Surgical anatomy of the axillary nerve and its implication in the transdeltoid approaches to the shoulder

Stecco, Carla; Gagliano, Giorgio; Lancerotto, Luca; Tiengo, Cesare; Macchi, Veronica; Porzionato, Andrea; De Caro, Raffaele; Aldegheri, Roberto

doi:10.1016/j.jse.2010.05.010

« Previous Next »Journal of Shoulder and Elbow Surgery
Volume 19, Issue 8 , Pages 1166-1174, December 2010

Surgical anatomy of the axillary nerve and its implication in the transdeltoid approaches to the shoulder

Carla Stecco, MD
- Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
- Reprint requests: Carla Stecco, MD, Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Via Gabelli 65, 35127 Padova, Italy.
Giorgio Gagliano, MD
- Clinic of Orthopaedic Surgery, Department of Medical Surgical Specialities, University of Padova, Padova, Italy
Luca Lancerotto, MD
- Clinic of Reconstructive and Plastic Surgery, Department of Medical Surgical Specialities, University of Padova, Padova, Italy
Cesare Tiengo, MD
- Clinic of Reconstructive and Plastic Surgery, Department of Medical Surgical Specialities, University of Padova, Padova, Italy
Veronica Macchi, MD
- Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
Andrea Porzionato, MD
- Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
Raffaele De Caro, MD
- Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
Roberto Aldegheri, MD
- Clinic of Orthopaedic Surgery, Department of Medical Surgical Specialities, University of Padova, Padova, Italy

published online 27 August 2010.

Background

Traumatic and iatrogenic injuries of the axillary nerve (AN) are frequent in clinical practice; nevertheless, its anatomy and its relationships with the transdeltoid approaches to the shoulder are not well documented.

Materials and methods

Anatomic study was performed on 16 shoulders of unembalmed cadavers. A proximal humeral internal locking system (PHILOS) plate was placed to simulate the osteosynthesis of a fracture of humeral surgical neck. The relationships between the plate and the nerve were evaluated. Selective dissection of all the nerve branches inside the deltoid muscle was performed.

Results

The mean distance between the point where the AN entered into the deltoid muscle and the humeral head was 5.0 cm, and it was 6.8 cm from the acromion. The mean distance between the origins of the anterior and posterior branches of the axillary nerve was 5.4 cm. The mean diameter of the AN was 0.57 cm, the anterior branch diameter was 0.40 cm, of posterior branch diameter was 0.33 cm, and the teres minor branch diameter was 0.24 cm. The application of the PHILOS plate demonstrated that in 100% of cases, the 2 distal holes of the plate of those dedicated to the humeral head coincided with the passage of AN.

Discussion

The different patterns of nerve branches inside the deltoid muscle show that the “safe zone” during transdeltoid approaches is the anterior region of the deltoid muscle for a maximum of 6.7 cm from the acromion. In addition, the insertion of the 2 distal screws of those dedicated to humeral head of the plate should be avoided.

Level of evidence: Basic Science Anatomy Study

Keywords: Axillary nerve, shoulder, deltoid, minimally invasive approach, plate osteosynthesis, orthopaedic surgery, nerve lesion