An extensor digitorum brevis manus coexisting with the typical extensor indicis muscle: a rare dissection finding

Area of Science:

• Anatomy
• Morphology

Background:

• The forearm and hand extensor tendons possess complex anatomy with significant morphological variability.
• Understanding these structures is crucial for surgical procedures in the hand and wrist region.

Purpose of the Study:

• To document and describe a rare anatomical variation of the hand extensor musculature.
• To emphasize the clinical significance of recognizing such variations.

Main Methods:

• Routine dissection of a donated male cadaver.
• Isolation and detailed examination of the right hand extensor structures.

Main Results:

• Identification of an accessory muscle, the extensor digitorum brevis manus (EDBM).
• The EDBM was observed inserting into the extensor indicis (EI) tendon.
• This variant has a reported prevalence of 0.36-0.38% in cadaveric studies.

Conclusions:

• The presence of an EDBM inserting into the EI tendon is a rare anatomical variant.
• Awareness of this variation is essential for orthopedic and plastic surgeons to prevent iatrogenic injuries during hand surgery.