An anatomical study of scalenus minimus muscle at the neural surface: its clinical significance

Objective To investigate the morphological characteristic of the neural surface of scalenus minimus muscle and its clinical significance. Methods Embalmed adult cadavers ( 64 sides ) were dissected,and the anatomy of scalenus minimus muscle, especially at the neural surface was observed. Results Scalenus minimus muscle was found in 84.4% of cadavers. They could be divided into 6 types at the interface between scalenus minimus muscle and lower trunk of brachial plexus: typeⅠ,tendon tissue at all surface ( 37% , most common type); type Ⅱ, tendon at the central part and muscle at the peripheral part; type Ⅲ, tendon at the lower half and muscle at the upper half; type Ⅳ, tendon at the medial half and muscle at the lateral half; type Ⅴ, tendon at the lateral surface and muscle at the medial surface; type Ⅵ, muscle at all surface. Conclusions The complete or partial fibrous tissue at the neural surface of scalenus minimus muscle is one of responsibility for compression of brachial plexus. The tendon of variable structure at the neural surface is easy to be mistaken as abnormal band during surgery.