Anthropometric Cadaveric Analysis of the Quadrangular Space and Deltoid Region: Anatomical Perspectives for Clinical...

Neurovascular structures beneath the deltoid, particularly the axillary nerve and posterior circumflex humeral artery, are vulnerable to injury from intramuscular injections or compression in the quadrangular space, especially in overhead athletes. Studies by Kakati et al (2013) and Desai et al (2019) report intramuscular injection-related nerve injury rates of 1.5% to 15% and 82.5%, respectively. However, there is a lack of cadaveric studies in the Indian population, prompting this anthropometric study.

Aims and objectives: This study aims to assess the dimensions of the quadrangular space and examine the branching pattern of the axillary nerve and its relationship with the posterior circumflex humeral artery.

This two-year cross-sectional study, approved by the Institutional Ethical Committee (Protocol ID: F-IM/15/2023), was conducted at AIIMS Rajkot in collaboration with Orthopaedics. Anthropometric measurements of the quadrangular space (height, width, and depth), deltoid muscle, distances of the axillary nerve and posterior circumflex humeral artery from the origin point and AXN-PCHA relationship patterns were obtained from 12 (seven male and five female) cadavers using vernier callipers.

Among the 24 specimens, type 1 branching pattern was the most common, observed in 12 specim ens (50 %), followed by type 2 in six specimens (25%), type type-3 in five specimens (21%), and type 4 in one specimen (0.041%). The dimensions of quadrangular space varied, with height ranging from 4.28 mm to 5.57mm, width from 10.57 mm to 13.75 mm, and depth from 9.97 mm to 12.84 mm.

The mean dimensions (in mm) of the quadrangular space in males and females were 4.77 for height, 11.79 for width, and 11.01 for depth. The type-1 branching pattern was the most frequently observed.