Surgical Anatomy Of Extend Anterolateral Acromial Approach For Surgery Of Proximal Humeral Fractures

Background: There are many surgical approaches for the shoulder joint. Two of which are widely used for proximal humeral fractures in clinic : the deltopectoral approach and the anterolateral acromia approach. Yet each of the existing surgical approach has advantages and disadvantages,furthermore, the development of new surgical technique challenges the traditional approaches .Objective: To observe the courses of the axillary nerve and relative structures of humerus and deltoid from lateral arm, and provide the anatomical information of a new surgical opproach for proximal humerous fracture.Methods: Twelve adult cadaveric upper limbs (male 7, female 5) were dissected to define the course of the anterior branch of axillary nerve in the anterior and middle compartments of deltoid muscle, measure the relative distance of them, compare the characteristics of the axillary nerve as it crosses the raphe between the middle and anterior heads of the deltoid.Simulation of surgical operation was implemented on a corpse after the initial data collection had been conducted.Result: The anterior branch of axillary nerve passed through the upper 1/3 of the deltoid muscle,the crossing of the anterior branch of axillary nerve and the line from the lateral tip of acromion to deltoidtuberosity was (6.0±1.3)cm below the level of acromon. A single motor branch was found to distribute the anterior head of the deltoid. An avascular raphe was located between the anterior and middle heads of the deltoid. The raphe could be identified as a white band of connective tissue between the two muscular heads. No branches to the anterior head of the deltoid cross the raphe was found. The cross stitch length in this group were greater than 1cm, the tension of the axillary nerve was low after the plate implanted.Conclusion: Through the raphe between the two muscular heads of deltoid, a surgical approach could be created for the exposure of proximal humerus,with easily extending distally after protecting the main motor branch of the axillary. This surgical approach is safe for fracture reduction directly, with subsequent plate fixation.