The following content is part of the Circumpendium.
Anatomy and function of the foreskin in detail
The foreskin covers the glans, thus protecting it from pollutants, friction, injury and drying out. It consists of two superimposed layers, which are only joined together at the very end.
While the outer foreskin layer is an extension of the penile shaft skin, the inner foreskin layer, which lies flat against the glans, is a mucous membrane. The inner layer is an extraordinarily complex tissue. It contains apocrine glands which produce Cathepsin B, lysozymes, chymotrypsin, neutrophil elastase, cytokines and pheromones such as androsterone. Indian scientists have shown that the subpreputial moisture contains lytic material which has an antibacterial and antiviral effect. The natural oils lubricate, moisten and protect the mucous membranes of both the glans and the inner foreskin layer. The tip of the foreskin is supplied with ample amounts of blood through important blood vessels. 
The foreskin serves as a pathway for many significant veins. In addition the foreskin is saturated with very many nerve endings and tactile corpuscles, the same receptors that exist in the fingertips. The enormous density of nerves and mechanoreceptors make the foreskin the most sensitive part of the body, approximately 10 times more sensitive than the fingertips. This also distinguishes the human penis from those of other mammals, which in contrast have the main concentration of nerves in the glans, and not in the foreskin.
The two foreskin layers provide a skin reserve, into which the growing shaft expands during an erection. Depending to the individual length of a man's foreskin, it thereby retracts more or less far. In some men, the foreskin still fully covers the glans during an erection, in others the glans is partly or completely exposed.
In addition, the foreskin, in combination with the shaft skin, allows a natural gliding action. During intercourse as well as masturbation the outer skin is in contact with the vagina or the hand respectively. The penile shaft moves mostly within its skin and the skin only moves at the end of its thrust. Due to this, the friction with the vagina or hand is reduced. The sexual stimulation mostly occurs through the stretching and movement of the foreskin, when it is pulled over the glans and back, as well as the direct stimulation of the inner foreskin when it is exposed and comes into direct contact with the vagina or the hand.
Medical indications and therapies
There is a group of typical conditions of the foreskin, that can occur in more or less distinct ways.
Short Frenulum (frenulum breve)
If the frenulum is too short, it can hinder or even prohibit retraction of the foreskin. Since the underside of the glans is attached to the inner foreskin by the frenulum, it can be bent downwards due to the resulting tension when the foreskin is retracted. If the mechanical strain is too great, the frenulum can tear or rip apart. If the frenular artery, which runs within, is damaged in the process, it can lead to considerable and prolonged bleeding. When only small tears appear, it may heal spontaneously.
To help the healing, lukewarm camomile baths or cremes containing panthenol can be applied. With a very short frenulum and previous large tears, surgical treatment is advised.
There are 3 surgical variants: 
- Frenectomy, the complete removal of the frenulum
- Frenuloplasty, where the frenulum is cut horizontally, and sewed together vertically
- Elongation of the frenulum with a skin graft.
Physiological phimosis can be divided into three main categories - symptom-free, in need of therapy and in need of surgery.
From a medical standpoint, an otherwise symptom-free phimosis, even after dissolution of preputial adhesions, does not require any treatment before the child enters puberty. The widespread notion that full retractability has to be achieved by a certain age, derives from obsolete assumptions and studies which only covered children's development until they entered school, but not beyond that point.
Even though the data from Jakob Øster's studies (see above) have been known for 45 years, some check lists for school doctors‘ examinations still erroneously refer to physiological phimosis as an abnormality.
The growth and hormonal surge during puberty alter both the size and size ratio of the penis and penile skin significantly. Also, the first masturbations aid the process of stretching of the skin and detachment of remaining adhesions.
If, after that, the foreskin still remains too tight, resulting in pain during sexual activities, and making genital hygiene difficult, treatment is indicated. The boy himself should engage in stretching exercises, if needed with the aid of corticosteroid cream. Depending on the active substances, success rates of 80-90% have been documented.     
Should those therapies not yield the desired outcomes, there is a surgical option, namely a preputioplasty.
This surgical method preserves the foreskin. A good cosmetic result and total preservation of the foreskin are achieved. The basic principle of most of those methods consists of making one or more small longitudinal incisions, and then suturing the wound or wounds transversely.
There are several different methods: 
- Dorsal slit with transverse suturing: this technique places a single lengthwise cut into the stenotic ring which is then closed transversely.
- Lateral preputioplasty: this is a refinement of the dorsal slit with transverse suturing. It consists of two lateral, longitudinal incisions sutured transversely.
- Triple incision: this is a method of foreskin widening. It typically consists of three incisions across the tight ring. They are closed from side to side, thereby increasing the circumference of the tight ring relative to the length of the cuts. From an aesthetic view, it has results far superior to those of a dorsal slit, and usually yields a good cosmetic result.
If after a failed attempt to stretch the foreskin with corticosteroid cream a surgical intervention is necessary, a preputioplasty is always to be preferred over classic circumcision, due to its lower morbidity, lower rate of complications and lower costs.
In pathological phimosis, the foreskin cannot be retracted over the glans without injury, due to a lack of elasticity caused by scarring or hardening.
Repeated infections of the tight foreskin cause this scarring. Also, forceful attempts to retract the foreskin cause tearing with subsequential scarred phimosis. Lichen sclerosus, that first leads to adhesion and then to shrinking, can also be the cause of phimosis. This rare, non-contagious chronic skin disease is partly genetically caused and considered incurable. 
Pathological phimosis requires treatment.
A circumcision is indicated in severe cases of pathological phimosis, where neither non-surgical methods with corticosteroid cream nor foreskin-preserving preputioplasty are promising (for example with chronic balanitis xerotica obliterans) or have failed in previous attempts.
- Dr.med Wolfram Hartmann, Stellungnahme zur Anhörung am 26. November 2012 im Rechtsausschuss des Bundestages
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