaca as well as draining sinus tracts.

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