D. J. (Daniel John) Cunningham.

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

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posterior border of the talus, then it turns forwards under
cover of the ligamentum laciniatum to gain the sole of the foot.
The flexor hallucis longus is supplied by the tibial nerve. It
is a flexor of the interphalangeal and metatarso-phalangeal
joints of the great toe, a plantar flexor of the foot, and it
assists in producing inversion of the foot.

M. Flexor Digitorum Longus. The flexor digitorum longus
arises from the posterior surface of the body of the tibia, distal to
the popliteus, and medial to the vertical ridge which descends
from the linea poplitea. It also derives fibres from the surface
of the fascia which covers the tibialis posterior. After
crossing superficial to the distal part of the tibialis posterior,
its tendon grooves the back of the medial malleolus on the
lateral side of the tendon of the tibialis posterior. It is con-
tinued under cover of the ligament laciniatum into the sole
of the foot. The flexor digitorum longus is supplied by the
tibial nerve. It is a flexor of the interphalangeal and meta-
tarso-phalangeal joints of the lateral four toes, and it assists
in producing plantar flexion and inversion of the foot.

M. Tibialis Posterior (O.T. Tibialis Posticus). The
tibialis posterior takes origin from the posterior surface of
the interosseous membrane, from the posterior part of the
medial surface of the body of the fibula, from the posterior
surface of the body of the tibia, on the lateral side of the



378 THE INFERIOR EXTREMITY

flexor digitorum longus, and from the fascia which covers it.
In Fig. 152, p. 340, the compartment which it occupies
is shown in a diagrammatic manner, and the surfaces from
which it takes origin are indicated. Towards the distal
part of the leg the tibialis posterior inclines medially,
under cover of the flexor digitorum longus, and its strong
flattened tendon grooves the back of the medial malleolus
to the medial side of the tendon of that muscle. Proceed-
ing under cover of the ligamentum laciniatum, its tendon is

Tibialis posterior

Flexor digitorum longu
Posterior tibial artery /
and tibial nerve \
Flexor hallucis longus
Tibialis posterior
Medial plantar nerve
Flexor digitorum longu

Lateral plantar artery

and nerve

Medial plantar artery
Abductor hallucis









Nerve to the Medial calcanean

quadratus plantae _, vessels and nerve

Abductor digiti qumti Q uadratus plantae

FIG. 167. Dissection of the medial side of the Ankle, showing the relations
of the lig. laciniatum (O.T. internal annular lig. ).

inserted into the tubercle of the navicular bone, and also, by
a number of slips, into certain of the tarsal and metatarsal
bones. Those slips will be dissected later. The tibialis
posterior is supplied by the tibial nerve. It is a plantar flexor
and an inverter of the foot.

Ligamentum Laciniatum. The connections of this
thickened band of the deep fascia should now be carefully
re-examined. It bridges across the hollow between the
medial malleolus and the medial prominence of the calcaneus,
and is attached to both. It has already been shown that its
proximal border is continuous not only with the deep fascia



THE LEG 379

covering the superficial muscles of the calf but also with the
septum which separates those muscles from the deeper
muscles of the leg (see p. 367), and it has been pointed out
that the septum takes a more important part in the formation
of the ligament than the more superficial layer of deep fascia.
Its distal or anterior margin is continuous with the medial
part of the plantar aponeurosis, and it gives attachment to
the abductor hallucis muscle which is subjacent to that
aponeurosis. It is pierced by the medial calcanean branches
of the posterior tibial artery and the tibial nerve, and by a
communicating vein which connects the great saphenous
vein with the venae comites of the posterior tibial artery.

The dissector should note that under cover of the ligament
lie (i) the termination of the posterior tibial artery and the
commencement of its two terminal branches, the medial and
lateral plantar arteries, with their accompanying veins; (2)
the distal part of the posterior tibial nerve and its medial
and lateral plantar terminal branches ; (3) the tendon of the
tibialis posterior; (4) the tendon of the flexor digitorum longus;
(5) the tendon of the flexor hallucis longus. From the medial
to the lateral side the structures lie in the following order :

1. Tendon of tibialis posterior.

2. Tendon of flexor digitorum longus.

3. Posterior tibial vessels.

4. Tibial nerve.

5. Tendon of flexor hallucis longus.

The tendons are isolated from one another, and from the
vessels and nerve, by septa which pass from the deep surface
of the ligament to ridges on the adjacent bones. The septa
can be demonstrated by slitting open the ligament for a short
distance along the line of each tendon. Each of the three
compartments will then be seen to be lined with a glistening
mucous sheath, and the dissector should investigate the
extent of each sheath as far as possible, with the aid of a
blunt probe, for as the sheaths have been freely opened it
will not be possible to inflate or inject them. The sheaths
end proximally about 25 mm. above the medial malleolus.
Distally the sheath of the tibialis posterior reaches to the
insertion of the tendon into the tubercle of the navicular
bone. The sheath of the flexor digitorum longus extends to
about the middle of the length of the foot, and that of the
flexor hallucis longus can be traced, under favourable circum-



3 8o



THE INFERIOR EXTREMITY



stances as far as the middle of the metatarsal bone of the
great toe (Fig. 168).

