Figure 7a. Transverse views of the MCP joints of the second and third fingers in extension, with anatomic correlation. T1-weighted spin-echo (a) conventional MR image (500/12) and (b) MR arthrogram (500/12) and (c) the corresponding anatomic section show the proximal attachments (open arrow), distal attachments (long straight black arrow), and taut body (long straight white arrow) of the accessory collateral ligament. In b, the accessory collateral ligaments are better depicted with intraarticular contrast agent enhancement. The sagittal bands (white arrowheads), interosseous muscles (short black arrow in c) and tendons (short white arrows), PP (curved black arrow), A1 pulleys (black arrowheads), and DTML (curved white arrow in a and c) also are well demonstrated.