Intra-articular bullet

A metallic foreign body is projected over the medial right hip joint. No fracture identified. No free gas.

The lung apices have been excluded. Lungs and pleural spaces are clear. No pneumothorax or free subdiaphragmatic gas. Allowing for the supine nature of the projection, cardiomediastinal contours are normal. No displaced rib fractures. No radiopaque foreign body.

Stranding and gas locules within the soft tissues anteriorly in the midline just below the level of the pelvic brim (at L5) correspond to the site of bullet entry. The bullet has traversed the right rectus muscle obliquely just medial to the right inferior epigastric vessles. The presence of intraperitoneal free gas is consistent with viscus injury, likely hollow viscus with no definite evidence of solid visceral injury. There is also free fluid (perihepatic, tracking along the right paracolic gutter and lateral to the bladder on the right) measuring up to approximately 50HU which is consistent with blood. There is no evidence of active contrast extravasation or pooling to suggest active hemorrhage at this time.

The bladder is intact.

There is moderate sized right extraperitoneal hematoma surrounding the external iliac artery and vein with involvement of the iliopsoas muscle. The right external iliac vein has a narrow, somewhat irregular caliber, this is likely due to compression from the adjacent hematoma, rather than representing a traumatic injury of this vessel.

The bullet has traversed the anterior column of the acetabulum resulting in a comminuted but non-displaced fracture and is lodged within the medial aspect of the right hip joint between the acetabulum and the femoral head. The femoral head appears intact with no evidence of fracture. Tiny osseous fragments within the extraperitoneal soft tissues are likely small fracture components.

No acute thoracic or lumbar spine fracture. 2 mm anterolisthesis of L5 on S1 and bilateral pars defects noted.

Conclusion

• The site of entry is in the midline just below the level of the pelvic brim. The bullet has traversed the right rectus abdominus muscle obliquely and is lodged within the medial right hip joint with an associated comminuted but undisplaced fracture of the anterior column of the acetabulum.
• Free intraperitoneal gas, intraperitoneal and extraperitoneal hematoma are demonstrated. Suspected hollow viscus injury but no definite evidence of solid visceral injury. Hematoma is demonstrated along the course of the bullet.