PERINEUM

GENERAL INFORMATION

The perineum is the area between the anus and the genitals, playing a critical role in supporting pelvic organs. It consists of skin, muscle and connective tissues and is part of the pelvic floor, which helps with bodily functions like urination, defecation and sexual health.

ORIGIN

The perineum includes several muscles that originate from the bones of the pelvis:

• Bulbospongiosus: Originates from the perineal body and covers the base of the penis in males and the vestibular bulbs in females.
• Ischiocavernosus: Originates from the ischial tuberosities and runs along the sides of the penis or clitoris.
• Superficial Transverse Perineal: Originates from the ischial tuberosities and stabilises the perineal body.

INSERTION POINT

The muscles of the perineum insert into various points within the pelvic region:

• Bulbospongiosus: Inserts into the perineal membrane and, in males, the base of the penis; in females, the clitoral body.
• Ischiocavernosus: Inserts into the corpus cavernosum of the penis or clitoris.
• Superficial Transverse Perineal: Inserts into the perineal body, stabilising this vital structure.

MAJOR ARTERIES

The perineum receives its blood supply from the following arteries:

• Internal pudendal artery: Supplies oxygenated blood to the perineal muscles, external genitalia and pelvic structures.
• Perineal artery: A branch of the internal pudendal artery that provides blood to the superficial perineal muscles and skin.

NEURAL INNERVATION

The following nerves innervate the perineum:

• Pudendal nerve: Responsible for sensory and motor innervation to the perineal muscles, contributing to control over urination, defecation and sexual functions.
• Perineal nerve: A branch of the pudendal nerve that innervates the skin and muscles of the perineum.

TRIGGER POINT

Trigger points can develop in the perineal muscles, leading to localised pain or discomfort. These trigger points often arise from muscle strain, overuse or trauma and can cause referred pain to surrounding areas.

CONCENTRIC FUNCTION

The concentric function of perineal muscles includes contraction during actions like:

• Bulbospongiosus: Assists in the expulsion of urine and semen in males and contributes to clitoral erection in females.
• Ischiocavernosus: Helps maintain an erection in both males and females by compressing the veins in the external genitalia.
• Superficial Transverse Perineal: Stabilises the perineal body, providing structural support during pelvic floor functions.

ECCENTRIC FUNCTION

Eccentric functions of the perineal muscles involve controlled relaxation during processes such as:

• Bulbospongiosus: Relaxation aids in emptying the bladder and proper blood flow regulation in the genital area.
• Ischiocavernosus: Slowly relaxes to allow blood to flow out of the genital area after sexual activity.
• Superficial Transverse Perineal: Relaxes pelvic floor muscles after contraction, maintaining pelvic stability.

ISOMETRIC FUNCTION

Isometric contraction of the perineal muscles provides support during static activities like:

• Bulbospongiosus: Contracts to maintain continence and support the pelvic organs.
• Ischiocavernosus: Holds tension to maintain erection, providing stability during sexual activity.
• Superficial Transverse Perineal: Provides stability to the perineal body and surrounding pelvic floor muscles.

RELATED MUSCLES SCIENTIFIC NAMES

• Bulbospongiosus: Involved in controlling urination and contributing to sexual function.
• Ischiocavernosus: Supports erectile function by compressing veins in the external genitalia.
• Superficial Transverse Perineal: Provides stability to the pelvic floor and perineal body.
• Levator Ani: Part of the pelvic diaphragm, supports the pelvic organs and assists in maintaining continence.
• Coccygeus: Supports the pelvic floor by aiding the levator ani in stabilising the pelvic organs.

ANTAGONIST

• Detrusor Muscle: Opposes the bulbospongiosus by relaxing during urination to allow the bladder to empty.
• Corpus Cavernosum: Opposes the ischiocavernosus by relaxing after sexual activity, allowing blood to flow out of the erectile tissue.
• Rectal Muscles: Oppose the superficial transverse perineal by controlling defecation and maintaining balance in pelvic floor function.

COMMON INJURIES

• Perineal Tears: Often occurring during childbirth, these involve damage to the perineal tissues, resulting in pain and potential complications for pelvic floor stability.
• Pudendal Neuralgia: Irritation or damage to the pudendal nerve, leading to chronic pain in the perineal region, often caused by trauma, cycling or prolonged sitting.
• Pelvic Floor Dysfunction: Weakness or tightness in the pelvic floor muscles can lead to issues such as urinary incontinence, pelvic organ prolapse or sexual dysfunction.
• Episiotomy Injury: Surgical incisions made in the perineum during childbirth may lead to scarring and long-term pelvic floor complications.
• Ischiocavernosus Strain: Overuse or injury to the muscle can cause discomfort and impact erectile function in both males and females.

EXERCISES

• Kegel Exercises: Targets the bulbospongiosus and other pelvic floor muscles, helping improve urinary continence and sexual function through repeated contraction and relaxation.
• Hip Bridges: Engages the perineal muscles by lifting the hips off the floor, strengthening the pelvic floor and improving core stability.
• Squats: Strengthens the lower body, including the perineal muscles, by engaging the pelvic floor and core during squatting.
• Planks: A core-strengthening exercise that also engages the perineal muscles to maintain pelvic stability during static holds.
• Lunges: Dynamic movement that targets the lower body and activates the pelvic floor, improving perineal muscle strength and balance.

STRETCHES

• Child’s Pose: Stretches the perineal muscles and lower back by sitting on the heels with arms extended forward, promoting relaxation in the pelvic floor.
• Seated Forward Bend: Stretches the pelvic floor and hamstrings by sitting with legs extended and reaching forward, releasing tension in the perineum.
• Happy Baby Pose: It opens the hips and stretches the perineal muscles by lying on the back and pulling the feet toward the chest.
• Pigeon Pose: Targets the perineum and hip muscles by extending one leg behind and bending the other in front, promoting flexibility in the pelvic region.
• Deep Squat: It involves lowering the body into a deep squat position, stretching the pelvic floor and perineal muscles and enhancing flexibility.