This document discusses the concept of angiosomes, which are composite blocks of tissue supplied by main source arteries. Angiosomes pieced together form the three-dimensional vascular territories of the body. The angiosome theory has become accepted in plastic and reconstructive surgery as it allows conceptualization of vascular supply. Arteries, veins and nerves are arranged in specific territories with arteries forming looping arcades and nerves taking more direct routes. Perforating vessels connect these vascular territories.

1. Angiosome Concept
By:Dr.Amit KumarChoudhary

2. • The angiosome (from the Greek angeion, meaning
vessel, and somite, meaning segment or sector of the
body derived from soma, body) is defined as a
composite block of tissue supplied by a main source
artery. The source arteries (segmental or distributing
arteries) that supply these blocks of tissue are
responsible for the supply of the skin and the
underlying deep structures.
• When pieced together like a jigsaw puzzle, they
constitute the three-dimensional vascular territories of
the body.

3. • The angiosome theory has
become well accepted in
the field of plastic and
reconstructive surgery and
allows the
conceptualization of the
vascular supply to all
tissues of the human body.
• An angiosome is a
composite block of tissue
supplied by a main source
vessel. The adjacent
angiosomes are linked
either by reduced caliber
choke anastomotic vessels
or vessels without
reduction in caliber – the
true anastomoses on the
arterial side.

4. • The vascular architecture of the body is arranged
anatomically as a continuous series of vascular loops, like
that increase in number while their size and caliber
decrease as they approach the capillary bed . The reverse
situation occurs on the venous side.
• The “keystones” of these arcades are represented usually
by reduced-caliber (choke anastomotic) arteries and
arterioles, matched on the venous side by avalvular
(oscillating) veins that permit bidirectional flow. Choke
arteries and avalvular veins have an essential role in
controlling this pressure gradient across the capillary bed.

5. Historical perspective
• In 1889, Manchot performed the first
examination of the vascular supply of the human
integument. His treatise, Die Hautarterien des
menschlichen Körpers [The Cutaneous Arteries of
the Human Body], was initially published in
German and later translated to English.
• Manchot identified the cutaneous perforators,
assigned them to their underlying source vessels,
and charted the cutaneous vascular territories of
the body .

7. • In 1893, Spalteholz published an important paper on
the origin, course, and distribution of the cutaneous
perforators in adult and neonatal cadavers. He
performed arterial injections of gelatin and various
pigments.
• Spalteholz’s main study concentrated on the detailed
circulation of the skin. He made an important
distinction between direct cutaneous vessels, which
supply the skin, and indirect cutaneous vessels, which
are terminal branches of vessels supplying the deeper
organs, especially the muscles.

8. • Salmon a French anatomist
and surgeon [1930].
• Manchot had defined
approximately 40 cutaneous
territories that excluded the
head, neck, hands, and feet.
• Salmon work Aided by
radiography, he was able to
delineate the smaller vessels
of the cutaneous circulation
and charted more than 80
territories encompassing the
entire body
• Salmon noted the
interconnections that exist
between perforators, and his
observation of the density
and size of the vessels in
different regions of the body
led him to define what he
called the hypervascular and
hypovascular zones

9. • In 1975, Schafer, published an important study on the arterial and
venous anatomy of the lower extremity
• In 1937, Webster again cited the work of Manchot when he
described a long, bipedicled thoracoepigastric flap based on named
arteries that extended from the groin to the axilla.
• The 1970s “anatomic revolution.” McGregor and Morgan
differentiated between large flaps based on a known axial blood
supply and those based on random vessels.
• Daniel and Williams reappraised the work of Manchot and others
and classified the cutaneous arteries into direct cutaneous and
musculocutaneous vessels.
• Studies on the free flap by Taylor and Daniel were published in
1973, and a few years later the musculocutaneous flap was revived
by McCraw and Mathes and Nahai

