Extensor tendons of the fingers: arrangement and variations--II

Area of Science:

• Anatomy
• Morphology
• Surgical Anatomy

Background:

• The extensor tendons on the dorsum of the hand are crucial for finger extension.
• Understanding the anatomical variations of these tendons is important for surgical procedures and understanding congenital anomalies.

Purpose of the Study:

• To investigate the detailed anatomical patterns of the extensor tendons on the dorsum of the human hand.
• To document the frequency and nature of variations, including multiple tendons and intertendinous connections.

Main Methods:

• Dissection of 181 human hands.
• Macroscopic examination and documentation of the extensor digitorum, extensor indicis, and extensor digiti minimi tendons.
• Identification and recording of intertendinous connections and accessory muscles.

Main Results:

• Extensor digitorum commonly presented multiple tendons for the middle and ring fingers, with variable intertendinous connections, most frequent between the ring and middle fingers.
• The index finger consistently received a single extensor digitorum tendon.
• Extensor indicis typically had one tendon, located ulnarly to the extensor digitorum tendon. Extensor digiti minimi often had two tendons and was consistently linked to the extensor digitorum.
• Two accessory muscles, extensor indicis brevis and extensor medii brevis, were observed.

Conclusions:

• Significant variations exist in the extensor tendon anatomy of the hand, particularly concerning the extensor digitorum.
• These variations, including accessory muscles, are important considerations for hand surgeons and anatomists.
• The consistent ulnar positioning of extensor indicis and the linkage of extensor digiti minimi to extensor digitorum highlight key anatomical relationships.