Quantified relationships of the radial nerve with the radial groove and selected humeral landmarks

Abstract

Anatomical relationships between the radial nerve, the deltoid muscle insertions and several bony landmarks have been investigated to assess the feasibility of surgical transfer of the deltoid transfer during humeral osteotomy. Eleven embalmed human specimens were dissected. Each specimen included the whole thorax, both shoulders and upper limbs. Spatial position of the radial nerve along the radial groove, the deltoid muscle, and several anatomical landmarks was digitised using a threedimensional (3D) digitiser. Sixteen distances and one angle characterizing the relationships between the path of the radial nerve and the landmarks were processed. Results showed that the average distance between the emergence of the radial nerve from the lateral intermuscular septum and the most distal insertion point of the deltoid muscle on the humeral bone shaft was 47.6 § 18.5 mm. The angle between a line extending from the entry of the radial nerve into the radial sulcus and its point of emergence (REN-REM line), and on the other hand a line running from the radial emergence and the deltoid muscle tip (REM-DEL-TIP line) was in average 23.5 § 6.7°. The length of four lines running perpendicular to REM-DELTIP and crossing each quarter of the REN-REM line were interpolated. The length of these four lines was, from proximal to distal, 31.3 § 11.5 mm; 23.0 § 7.8 mm; 16.5 § 6.2 mm; and 7.6 § 2.6 mm, respectively. These results described in a quantitative way the path of the radial nerve in respect to the humeral bone and the deltoid muscle. These data will be used for further development of a humeral osteotomy protocol taking into account the spatial position of the radial nerve to orientate safely the surgical tools used to cut the humeral shaft.

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

“…So, identification and localisation of the RN is a prerequisite for surgical repair of the fractured humerus. Various authors have studied the location of RN in relation to the bony landmarks (lateral epicondyle, tip of acromion, tip of olecranon, and radial groove) [6,9,13,14,25,28]. Most of these studies did not have any correlative value, with wide inter-observer variability, and are difficult for surgeons to access intraoperatively [2,15].…”

Localisation of the radial nerve at the spiral groove: A new technique

“…In these studies, the distance from the lateral epicondyle to the entrance of the RN into the spiral groove was reported to be 6–16 cm. Introducing these findings into the operating theatre least likely delineates recommendations for optimal surgical exposures [1], [9], [10], [11], [12], [13], [14]. All these cadaver studies used similar methods for predicting the location of the nerve, but all with confusing landmarks such as entrance or emergence of the nerve into or from the spiral groove and osseous areas which were described as anatomical landmark definitions.…”

“…All these cadaver studies used similar methods for predicting the location of the nerve, but all with confusing landmarks such as entrance or emergence of the nerve into or from the spiral groove and osseous areas which were described as anatomical landmark definitions. As Van Sint Jan et al stated that these relatively broad bony areas may lead to imperfect localisation of the nerve, strict definitions for these landmarks should be proposed [13]. Apart from these cadaver studies, Arora and Goyal published an excellent study in which the distance of the RN was measured along the shaft of the humerus beneath the two heads of triceps muscle in trauma patients during surgical exposure [7].…”

“…Until now, numerous studies have been published to predict the location of the RN in the spiral groove. These studies have used anatomic landmarks such as lateral and medial epicondyles, angle of acromion or bifurcation of triceps aponeurosis [2], [7], [8], [9], [10], [11], [12], [13]. All the previous methods have some degree of success in predicting the location of the nerve but have certain problems such as proposing wide range of measurements in generalised population and broad definition of landmarks.…”

Relation of radial nerve to superficial bony and soft tissue landmarks- a cadaveric study

“…1,2 Numerous bony landmarks like lateral and medial epicondyle, olecreanon process were taken as landmark to foresee the location of the RN in spiral groove. 1,[7][8][9][10][11][12][13] Conversely, the bony elements have lost their accurate positioning as in commuted fractures, humeral malunion /non-union, other landmarks need to be taken into attention to avoid iatrogenic injury to the nerve. 7,8 So soft tissue landmarks like the triceps aponeurosis was used to identify the RN in various cadaveric study.…”