D. J. (Daniel John) Cunningham.

Cunningham's manual of practical anatomy (Volume 1) online

. (page 36 of 44)
Online LibraryD. J. (Daniel John) CunninghamCunningham's manual of practical anatomy (Volume 1) → online text (page 36 of 44)
Font size
QR-code for this ebook


Now make a transverse incision across the distal part of the
heel and carry the extremities of the incision forwards, along
the medial and lateral borders of the foot respectively, then
remove the skin from the whole of the back of the leg, com-
mencing the reflection either from the medial or lateral border
as may be most convenient. As the reflection proceeds keep
the edge of the knife always against the skin to avoid injury to
the superficial veins and nerves.

Superficial Fascia. The superficial fascia of the posterior
crural region presents no special or peculiar features, but it
contains the following structures which must be displayed by
the dissector :

Superficial ( Part of the great saphenous vein,
veins, \ Part of the small saphenous vein.

Superficial lymph vessels.

Part of the saphenous nerve.

The terminal part of the posterior branch of the medial

cutaneous nerve of the thigh.
Cutaneous J The terminal part of the posterior cutaneous nerve of the thigh,
nerves, | The medial cutaneous nerve of the calf.
The anastomotic peroneal nerve.
The sural nerve,
^he medial calcanean nerves.

Dissection. The superficial veins and the cutaneous nerves
must now be followed and cleaned. The lymph vessels cannot
be demonstrated in an ordinary dissection ; the majority of
them accompany the veins and their tributaries. The great
saphenous vein and the saphenous nerve have already been
traced across the distal third of the medial surface of the tibia



THE LEG 359

(P- 336). Now follow them proximally along the posterior
margin of the medial surface of the tibia to the medial side of
the knee, where they were displayed when the superficial part of
the medial region of the thigh was dissected (p. 227). The vein
and nerve lie close together.

The posterior branch of the medial cutaneous nerve of the
thigh was also found when the medial side of the thigh was
dissected. In the calf it lies lateral and posterior to the saphenous
nerve, and should now be traced to its termination in the area
of the medial head of the gastrocnemius (Fig. 161).

The terminal part of the posterior cutaneous nerve of the
thigh was found when the popliteal area was being dissected
(p. 306). It pierces the popliteal part of the deep fascia a little
below the middle of its length, and should now be traced as it
descends through the superficial fascia to the middle of the
calf (Fig. 161). Deep to the terminal part of the posterior
cutaneous nerve of the thigh, in the groove between the two
heads of the gastrocnemius, lie the upper part of the small
saphenous vein and the medial cutaneous nerve of the calf.
Both structures have been already partially investigated. When the
popliteal fossa (p. 309) was dissected the vein was found piercing
the popliteal fascia and ending in the popliteal vein, whilst the
nerve was found arising from the tibia! nerve ; and, in the
dissection of the dorsum of the foot (p. 336), the vein was seen
commencing from the lateral end of the dorsal venous arch,
whence it passed backwards below, and upwards behind the
lateral malleolus. The remaining part of the vein must now
be cleaned. It ascends along the lateral border of the tendo
calcaneus, accompanied by the sural nerve, and then in the
groove between the two heads of the gastrocnemius, accom-
panied by the medial cutaneous nerve of the calf. The sural
nerve was found, in a previous dissection (p. 338), lying
in close association with the small saphenous vein behind
the lateral malleolus. Trace it upwards to the point where it
is formed by the union of the medial cutaneous nerve of the
calf and the anastomotic peroneal nerve ; the union usually
takes place at the lateral border of the proximal part of the
tendo calcaneus. From the commencement of the sural nerve
follow the medial cutaneous nerve of the calf upwards to the
point where it pierces the deep fascia, about midway between
the knee and the ankle, then follow the peroneal anastomotic
nerve to the point where it pierces the deep fascia in the proximal
part of the calf, superficial to the lateral head of the gastro-
cnemius (Fig. 161). The medial calcanean nerves will be found
piercing the thickened portion of deep fascia called the ligamen-
tum laciniatum which crosses the interval between the medial
malleolus and the calcaneus. They are accompanied by small
branches of the posterior tibial artery.

At this stage the dissector should revise the saphenous
veins and the cutaneous nerves which have been seen in
previous dissections, but which are now, for the first time,
displayed from beginning to end (Figs. 163, 164, 107).

