Scapholunate ligament.

Scapholunate ligament:

• It is a triangular ligament connecting between scaphoid bone and lunate bone.
• For proper evaluation we should do MR arthrography.
• Scapholunate interval is the distance between scaphoid and lunate bones. If this is seen increased in distance in the plain film you can diagnose scapholunate tear with no need for MR imaging.
• If the distance is normal with clinical suspicious do MR arthrography.
• The scapholunate ligament attachment on the scaphoid side is weaker than the other side related to lunate. So the majority of tears of scapholunate ligament is usually in the center or to the side of scaphoid rather than that near lunate.
• Normally; if we inject dye or water in the scapholunate interval it does not reach distal radioulnar joint.
• If triangular fibrocartilage (TFC) is teared; the dye in this condition will reach the distal radioulnar joint (an important sign for diagnosis of tear of TFC).

Torn scapholunate ligament from its middle parenchyma.

Normal Scapholunate ligament