Pronunciation: [hˌɪzɪz ˈɪsθməs] (IPA)
The correct spelling of the word "His's isthmus" is "His isthmus". The IPA phonetic transcription for the word is /hɪs ˈɪsθməs/, which consists of two syllables. The first syllable is pronounced using the short "i" sound, followed by the voiceless "h" sound. The second syllable begins with the voiced "i" sound, followed by the voiceless "s" sound and the voiceless "th" sound. The word refers to a narrow strip of land that connects two larger land masses.
I. rhombencephali.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.