The Effect of Posture on the Neck and Shoulder Suspension Apparatus of Humans: A 3D Biomechanical Analysis

Abstract

Clinical issues arising from bad posture and misalignment of the neck can significantly affect the quality of life of individuals. An understanding of the physical configuration and biomechanics of the neck and its associated parts in various postures is fundamental for successful treatments. We have re‐conceptualized the human head, neck and shoulder complex as a shoulder suspension apparatus, and we hypothesize that habitual bad postures lead to changes in the balance of forces acting on this apparatus. We tested our hypothesis by comparing the forces acting on the shoulder suspension apparatus of persons with different postures as ascertained from clinical x‐ray images. We applied the free‐body diagram force analysis to 3D models of the shoulder suspension apparatus in good and poor postures, which were reconstructed from data of x‐ray CT scans of a patient. Our biomechanical model suggests that in a good posture the head and neck are stabilized by the core muscles, the nuchal ligament is relaxed, and the shoulders are suspended from the head by fascia and the connective tissue of the clavotrapezius and cleidomastoid muscles. In poor postures, various muscles must be recruited to re‐balance the shoulder suspension apparatus, which, in turn, may cause tightened muscles, myo‐fascial pain, poor circulation to the head, head‐aches, and inflammation of the joints.Grant Funding Source: LSU Foundation to DGH