UPPER LIMB ALIGNMENT

HEAD AND NECK

The ideal alignment of the head and neck is one in which the head is in a well-balanced position that is maintained with minimal muscular effort. In lateral view, the reference line coincides with the earlobe and the neck presents the normal anterior curve. In the posterior view, the reference line coincides with the midline of the head and with the cervical spinous processes. The head is not tilted up or down and is not tilted to the sides or rotated. The chin is not retracted. Good upper back alignment is essential for good head and neck alignment; misalignment of the upper back negatively affects the alignment of the head and neck. If the upper back bends into a rounded position when sitting or standing, there will be a compensatory change in the position of the head and neck. If the head position remained fixed with the neck held in its normal front bend while the upper back flexes into a rounded upper back position, the head would be tilted forward and down. However, "the eyes seek eye level" and the head must be raised from that position by extending the cervical spine. In the normal extension of the cervical spine there is an approximation of the occiput and the seventh cervical vertebra. When the head is raised to seek eye level, the distance between the occiput and cervical seventh is greatly reduced. With respect to the distance between the two points in the ideal alignment, there can be up to 2 or 3 inches of difference between the two locations. The forward head position is one in which the neck extensors are in a shortened and strong position, and there is the potential for adaptive shortening in these muscles to develop. The anterior flexors of the vertebral neck are in a stretched position and show evidence of weakness when their strength is tested.

UPPER BACK

In ideal alignment, the thoracic spine curves slightly posteriorly. As well as the positions of the head and the neck are affected by the position of the thoracic spine, so the thoracic spine is affected by the positions lower back and pelvis. With the pelvis and lumbar spine in ideal alignment, the thoracic spine can take over the ideal location. If a normally flexible individual assumes a lumbar lordosis position (i.e. greater front curve), the upper back tends to straighten, decreasing the normal back curve. On the other hand, habitual positions and repetitive activities can lead to the development of a lordotic-kyphotic posture, in which one tends to compensate for the other. In a lean back position, the higher back curvature position of the upper back compensates for the forward deflection of the pelvis.

SHOULDER

In ideal shoulder alignment, the lateral view reference line passes through the center of the joint. In any case, the the position of the arm and shoulder depends on the positions of the shoulder blades and upper back. In good alignment, the shoulder blades are flat against the upper back, approximately between the second and seventh thoracic vertebrae, and about 4 inches apart (more or less depending on the size of the individual). Bad locations shoulder blades adversely affect shoulder position and misalignment of the glenohumeral joint can predispose to injury and chronic pain. On the opposite page a drawing of the standard posture appears. Legends indicate skeletal structures that coincide with the reference line. For comparison, next to the drawing is a photograph showing a subject whose alignment is very close to standard posture. In a side view drawing of the standard pose, the artist attempted to present a composition of the male and female pelvis and shows an average in terms of the shape and length of the sacrum and coccyx.

Post a Comment

0 Comments