Extensor Carpi Ulnaris Tendon Anatomy May Mimic Tears.

Area of Science:

• Anatomy
• Orthopedics
• Radiology

Background:

• Incidental extensor carpi ulnaris (ECU) tendon abnormalities are common on wrist imaging.
• Previous studies noted these findings but lacked anatomical correlation.

Purpose of the Study:

• To investigate gross anatomical variations of the extensor carpi ulnaris tendon.
• To determine if anatomical variations could explain incidental findings on MRI and ultrasound (US).

Main Methods:

• Dissection of 17 formalin-preserved upper extremity cadavers.
• Examination of the extensor carpi ulnaris tendon for anatomical variations, including intra-tendinous splits.
• Measurement of split length and distance to insertion and extensor retinaculum.

Main Results:

• 64% of specimens (11 of 17) exhibited at least one longitudinal split in the distal ECU tendon.
• The mean split length was 3.52 cm, and the mean distance from the distal edge to insertion was 2.4 cm.
• No correlation was found between age and the number of tendon splits.

Conclusions:

• Longitudinal splits in the distal extensor carpi ulnaris tendon are highly prevalent.
• The common anatomical occurrence of these splits correlates with observed abnormalities on MRI and US imaging.