Vena Saphena Magna. The great saphenous vein com-



360 THE INFERIOR EXTREMITY

mences at the medial border of the foot, where it is formed
by the union of the medial end of the dorsal venous arch of
the foot with the medial digital vein of the great toe. It
ascends anterior to the medial malleolus, passes obliquely
upwards and backwards across the medial surface of the distal
third of the tibia, and then vertically upwards, along the
medial border of the tibia, to the posterior part of the medial
side of the knee. Thence it passes obliquely upwards,
forwards, and laterally, through the superficial fascia of the
medial and anterior areas of the thigh, to the fossa ovalis,
where it pierces the cribriform fascia and the femoral sheath
and terminates in the femoral vein (Figs. 163, 107, 106).

Its named tributaries are the dorsal venous arch, the
medial digital vein of the great toe, the lateral and medial
femoral circumflex veins (p. 230), the superficial pudendal,
epigastric, and circumflex iliac veins (p. 230), but it receives
in addition numerous other tributaries from the dorsum of
the foot, and from the front, medial side, and back of the
leg. Further, it forms numerous communications with the
deep veins of the limb by anastomosing channels which
pierce the deep fascia. A fairly large communicating
vein pierces the ligamentum laciniatum and curves below the
medial malleolus to join the great saphenous vein at the
anterior border of that process ; others pierce the deep fascia
along the medial borders of the tibia and in the distal third
of the thigh.

The great saphenous vein is accompanied by numerous
superficial lymph vessels. They drain the regions from
which the tributaries of the vein issue, and they terminate
in the medial and lateral groups of subinguinal lymph glands,
which lie at the sides of the proximal part of the vein in the
region of the femoral triangle. It is also accompanied by
several cutaneous nerves from the fossa ovalis to the middle
of the thigh by branches of the medial cutaneous nerve of
the thigh, from the middle of the thigh to the knee by the
anterior terminal branch of the medial cutaneous nerve of the
thigh, and from the knee to the medial border of the foot
by the saphenous nerve.

It contains a number of valves which help to divide the
long column of blood into a series of segments, and so
diminish the pressure on the walls of the more distal parts
of the vein.



THE LEG 361

Vena Saphena Parva. The small saphenous vein is
formed, in the lateral border of the foot, by the union of the
lateral digital vein of the little toe with the lateral end of the
dorsal venous arch of the foot. From its point of commence-
ment it runs backwards below the lateral malleolus, and
then upwards behind the lateral malleolus, in company with
the sural nerve, and superficial to the peroneal retinacula.
Afterwards it ascends, parallel with the lateral border of the
tendo calcaneus, where it is still associated with the sural
nerve. Above the level of the tendo calcaneus it ascends
along the median line of the calf to the lower part of the
popliteal region, where it pierces the popliteal fascia and
terminates in the popliteal vein. In the lower part of its
ascent along the median line of the calf it is associated with
the medial cutaneous nerve of the calf, and in the upper
part by the distal portion of the posterior cutaneous nerve
of the thigh. The small saphenous vein receives tributaries
from the lateral border of the foot, the heel, and the back
of the calf. It is accompanied by superficial lymph vessels
which commence in the areas in which the tributaries of
the vein arise, and which terminate in the popliteal lymph
glands (Figs. 163, 164).

The two saphenous veins are connected together by the
medial femoral circumflex vein, which commences from the
small saphenous vein, immediately before it pierces the deep
fascia, and terminates in the great saphenous vein above the
middle of the thigh. In some cases the medial femoral
circumflex vein forms the direct continuation of the small
saphenous vein, and in those cases the small saphenous vein
has either only a very small connection, or no connection at
all, with the popliteal vein.

The Lymph Vessels and Lymph Glands of the Inferior Extremity.
The lymph vessels of the inferior extremity cannot be displayed in an
ordinary " part," but some at least of the lymph glands are always found,
and as both lymph vessels and lymph glands are of great practical
importance, it is essential that the dissector should have a general know-
ledge of their positions and functions. The lymph vessels contain a
colourless fluid called lymph, which drains into their finer tributaries from
the surrounding tissues. Micro-organisms which have gained access to
the tissues, and the cells of malignant tumours growing in the tissues, may
enter the lymph vessels and so be carried onwards in the lymph stream.
The lymph carried by the lymph vessels eventually passes into two
terminal trunks, the tJioracic duct and the right lymph duct, each of which
terminates in a large vein ; therefore the lymph, and micro-organisms or
poisons formed by micro-organisms which have entered the lymph, are



362



THE INFERIOR EXTREMITY



eventually poured into the blood, and by it are dispersed to all parts of the
body. Both terminal lymph vessels end at the root of the neck behind
the sternal end of the clavicle, the thoracic duct in the left innominate
vein and the right lymph duct in the right innominate vein (Fig. 14).



