The Ins and Outs of Penis Anatomy: A Comprehensive Guide

By Dr. Zarina Vitebsky, DPT, MSPT, PRPC, TPS, LPF, DN on 10/10/2023

Clip Art of a Pelvic Floor Physical Therapy Patient's Anatomy


The penis is a male reproductive organ that plays a crucial role in sexual activity and the reproductive process. It is a complex and fascinating organ that has been the subject of much curiosity and discussion throughout history.

Definition and Function

The penis is a cylindrical organ located between the scrotum and the anus. It is made up of three main parts: the root, the shaft, and the glans. The main function of the penis is to transfer sperm from the male body into the female reproductive system during sexual intercourse.

  1. Reproductive organ: The penis is responsible for delivering sperm into the female reproductive tract, where it can fertilize an egg and lead to pregnancy.

  2. Role in sexual activity: The penis also plays a vital role in sexual activity, as it is the primary source of pleasure and stimulation for both partners during intercourse.

Anatomy of the Penis

The penis is the male reproductive organ responsible for urination and sexual function. It is a complex structure with both external and internal components.

External Structures

  1. Penile Shaft: The penile shaft is the main body of the penis, consisting of three cylindrical-shaped layers of tissue. These layers include the outer layer of skin, a middle layer of smooth muscle, and an inner layer of connective tissue and blood vessels.

  2. Glans Penis: The glans penis is the rounded tip of the penis, also known as the head. It is highly sensitive and contains numerous nerve endings, making it a key erogenous zone during sexual stimulation.

  3. Foreskin/Prepuce: The foreskin, also called the prepuce, is a retractable fold of skin that covers the glans penis. It is often removed during circumcision, but for uncircumcised men, it serves as protection for the sensitive glans and can enhance sexual pleasure.

  4. Urethral Opening: The urethral opening is the opening at the tip of the penis that allows urine and semen to pass through. It is also the site of the external opening of the male reproductive system.

Internal Structures

  1. Corpus Cavernosum: The corpus cavernosum is the spongy tissue that fills with blood during an erection, causing the penis to become firm and erect. It is made up of two chambers that run along the top of the penis and are responsible for most of the penile rigidity.

  2. Corpus Spongiosum: The corpus spongiosum is a smaller chamber of spongy tissue that runs along the bottom of the penis. It contains the urethra and helps to maintain the shape and rigidity of the penis during an erection.

Nerve and Blood Supply

  1. Nerves: The penis is richly supplied with nerves, making it a highly sensitive organ. The main nerves responsible for sexual sensation and function are the dorsal nerve, which runs along the top of the penis, and the pudendal nerve, which runs along the bottom.

  2. Arteries and Veins: The penis also has a complex network of blood vessels that are responsible for supplying blood to the penis during an erection. The main arteries are the cavernous arteries, which branch off from the internal iliac artery, and the main veins are the deep dorsal vein and the superficial dorsal vein.

The anatomy of the penis is essential to understand for both sexual and reproductive health. Any abnormalities or issues with the structures and functions of the penis should be discussed with a healthcare provider for proper diagnosis and treatment.

Development of the Penis

The penis is a male reproductive organ that plays a significant role in sexual function and urination. It is a complex structure that undergoes various changes throughout a man's life, from prenatal development to aging. In this section, we will explore the different stages of development of the penis and the factors that influence its growth and function.

Prenatal Development

The development of the penis begins in the fetus stage, around the eighth week of pregnancy. At this stage, the genital tubercle, which is a small bud-like structure, starts to form. The genital tubercle contains cells that will eventually differentiate into either a penis or a clitoris, depending on the presence or absence of the Y chromosome.

The Y chromosome contains a gene called the SRY gene, which triggers the development of the male reproductive system. In the absence of this gene, the genital tubercle will continue to develop into a clitoris. However, when the SRY gene is present, it signals the release of testosterone, a male sex hormone, which promotes the growth and development of the penis.


