What is the MRI appearance of degenerative injuries to the TFCC? Either thinning or a full-thickness defect of the TFCC may be seen. There is also thinning of the articular cartilage on both the distal ulna as well as the apposed surface of the lunate, both of which may be hard to visualize. High signal …
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What is the MRI appearance of traumatic injuries to the TFCC? Traumatic injuries to the TFCC generally appear as the presence of high signal intensity on T2-weighted images extending through the full thickness of normally low signal intensity articular disc of the TFCC close to its attachment to the radius. The detection of tears close …
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What are the boundaries and contents of the carpal tunnel? The carpal tunnel is bounded by the bones of the wrist on its deep margin and a taut fibrous band, the flexor retinaculum, on its superficial margin. The major contents are the long flexor tendons of the fingers and thumb, the flexor carpi radialis tendon, …
What are the boundaries and contents of the ulnar tunnel (Guyon’s canal)? The ulnar tunnel (Guyon’s canal) is located superficial to the carpal tunnel on the ulnar aspect of the wrist and contains the ulnar nerve, artery, and vein. The flexor retinaculum is the floor. The radial surface of the pisiform is the ulnar margin. …
What is the normal MRI appearance of the wrist? The predominant signal intensity of normal bone marrow is the same as that of the subcutaneous fat and is generally bright unless specific measures have been taken to suppress it. Cortical bone has very low signal intensity on all standard imaging sequences. Cancellous bone is seen …
What is meant by the term intercalated segment? The intercalated segment is the proximal row of carpal bones. The name derives from the fact that there are no tendinous insertions on the proximal carpal bones and that they are inserted (“intercalated”) between the radius and the distal carpal row. The use of this term will …
What is ulnar variance? Ulnar variance describes the relationship between the lengths of the radius and ulna as seen at the wrist. Positive ulnar variance refers to the situation in which the ulna is longer than the radius and is associated with degenerative disease of the TFCC. Negative ulnar variance describes the situation in which …