sulcation

sulcation (countable and uncountable, plural sulcations)

1. A channel or furrow.
2. Markings resembling channels or furrows, especially in shells, fossils, etc.
   • 1865, Thomas Oldham (ed.), Memoirs of the Geological Survey of India, Volume 1, page 8 (Google preview):

     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.

   • 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):

     [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.

3. (neuroscience) The development of or resulting formations of sulci in a brain cortex.
   • 2004, Devin K. Binder, Helen E. Scharfman, Recent Advances in Epilepsy Research, page 146:

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

   • 2011, Denise Pugash et al., "Fetal MRI of Normal Brain Development" in Fetal MRI, →ISBN, p. 155 (Google preview):

     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.

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

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

• sulcate

• suctional, unstoical