The skin drainage
relies on two strictly different circulations:
-
The venous circulation
-
The lymphatic circulation
Description:
-
The superficial
venous circulation
The superficial
venous circulation is divided in 3 sectors: the sub-papillary, the intra-dermal,
and the hypodermal. The first 2 sectors represent the dermal circulation,
which is formed by 2 horizontal plexi, one sub-epidermal, another intra-dermal.
Those 2 circulatory plexi make an anastomosis and join the hypodermal venous
system.
The hypodermal
venous circulation penetrates the adipose tissue by means of interlobular
pathways, hence, free of any contact with the adipocytes. However,
the more the adipocyte are saturated with fatty acids, the more tissue
tension you get, which impairs the venous circulation. The volume
augmentation in the adipocyte can trigger such a local change as to create
an outbreak of telangectasis.
The superficial
lymphatic circulation
The superficial
lymphatic circulation consists of:
a. the
original intra-dermal lymphatic pathways
b. the intra-dermal
pre-ducts
c. the dermal
lymphatic ducts
a.
The original intra-dermal lymphatic pathways
The original
intra-dermal lymphatic pathways are arranged in very dense network.
They are valve-less. Some authors consider that the original lymphatic
pathways follow the organised interstitial space, also called the pre-lymphatic
territory. Its purpose is to collect the interstitial liquid.
b. The intra-dermal
pre-ducts
They follow the
original lymphatic network. Those vessels have valves, winding, and
they carry the lymph to the hypodermal ducts. Due to their interlobular
location the pre-ducts are subjected to stress from the saturated adypocytes.
The adipose mass impairs tissue mobility and therefore inhibits the vasomotor
lymphatic flow.
c. The dermal
lymphatic ducts
The dermal lymphatic
ducts collect the lymph brought by the pre-ducts. Their route is
more linear. They sometimes accompany the hypodermic veins by means
of a lymphatic pedicle. The pedicle is often made of several vessels.
The two forms of
drainage (venous, lymphatic) are mechanically dependent on the skin mobility.
The skin mobility or mechanical stretch follows two main directions:
1. Vertical
direction: the skin is progressively submitted to a cycle of compression
and relaxation. The cycle enhances the mobility of the intra- and
hypodermic liquids.
2. Transverse
direction: introduces shearing forces between two adjacent dermal fractions.
The mechanical stretch
is under control of the intra-dermal elastic fibres whose properties are
link to the skin quality.
Conclusion:
From all the
elements described above, the two types of return circulation, the adipocyte
volume, the decreased tissue mobility, we now have a better understanding
of the consequences that can arise from a thickened, infiltrated, fibrous,
and rigid skin. One can really appreciate that the skin drainage
holds a key role in the oedema treatment.
return
|
