The purpose of this prospective study is to evaluate and compare the accuracy of elbow ultrasonography with X Ray radiography for the diagnosis of elbow fractures in children following trauma in order to detect the validity of US in diagnosis of fractures as a dependent tool.

Acute bone fractures in children are common and account for 10-25% of total injuries in early ages with considerable effects on activity restriction and subsequent high socioeconomical impact. In these cases, the elbow is a common site of pediatric fractures (account for up to 15% of all fractures) referring to the emergency department, and diagnostic testing with X-ray, including standard 2-way anteroposterior and lateral views, are required primarily for the evaluation of elbow injuries. In the setting of elbow trauma, the posterior fat pad sign on lateral radiographs is highly sensitive for fracture . However, radiological assessment of the elbow may be challenging in early ages due to the non-ossifed epiphysis and often non-exact two- plane radiographs in uncooperative children. Because of the higher sensitivity of growing bones to ionizing radiation, and dose-dependent radiation exposure is both CT scans and X-ray, every imaging should be minimized in children. Therefore, alternative imaging methods, such as US, have become a current issue to reduce exposure to radiation . Ultrasound is radiation-free, it is a real-time bedside assessment, it can be immediately performed and is easily accessible, and it is fast and reliable ,Ultrasonography can detect cortical disruption and irregularity, which directly indicates fractures. However, an elevated posterior fat pad can be easily identified by US, indirectly indicates intracapsular fractures . Ultrasonography is superior to radiography in detecting posterior fat pad elevation. Elbow joint effusion is a classic finding after trauma.

It is not always associated with a cortical fracture, whereas lipohaemarthrosis, corresponding to the presence of blood and lipid material in the posterior fat pad, indicates an intraarticular elbow fracture, too.

Lipohemarthrosis, as well as an elevated posterior fat pad, can easily be identifed on ultrasound.

Inclusion Criteria:

• The patients' age between 7 month and 14 years with a suspected elbow fracture.
• Patients who less than 7 days after the injury of elbow.

Exclusion Criteria:

• Patients with a an open injury in elbow.
• Patients with suspected vascular injury.
• Patients with unstable vital signs .

Ultrasonography examination is done by a 5-10 MHz linear probe. Immediately after it , sonographic fndings are recorded the on data collection forms and after that standard two-view radiographic imaging (AP and lateral elbow X-ray) of the elbow is performed and compared with US results. For performing elbow ultrasonography, patients took a sitting position in front of the examiner. In this position, the elbow flexed to 90 degrees , then the transducer was placed over the posterior-midline aspect of the distal humerus. Both transverse and longitudinal views of the elbow are obtained, and still, pictures and video clips are recorded in each orientation.