Inguinal ligament.

Proximal subinguinal

lymph gland



Fossa oval

Lateral distal sub-
l lymph
glands



nguinal lymph V



Cisterna chyli



Lumbar lymph gland



/ Common iliac gland
V* External iliac glands

p. -Pubic subinguinal
lymph gland
Deep femoral lymph
gland

^Medial distal sub-
inguinal lymph glands



Lymph vessels which
accompany the great
iphenous vein



FIG. 159. Diagram of the Lymph Vessels of the front of the
Inferior Extremity.



All the lymph, however, before it reaches the terminal lymph vessels,
passes through one or several lymph glands, usually several, for the glands
are interposed, like small filtering sponges, in the courses of the lymph
vessels ; therefore the lymph collected from the tissues is carried in the
first instance to a lymph gland, and then, as a rule, it passes through several
other glands before it reaches terminal lymph vessels. The lymph vessels



THE LEG



363



Cisterna chyli



Lumb



ir lymph ,
glands'"!



Crest of ilium ^ ..
Common iliac,,
lymph gland

Hypogastric
lymph glands'



which carry lymph to a gland are called afferent lymph vessels, and those
which carry it away are efferent lymph vessels. All the lymph from both
inferior extremities flows to the commencement of the thoracic duct which
lies in the abdominal region in
front of the second lumbar verte-
bra, where it frequently possesses
a dilated extremity called the
ci sterna chyli. On its way it
passes through a series of glands,
and as noxious materials which
have entered the lymph vessels
may be caught in the glands and
there set up inflammation or pro-
duce new malignant growths, it is
important to bear in mind con-
stantly the general positions of the
glands and the areas from which
they receive lymph.

There are two sets of lymph
vessels and lymph glands in the
inferior extremity, the deep and
the superficial.

The deep lymph glands are,
(i) the anterior tibial, (2) the
popliteal, (3) the deep subinguinal.
The anterior tibial gland lies close
to the proximal end of the anterior
tibial artery in the anterior com-
partment of the leg. The popliteal
glands lie in the popliteal fossa
around the popliteal vessels. The
deep subinguinal glands are situ-
ated in the femoral triangle, in
the femoral canal of the femoral
sheath. The deep lymph vessels
which pass to the deep glands run
along the main blood-vessels, and
they carry lymph drained from all
the deeper structures of the limb,
the muscles, ligaments, bones, and
joints. The lymph from the deep
parts of the leg, foot, and knee
passes through the popliteal glands
to the deep subinguinal glands ;
that from the medial, anterior,
and lateral parts of the thigh is
carried to the deep subinguinal
glands ; but the lymph from the
deep parts of the back of the
thigh and the buttock, flowing
through lymph vessels which accompany the inferior and superior gluteal
vessels, passes into the pelvis to the hypogastric glands, and through
them to the common iliac and lumbar glands on its way to the thoracic
duct.

The superficial lymph glands of the inferior extremity are the subinguinal
lymph glands to which attention was directed in association with the



Lymph vessels
which convey lymph |
to lower medial sul> - <
inguinal lymph
glands



Popliteal lymph gland"
Lymph vessels which
accompany the small,
saphenous vein



FIG. 160. Diagram of the Lymph
Vessels of the back of the Inferior
Extremity.



364 THE INFERIOR EXTREMITY

superficial dissection of the anterior part of the thigh (see p. 228). They
form two groups, a proximal and a distal. The proximal group was found
lying parallel with and close to the inguinal ligament, and the distal
group at the sides of the proximal part of the great saphenous vein
(Figs. 1 06, 159).

All the lymph from the skin and the subcutaneous structures of the
inferior extremity, except that derived from the lateral side of the foot,
the back of the heel, and the back of the leg, passes through one or other of
the two groups of superficial subinguinal glands, and from them it is
carried to the deep subinguinal glands by efferent vessels which pierce the
cribriform fascia and the anterior wall of the femoral sheath. The lymph
from the dorsum and medial side of the foot, the front and medial side of
the leg, the medial side and the greater part of the front of the thigh, is
conveyed to larger lymph vessels which accompany the great saphenous
vein and end in the distal subinguinal glands. The lymph from the
buttock and back of the thigh flows to the proximal subinguinal glands.
The lymph from the lateral side of the foot, the back of the heel and
the leg, passes into lymph vessels which accompany the small saphenous
vein and terminate in the popliteal lymph glands.

