In general, a raphe (pronounced "RAY-fee") is a seam. It is most commonly used when describing diatoms, seeds, and human anatomy.

In the field of anatomy, the term refers to a continuous ridge of tissue. There are several different significant raphes:

• The perineal raphe extends from the anus, through the mid-line of the scrotum (scrotal raphe) and upwards through the posterior mid-line aspect of the penis (penile raphe). It is observed as a noticeable line. It is the result of a fetal developmental phenomenon whereby the scrotum (the developmental equivalent of the labia in females) and penis close toward the midline and fuse. The resulting ridge of tissue is evident as the perineal raphe.

• The buccal raphe which is on the cheek and evidence of the fusion of the maxillary and mandibular processes.

• The lingual raphe on the tongue. Obvious physical evidence of the lingual raphe includes the frenulum (also called the frenum), or band of mucous membrane that is visible under the tongue attaching it to the floor of the mouth. If this raphe is too tight at birth, movement of the tongue is restricted and the child is said to be "tongue tied".

• The palatine raphe on the roof of the mouth (or palate). Incomplete fusion of the palatine raphe results in a congenital defect known as cleft palate.

• The pharyngeal raphe is near the pharyngeal constrictors.

• The raphe nucleus is a moderate-size cluster of nuclei found in the brain stem which releases serotonin to the rest of the brain. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act at these nuclei.

• The anococcygeal raphe

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Anatomy