The anatomic relationships of the axillary nerve and surgical landmarks for its localization from the anterior aspect of the shoulder

Abstract

The axillary nerve has long been known to be one of the nerves vulnerable to damage during shoulder arthroscopic and open surgical procedures. The relationship of the axillary nerve to the shoulder capsule and the subscapularis muscle has not been well defined in orthopedic literature. This descriptive anatomical study aimed to present the course and the relations of the axillary nerve with neighboring neurovascular structures and the shoulder capsule and to define anatomical landmarks and regions that can be used practically in anterior surgical approaches to the shoulder region. To investigate the course of the axillary nerve and its relationship with neighboring structures, 30 shoulders of 15 fixed adult cadavers were dissected under the microscope through an anterior approach. A triangle-shaped anatomic area containing the axillary neurovascular bundle was defined. The closest distance between the axillary nerve and the anteromedial aspect of the coracoid tip and the glenoid labrum was measured as 3.7 cm and 1.1 cm on average, respectively. The distance between the anteromedial aspect of the coracoid tip and the point where the nerve passes through the medial edge of the subscapularis was measured as 2.5 cm on average. The results of this study demonstrate the anatomic pattern and the course of the axillary nerve and its relations with the shoulder capsule. Knowing the exact localization of the axillary nerve under the guidance of the defined anatomic triangle may provide a safer surgery.

Anatomy of Axillary Nerve and Its Clinical Importance: A Cadaveric Study

“…The mean distance between the tip of anteromedial aspect of the coracoid process and the medial edge of the subscapularis muscle was measured to be 2.5 cm [12].…”

An Anterosuperior Deltoid Splitting Approach for Plate Fixation of Proximal Humeral Fractures

“…However, a disadvantage of this approach is that it is associated with high incidence of axillary nerve injury. [17][18][19] Axillary nerves are in fact one of the most commonly injured nerves during shoulder-related surgeries. 20) Gardner et al 13) reported that the axillary nerve is positioned on average 63.3 mm lateral to the acromion and 35.5 mm posterior to the greater tuberosity of the humerus.…”

Deltopectoral approach for shoulder arthroplasty: anatomic basis

“…In the superior part, the subacromial space is located by following the incision along the lateral edge of the conjoint tendon to the tip of the coracoid process and then continuing along or across the front edge of the coracoacromial ligament up to its acromial footprint. For the inferior part, it must be remembered that the lower dead end of the subdeltoid bursa is located above the axillary nerve around the humerus [11]. Thus, as long as we remain in the bursa, there is no risk for the nerve.…”

“…11 Location of suture under humeral osteotomy area with prosthesis in place in lesser tuberosity osteotomy (cadaveric right shoulder); 52×34 mm (300×300 DPI) Fig. 12 Final "corner buttress" in lesser tuberosity osteotomy (cadaveric right shoulder): a bony fragment, b subscapularis tendon, c bicipital groove (empty), d conjoint tendon; 52×34 mm (300×300 DPI) through the insertion of the latissimus dorsi as base, the conjoint tendon as lateral side and the pectoralis minor as medial side [11].…”

“…The inferior edge of the subscapularis is a high-risk area for the axillary nerve. The entry point of the nerve into the quadrilateral space of Velpeau was observed 1-2 cm below the inferior edge of the subscapularis [11] and up to 7 mm medially to the medial part of the humeral shaft [45]. To avoid axillary nerve injury, we recommend positioning the arm in external rotation and adduction and always staying close to the humerus, in particular for release of the capsule on the humeral side.…”