The dorsal penile nerve (DPN) is a specialized sensory nerve that transmits feeling from the external male genitalia. It functions as the main pathway carrying information about touch, pressure, and temperature from the skin and underlying tissues to the central nervous system. The DPN is fundamental to general tactile sensation and the mechanics of the male sexual response. Understanding its structure and function explains the sensitivity of the external genitalia.
Anatomical Path and Origin
The dorsal penile nerve is an extension of the pudendal nerve, originating from the sacral nerve segments S2, S3, and S4. It represents the deepest and final branch of the pudendal nerve after passing through the pelvic region. The nerve travels forward, following the ischiopubic ramus and entering the deep perineal space.
The nerve continues its course by joining the deep dorsal vein of the penis and the dorsal artery. It runs along the dorsal surface of the penis, situated beneath Buck’s fascia, placing it relatively close to the surface of the penile shaft.
As the DPN progresses toward the tip, it divides into numerous smaller nerve bundles. These terminal branches supply sensory innervation to the skin of the penile shaft and the corpus cavernosum (erectile tissues). The nerve bundles ultimately terminate in a concentrated network of sensory endings in the glans, or head of the penis.
Role in Sensation and Sexual Response
The primary function of the DPN is to act as the sensory conduit for the penis, relaying information crucial for sexual function. It is the major source of afferent input, carrying signals to the spinal cord and brain. These signals include light touch, vibration, and pressure, which are processed as erotic sensation.
Specialized nerve endings, such as Pacinian corpuscles, are abundant along the DPN’s path and effectively detect vibratory stimulation. This tactile information is a necessary trigger for the complex spinal reflex that initiates and helps maintain a penile erection. The sensory input travels to the sacral spinal cord, where it interacts with other nerves to coordinate the vascular changes needed for engorgement.
The glans penis is the most sensitive region of the external genitalia due to the dense concentration of DPN terminal branches. This rich innervation pattern reinforces the glans’ role as the primary source of tactile sensation, which is fundamental to sexual arousal and response.
Clinical Relevance and Nerve Blocks
The anatomical path of the dorsal penile nerve makes it a frequent target for medical procedures requiring local anesthesia. A dorsal penile nerve block involves injecting a local anesthetic solution near the nerve at the base of the penis. This procedure temporarily numbs the nerve, allowing minor surgical interventions without general anesthesia.
The block is commonly used for procedures such as circumcision, repair of lacerations, and the treatment of conditions like paraphimosis. This method provides rapid pain relief and effectively desensitizes the shaft and glans. Potential complications of the nerve block can include minor issues like bruising at the injection site or, rarely, glans ischemia if certain types of anesthetic agents are used.
Beyond planned medical procedures, the DPN is clinically relevant in cases of nerve damage, or neuropathy. Injury to the nerve, often resulting from trauma or complications from pelvic surgery, can lead to chronic pain (neuralgia) or a loss of sensation. Surgical decompression of the nerve, a procedure called neurolysis, may be considered in some patients to relieve chronic pain and potentially restore feeling.