sulcation

plural sulcations

1. countableuncountableA channel or furrow.
2. countableuncountableMarkings resembling channels or furrows, especially in shells, fossils, etc.

   [T]he presence of sulcation in the brow horns of all the Arrhinoceratops specimens known at the present time suggests a certain constancy in this genus.

   1946, Charles W. Gilmore, "Reptilian Fauna of the North Horn Formation of Central Utah", Professional Paper 210-C, U.S. Dept. of the Interior, p. 45 (Google preview)

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   The ornamentation of the shell is a character of considerable palaeontological importance. . . . The types of ornamentation are two; longitudinal striation, and transverse sulcation conformable to the shape of the aperture.

   1865, Thomas Oldham (ed.), Memoirs of the Geological Survey of India, Volume 1, page 8 (Google preview)

3. countableuncountablemedicineThe development of or resulting formations of sulci in a brain cortex.

   Gyration and sulcation occur during neuronal migration and continue until after birth.

   2014, Dario Paladini, Paolo Volpe, Ultrasound of Congenital Fetal Anomalies: Differential Diagnosis and Prognostic Indicators, page 66

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   Lissencephaly refers to a diffusely smooth-surfaced cerebral hemisphere without sulcation.

   2004, Devin K. Binder, Helen E. Scharfman, Recent Advances in Epilepsy Research, page 146

   Since the appearance and development of sulci in the fetal brain follows a predictable pattern, the degree of sulcation may be used as an indicator of gestational age-related cortical development, both at autopsy and in vivo with fetal MRI.

   2011, Denise Pugash et al., “Fetal MRI of Normal Brain Development”, in Fetal MRI, →ISBN, page 155