Anatomy

1. Anatomy of the Leg and
dorsum of the foot
Dr. Mohammed Mahmoud Mosaed

2. Anatomy of the Leg
The leg is the region between
the knee joint and the ankle
joint, it contains the tibia and
fibula.
The interosseous membrane
binds the tibia and fibula
together and provides
attachment for neighboring
muscles

3. Deep fascia of the leg
■ The deep fascia surrounds the leg and is
continuous above with the deep fascia of the
thigh. Below the tibial condyles it is attached to
the periosteum on the anterior and medial
borders of the tibia.
■ The leg is divided into three compartments,
anterior, lateral and posterior, by the anterior
and posterior intermuscular septa, the
interosseous membrane and the two leg bones
■ Each department having its own muscles, blood
supply, and nerve supply

4. The Front of the Leg
Cutaneous Nerves
■ The lateral cutaneous nerve of
the calf, a branch of the common
peroneal nerve, supplies the skin on
the upper part of the lateral surface of
the leg.
■ The superficial peroneal nerve,
a branch of the common peroneal
nerve, supplies the skin of the lower
part of the anterolateral surface of the
leg.
■ The saphenous nerve, a branch of
the femoral nerve, supplies the skin on
the anteromedial surface of the leg.

5. Contents of the Anterior
Compartment of the Leg
Muscles:
Tibialis anterior
Extensor digitorum longus
Peroneus tertius
Extensor hallucis longus
Blood supply: Anterior tibial artery
Nerve supply: Deep peroneal nerve

7. Tibialis Anterior
Origin:
Upper half of lateral surface of
tibia and interosseous membrane.
Insertion:
Medial cuneiform and base of 1st
metatarsal bones.
Nerve Supply:
Deep peroneal nerve (Anterior
tibial nerve).
Action:
Dorsiflexion and inversion of the
foot.
Maintenance of the medial
longitudinal arch of the foot.

8. Extensor Digitorum Longus
Origin:
Upper 2/4th of anterior
surface of fibula and
interosseous membrane.
Insertion:
Extensor expansions of the
lateral 4 toes.
Nerve Supply:
Deep peroneal nerve.
Action:
Extension of the lateral 4
toes.
Dorsiflexion of the foot.

9. Extensor Hallucis Longus
Origin:
Middle 1/4th of anterior surface
of fibula and interosseous
membrane.
Insertion:
Base of the distal phalanx of the
big toe.
Nerve Supply:
Deep peroneal nerve.
Action:
Extension of the big toe.
Dorsiflexion and inversion of the
foot.

10. Peroneus Tertius
Origin:
Lower 1/4th of anterior surface of
fibula and interosseous membrane.
Insertion:
Medial side of the dorsal aspect of
the base of 5th metatarsal bone.
Nerve Supply:
Deep peroneal nerve.
Action:
Dorsiflexion of the foot (ankle
joint).
Eversion of the foot (sub-talar
joints).

12. Anterior Tibial Artery
■ Origin: is the smaller of the 2 terminal
branches of the popliteal artery.
■ Course: It arises at the level of the lower
border of the popliteus muscle and passes
forward into the anterior compartment of
the leg through an opening in the upper
part of the interosseous membrane.
■ It descends on the anterior surface of the
interosseous membrane, accompanied by
the deep peroneal nerve.

14. ■ In the lower part of its
course, it lies superficial
in front of the lower end
of the tibia here its
pulsations can easily be
felt in the living subject.
It passed behind the
superior extensor
retinaculum.
■ Termination: in front of
the ankle joint, the artery
becomes the dorsalis
pedis artery

15. Branches
■ Muscular branches to
neighboring muscles
■ Anterior and posterior
tibial recurrent arteries
■ Anterior medial malleolar
and anterior lateral
maleolar.
Veins in the font of the leg
■ Venae comitantes of the
anterior tibial artery join
those of the posterior tibial
artery in the popliteal fossa
to form the popliteal vein.

16. Deep Peroneal Nerve
■ Origin: The deep peroneal nerve is one of the terminal branches
of the common peroneal nerve.
■ Course: It arises in the substance of the peroneus longus muscle
on the lateral side of the neck of the fibula.
■ The nerve enters the anterior compartment by piercing the
anterior fascial septum. It then descends deep to the extensor
digitorum longus muscle, first lying lateral, then anterior, and
finally lateral to the anterior tibial artery. The nerve passes
behind the extensor retinacula.
■ Branches
■ Muscular branches to the tibialis anterior, the extensor digitorum
longus, the peroneus tertius, and the extensor hallucis longus
■ Articular branch to the ankle joint
■ Cutaneous; to a small area of skin in the web between the 1st and
2nd toes.

18. Retinacula of the Ankle
■ The retinacula are thickenings
of the deep fascia that keep the
long tendons around the ankle
joint in position and act as
pulleys.

19. Extensor Retinacula
Superior Extensor Retinaculum
■ It is attached to the distal
ends of the anterior borders
of the fibula and tibia.
Inferior Extensor Retinaculum
■ It is a Y-shaped band located
in front of the ankle joint.

