What Is a Germ Line?

The external genitalia are located outside the abdominal cavity. The male external genitalia includes the penis and scrotum, and the female external genitalia includes the clitoris, labia minora, clitoris, urethral opening, and vestibular part.

The external genitalia are located outside the abdominal cavity. The male external genitalia includes the penis and scrotum, and the female external genitalia includes the clitoris, labia minora, clitoris, urethral opening, and vestibular part.

Chinese name

External genitalia

Meaning

Refers to the external part of the reproductive system

Use

Mating, fertilization, spawning

Male part

Including testis, epididymis, urethra, scrotum

Female part

Including pumas, labia majora, labia minora, etc.

External genital anatomy:

(1) Female genitalia:

Female genitalia, also known as female vulva, includes the clitoris, labia majora, clitoris, vaginal vestibule, and perineum, located between the two medial legs, the pubic symphysis is anterior, and the perineum is posterior.

Perineum refers to the soft tissue between the vaginal opening and the anus. Yinfu is the adipose tissue covering the pubic symphysis, with skin layers and pubic hair growing. The diamond-shaped area is the vaginal vestibule, which includes the vestibular sphere (also known as the spherical sea surface body), the vestibular large gland (also known as the Pap gland, which opens in the groove between the labia minora and the hymen behind the vestibule), the urethral opening, the vaginal opening, and the hymen . The labia majora is rich in subcutaneous fat, blood vessels, lymphatic vessels and nerves. The labia minora is located inside the labia majora and is rich in nerve endings. The inner tip of the labia minora on both sides is the clitoris, which is sensitive and erectile.

(2) Male genitalia:

The male external genitalia includes three parts: the penis, the penis, and the scrotum. The clitoris is located at the joint of the pubic bone, with a triangular shape, the bottom edge is on the top, bordered by the shallow transverse sulcus and the abdomen, and the sides are the lower part of the groin. The subcutaneous fat is richer, and the penis and scrotum are drooping.

Embryonic development of female genitalia:

At the 5th week of the embryo, wrinkles form on both sides of the cloaca, meeting forward at the midline to form genital nodules. As the cloaca is separated by the urinary rectum and the subsequent perineum, the cloaca in the front is called the urogenital fold, and the rear is called the anal fold. Reproductive nodules begin to grow. In female embryos, they grow slowly and become clitoris; urogenital folds form the labia minora. In male embryos, genital nodules continue to grow and form a penis; urogenital folds fuse with each other and surround the penis and urethra. On the outside of the urogenital fold, another pair of bulges are formed, which are called labial and scrotal processes in the undifferentiated stage. In the absence of androgens, this pair of carinas does not fuse, forming the labia majora. The genitourinary sinus eventually develops into the vaginal vestibule, where the urethra, vagina, and vestibular glands open.

Female external genitalia:

1. Yinfu:

The clitoris is a bulge of the skin in front of the pubic bone, rich in sebaceous and sweat glands, lined with fatty tissue under the skin. After puberty, pubic hair grows on the skin. The pubic hair is a triangle with a pointed downward point. Pubic hair is one of the female's second sexual characteristics. The lower part of the clitoris continues to the sides of the labia majora.

2. Labia majora:

The labia majora are two longitudinally raised fibrous fat folds containing subcutaneous fat, blood vessels, lymphatic vessels and nerves. Such as trauma, hematoma is easy to form, and the pain is severe. Extending from the phallus downwards and backwards, meeting the posterior lacing in front of the anus at the midline. The labia majora contains round ligament stops, and occasionally a perineal diverticulum, the Nuck duct.

The crevice between the labia majora is called a labia. The front of the labia majora is thicker and connected to form an anterior commissure. The posterior ends of the labia majora are parallel and backward, continuing to the adjacent skin, and the skin connected between them forms a lower ridge, which is called posterior commissure. The posterior lip joint covers the perineal body, forming the posterior boundary of the female vulva. The labia majora is divided into inner and outer sides. The inner surface is like a mucosa, pink, smooth, and has a large amount of sebaceous glands. It is the same as the skin on the outside, containing sweat glands, sebaceous glands and pigments, and has thin pubic hair. The subcutaneous tissue between the inside and outside is loose, rich in fat, and contains elastic fibers and a small amount of smooth muscle, as well as blood vessels, lymphatic vessels, nerves and glands. The uterine round ligament stops after passing through the inguinal canal and stops on the fatty tissue or skin on the front of the labia majora. The hernia contents of patients with congenital oblique inguinal hernia can slide down the inguinal canal to the subcutaneous labia majora.