Anastomosis around the Ankle Joint. The dissector
should next satisfy himself with regard to the anastomosis of
arteries which takes place around the ankle joint. On the
lateral aspect of the joint he will observe inosculations taking



Tibia

Flexor digitorum longus ,

Tibialis anterior
Ligamentum transversum -
Sheath of tibialis posterior'




Ligamentum cruciatum -J



Sheath of tibialis anteri
Sheath of extensor hallucis longi



i Abductor hallucis
I Lateral plantar artery and nerve
Quadratus plantae
| Flexor digitorum brevis
Navicular bone



2. Nervus tibialis.
4. Tendo calcaneus

6. Calcaneus.

7. Ligamentum laciniatum.



Flexor hallucis brevi

Abductor hallucis
, Flexor hallucis longus

FIG. 1 68. Dissection of Leg and Foot showing Mucous Sheaths of Tendons.

i. Arteria tibialis posterior.

3. Flexor hallucis longus.

5. First intermuscular septum of posterior

crural region taking part in the formation

of the ligamentum laciniatum.

place between branches of the following arteries : (a) lateral
malleolar ; (ti) perforating branch of peroneal ; (c) terminal
part of peroneal ; and (d) lateral tarsal.

On the medial aspect of the joint the medial malleolar
branch of the anterior tibial anastomoses with small twigs
from the medial calcanean branches of the posterior tibial.



SOLE OF THE FOOT 381

SOLE OF THE FOOT.

In this dissection the dissector will meet with the follow-
ing structures :

1. Superficial fascia and cutaneous vessels and nerves.

2. Plantar aponeurosis.

T Abductor hallucis.

3. Superficial muscles, -| Flexor digitorum brevis.

^ Abductor digiti quinti.

4. Lateral and medial plantar vessels.

5. Lateral and medial plantar nerves.

6. Tendons of flexor hallucis longus and flexor digitorum longus.

7. Quadratus plantse and lumbrical muscles.

8. Flexor hallucis brevis. Adductor hallucis, transverse and oblique heads.

9. Flexor brevis digiti quinti.

10. Plantar arterial arch.

11. Plantar metatarsal arteries.

12. Plantar digital arteries.

13. Tendons of peronseus longus and tibialis posterior.

14. Interosseous muscles.

Before commencing the dissection of the sole of the foot
the dissector should note the thickness of the skin over the
heel, on the balls of the toes, which correspond with the heads
of the metatarsal bones, and, to a less extent, along the
lateral border of the foot, on all of which parts the weight of
the body presses in the erect posture. Other noticeable
features are the relative shortness of the toes as contrasted
with the length of the fingers, and the fact that the longest
digit of the foot is either the second or the first, and not, as
in the case of the hand, the middle digit.

Dissection. Reflection of Skin. The limb should be placed
upon the table, with the sole of the foot facing the dissector,
and the ankle supported by a good-sized block. Two incisions
are required (i) a longitudinal incision along the middle line
of the sole, from the heel to the root of the middle toe ; (2) a
transverse cut, at the digital extremity of the median incision,
across the sole at the roots of the toes. The skin should also
be reflected from the plantar surface of each of the toes. This
can be done after a longitudinal incision has been made along its
middle line.

Superficial Fascia. When the flaps of skin mapped out
are reflected, the peculiar character of superficial fascia
becomes apparent. Along the lateral border of the foot,
over the heads of the metatarsal bones, and in the region
of the heel, it is thick. It is tough and granular, and in



3 8 2



THE INFERIOR EXTREMITY



some respects resembles the superficial fascia which covers
the ischial tuberosity. Traversing it are tough fibrous



Cutaneous branches

from lateral plantar

artery and nerve



Third and fourth
lumbricals



Digital nerves from
lateral plantar




Calcaneus



Medial calcanean
nerve and artery



Lateral part of plantar
aponeurosis

Cutaneous branches
r~ from medial plantar
| artery and nerve
^Intermediate part of
plantar aponeurosis



Medial part of
plantar aponeurosis



Digital nerves from
medial plantar



FIG. 169. Superficial Dissection of the Sole of the Foot ; the Skin and
Superficial Fascia alone removed.

bands, which subdivide the fatty tissue into small lobules,
and connect the thick skin of the sole with the plantar
aponeurosis.



