This diagnostic image consists of multi-planar T2-weighted MRI scans of a human elbow joint, presented in sagittal (A) and axial (B) views. The scans demonstrate the complex anatomy of the radiohumeral (humeroradial) joint, showing the distal humerus, proximal radius, and ulna. A prominent clinical finding is highlighted by red arrows in both views: a localized area of low signal intensity representing the annular ligament, which has become incarcerated or 'stuck' within the radiohumeral joint space. In the sagittal view, this interposed soft tissue is seen disrupting the normal articulation between the radial head and the humeral capitellum. In the axial slices, the displaced ligament is visualized as a dark, hypointense structure contrasting against the brighter (hyperintense) joint fluid. This finding is characteristic of a complex radial head dislocation where soft tissue entrapment prevents successful closed reduction. The image is a critical educational resource for understanding mechanical blocks in pediatric elbow trauma and the utility of MRI in identifying ligamentous interposition.

This diagnostic image consists of two radiographic views of the left elbow joint: an anteroposterior (AP) view (A) and a lateral view (B). The X-rays demonstrate the skeletal anatomy of the distal humerus, proximal radius, and proximal ulna. In the AP view, a red arrow points to the medial epicondyle of the humerus, where the bony architecture appears preserved with normal cortical thickness and trabecular patterns. The radiohumeral and ulnohumeral joint spaces are well-maintained, indicating a lack of significant degenerative changes or acute inflammatory destruction. The lateral view shows congruent alignment of the humeroulnar and radiocapitellar joints, with the red arrow again highlighting the medial epicondylar region from a side profile. These follow-up images show no evidence of active lytic lesions, cortical erosions, or recurrence of previously treated disease such as musculoskeletal tuberculosis. The surrounding soft tissues appear normal without significant swelling or calcification, confirming clinical stability at one year post-treatment.

This diagnostic X-ray (radiography) captures a lateral view of a human elbow joint, illustrating a congenital or acquired radiohumeral synostosis. The image demonstrates a clear bony fusion between the distal humerus and the proximal head of the radius. Specifically, there is a total lack of a visible joint space at the radiohumeral articulation, with continuous cortical and trabecular bone spanning the two structures. In contrast, the ulnohumeral articulation appears relatively spared, with a discernible joint space maintained between the trochlea of the humerus and the trochlear notch of the ulna. The olecranon process of the ulna is visible posteriorly. This radiographic finding is clinically significant as a manifestation of rare skeletal dysplasias or as a solitary orthopedic anomaly, leading to a complete loss of pronation and supination at the forearm. The image serves as a textbook example for orthopedic and radiological training in identifying joint fusion and anomalous skeletal developments.

Two-view conventional radiographs of a human right elbow joint, including an anteroposterior (AP) view (a) and a lateral view (b), demonstrating post-surgical sequelae and secondary osteoarthritis. The AP view shows a widening or separation at the proximal radioulnar joint (PRUJ) and marked articular surface irregularity of the radiohumeral joint. The lateral view, taken in 90 degrees of flexion, reveals joint space narrowing and prominent anterior osteophyte formation on the distal humerus near the radiohumeral compartment. There is evidence of previous surgical intervention in the lateral epicondyle region of the humerus, leading to altered joint morphology. Findings are consistent with advanced degenerative changes following ligamentous instability and wide resection for an orthopedic tumor. Key educational features include the radiographic signs of secondary elbow osteoarthritis: subchondral sclerosis, osteophytosis, and joint space loss, particularly affecting the radiohumeral and ulnohumeral articulations.