According to big data, the normal penis length of adult males in China ranges from 4.5 to 6.55 centimeters, with a circumference of 7 to 9.5 centimeters in a regular state. The length during erection is 7 to 16 centimeters (average normal range: 10.87 to 15.27 centimeters), and the circumference is 9 to 12.5 centimeters. Penis size is considered normal within these ranges. The penis will no longer grow after the body matures; normally, the penis matures around the age of 18 for males and will not grow further.
1. The penis is propelled by blood supply. When a male is aroused, the three branches of the dorsal artery of the penis and its small arteries dilate, increasing the perfusion blood flow. The arteriovenous anastomosis is blocked, reducing venous return, and the corpora cavernosa sinusoids become congested, causing the penis to become erect. The head of the penis has rich nerve endings, making the frenulum of the penis, the coronal sulcus, and the area around the urethral orifice particularly sensitive to external mechanical stimulation. The sensory afferent nerve is the dorsal nerve of the penis, which transmits to the low-level sexual response center in the sacral cord, and then the parasympathetic nerves innervate the smooth muscle of the penis's blood vessels, changing their state. Lesions in the blood vessels and nerves of the penis can affect mating function.
2. When a man's penis is erect, the overall length of the penis increases by 1 to 2 times, accompanied by an increase in volume and stiffness. It is generally believed that the expansion rate of a penis with a smaller volume in a relaxed state is greater than that of a penis with a larger original volume. Therefore, it is rare for mating to be affected by a penis that is too small or too large in volume.
