The folds in both sexes are within the larynx. They are attached at the back of (side nearest the spinal cord) to the arytenoid cartilages, and at the foremost (side under the chin) to the thyroid cartilage. They have no outer crust as they blend into the sidewise of the breathing tube (the illustration is out go of date and does not show this well) while their inner edges or "margins" are free to vibrate (the hole). They have a three layer construction of an epithelium, articulated ligament, then muscle (vocalis muscle), which can shorten and bulge the folds. They are flat triangular bands and are pearly white in color. Above both sides of the vocal cord is the vestibular fold or false vocal cord, which has a microscopic sac between its two folds (not illustrated).
Vocal registration refers to the system of expressed registers within the human voice. A register in the human intonation is a particular progression of tones, produced in the same vibratory pattern of the vocalic folds, and possessing the same quality. They occur because the articulated folds are capable of producing several contrastive vibratory patterns. Each of these vibratory patterns appears within a particular range of pitches and produces assured characteristic sounds. The term register can be somewhat confusing at it encompasses infrequent aspects of the human voice. The expression register can be absorbed to refer to any of the following.