SOLE OF THE FOOT 383

Dissection. Themedial calcanean nerves, which have already
been found piercing the ligamentum laciniatum, should be traced
to their distribution. They supply the skin of the sole in the
neighbourhood of the heel, and are accompanied by ramifications
of the medial calcanean branches of the posterior tibial and
lateral plantar arteries.

The superficial fascia may now be removed. Divide it along
the middle line of the sole, and turn it laterally and medially,
cleaning at the same time the plantar aponeurosis. As the
dissector approaches the lateral and medial margins of the foot
respectively, he will note, on each side, a furrow ; the furrows
extend forwards at the sides of the intermediate part of the plantar
aponeurosis. Along the furrows a number of blood-vessels and
some nerves will be seen piercing the deep fascia in order to
reach the skin. Towards the intervals between the heads of the
metatarsal bones the metatarsal arteries and the plantar digital
nerves are unprotected by the aponeurosis, and the dissector must
proceed cautiously. The nerves and vessels which go to the
medial side of the great toe and to the fibular side of the little
toe are especially liable to injury, as they perforate the aponeu-
rosis farther back than the others. A band of transverse fibres,
which crosses the roots of the toes and lies over the digital vessels
and nerves, should be noticed. It is the superficial transverse
ligament of the toes, and is closely connected with the skin where
that forms the cutaneous webs between the toes. By forcibly
separating the toes its connections will become evident. When
the relations of the ligament have been studied it may be removed.

Aponeurosis Plantaris (O.T. Plantar Fascia). The plantar
aponeurosis, which is now brought into view, consists of three
portions (a) a medial, () an intermediate, and (c) a lateral
part. The subdivision is indicated by a difference in the
density of the three parts and by two shallow furrows which
traverse the foot in a longitudinal direction, one upon each side
of the strong intermediate portion of the aponeurosis. Each
of the three portions is in relation to a subjacent muscle.
The intermediate portion covers the flexor digitorum brevis ;
the lateral part clothes the abductor digiti quinti ; and the
medial part covers the abductor hallucis.

The intermediate portion of the plantar aponeurosis stands
out in marked contrast to the lateral and medial portions
in point of strength and density. Posteriorly, where it
is attached to the medial process of the calcaneus, it is
narrow, but it expands as it passes forwards, and, near the
heads of the metatarsal bones, splits into five processes,
which are bound together by transverse fibres. In the
intervals between the digital slips the metatarsal vessels, the
digital nerves, and the lumbrical muscles appear. Trace
the processes forwards. One goes to the root of each toe ;



384 THE INFERIOR EXTREMITY

there it divides into two slips. The two slips embrace the
flexor tendons of the toe, and become fixed to the flexor
sheaths, and to the transverse ligament of the heads of
the metatarsal bones. The general characters, therefore,
of the intermediate part of the plantar aponeurosis closely
resemble those of the intermediate part of the palmar
aponeurosis.

The lateral and medial parts of the plantar aponeurosis are
weak, in comparison with the intermediate portion. They"
merely constitute fascial coverings for the muscles which
lie subjacent. A strong band is to be noted in connection
with the lateral part. It stretches between the prominence
formed by the base of the fifth metatarsal bone and the
lateral process of the tubercle of the calcaneus.

In connection with the plantar aponeurosis two inter-
muscular septa also have to be studied. These pass dorsally
into the sole, along the lines of the longitudinal furrows
which mark off the intermediate from the medial and lateral
parts of the aponeurosis. They consequently lie one upon
each side of the flexor digitorum brevis, and form partitions
which separate it from the abductor hallucis on the one side,
and the abductor digiti quinti on the other.

Dissection. To demonstrate the above-mentioned septa,
make a transverse incision through the intermediate portion of
the plantar aponeurosis, about an inch in front of the medial
process of the tubercle of the calcaneus, and also a longitudinal
cut through the same piece of aponeurosis, extending from the
first incision along the middle line of the foot. Now raise the
divided aponeurosis and throw it laterally and medially. Some
difficulty will be experienced owing to the deep surface of the
aponeurosis affording origin, in its posterior part, to the subjacent
flexor digitorum brevis. As the margins of this muscle are
approached the septa are brought into view. As the anterior
part of the divided aponeurosis is reflected, care must be taken
to avoid injury to the plantar digital arteries and nerves which
lie close to the deep surface of the aponeurosis.

