Download Anterior compartment of the leg

Front of the leg and dorsum of the foot
Dr. Eman
The deep fascia (crural fascia)
the fascia lata of the thigh continuous onto the leg and called the crural
fascia.
It is connected to the bones by intermuscular septa,and forms thickened
bands at the ankle called retinacula which act as a pulley around the
tendons of ms.
The Retinacula:
1- superior extensor retinacula it is broad extends between
and the medial surface of the tibia.
2- Inferior extensor retinacula is Y shaped.
the fibula
3-Superior peroneal retinaculum extends from the lateral malleolus
downwards and backwards attached to the lateral surface of the
calcaneum
4-Inferior peroneal retinaculum attached to the lateral surface of the
calcaneum above and below the peroneal muscles.
5-Flexor retinacula extends from the medial malleolus downwards and
backwards to be attached to the medial tubercle of calcaneum
The dorsum of the foot contains the structures which extend from the
anterior compartment of the leg.
The fascia of the dorsum of the foot is thin, it is continuous with the
extensor retinacula curves over the margins of the foot and becomes the
fascia of the sole.
Intermuscular septa:
These are extensions from the deep fascia of the leg to the tibia and fibula
so that it separate the leg into 3 compartments. These septa are:
1- The interosseous membrane between the tibia and fibula separate the
anterior and posterior compartments.
2- Anterior intermuscular septa attached to the anterior border of the fibula
separate the anterior and lateral compartments.
3- The posterior septa attached to the posterior border of the fibula separate
the posterior and lateral compartments. From the posterior septa a broad
transverse intermuscular septa separating the superficial and deep groups
of calf muscles.
Anterior compartment of the leg
the anterior compartment ( dorsiflexion) lies in front of interosseous
membrane and the fibula,. it contains the following muscles:,Tibialis
anterior m.,.extensor hallucis longus m., extensor digitorum longus m.,
peroneus tertius m.
Vessels of this compartment are the anterior tibial vessels and the
nerve is the deep peroneal nerve.
muscle
origin
Tibialis anterior( TA)
Upper 2/3of lateral
surface
of
tibia
+interosseous membr.
Extensor digitorum Upper 3/4of anterior
longus(EDL)
surface
of
fibula
+interosseous membr
Extensor
halucis Middle 1/3of ant. surface
longus (EHL)
of fibula +interosseous
membr
insertion
Medial
cuneiform
+adjacent part of first
metatarsal.
Via 4 tendon into the
lateral
toes
,for
extensor expantion
Base of distal phalanx
of big toe
Peroneus tertius (PT)
lower
1/4of
antrior base of 5 metatarsal
surface
of
fibula
+interosseous membr
Action : TA: dorsiflexion of foot (at ankle)+ inversion of foot.
EDL:extension of toes +dorsiflexion of foot. EHL:extension of big
toe+dorsiflexion. PT:eversion of foot
Extensor expansions
It is formed on the dorsum of the proximal phalanx by the union
of 5 tendons: 1- tendon of the extensor digitorum longus 2- tendon of
the extensor digitorum brevis 3- tendon of one lumbrical muscle. 4tendon of two interossel m. the expantion divides into 3 parts .The
thick central part inserted in the base of the middle phalanx. The
lateral and medial parts of the expansion continue distally fused
together and inserted in the base of the distal phalanx. The big toe
has no ext.expantion. the ext. expantion of little toe is formed by the
union of 3 tendone
1-tendone of extensor digit. Longus
2- tendon of one lumbrical muscle
3- tendon of one interossel m.
Anterior tibial artery
Arises from the popliteal artery at the lower border of the popliteus
m. it passes forwards above the upper border of the interosseous
membrane close to the neck of the fibula then descends forward on the
membrane with the deep peroneal nerve passing behind the superior
extensor retinaculum. The tendon of extensor hallucis m. lies on its
medial side and the deep peroneal nerve and tendons of extensor
digitorum m. on its lateral side. It ends in the front of the ankle joint
by becoming the dorsalis pedis artery midway between the malleoli.