10. Overview of the arterial,
venous, and nervous territories

11. Arterial territories
• The arterial network of the
body forms a continuous
interlocking arcade of
vessels throughout each
tissue and throughout the
body, linked together as
loops of vessels, often of
reduced caliber.
• The course of the cutaneous
perforators depends on the
proximity of the source
artery to the undersurface
of the deep fascia
• Arteries generally fall into
two groups, direct and
indirect

12. • The direct cutaneous vessels pass between the deep tissues before
piercing the outer layer of the deep fascia. They are usually the
primary cutaneous vessels, their main destination being the skin.
They tend to supply the skin with larger-diameter vessels which
have a large vascular territory (e.g., circumflex scapular artery).
• The direct branches include direct cutaneous vessels (sometimes
called axial vessels) and septocutaneous vessels.
• The indirect vessels can be considered the secondary cutaneous
supply. They emerge from the deep fascia as terminal branches of
arteries which supply the muscles and other deep tissues. The
majority of indirect branches are musculocutaneous perforating
branches which emerge to supply the skin

13. • The direct cutaneous vessels arise from:
(1) source arteries just beneath the deep fascia
(e.g., the superficial inferior epigastric artery)
(2) direct continuation of the source artery (e.g., the
cutaneous branches of the external carotid artery)
(3) deeply situated source artery or one of its
branches to a muscle; they follow the
intermuscular septa to the surface (e.g., septal
cutaneousbranches of the lateral circumflex
femoral artery).

14. • The direct cutaneous perforators pierce the deep fascia
near where it is anchored to bone or the intermuscular and
intramuscular septa.
• These lines and zones of fixation also correspond to the
fixed skin areas of the body. From these points, the vessels
flow toward the convexities of the body surface, branching
within the integument. The wider the distance between the
cavities and the higher the summit, the longer the vessel.

15. • Indirect cutaneous vessels generally emerge
from the main source artery as it courses on
the undersurface of a muscle and penetrate
through the muscle; e.g., musculocutaneous
perforators of the deep inferior epigastric
arteries (DIEA).
• In the human body, there are approximately
400 perforators, about 40% of vessels are
direct and 60% indirect perforators.

17. • The course of the cutaneous perforators between the
deep fascia and the skin also varies in different regions.
• They follow the connective tissue framework of the
superficial fascia, interconnecting at all levels. They
ramify on the undersurface of the subcutaneous fat
adjacent to the deep fascia and then branch and course
toward the subdermal plexus,working their way
between the fat lobules.
• The smaller vessels tend to course vertically toward the
skin, whereas the larger vessels branch in all directions
in a stellate pattern or course in a particular axis,
branching as they pass parallel to the skin surface.

18. • In the loose skin areas of the body, the direct cutaneous
vessels course for a variable distance parallel to the deep
fascia. They are more intimately related to the
undersurface of the subcutaneous fat, however, being
plastered to it by a thin fascial sheet that separates them
on their deep surface from a plexus of smaller vessels.
• This plexus lies in loose areolar tissue on the surface of the
deep fascia. It is formed by branches that arise from the
direct perforators.
• The large direct perforators then pierce the subcutaneous
layer. They ascend within the superficial fascia
(subcutaneous fat) to reach the rich subdermal plexus.

19. Venous drainage
• The cutaneous veins also form
a three-dimensional plexus of
interconnecting channels
throughout the body. There
are valved segments in which
valves direct flow in a
particular direction, and there
are avalvular segments where
no valves are present.
• The avalvular or oscillating
veins allow bidirectional flow
between adjacent venous
territories They connect veins
whose valves may be oriented
in opposite directions, thus
providing for the equilibration
of flow and pressure.

20. • There are many veins whose valves direct flow initially
in a distal direction, away from the heart, before
joining veins whose flow is proximal. An example of
this is the superficial inferior epigastric vein that drains
the lower abdominal wall integument toward the
groin.
• In some regions, valved channels direct flow radially
away from a plexus of avalvular veins, for example, in
the venous drainage of the nipple–areola complex.
• In other areas, valved channels direct flow toward a
central focus, as seen in the stellate branches of the
cutaneous perforating veins of the limbs.

