Accurate motion data on the scapula is difficult to obtain, due to the position of the bone and
the way the skin moves over the bone. Numerous studies have been conducted to collect accurate
data, but the most accurate is to place bone pins in a subject’s scapula and track the movement of
the pins. This is very invasive and painful for the subjects. Placing markers on the skin and
tracking the motion of the scapula is difficult, but methods for compensating with error are being
developed and refined. We seek to build on these existing methods for error compensation and
further refine them in an effort to collect accurate data of scapula motion from non-invasive skin
Gather positioning data on the scapula by Spring 2010 based on movement of the humerus through motion capture using multiple marker arrangements to compare to current scapula movement regressions.
We aim to track the motion of several points on the scapula given in figure 1.
The data that we aim to obtain through this project:
(a.) Data displaying positioning of points on scapula vs. humerus angle in several different motions
(b.) Methods for coping with experimental error from tissue interference in Motion Analysis
(c.) A physical model describing the motion of the scapula
Tracking the scapula can be very difficult due to tissue interference between the surface and the bone. Figure 2 shows the amount of movement of the spine of the scapula when lifting the arm in front of the body. One method as a solution for this interference is a grid method. We will try to locate the landmarks of the scapula based on the distortion of the grid. Figure 3 shows the basic concept of the grid method.