(A) Kinetochore pairs in centre (centre) and periphery (right) from a metaphase plate (left) showing Gaussian-fitted spot centres, y-swivel, sister-sister axis and marker-marker axis. (B) 2D histogram of y-swivel vs. spindle position in y (n = 4291). White dashed lines divide spindle into the central and peripheral regions, separated at 4 µm. White curve is best-fit degree-3 polynomial, with coefficient of determination, R2 = 0.97. (C) Pairs of sister kinetochores expressing eGFP-CENP-A, Ndc80-tagRFP and stained with αTubulin antibodies. (D) Best-fit sheet through y-swivel against spindle position in y (degree-3 polynomial) and metaphase plate thickness (degree-1 polynomial; n = 3987), with coefficient of determination, R2 = 0.95. (E) Absolute y-swivel (blue, left axis), and Δ 1D and Δ 3D (gold, right axis), for central and peripheral kinetochores for early (> 0.65) and late (< 0.45) metaphase (E, L, respectively) as determined by plate thickness. Statistical tests were significant (p < 10–4) except where n.s. (no significance) is stated. Values are given in Figure 4—source data 1. (F) Examples of kinetochore pairs at spindle periphery during early (left) and late (right) metaphase. (G) (i) Schematic of dependency of swivel on spatial position, attachment status, and progression through metaphase towards anaphase onset. Light blue box indicates thickness of the metaphase plate. (ii) Mechanical degrees of freedom in kinetochore include changes in intra-kinetochore distance (delta; ∆ – black arrow) and swivelling ( – blue arrows), which may involve remodelling of the kinetochore domains and/or tilting of the entire kinetochore structure within the chromosome. All scale bars 500 nm.