Bundle Of Ulnar Collateral Ligament Research Articles

In Vivo Assessment of Stiffness of Anterior Oblique Bundle of Ulnar Collateral Ligament Using Ultrasound Elastography

The Anterior oblique ligament (AOL) of the ulnar collateral ligament (UCL) attaches to the inferior aspect of the medial epicondyle of the humerus and the coronoid process of the ulna, and has an important role in life and exercise by inhibiting flexion and valgus of the elbow. Understanding the mechanical function of the UCL in vivo is important for the diagnosis and prevention of elbow injuries caused by baseball and other sports. In this study, we aimed to measure the stiffness of the AOL during changes in elbow flexion angle and pronation and supination using ultrasound elastography. The stiffness of the AOL decreased with increasing elbow flexion angle in all conditions, and was less affected by pronation and supination compared to the intermediate position at the same elbow flexion angle.

Relationship between morphology of transverse bundle of ulnar collateral ligament and adjacent tissues.

The purpose of this study was to clarify the incidence of the transverse bundle (TB) of the ulnar collateral ligament (UCL), the relationships between TB morphology and morphology of the anterior bundle (AB) or posterior bundle (PB) of the UCL, and the relationship between the TB and the posterior common tendon (PCT). This study examined 38 elbows from 23 cadavers. TB, AB, and PB were classified morphologically. The TB was classified as: type I, TB does not continue the entire length of the AB; or type II, TB continues the entire length of the AB. The AB and PB were classified as: type I, could be separated as single bundles; or type II, could not be separated. We also observed specimens by focusing on the continuity between the TB and PCT. Fisher's exact test was used to examine the relationship between TB type and AB or PB type. A TB was identified in all 38 elbows (100%), and continued to the AB in all specimens. No significant relationship was evident between TB type and AB or PB type. Continuity of TB fibers and the PCT was seen in 26 elbows (72%). This study suggested that the morphology of the transverse bundle may be unrelated to the morphology of the anterior bundle or posterior bundle.

Anterior bundle of ulnar collateral ligament: evaluation of anatomic relationships by using MR imaging, MR arthrography, and gross anatomic and histologic analysis.

To evaluate the gross and microscopic anatomy and the magnetic resonance (MR) imaging and MR arthrographic appearance of the anterior bundle of the ulnar collateral ligament (UCL) of the elbow. The origin and insertion of the anterior bundle of the UCL, the bundle's relationship to the overlying flexor tendons, and the presence of a layered configuration were assessed through inspection and dissection of an elbow specimen. T1-weighted spin-echo MR imaging and MR arthrography in standard imaging planes and a coronal oblique plane were performed in eight other elbow specimens. Additional MR arthrography was performed in four specimens by using the coronal plane with the elbow in 20 degrees of flexion. The specimens were then cut in planes corresponding to those of the MR images. Histologic analysis of two specimens was performed. The anterior bundle of the UCL appeared as a low-signal-intensity structure on T1-weighted spin-echo MR and MR arthrographic images. It consisted of a uniform layer of parallel collagen fibers attaching proximally to the base of the medial epicondyle of the humerus and distally to the medial aspect of the coronoid process of the ulna (sublime tubercle). A layer of synovium separated the anterior bundle from the more superficial tendon of the flexor digitorum superficialis muscle. MR imaging-anatomic comparison in four (50%) specimens revealed separation between the anterior bundle of the UCL and the sublime tubercle. Results of histologic analysis of two of these specimens confirmed insertion of the anterior bundle of the UCL 3 and 4 mm distal to the articular margin. Ligamentous degeneration was detected in only one of these specimens. There is variability in the distal insertion of the anterior bundle, and this suggests that caution should be exercised in the diagnosis of its partial detachment from the sublime tubercle of the ulna.