Muscles and Tendons of the Sole. It is customary to
look upon the muscles and tendons found in the dissection
of the sole as being disposed in four strata, in or between
which lie the plantar vessels and nerves and their branches,
whilst the layers themselves are separated from one another
by fibrous partitions, viz. :

( Abductor hallucis.

First layer. -! Flexor digitorum brevis.

^ Abductor digiti quinti.



SOLE OF THE FOOT 385

( Tendon of flexor digitorum longus.

c j i I Ouadratus plantse.

Second layer. umbrical ^^

\ Tendon of flexor hallucis longus.

( Flexor hallucis brevis.
Third layer. -j Adductor hallucis, oblique and transverse heads.

( Flexor digiti quinti brevis.

( Interosseous muscles.
Fourth layer. -j Tendon of peronseus longus.

I Tendon of tibialis posterior.

Dissection. Separate the lateral and medial portions of
the plantar aponeurosis from the subjacent muscles. Whilst
that is being done great care must be taken to avoid injury to
the digital branch from the lateral plantar nerve to the lateral
side of the little toe, and the digital branch of the medial plantar
nerve and the digital artery to the medial side of the great toe.
To avoid injuring those structures seize a reflected portion of
the intermediate part of the plantar aponeurosis and cut, hori-
zontally through the septum which dips deeply from it at the
side of the flexor digitorum brevis, lateral or medial side as the
case may be, then keep the edge of the scalpel playing closely
against the deep part of the aponeurosis from which the septum
springs. Difficulty will be experienced in the posterior part of the
foot, where the deep surface of each piece of the aponeurosis gives
origin to fibres of the subjacent muscle. The muscular fibres
must be detached and the posterior ends of the two pieces of
aponeurosis must be separated from the calcaneus.

When the reflection of the medial and lateral parts of the
aponeurosis is completed the following structures are exposed.
Medially, the abductor hallucis and the digital artery and nerve
to the medial side of the great toe. Laterally, the abductor digiti
quinti and the digital artery and nerve to the lateral side of the little
toe. In the intermediate area, the flexor digitorum brevis and its
four terminal tendons, and the tendon of the flexor hallucis longus
will be found, with the digital vessels and nerves and the lumbri-
cal muscles in the intervals between the flexor tendons ; whilst
deep to the tendon of the flexor hallucis longus, part of the flexor
hallucis brevis is visible, and between the abductor digiti quinti
and the flexor digitorum brevis the flexor digiti quinti brevis and
the interossei in the fourth space can be seen.

When the structures mentioned have been identified cut
down into the posterior part of the interval between the abductor
hallucis and the flexor digitorum brevis, immediately in front
of the medial process of the calcaneus, and secure the posterior
parts of the medial and lateral plantar nerves and arteries ; then
follow the medial plantar nerve forwards and secure first the
branches which it gives to the abductor hallucis and the flexor
digitorum brevis, and then its four terminal digital branches.
As the first digital branch, that to the medial side of the great
toe, is followed it will be found to give a twig to the flexor hallucis
brevis, whilst the second digital branch, which supplies the
adjacent sides of the first and second toes, gives a twig to the
first lumbrical muscle, and the fourth digital branch is connected
by a communicating strand with the medial digital branch of
the lateral plantar nerve.
VOL. I 25



386 THE INFERIOR EXTREMITY

The trunk and branches of the relatively small medial plantar
artery accompany the trunk and branches of the medial plantar
nerve, and must be cleaned as the nerve and its branches are
dissected out of the surrounding fascia.

When the medial plantar vessels and nerves have been dis-
played, cut down into the interval between the flexor digitorum
brevis and the abductor digiti quinti, behind the pi ejecting base
of the metatarsal bone of the fifth toe, and secure the trunk of
the lateral plantar nerve, before it divides into its superficial and
deep divisions, and the accompanying lateral plantar artery
which lies lateral to the nerve. As the nerve passes forwards
it divides into a superficial and a deep branch, at the level of the
base of the fifth metatarsal bone and, at the same level, the lateral
plantar artery, accompanied by the deep branch of the nerve,
turns medially and deeply to become the plantar arterial arch.
Follow the superficial division of the nerve forwards, and secure

(1) the muscular branches which it gives to the flexor digiti
quinti brevis, and the interossei of the fourth interosseous space ;

