The volar and dorsal aspects of the attachment correspond to slip insertions of the radioulnar ligaments into bone.
The central portion of the attachment appears as an insertion into the hyaline cartilage of the radius
The triangular fibrocartilage or articular disc of the TFCC has a broad attachment to the hyaline cartilage of the sigmoid notch of the distal radius, whereas, the dorsal and volar distal radioulnar ligaments insert directly into the distal radius.
The hyaline cartilage at the central portion of the attachment of the TFCC to the radius demonstrates intermediate signal intensity, which should be interpreted as a normal finding.
In the coronal plane, the ulnomeniscal homologue has a typical triangular shape, with the base of the triangle located along the ECU tendon sheath.
It adheres to the ulnar joint capsule and merges with the ulnar collateral ligament (UCL) and the sheath of the extensor carpi ulnaris (ECU) tendon.
The ulnar collateral ligament (UCL) may not be a distinct anatomical structure located in between the extensor carpi ulnaris tendon (ECU) sheath and the UMH.
These structures normally cannot be differentiated by imaging.
The entrance to the prestyloid recess is seen as a small aperture in the styloid portion that widened to form a small channel that enlarged to become the prestyloid recess at the anterior aspect of the ulnar styloid process.
There are several variations in the shape of the prestyloid recess, narrow-opening, wide-opening and no-opening UMH types with respect to the entrance to the prestyloid recess.
In addition, the apparent width of the opening is heavily dependent on the imaging position. In maximal ulnar deviation, the entrance to the prestyloid recess collapsed, simulating the no-opening type.
The membranous component most commonly appears as a triangular or deltoid region of low signal intensity.
The LTL segments could be viewed as the reverse of the SLL segments, in that the volar LTL is thicker and potentially more important than the dorsal LTL, whereas the dorsal SLL is thicker than the volar SLL
The dorsal and volar components of the LTL are true ligamentous components, consisting of collagen fascicles.
The histologic nature of the membranous component of the LTL is different from that of the volar and dorsal components; it consists of fibrocartilaginous tissue similar to that of the triangular fibrocartilage.