20. ■ Structures that pass anterior to
the extensor retinacula from
medial to lateral
■ Saphenous nerve and great
saphenous vein
■ Superficial peroneal nerve
(medial and lateral branches)
■ Structure passes deep to the
superior and inferior extensor
retinacula from medial to lateral
■ Tendons of tibialis anterior,
■ extensor hallucis longus,
■ anterior tibial vessels,
■ anterior tibial nerve,
■ extensor digitorum longus and
peroneus tertius

21. Flexor Retinaculum
■ It extends from the medial malleolus
downward and backward to be
attached to the medial surface of the
calcaneum. It binds the tendons of the
deep muscles of the back of the leg to
the back of the medial malleolus each
tendon is lined by a synovial sheath.
■ The structures pass deep to the
flexor retinaculum from medial to
lateral:
■ The tendons of tibialis posterior
■ Flexor digitorum longus,
■ The posterior tibial vessels
■ The tibial nerve
■ The tendon of flexor hallucis longus

23. Peroneal Retinacula
■ Superior Peroneal Retinaculum
■ It connects the lateral malleolus to the
lateral surface of the calcaneum.
■ The structures passing deep to it:
the tendons of the peroneus longus and
brevis with a common synovial sheath
■ Inferior Peroneal Retinaculum
■ It attached to the lateral surface of
calcaneum
■ The structures passing deep to it:
the tendons of the peroneus longus and
brevis muscle, each tendon possess a
synovial sheath
■ Structures that pass behind the
lateral malleolus superficial to the
Superior Peroneal Retinaculum:
Sural nerve and small saphenous
vein

24. FOOT
The foot is the region of the lower limb
distal to the ankle joint. It is subdivided
into the ankle, the metatarsus, and the
digits.
The foot has a superior surface (dorsum of
foot) and an inferior surface (sole of the
foot)
The foot is the body's point of contact with
the ground and provides a stable
platform for upright stance. It also
levers the body forward during walking.

25. Bones of the foot

26. The cutaneous innervation of the dorsum of the foot
■ The deep peroneal nerve
supplies the web of skin
between the contiguous sides
of the first and second toes
■ The superficial peroneal
nerve supplies the remainder
of dorsum of foot.
■ Medial side by the saphenous
nerve, which extends distally
to the head of the first
metatarsal.
■ Lateral side by the sural nerve

27. Dorsal Venous Arch
■ The dorsal venous arch lies in the subcutaneous tissue
over the heads of the metatarsal bones and drains on the
medial side into the great saphenous vein and on the
lateral side into the small saphenous vein.
■ The great saphenous vein leaves the dorsum of the foot
by ascending into the leg in front of the medial
malleolus.
■ The small saphenous vein ascends into the leg behind the
lateral malleolus.
■ The greater part of the blood from the whole foot drains
into the arch via digital veins and communicating veins
from the sole, which pass through the interosseous
spaces

29. DEEP FASCIA OF THE DORSUM OF THE FOOT
■ The deep fascia is thin on the dorsum of the foot, where
it is continuous with the inferior extensor retinaculum
MUSCLE OF THE DORSUM OF THE FOOT
■ Extensor Digitorum Brevis
■ Origin: upper surface of the calcaneum and from the
inferior extensor retinaculum
■ Insertion: by four tendons into the proximal phalanx of
big toe and long extensor tendons to second, third, and
fourth toes
■ Nerve Supply: Deep peroneal nerve.
■ Action: Extension of the medial 4 toes.

30. MUSCLE OF THE DORSUM OF THE FOOT

31. The Insertion of the Long Extensor Tendons
■ The tendon of extensor digitorum longus passes deep to the
superior and inferior extensor retinacula. The tendon divides into four,
which pass to the lateral four toes. Opposite the metatarsophalangeal
joints of the second, third, and fourth toes, each tendon is joined on its
lateral side by a tendon of extensor digitorum brevis.
■ The Extensor Expansion On the dorsal surface of each toe, the
extensor tendon joins the fascial expansion called extensor expansion
■ Near the proximal interphalangeal joint, the extensor
expansion splits into three parts: a central part, which is
inserted into the base of the middle phalanx, and two lateral
parts, which converge to be inserted into the base of the
distal phalanx .
■ The dorsal expansion, receives the tendons of insertion of the
interosseous and lumbrical muscles

34. Synovial sheath of the tendon of extensor
digitorum longus
■ The extensor digitorum
longus and peroneus tertius
tendons are surrounded by a
common synovial sheath as
they pass beneath the
extensor retinacula.
■ The sheath extends
proximally for a short
distance above the malleoli
and distally to the level of
the base of the fifth
metatarsal bone.

35. The dorsalis pedis artery
■ Origin: It is the direct continuation of the anterior tibial
artery.
■ Course: It begins midway between the 2 malleoli (at the
ankle joint) superficial in position and is crossed by the
inferior extensor retinaculum and the first tendon of
extensor digitorum brevis.
■ Relations: On its lateral side lie the terminal part of the
deep peroneal nerve and the extensor digitorum longus
tendons. On the medial side lies the tendon of extensor
hallucis longus. Its pulsations can easily be felt.
■ Termination by passing downward into the sole between
the two heads of the first dorsal interosseous muscle,
where it joins the lateral plantar artery and completes
the plantar arch

36. a. deep plantar artery
b. dorsalis pedis artery
c. anterior tibial artery

37. Branches of the dorsalis pedis artery
■ 1. The medial and lateral tarsal
arteries
■ 2. The first dorsal metatarsal
artery which supplies both sides of
the big toe
■ 3. The arcuate artery, which gives
off the second, third, and fourth
dorsal metatarsal arteries, which run
to the clefts of the toes, where each
of them divides into two dorsal
digital arteries.
■ 4. The deep plantar artery passes
deeply to enter the sole of the foot,
where it joins the lateral plantar
artery to form the deep plantar
arch.

38. Deep Peroneal Nerve (The anterior tibial nerve )
■ The deep peroneal nerve enters the dorsum of the
foot by passing deep to the extensor retinacula on
the lateral side of the dorsalis pedis artery.
It divides into medial, and lateral branches.
■ The medial branch supplies the skin of the adjacent
sides of the big and second toes.
■ The lateral branch supplies the extensor digitorum
brevis muscle.
■ Both terminal branches give articular branches to
the joints of the foot.