Thoracic kyphosis and lumbar lordosis occur with accompanying stretch weakness to the back extensors and shortening to the rectus abdominals. Generally patients forward flex at the level of the trunk where the ribcage ends. Because muscles stabilizing the ribs are also flaccid there is a lack of ribcage stability. This occurs primarily as a result of gravitational forces. Because of the trunk position described above, this position of downward rotation and elevation is encouraged.
Gravity pulls the scapula into downward rotation.
The client's posture of forward trunk flexion reinforces scapular downward rotation and promotes elevation of the scapula on the thorax. Sternocleidomastoid becomes tightened leading to altered line of pull of the AC and SC joints. Orientation of the Glenoid Fossa changes so that instead of facing upward, forward and outward it orients downward. This compromises the structural stability of the gleno-humeral joint. Tipping and winging of the scapula results.