The articular surfaces of the proximal segment of ulna: Morphometry and morphomechanics based on digital image analysis and concepts of fractal geometry

Introduction

The elbow joint is a compound joint made of articulations in between the humerus, ulna and the radius. The coupling areas (joints) are of prime importance from the kinetic-biomechanical perspective and of potential inter-ethnic significance. These articulations can be affected by several pathologies that may require medical and surgical interference. This experimental analysis aims to infer data in relation to the morphometry of the proximal segment of the ulna and its articular surfaces represented by the greater sigmoid notch (trochlear notch) and lesser sigmoid notch (radial notch).

Methods

A sample of fifty ulnae (n = 50, 27 right and 23 left) was studied in connection with; the surface area of the sigmoid notches (SA), weight of ulna, and the volume of proximal portion of ulna (including the olecranon process and reaching inferiorly to the lowest margin of the radial notch), the length of ulna (L). Longitudinal dimensional parameters were also studied including; the straight distance between the highest point (tip) of the olecranon and that of the coronoid process (OCD), and the mid-olecranon thickness in mediolateral (T1) and anteroposterior orientation (T2).

Results

It has been inferred that there were no significant differences in between right versus left ulnae and in relation to the majority of morphometric parameters with an exception for OCD (22.47 vs 20.75, p-value = 0.002). There was a positive correlation in between all the parameters, although the strongest associations were observed in between OCD, the area of the trochlear notch, and the weight of ulna.

Discussion

A precise conclusion was reached in relation to morphometry, volumetry and the pertinent biomechanics of the proximal segment of the ulna. Key findings are of value to biomedical engineers, medical professionals including orthopaedic surgeons and rheumatologists, evolutionary biologist, and physical anthropologist. Data from this study can be used to (reverse) engineer the perfect implant for the elbow joint.