21. • In general, venous
anatomy parallels arterial
anatomy
• From dermal and
subdermal venous
plexuses, the veins collect
either into horizontal
large caliber veins, or
alternatively in centrifugal
or stellate fashion into a
common channel that
passes vertically down in
company with the
cutaneous arteries to
pierce the deep fascia.

22. The muscles can be classified into three types on the basis of
their venous architecture
Type I muscles have a single venous territory that drains in one direction.
Type II muscles have two territories that drain from the oscillating vein in
opposite directions.
Type III muscles consist of three or more venous territories that drain in
multiple directions

23. The extramuscular veins are of two types.
• The first group consists of the efferent veins.
They contain valves and drain the muscles to
their parent veins.
• The other group consists of the afferent veins.
They are derived from the overlying
integument as musculocutaneous perforators
or from adjacent muscles.

24. Neurovascular territories
• The most obvious feature seen throughout the
skin and muscle is the linear arrangement of the
nerves and their branches, compared with the
looping arcades of the interconnecting vessel
network.
• Nerves taking the shortest route between two
points.
• In general, the orientation of cutaneous nerves is
longitudinal in the limbs, transverse or oblique in
the torso, and radiating from loci in the head and
neck.

25. • Each cutaneous nerve is
accompanied by an artery,
but the relationship is
variable.
• In each case, either a long
artery or a chain-linked
system of arteries
“hitchhikes” with the nerve.

26. • When the cutaneous
nerve and artery
appear at the deep
fascia together, their
relationship is often
established early .
• However, the nerve
sometimes pierces the
deep fascia at a point
remote from the
emergence of its
associated artery (e.g.,
the lateral cutaneous
nerve of the thigh and
the superficial
circumflex iliac artery
below the inguinal
ligament.

29. The angiosome concept
• Following a review of the works by Manchot and Salmon,
along with the results of our total body studies of blood
supply to the skin and the underlying deep tissues, it has
been possible to segregate the body anatomically into
three-dimensional vascular territories named angiosomes.
• Each angiosome can be subdivided into matching
arteriosomes (arterial territories) and venosomes (venous
territories).
• Each angiosome is linked to its neighbor at every tissue
level, either by a true (simple) anastomotic arterial
connection or by a reduced-caliber choke anastomosis. A
similar pattern with avalvular (bidirectional or oscillating)
veins on the venous side defines the boundaries of the
venosome

30. Vascular territories of the body
• Vascular territories of the forearm

33. Vascular territories of the lower leg

37. Vascular territories of the head and
neck
• The muscles usually have vessels of two or more
angiosomes supplying them.
Head and neck skin and superficial
musculoaponeurotic system
• The blood supply to the skin of the face, scalp, and
neck follows the connective tissue framework. The
main skin perforators pierce the deep fascia from fixed
skin sites, especially around the base of the skull,
around the orbits, around the nostrils, over the parotid
gland, along the skin crease lines of the face, and
beside the muscles in the neck.

42. Anatomic concepts related to flap
design

43. Vessels follow the connective tissue framework
of the body
• This concept is fundamental to the design of flaps in
general and to fasciocutaneous and septocutaneous flaps in
particular. The connective tissue framework of the body is a
continuous syncytium, like the walls of a honeycomb. The
vessels follow this framework down to the microscopic
level.
• In general, if the connective tissue is rigid, such as
intermuscular septa, periosteum, or deep fascia, the vessels
travel beside or on it. If the connective tissue is loose, they
travel within it. The vessels occasionally travel in a fibrous
sheath or a bony canal, but this tunnel always contains
loose areolar tissue, physiologically, to allow the veins to
dilate and the arteries to pulsate.

44. Arteries radiate from fixed to mobile areas and
veins converge from mobile to fixed areas
• The cutaneous vessels pierce and emerge
from the outer layer of the deep fascia near
where it is anchored, either to its deep septa
or to bone. The veins course parallel to the
plane of mobility, often for long distances, and
cross where the tissues are anchored to fascia
or bone. This is seen at the same site as the
arteries.