During puberty, which typically occurs between the ages of 9 and 14, the penis undergoes significant changes in size and function. The testicles start to produce higher levels of testosterone, which leads to an increase in penis size and the development of secondary sexual characteristics such as facial and body hair.

The growth and enlargement of the penis during puberty are influenced by genetics, nutrition, and physical activity. Studies have shown that boys who are overweight or obese may experience delayed puberty, which can affect the growth and development of their penis. On the other hand, regular physical activity and a balanced diet can promote healthy growth and development of the penis.

Testosterone, the male sex hormone, also plays a crucial role in the development of the penis during puberty. It helps to increase the size of the penis, promote the growth of pubic hair, and stimulate the production of sperm.


As men age, their penis also undergoes changes in size and function. The most noticeable change is a decrease in penis size, which is a result of decreased blood flow to the penis and a decrease in testosterone levels. These changes are a natural part of the aging process and are often accompanied by other symptoms such as erectile dysfunction and decreased libido.

Common issues with aging that can affect the penis include erectile dysfunction, which is the inability to achieve or maintain an erection, and Peyronie's disease, which is the development of scar tissue in the penis, causing it to curve during an erection. These conditions can be managed with medication, surgery, or other treatments, and it is essential to consult a doctor if you experience any changes in your penis as you age.

The development of the penis is a complex process that involves various factors, including genetics, hormones, and lifestyle. Understanding these stages of development can help men to monitor their penis health and identify any potential issues that may arise. By maintaining a healthy lifestyle and seeking medical attention when needed, men can promote the overall health and function of their penis throughout their lives.

Functions of the Penis

The penis is a complex organ that serves various functions in the male body. Beyond its primary role in reproduction, the penis also plays a crucial role in urination and has psychological and social functions as well.

Sexual Function

The primary function of the penis is sexual in nature. It is responsible for enabling sexual intercourse and facilitating pleasure and orgasm. The penis contains erectile tissue, which fills with blood during arousal, causing it to become erect and allowing for penetration during intercourse.

  1. Role in Intercourse:

    The penis is essential for sexual intercourse. During arousal, the penis becomes erect and is able to penetrate the vagina, allowing for the transfer of sperm and the potential for fertilization of an egg.

  2. Pleasure and Orgasm:

    The penis is also a source of pleasure for men during sexual activity. The glans, or head, of the penis is particularly sensitive and can lead to orgasm when stimulated.

Urinary Function

In addition to its sexual function, the penis also plays a crucial role in urination. The urethra, a tube that runs through the penis, is responsible for carrying urine from the bladder out of the body.

  1. Role in Urination:

    The penis serves as the external opening for the urethra, allowing for the passage of urine out of the body.

  2. Urethral Function:

    The urethra also plays a role in ejaculation. During orgasm, the muscles in the penis contract, forcing semen through the urethra and out of the body.

Psychological and Social Functions

Beyond its physical functions, the penis also has psychological and social implications for men.

  1. Body Image and Self-Esteem:

    The size and appearance of the penis can have a significant impact on a man's body image and self-esteem. Society often places a great deal of importance on the size and performance of the penis, leading to feelings of inadequacy or insecurity for some men.

  2. Gender Identity and Expression:

    The penis is also closely connected to a man's sense of gender identity and expression. For transgender men, the appearance and functionality of the penis can play a significant role in their transition and overall sense of self.

Common Penis Related Issues and Treatment

The penis is a complex organ that can be affected by a variety of issues. Some of these issues are common and easily treatable, while others may require more extensive treatment. In this section, we will discuss the most common penis related issues and their treatment options.

Erectile Dysfunction

Erectile dysfunction (ED) is a condition where a man has difficulty achieving or maintaining an erection. It can be caused by a variety of factors, including physical and psychological issues.

  1. Causes and risk factors:

    Some common causes of ED include diabetes, heart disease, obesity, smoking, and certain medications. Psychological factors such as stress, anxiety, and depression can also contribute to ED.

  2. Treatment options:

    Treatment for ED depends on the underlying cause. Medications such as Viagra, Cialis, and Levitra are commonly prescribed to help with ED. Other treatment options include vacuum pumps, penile implants, and therapy to address any psychological factors.