3. Labia minora:

The labia minora is located on the inside of the labia majora and is a pair of thinner skin folds. The labia minora is located on the inside of the labia majora and blends with the labia majora at the rear. The front of the labia minora is divided into two folds near the clitoris. The front folds meet to form the clitoral foreskin or clitoral crown, and the rear folds form clitoral ties on the lower surface of the clitoris. The size and shape of the labia minora varies from person to person. The surface is smooth, moist, and reddish. The surface is stratified squamous epithelium, without pubic hair. The fibrous elastic matrix is rich in neurovascular components and is very sensitive. The area between the posterior portions of the labia minora forms a vaginal vestibule. Sometimes there is another labial fold between the labia minora and the labia majora on one or both sides, called the third labial fold.

4. The clitoris:

The clitoris (clitoris) is an erectile structure that is homologous to the male penis. The clitoris contains two clitoral sponges. The clitoral sponge can be divided into three parts: the clitoris foot, the clitoris body and the clitoris head. The clitoris feet are cylindrical, attached to the ischial and subpubic branches, and the surface is covered with sciatic cavernous muscle. Near the lower edge of the pubic symphysis, the clitoris on both sides are connected to form the clitoral body. There is an incomplete sponge septum (also called a comb-like septum) between the two clitoris to separate them. The clitoris turns to the front and bottom, and its free end is the clitoral head. The clitoral head is a small round nodule with a diameter of 6 to 8 mm and is surrounded by the clitoral foreskin. There is often clitoral dirt in the clitoral groove between the clitoral head and the clitoral foreskin. The clitoris is attached to the labia minora under the head. The clitoral sponge has a fold on the outside of the bread, and the clitoral fascia on the outside of the white film. There are two shallow and deep connective tissue cords between the dorsal side of the clitoris and the pubic bone. The superficial cable is the clitoral ligament, and the deep cable is called the clitoral overhang ligament. The clitoral cavernous body can also be congested and erect, and the nerve endings of the clitoral head are rich, highly sensitive, and susceptible to erections due to stimulation, which are important structures of sexual response.

5. Vaginal vestibule:

The vaginal vestibule is a diamond-shaped area between the labia minora on both sides. The vaginal vestibule has a vaginal opening, a urethral opening, two large vestibular glands and their openings, and many mucous vestibular small glands. There is a shallow vestibular fossa between the vaginal opening and labial lacing.

The outer urethra is located in front of the vaginal opening, approximately 2.5 cm below the clitoral head. There is an opening of the paraurethral duct at the posterolateral side of the outer urethra. [1]

The vaginal opening is located in the back half of the vestibule and is a sagittal fissure behind the urethral opening. The vaginal opening can be extremely dilated during childbirth and slightly dilated during intercourse. There are hymen or hymen marks around the vaginal opening. There are openings of the vestibular large gland drainage tube on the posterolateral and lateral sides of the vaginal opening, and the openings of the small vestibular glands are located near the external urethral and vaginal openings.

The hymen is a layer of perforated film covering the vaginal opening. It is generally annular, semilunar, and can also be sieve, petal, or other shapes. Both sides are covered with stratified flat epithelium, which contains connective tissue, blood vessels and nerve endings. The shape, thickness, and position of the hymen vary greatly.

There are also differences in the size of the hymen. Some are too small to pass one finger, and some are large enough to accommodate two fingers. The hymen is generally about 0.2cm thick, and some individuals are very thin. A few hymen tissues are tough or non-porous atresia (hymen hysteresis or non-porosity hymen), and they are even like this. If there is a non-porous hymen, menstrual blood cannot be discharged after menarche, which can form hemorrhage in the vagina, uterus, and fallopian tubes, which requires surgical incision and drainage. When the hymen breaks, small, round hymen marks are left behind.