It follows, from what has already been stated, that all the lymph of the
inferior extremity, except that from the deep parts of the buttock and back
of the thigh, passes through the deep subinguinal glands. From the deep
subinguinal glands the lymph passes into the external iliac glands, which lie
in the lower and anterior part of the abdomen close to the inferior end of
the external iliac artery and immediately above the inguinal ligament, and
from them it is conveyed through the common iliac glands, which lie at a
higher level, to the lumbar glands. The lumbar glands are situated still
higher in the abdomen opposite the lumbar vertebrae at the sides of the
aorta, and they are the last glands through which the lymph of the inferior
extremities passes before it enters the thoracic duct (Figs. 159, 160).

Nervi Cutanei. Before proceeding to display the deep
fascia of the back of the leg the dissector should revise the
numerous cutaneous nerves.

N. Saphenus. The saphenous nerve is the most medial
of the deeper group of branches of the femoral nerve.
It commences therefore in the femoral triangle, where it
descends along the lateral border of the femoral artery ; it
accompanies the artery through the adductor canal, lying
first on its lateral side, then in front of it, and finally in the
distal part of the canal on its medial side. It does not
accompany the artery through the opening in the adductor
magnus, but, at the distal end of the adductor canal it
passes between the sartorius and gracilis muscles accompanied
by the saphenous branch of the arteria genu suprema. At
the medial side of the knee it pierces the deep fascia, enters
the superficial fascia, and then it accompanies the great
saphenous vein to the medial border of the foot. In the
adductor canal it gives twigs to the subsartorial plexus.
After it leaves the canal, and before it emerges between the



THE LEG



365



sartorius and gracilis, it gives off an infrapatellar branch,
which pierces the sartorius

Lumbar nerves



Lateral cutaneous

branches of last

thoracic and ilio-

hypogastric

Sacral nerves



Perforating
cutaneous

Branches from

posterior cutaneous

nerve of thigh

Lateral cutaneous

Perineal rami of

posterior cutaneous

nerve of the thigh

Posterior cutaneous

nerve of the thigh

Medial cutaneous

nerve of the thigh

Lateral cutaneous
nerve of the thigh



Medial cutaneous_
nerve of the thigh



Peronaeal anastomotic
nerve

Posterior cutaneous
nerve of the thigh



Medial cutaneous nerve

of the calf (O.T. ramus

communicans tibialis)



Nervus suralis
(O.T. short saphenous)





on its way to the patellar
plexus. Beyond the knee
its branches are distributed
to the skin of the medial
side of the leg, including
the medial crural region,
the medial part of the
posterior crural region,
and the medinl part of
the dorsum of the foot.

N. Cutaneus Surae
Medialis. The medial
cutaneous nerve of the
calf springs from the tibial
nerve in the popliteal
fossa, descends between
the two heads of the gas-
trocnemius, pierces the
deep fascia of the leg,
about midway between the
knee and the ankle, and
unites with the anastomotic
branch of the peroneal
nerve to form the sural
nerve at the lateral border
of the proximal part of the
tendo calcaneus. It sup-
plies the skin of the middle
part of the calf of the leg.

N. Anastomoticus Per-
onseus. The anastomotic
branch of the common
peroneal nerve springs
from the common peroneal
nerve in the popliteal fossa,
crosses superficial to the
lateral head of the gastro-
cnemius, where, as a rule,
it pierces the deep fascia ; then it passes downwards and
medially to the proximal end of the lateral border of the









Medial calc



:anean nervi



FIG. 161. Cutaneous Nerves on the
posterior aspect of the Inferior Extremity.



366 THE INFERIOR EXTREMITY

tendo calcaneus, where it joins with the medial cutaneous
nerve of the calf in the formation of the sural nerve. It
supplies the skin of the proximal two-thirds of the posterior
surface of the calf.

N. Suralis. The sural nerve is formed, by the union of
the anastomotic branch of the peroneal nerve and the medial
cutaneous nerve of the calf, in the superficial fascia at the
level of the proximal end of the lateral border of the tendo
calcaneus. It descends, alongside of the small saphenous
vein, behind the lateral malleolus ; then it turns forwards, below
the lateral malleolus, to the lateral border of the dorsum of
the foot ; there it gives a communicating twig to the branch of
the superficial peroneal nerve which is distributed in the
adjacent sides of the fourth and fifth toes, and then continues
forwards to the lateral part of the dorsum of the little toe.
In the region of the dorsum of the foot it is known as the
lateral dorsal cutaneous nerve of the foot, a superfluous and
unnecessary term.

