The Tricipital Aponeurosis — A Reliable Soft Tissue Landmark for Humeral Plating

Abstract

This study aims to identify the relationship of the radial nerve as it descends across the humerus with reference to a reliable soft tissue landmark, the tricipital aponeurosis. Following cadaveric dissection of 10 adult humerii, the radial nerve was located as it crossed the lateral midsagittal point of the humeral diaphysis. A horizontal line was then subtended medially from this point to another line subtended vertically from the lateral border of the tricipital aponeurosis. The vertical distance from this intersection to the lateral apex of the aponeurosis was recorded in three positions (full flexion, 90° of flexion and full extension). The location of the radial nerve on the posterior aspect of the humeral diaphysis to the medial apex of the tricipital aponeurosis was also noted. In 90° of flexion the radial nerve at the lateral midsagittal point of the humerus was 0.9 mm proximal to the lateral apex of the tricipital aponeurosis. Flexion and extension of the elbow changed the interval to 16.3 mm (nerve proximal) in full flexion and 7.1 mm in full extension (nerve distal). On the posterior aspect of the humerus the radial nerve was 21.8 mm proximal to the medial aspect of the tricipital aponeurosis. The aponeurosis provides a reference point from which the nerve can be easily located on the lateral aspect of the humerus intraoperatively in a range of positions, whilst the medial apex provides a guide to the location of the nerve on the posterior aspect of the arm.

The radial nerve at revision/redo surgery – using the lower lateral cutaneous nerve to prevent a postoperative radial nerve deficit

“…A summary of prior studies is given in Table I . 1 , 2 , 3 , 4 , 6 , 7 , 8 , 9 , 10 , 12 , 14 , 15 , 17 , 19 , 22 , 23 …”

“… 10 McCann PA, Smith GCS, Clark D et al. 14 2015 Cadaveric (10) Triceps aponeurosis Interval between the lateral border the triceps aponeurosis and nerve as it crossed the mid sagittal aspect of the humerus varied between 16.25 mm in full flexion and to 1 mm in 90° flexion and 6.6 mm in full extension 11 Park KJ, Romero BA, Ahmadi S 16 2019 Cadaveric(17) Deltoid tuberosity and brachioradialis The radial nerve was identified within the distal 2/3 of the distance between the deltoid tuberosity and the origin of brachioradialis. 12 Park J-K, Choi S-M, Kang S-W, Kim K-J, Min K-T 15 2020 Radiological CT–based reconstructed images (652) In vivo anatomic study using a 3D reconstruction technique and CT scan images.…”

Modified bilaterotricipital approach to the distal humerus: a triceps preserving technique

“…This is a useful landmark for the identification of the radial nerve because, in 90° of elbow flexion, the radial nerve can reliably be found 1 cm proximal to the lateral aspect of the tricipital aponeurosis. 6 If indicated, the radial nerve can be identified and protected, by blunt dissection of the muscle fibres.…”

The morphological and morphometric analysis of the variant patterns of the tricipital aponeurosis: a new anatomical classification with possible clinical implications

“…However, the anatomical variations in the shape and dimensions of the TA have not been described in detail despite these details are imperative for an orthopaedic surgeon to know [19]. Such variations are pivotal in its universal acceptance as a reliable surgical landmark.…”