Table 2.

Eigenvectors are here reported from the first principal component of the single subject repeated swallows and the between subject swallows. Eigenvectors indicate the direction of variance in the covariance matrix for each landmark with a common origin of (0,0) set for each eigenvector. A magnitude for each vector was calculated using Pythagoras’ theorem. The magnitude should not be construed as relative distance of shape change, rather a reflection of the distribution of covariance in shape change. Greater magnitude reflects a tighter distribution of covariance meaning that shape changes were less random.

Anatomical Landmark	Eigenvectors of single subject repeated swallows			Eigenvectors of between subject hyolaryngeal excursion
	x- component	y- component	Magnitude of resulting vector	x- component	y- component	Magnitude of resulting vector
1-mandible	−0.09	−0.34	0.35	−0.17	−0.24	0.29
2 -hard palate	−0.09	−0.04	0.10	−0.05	−0.15	0.16
3-atlas	0.15	−0.03	0.15	0.13	−0.20	0.24
4-C2	0.30	−0.15	0.33	0.31	−0.21	0.37
5-C4	0.48	−0.23	0.53	0.37	−0.17	0.41
6-hypopharynx/UES	−0.09	0.36	0.37	0.07	0.34	0.35
7-posterior larynx	−0.05	0.25	0.26	−0.09	0.34	0.35
8-anterior larynx	−0.18	0.17	0.25	−0.15	0.30	0.34
9-hyoid	−0.43	0.01	0.43	−0.41	0.00	0.41