The Berrettini Anastomosis' Morphology and "Probable Zone": A Cadaveric Study

Area of Science:

• Anatomy
• Neuroscience
• Surgical Anatomy

Background:

• Neural connections between the median nerve (MN) and ulnar nerve (UN), such as the Berrettini anastomosis (BA), impact hand sensory innervation.
• While often asymptomatic, anatomical variations in the BA can pose clinical challenges, especially during surgical interventions.
• Understanding the prevalence and variations of the BA is essential for preventing iatrogenic nerve injury.

Purpose of the Study:

• To investigate the prevalence and anatomical variations of the Berrettini anastomosis (BA) in cadaveric hands.
• To determine the probable anatomical location of the BA for surgical reference.
• To classify the different types of BA branching patterns.

Main Methods:

• Dissection of 104 fresh Caucasian cadaveric hands (52 male, 26 female).
• Focus on the origin, insertion, and branching patterns of the BA.
• Measurement of the BA's 'probable zone' using standardized reference points and categorization of variations into five types.

Main Results:

• The Berrettini anastomosis (BA) was identified in 80% of the dissected hands.
• The most common type (38%) was Type I, a single connection from the UN to the MN; other variations included bifurcating, dual origin, reverse, and complex fibrous patterns.
• The average BA length was 22.03 mm, with its 'probable zone' located between 26.11-44.21% of hand width and 36.63-50.21% of hand length.

Conclusions:

• The Berrettini anastomosis (BA) is a common neural structure with considerable anatomical variability.
• Identification of the BA's 'probable zone' offers critical guidance for surgeons, aiding in the prevention of sensory deficits.
• Further research is recommended to build upon these anatomical findings and their clinical implications.