The study examined the role of the syllable and of jaw movement in determining syllable-related consonant duration patterns. Finnish speakers were asked to produce intervocalic obstruent-sonorant and sonorant-obstruent sequences, and the duration patterns of these sequences were measured. The results indicated that Finnish speakers produce the obstruent-sonorant sequences with a long-short duration pattern that is typical of onset clusters. Since Finnish phonology does not allow onset cluster, the results were taken to show that the duration patterns are not tied to the syllable in production, but originate from more basic articulatory processes. The study explored one such process, namely, a coarticulatory origin for the pattern, conditioned by a biomechanical constraint of jaw movement on segment articulations. The same Finnish speakers produced the sequences with a fixed-jaw. In spite of the articulatory disruption to the system, the same consonant duration patterns were preserved. Future work will test alternative articulatory explanations for the origin of the syllable-related consonant duration patterns.