The medial cutaneous nerve of the thigh, the posterior
cutaneous nerve of the thigh, and the lateral cutaneous
nerve of the leg have already been sufficiently described
(see pp. 257, 306, 315).

Dissection. After the cutaneous veins and nerves of the
posterior region of the leg have been studied, remove the remains
of the fatty superficial fascia, and clean the deep fascia which
lies subjacent to it.

Deep Fascia. In the proximal part of the calf the deep
fascia is thin and transparent ; it thickens considerably as
the region of the heel is approached. In no part of its
extent is it very dense, but as it passes from the back of the
leg to the medial side of the ankle, and covers the interval
between the medial malleolus and the calcaneus, it is greatly
strengthened to form the ligamentum laciniatum (O.T.
internal annular ligament), whilst at the lateral side of the
ankle it is also thickened to form the peroneal retinacula

(P- 339)-

It is continuous proximally with the popliteal fascia, and, a

short distance distal to the knee on the medial side, it receives
reinforcements of fibres from the tendons of the sartorius,
gracilis, and semitendinosus. Distally, on the medial side, it
is continuous with the ligamentum laciniatum (O.T. internal



THE LEG 367

annular ligament), which crosses the interval between the
medial malleolus and the calcaneus, and, on the lateral side,
with the superior peroneal retinaculum which extends from
the lateral malleolus to the calcaneus. On the medial side
the deep fascia is attached to the medial border of the tibia,
where it blends with the periosteum on the medial surface of
that bone, and on the lateral side it joins the posterior fibular
intermuscular septum, by which it is attached to the lateral
crest of the fibula (Figs. 152, 155), thus it forms the posterior
boundary of the great posterior osteo-fascial compartment of
the leg.

Posterior Osteo-fascial Compartment of the Leg. The posterior
osteo-fascial compartment of the leg is bounded, posteriorly, by the deep
fascia and, anteriorly, by the tibia, the interosseous membrane, and the
fibula. It contains the muscles, vessels, and nerves of the back of the leg,
and is divided into three portions by two fascial partitions which stretch
across it. The first partition is attached, medially, to the popliteal line of
the tibia (Fig. 152), and to the distal two-thirds of the medial border of the
tibia, and, laterally, to the posterior surface of the fibula, below the attach-
ment of the soleus, and to the lateral crest of the fibula (Fig. 152). Its
upper portion forms a fibrous arch which covers the terminal part of the
popliteal artery, and, in the distal part of the leg, it blends with and
plays a very important part in the formation of the laciniate ligament. It
separates the gastrocnemius, soleus, and plantaris, which lie in the posterior
portion of the osteo-fascial compartment, from the flexor digitorum longus,
the flexor hallucis longus, the tibial nerve and the posterior tibial artery
and its branches which lie in the middle area.

The second septum, known as the fascia covering'the tibialis posterior,
is attached, medially, to the proximal part of the popliteal line of the tibia
and to the vertical ridge on the posterior surface of the tibia and, laterally,
to the medial crest of the fibula. Above, it blends with the interosseous
membrane, and below it fuses with the deep surface of the first septum in
the distal part of the leg. It separates the structures in the middle
part of the osteo-fascial compartment from the tibialis posterior which
occupies the anterior section of the compartment. Parts of the flexor
hallucis longus and the flexor digitorum longus arise from its posterior
surface, and fibres of the tibialis posterior spring from its anterior surface.

It follows, from what has been stated, that the great posterior osteo-
fascial compartment of the leg is divided into three sections posterior,
middle, and anterior. The posterior section is bounded behind by the
deep fascia of the leg and in front by the first septum. It contains the
gastrocnemius, the soleus, the plantaris, which are called the superficial
muscles of the calf, and the tendo calcaneus, which is the common tendon
of insertion of the gastrocnemius and the soleus.

The middle section is bounded posteriorly by the first septum and
anteriorly by the medial part of the tibia, the second septum, and the
posterior surface of the fibula. It contains the long flexor of the toes, the
long flexor of the great toe, the tibial nerve and its branches, and the
posterior tibial vessels and their branches and tributaries.

The anterior section of the compartment is bounded posteriorly by the
second fascial septum, and anteriorly by the tibia and the interosseous



Online LibraryD. J. (Daniel John) CunninghamCunningham's manual of practical anatomy (Volume 1) → online text (page 36 of 44)