"iDoctor – Medical Blog"

OBJECTIVE. As part of the lateral ligament complex of the elbow, the
annular ligament has an adjunctive role in stabilizing the proximal radioulnar
joint. Knowledge of the anatomy of this ligament may enhance our understanding
of its functional role in maintaining integrity of the elbow joint in fracture
and dislocation. The purpose of this study is to provide a detailed analysis
of the anatomy of the annular ligament using MR arthrography with anatomic and
histologic correlation in cadavers.

MATERIALS AND METHODS. MR arthrography of six fresh cadaveric elbows
using coronal, axial, and sagittal planes was performed after injection of
intraarticular contrast material. The MR arthrography appearance of the
annular ligament was correlated with anatomic sectioning and histologic
analysis.

RESULTS. On MR arthrography, the axial and sagittal planes provided
the best evaluation of the annular ligament. Although the anterior attachment
of annular ligament was a single band, the posterior attachment was
fenestrated in two of six specimens. Anatomic inspection confirmed the MR
observations. On histology, the annular ligament appeared to be part of a
complex supporting structure continuous with the elbow joint capsule, adjacent
ligaments, and muscles.

CONCLUSION. The annular ligament is a complex structure formed from
the capsule, lateral collateral ligamentous complex, and supinator muscle that
act in unison to stabilize the proximal radioulnar joint. Its posterior
attachment to the ulna can be fenestrated normally. A detailed analysis of
anatomy of this ligament allows us to better understand its functional role in
fractures and dislocations of the elbow joint.