Kinclongmu Dimulai dari Sini!
Channel: M. Rifki Al Ikhsan, MD
Date: 28/11/2020

The skin covering the body has with 1.5–2 m2 the largest extension
or surface area of all organs of the body. It has a total weight between
3 and 4 kg (and together with the subcutaneous fat up to 16
kg). The thickness of the skin varies between 1 and 2 mm depending
on the body region. It has the following functions: • Protection (as a mechanical, thermal, chemical or immunological
barrier)
• Registration of pressure, touch, vibration, pain, temperature
• Energy storage
• Heat insulation
Condition and appearance of the skin and skin appendages significantly
influence the social acceptance and the subjective impression
of a person. For the medical professionals they provide information
about age, life style, health, general condition and mood of
a person.
For a grading of burns by the body surface affected, the Neuner
rule is applied, which allows a prognostic estimation of the
burnt skin surface:
• Adults:
– Arms and head 9 % respectively
– Chest/abdomen, back and legs 18 % respectively
– Palm of hands including fingers and genital region 1 %
respectively
• Children up to 5 years:
– Arms 9.5 %
– Chest/abdomen, back 16 % respectively
– Legs 17 %
– Head 12 % (age-dependent)
If more than 20 % of the skin surface is burnt, it is a severe
burn. From 40 % on the probability is extremely high that the
patient dies. From 5 % in children and 10 % in adults there is
a risk of shock. Inpatient treatment in a hospital is nearly always
indicated, and should be reserved for specialised centres
for patients with burns, in order to treat the patient in the
best way possible.

Meshed and ridged skin
A distinction is made due to the morphological structure between
meshed and ridged skin. Meshed skin has glands and hairs and
makes up the largest part of the body surface area. It has a variable
thickness in different regions of the body. Ridged skin forms the
surface relief of the palms and soles and is – being genetically
determined
– an individual characteristic of each person (fingerprint).
This enables an individual identification.
Skin layers
The skin (Cutis) consists of epidermis, dermis and subcutis
(› Fig. 1.10 ).
Epidermis
The epidermis (Epithelium) is the surface of the skin and has
characteristic layers:
• Stratum corneum
• Stratum lucidum (only ridged skin)
• Stratum granulosum
• Stratum spinosum
• Stratum basale
It is a multi-layer (or stratified) squamous epithelium without
blood vessels, containing numerous sensory receptors in the form
of free nerve endings (mechanical, temperature and/or pain perception)
and MERKEL cells (pressure sensation). In addition, there
are melanocytes and dendritic cells (immune cells, LANGERHANS
cells).
Dermis
The layer below the epidermisis the dermis (or Corium), is a layer
of connective tissue with a superficial capillary plexus (Plexus superficialis)
on the border between the epidermis and dermis and a
deep vascular plexus (Plexus profundus) on the border between
dermis and underlying subcutis. These vascular plexuses not only
play a role in the blood circulation, but also in the heat regulation.
The dermis has two layers:
• Stratum papillare: papillae of collagenous and elastic connective
tissue link (indent) the dermis with the epidermis. In each papilla
a capillary of the Plexus superficialis runs to the tip.
• Stratum reticulare: tense collagenous and elastic connective
tissue
The dermis is well vascularised and innervated. It houses various
specialised receptors:
• MERKEL cells for pressure sensation
• MEISSNER tactile corpuscles for touch (especially Stratum
papillare)
• RUFFINI corpuscles for stretching sensation (especially Stratum
reticulare)
• VATER-PACINI corpuscles for vibration sensation
• Free nerve endings for mechanical, thermal and/or pain perception
Furthermore there are nerves, lymphatic vessels, immune cells,
melanotropin-producing cells (UV protection), sweat glands, hair
follicles, sebaceous glands and smooth muscle cells in the dermis.
Epidermis and dermis are linked via the papillae of the Stratum
papillare. Below this follows the Stratum reticulare of the dermis.
The latter is mainly responsible for the elasticity of the skin.
The epidermis and the Stratum papillare of the dermis (dermo-
epidermal transition zone) are interlocked by various proteins
and other structures. If one or more of these proteins or
adhesive structures is missing (e. g. genetically) or undergoes
destruction (e. g. mechanically), bubbles (Bullae) may occur,
and in rare cases there may be a large-scale detachment of the
epidermis. There are also conditions such as the bullous pemphigoid,
in which antibodies are formed against components
of the adhesive structures (auto-antibodies). In the case of
pemphigus the antibodies disturb the adhesion of the cells
within the epidermis.
The main orientation of the collagen fibres in the Stratum reticulare
of the dermis determines the so-called cleavage lines
of the skin, which play an important role for correct incisions
in surgery.