Normal picture of the penis in static state

The penis is the main reproductive organ of men, which has the functions of sexual intercourse, urination and ejaculation. The penis is mainly composed of two corpora cavernosa and one corpora cavernosa, and is covered with basal muscle fascia and skin. The following discusses the normal situation of the penis under static data.

Two natural situations

1. When loose, hanging just below the ischial tuberosity, the average length is X=6.55, S=1.023, X±1.96S=6.55±2.046 (4.5～8.6) cm, the maximum value is 10.6 cm, and the minimum value is 3.7 cm; the average thickness is X=2.57.S=0.255, X±1.96S=2.57±0.57 (2.06～3.08) cm, the maximum value is 4.3 cm, and the minimum value is 1.9 cm.

2. When erect, the penis is 90° or more than 90° with the pubic mons, with the ischial tuberosity as the axis, and the length increases by 1 to 2 times compared to normal, with the volume and strength increasing accordingly. It is generally believed that the water content of the penis with a smaller volume during relaxation is higher than that of the penis with a larger volume, so it is rare for the breeding to be affected by the penis volume being too small or too large.

Anatomical structure

1. It is divided into three parts: root, body and head. The back is the male genital root, which is attached to the lower branch of the toe bone, the sciatic nerve branch and the urogenital diaphragm; the middle is the male genital body, which is cylindrical and hangs just below the ischial tuberosity; the front is the glans penis, with a sagittal fissure at the top of the head called the external urethral orifice, and there is a circular groove at the intersection of the head and body called the male genital neck or coronal groove.

2. The corpus cavernosum is a thin cylinder on each side, one on the left and one on the right, located between the bones of the penis. The left and right are closely connected, widening forward, narrowing at the front end, and placed in the indentation at the bottom of the glans penis. The rear end of the corpus cavernosum develops and separates, called the genital crus, which are attached to the lower abdominal branch and sciatic nerve branch of the toe bones on both sides. The urethral corpus cavernosum is located in the internal oblique muscle of the corpus cavernosum, and the urethral opening surrounds its total length. It is cylindrical in the middle, with the front end expanding to form the glans penis and the rear end expanding to form the urethral opening bulb, located in the middle of the two genital crus, fixed to the muscle fascia below the urogenital diaphragm. Each corpus cavernosum is covered with a thick chemical fiber membrane, called the tunica albuginea of ​​the corpus cavernosum. The interior of the corpus cavernosum is composed of many posterior corpus cavernosum capsules and cavities, which are actually sinus spaces that communicate with blood vessels.

When this cavity is swollen with blood, the penis becomes wide and hard; otherwise, it becomes loose. The three corpora cavernosa are surrounded by shallow and deep muscle fascia and skin. The membrane of the penis is thin and soft, and quite flexible. The skin spreads forward to the neck of the penis, forming two layers of annular wrinkles that surround the glans penis, called the foreskin, which folds back at the neck of the penis and changes to the skin of the glans penis. The cavity between the prepuce and the glans penis is called the prepuce cavity. On the center line of the internal oblique muscle of the glans penis, the skin wrinkles where the prepuce is connected to the external urethra are called the frenulum. Long, tight, and infected foreskin may cause pain during sexual intercourse. In children, the foreskin is longer and covers the entire glans penis. As the child ages, the foreskin gradually moves backwards and the foreskin opening expands relatively. If the foreskin covers the urethral opening but can be turned up to expose the urethral opening and the glans penis, it is called foreskin. When the foreskin opening is too small and the foreskin completely covers the glans penis and cannot be opened, it is called foreskin. In both cases, it is easy to cause inflammation due to the irritation of waste in the foreskin cavity, which can also become a factor in causing penile cancer. Excessive foreskin should be surgically removed to expose the glans penis.