Phimosis is a condition where the foreskin cannot be pulled back over the head of the penis. It can be caused by tight foreskin or scarring, and it can lead to discomfort and difficulty with hygiene.

  1. Definition and causes:

    Phimosis can be caused by a variety of factors, including poor hygiene, infections, and scar tissue from previous injuries.

  2. Treatment options:

    Treatment for phimosis depends on the severity of the condition. In some cases, a simple stretching routine or topical steroid cream can help loosen the foreskin. In more severe cases, a circumcision may be necessary to remove the foreskin.

Sexually Transmitted Infections (STIs)

STIs can affect the penis and can have serious consequences if left untreated. It is important to practice safe sex and get regularly tested to prevent the spread of STIs and to catch them early for effective treatment.

  1. Common STIs affecting the penis:

    Some common STIs that can affect the penis include chlamydia, gonorrhea, syphilis, HPV, and herpes.

  2. Prevention and treatment:

    The best way to prevent STIs is to practice safe sex by using condoms and getting regularly tested. If diagnosed with an STI, treatment options will depend on the specific infection and may include antibiotics, antivirals, or other medications.

Psychological Issues and Therapy

Body dysmorphia, or an obsessive concern with perceived flaws in one's appearance, can also affect the penis. It is essential to address these issues and seek therapy to improve self-esteem and overall well-being.

  1. Body dysmorphia:

    Body dysmorphia is a psychological disorder that can cause individuals to have an unrealistic and negative perception of their appearance, including their penis size.

  2. Therapeutic options:

    Therapy, such as cognitive-behavioral therapy, can be helpful in addressing body dysmorphia and improving self-esteem. It is also essential to have open and honest communication with sexual partners to dispel any insecurities and promote a healthy body image.


The penis is a complex and multifaceted organ that plays a crucial role in male sexual and reproductive health. Throughout this article, we have explored the anatomy, function, and common issues associated with the penis. Now, let's take a moment to recap the key points and discuss the importance of understanding the penis for overall sexual health and well-being.

Recap of Key Points

  1. The penis is composed of three main parts: the root, shaft, and glans. It also contains a network of blood vessels, nerves, and muscles that work together to facilitate sexual function.

  2. The primary function of the penis is to facilitate sexual intercourse and urination.

  3. Common issues associated with the penis include erectile dysfunction, phimosis, and Peyronie's disease.

  4. Regular self-examination and communication with a healthcare provider are essential for early detection and treatment of any potential issues.

Importance of Understanding the Penis for Sexual Health

Understanding the anatomy and function of the penis is crucial for maintaining overall sexual health. By learning about the different parts and how they work, individuals can better identify and address any potential issues that may arise. This is especially important for men experiencing sexual dysfunction, as early detection and treatment can improve their quality of life and prevent further complications.

Furthermore, understanding the penis can also lead to improved sexual experiences. By knowing how the organ works and what feels good, individuals can communicate their needs to their partners and explore new ways to enhance pleasure and intimacy.

Future Research and Developments

As with any aspect of the human body, there is always ongoing research and advancements in our understanding of the penis. Currently, there is a growing interest in the study of penile microbiome and its role in sexual health. This area of research may lead to new treatments for common issues such as urinary tract infections and sexually transmitted infections.

Additionally, there is ongoing research on the link between erectile dysfunction and cardiovascular health. This highlights the importance of understanding the penis not only for sexual health but also for overall well-being.

Final Thoughts

The penis plays a significant role in our physical and emotional health. By educating ourselves and seeking proper care, we can maintain a healthy and fulfilling sex life. Remember to regularly self-examine and communicate any concerns with a healthcare provider to ensure optimal sexual and reproductive health.

If you or anybody you know is experiencing pelvic floor dysfunctions, please reach out to us at Pelvic Health Center in Madison, NJ to set up an evaluation and treatment! Feel free to call us at 908-443-9880 or email us at

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