Feline Penile Spines Study Guide

Overview and Clinical Importance

Penile spines are testosterone-dependent keratinized papillae unique to the feline penis that play a critical role in feline reproduction. Understanding penile spines is essential for NAVLE success because they represent a key intersection of reproductive anatomy, endocrinology, and clinical diagnostics. The presence or absence of penile spines is a valuable clinical tool for differentiating castrated males from cryptorchid toms, making this topic highly testable on veterinary board examinations.

The domestic cat (Felis catus) is classified as an induced ovulator, meaning that ovulation does not occur spontaneously but requires vaginal stimulation during mating. The penile spines are the anatomical structure responsible for providing this critical stimulus, triggering the neuroendocrine cascade that leads to ovulation in the queen.

Anatomy of Feline Penile Spines

Gross Anatomy

The tomcat penis is directed caudally from the perineum, unlike the canine penis which is carried between the upper thighs. The penis is located ventral to the testicles and points caudally unless erect. When non-erect, the feline penis is sheathed by the prepuce. During erection, the conical-shaped penis comes into view and points cranially.