(2) its two digital branches, one to the lateral side of the little toe,
and one which divides to supply the adjacent sides of the fourth
and fifth toes ; the latter is connected, by a communicating twig,
with the fourth digital branch of the medial plantar nerve. Clean
also the arteries which accompany the nerves. Now divide
the muscular belly of the flexor digitorum brevis, transversely,
at the middle of its length ; turn the posterior part backwards,
and define its attachments to the medial and lateral processes
of the calcaneus ; throw the anterior part forwards towards the
toes where its tendons enter the flexor sheaths, which will be
examined later. Next detach the abductor hallucis from the
medial process of the calcaneus, but not from the laciniate
ligament, and turn it medially. The structures now exposed
are (i) the first parts of the lateral plantar vessels and
nerve, and their branches ; (2) deep to the vessels and nerve,
the quadratus plantae ; (3) posteriorly, between the two heads
of the quadratus plantae, the posterior part of the long plantar
ligament ; (4) medial to the quadratus plantae the tendon of
the flexor digitorum longus dividing, anteriorly, into four
slips from which the lumbrical muscles arise; (5) medial to
the flexor longus digitorum a further portion of the tendon
of the flexor hallucis longus lying between the two heads of
the flexor hallucis brevis (Figs. 170, 171).

Clean, first, the lateral plantar nerve and its muscular branches.
The first branch is the branch to the abductor digiti quinti. It
lies far back, close to the processes of the calcaneus. The
branch to the quadratus plantae is a little further forward. In
addition there are a number of cutaneous branches which become
superficial along the interval between the abductor digiti quinti
and the flexor digitorum brevis. Next clean the lateral plantar
artery and follow its medial calcanean branch to the posterior
part of the interval between the flexor digitorum brevis and the
abductor hallucis where it becomes superficial. It is distributed
to the fat and skin of the heel. After the vessels and nerves are
cleaned clean the muscles and tendons.

M. Flexor Digitorum Brevis. The short flexor of the
toes arises from the medial process of the calcaneus, from



PLATE XXXIV




Plantar aponeurosis (intermediate
part)



- Flexor digitorum brevis
- Lateral plantar artery
Lateral plantar nerve

Quadratus plantae

Medial plantar nerve
Medial plantar artery



Plantar aponeurosis on abductor
digiti quinti

Abductor digiti quinti __
Quadratus plantae



Tendon of peronaeus longus

Lateral plantar artery
Lateral plantar nerve.



Flexor digiti quinti brevis
nd 3rd plantar interosseous

'Digital nerve and 5th

plantar metatarsal artery

4th dorsal interosseous

muscle

4th lumbrical

Tendon of flexor brevis '
digitorum

3rd lumbrical.



th plantar metatarsal artery.
3rd plantar metatarsal artery



Tendon of flexor. brevis digitorum



FIG. 170. Superficial dissection of the Sole of the Foot. The plantar
aponeurosis has been removed. The abductor digiti quinti and the
abductor hallucis have been pulled aside.



Digital artery and nerve
Flexor hallucis brevis

- - Flexor hallucis longus

Branch of ist plantar
' metatarsal artery

- ist lumbrical

- and lumbrical

Branch of ist plantar
"metatarsal artery



SOLE OF THE FOOT 387

the deep surface of the intermediate part of the plantar
aponeurosis, and from the intermuscular septum on each side
of it. About the middle of the sole the fleshy belly divides
into four slips, which end in slender tendons for the lateral
four toes. The tendons enter the fibrous flexor sheaths of
the toes, and will be afterwards studied. The flexor digitorum
brevis is supplied by the medial plantar nerve. It is a flexor
of the first interphalangeal joints and the metatarso-phalangeal
joints of the lateral four toes.

M. Abductor Hallucis. The abductor of the great toe
takes origin from the medial aspect of the medial process of
the tubercle of the calcaneus, from the medial intermuscular
septum, from the distal border of the ligamentum laciniatum,
and from the medial part of the plantar aponeurosis, which
covers it. A strong tendon issues from the fleshy belly.
This is joined, on its lateral and deep surface, by fibres of
the medial head of the flexor hallucis brevis, and it is
inserted into the medial aspect of the base of the proximal
phalanx of the great toe. The abductor hallucis is supplied
by the medial plantar nerve. It abducts the great toe from
the middle line of the second toe.

M. Abductor Digit! Quinti (O.T. Abductor Minimi Digiti).
The origin of the abductor of the little toe extends



Online LibraryD. J. (Daniel John) CunninghamCunningham's manual of practical anatomy (Volume 1) → online text (page 38 of 44)