45. Vessels “hitchhike” with nerves
• There is an intimate relationship between nerves and blood
vessels throughout the deep tissues and the skin and
subcutaneous tissues of the body, especially where a
cutaneous nerve courses on the surface of the deep fascia.
An artery may accompany the nerve for a considerable
distance, often connecting with its neighbor in chain-link
fashion to provide the basis for an axially oriented
neurovascular flap.
• The cutaneous vessels and the nerve are occasionally in
juxtaposition; in other situations, they course parallel to
each other but at a distance.
• When the cutaneous nerve crosses a fixed skin site, it
frequently “picks up” its next vascular companion.

46. Vessel growth and orientation are products of
tissue growth and differentiation
• There are numerous examples to support this
hypothesis.
• The sternomastoid and trapezius muscles split
from the same somite. The trapezius “drags”
its supplying transverse cervical artery (and
nerve) across the root of the neck to the back,
together with a large band of skin that it
nourishes.

47. Vessels interconnect to form a continuous
three-dimensional network of vascular arcades

48. Vessels obey the law of equilibrium
There are numerous venous channels, large
and small, that are free of valves and allow
flow within their lumens in either direction.

49. Vessels have a relatively constant destination but
may have a variable origin
• This is typical of the vessels that emanate from
the groin to supply the skin of the lower
abdomen and upper thigh. The superficial inferior
epigastric and the superficial circumflex iliac
arteries, for example, may arise either separately
from the common femoral artery or as a
combined trunk from that vessel or from one of
its branches. Whatever the case, their destination
is constant to supply the integument of the lower
abdomen and the hip .

50. Venous networks consist of linked valvular and
avalvular channels that allow equilibrium of
flow and pressure
• Directional veins-Directional veins are valved
veins which exist either as longitudinal channels,
well developed in the subcutaneous and deep
tissues of the limbs, or as a stellate pattern of
collecting veins, which converge on a pedicle.
• Oscillating avalvular veins-Oscillating avalvular
veins are avalvular vessels which are numerous
and may reach large dimensions. They connect
and allow free flow between the valved channels
of adjacent venous territories, territories whose
valves are oriented in the opposite direction.

53. Applications of
angiosome concept

54. Clinical implications
• 1. Each angiosome defines the safe anatomic boundary of tissue in
each layer that can be transferred separately or combined on the
underlying source vessels as a composite flap. Also, the anatomic
territory of each tissue in the adjacent angiosome can usually be
captured with safety when it is combined in the flap design.
• 2. Because the junctional zone between adjacent angiosomes
usually occurs within muscles of the deep tissue, rather than
between them, these muscles provide an important anastomotic
detour (bypass shunt) if the main source artery or vein is
obstructed.
• 3. Because most muscles span two or more angiosomes and are
supplied from each territory, one is able to capture the skin island
from one angiosome by muscle supplied in the adjacent territory.
As we shall see later, this fact provides the basis for the design of
many musculocutaneous flaps.

55. The Doppler Probe and Mapping of
Perforators
• The Doppler probe allows surgeons to locate
cutaneous perforators with precision in
individual cases. By use of the knowledge that
most cutaneous arteries emerge from fixed
skin sites a their expected origin can be
anticipated and located rapidly.

56. Flap design
• It has been determined clinically and
experimentally that flaps can be safely
designed by identifying a cutaneous
perforator and an adjacent perforator; a line
drawn between the two perforators should
represent the axis of a viable flap.

57. Axes of skin flaps
• The cutaneous arteries
of the skin have
provided the basis of
“axial” flaps used
extensively in plastic and
reconstructive surgery.
• The origin, course, size,
density, and
interconnections of the
cutaneous perforators. It
therefore provides for
the logical planning of
the base and axis of a
skin flap.

58. Skin flap dimensions
• The survival length of a skin flap must depend on:
• (1) the caliber and length of the dominant
vessels on which the flap is based;
• (2) the caliber and span of the adjacent captured
artery or arteries, vein or veins;
• (3) the caliber and length of the connecting choke
vessels; and
• (4) an anatomically favorable or unfavorable
venous return.

59. The Delay Phenomenon

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