• The ulnar nerve passes posterior to the medial epicoydyle within the cubital tunnel.
• the floor of the tunnel is made up of the bony floor, augmented by fibres from the CFO.
• The roof is formed in its proximal part by Osbornes ligament and
• distally by the two heads of flexor carpi ulnaris.
Neural compression may arise from
• a tight canal, or
• from impingement from adjacent osteophytes.
In some cases, no compressive lesion is present and symptoms are thought to be due to chronic traction.
Ulnar nerve subluxation may pre dispose to injury although it can be present in up to 16% of the population.
• Look for thickened nerve and
• Signs of denervation - but may not be in the same FOV
• Thickened nerve easily demonstrated
• Dynamic study may show subluxationLook for thickened ligaments underlying compression