Branches:
1- muscular branches to the muscles of the anterior compartment.
2- Anterior tibial recurrent artery passes upwards to the knee joint.
3- Medial and lateral malleolar arteries to the lateral and medial
malleoli,
Deep peroneal nerve( ant. Tibial nerve)
Arises from the common peroneal nerve lateral to the neck of the
fibula. it pierces the peroneus longus m and descends in the anterior
compartment between EDL and TA in upper part then between EHL
and TA. It pass lateral to the anterior tibial vessels, near the ankle
joint it crossed by the extensor hallucis longus m. enters the dorsum of
the foot midway between the malleoli with the dorsalis pedis artery. It
gives :
1. articular branch to ankle joint
2. Muscular branches to all muscles of the anterior
compartment.
Lateral side of the leg
Composed of the muscles which cover the lateral surface of the leg.
These are peroneus longus and brevis ms. supplied by the superficial
peroneal nerve.
muscle
origin
insertion
lateral In the base of 1st
metatarsal and medial
cuneiform on their
lateral sides
Peroneus brevis
Lower 2/3 of lateral On the medial aspect
surface of fibula
of base
of
5th
metatarsal bone
Action :both act as everter of foot (mainly) .
Assist in planter flexion.
Peroneus longus
Upper 2/3 of
surface of fibula
Superficial peroneal nerve:
Descend in the peroneus longus m. to reach the peroneus brevis m.
supply both muscles, then it descend between it and extensor
digitorum longus m. pierce the deep fascia in the distal 1/3 of the leg
and divides into medial and intermediatecutaneous nerves. It
supply the skin of the lower third of the front of the leg, the greater
part of the dorsum of the foot and most of the dorsal surface of the
toes expect the first interdigital cleft and the lateral side of the little
toe.
The back of the leg
The transverse intermuscular septa divide the back of the leg into
superficial posterior compartment
and the deep posterior
compartment, they supplied by the tibial nerve. The superficial layer
consist of the muscles which inserted in the heel by the
tendocalcaneus, these muscles are the powerful planter flexors of the
ankle joint, include gasterocnemius, soleus and plantaris muscles.
the deep layer consist of long flexors muscles of the toes these are,
flexor hallucis and flexor digitorum longus muscles and popliteus,
,tibialis posterior.
muscle
origin
insertion
gastrocnemius
Arises by 2 heads
lateral and medial
from lateral and
medial condyle of
femur
1-Post. Surface of
head of fibula +post .
surf. Of upper 1/3 of
fibula 2-Solial line of
tibia
Lower part of lateral
supracondylar ridge
of femur
By tendocalcaneus
tendon
into
the
dorsum of calcaneum
bone
soleus
plantaris
Back of calcaneum
Action :raises the heel of the foot on the ground on propulsive movement
during walking in addition they share in planter flexion of foot.
muscle
origin
insertion
popliteus
Lateral
surface
of Posterior surface of tibia
lateral condyle of femur above the soleal line
Flexor digitorum longus Posterior surface of Via its 4 tendon to the bases
tibia
of the distal phalanges of
lateral 4 toes
Flexor halucis longus
Lower 2/3of Posterior Distal phalanx of big toe
surface of fibula
Tibialis posterior
Posterior surface of Mainly into tuberosity of
tibia and fibula
navicular bone and to the
all tarsal bone except the
talus
Action: fl. Hallucis :flexion of big toe +planter flexion
Fl.digit. flexion of toes+planter flexion
Tibialis post. Inversion of foot +planter flexion
The princible nerve of the back of the leg is the Tibial nerve
(L4,5,S1,S2,S3) passes under the tendinous arch of the soleus muscle and
descend under the transverse intermuscular septum superficial to the
posterior tibial vessels. in the upper part of the leg it lies on the popliteus
m. then posterior to the tibialis posterior m. in the lower third of the leg it
lies between tendons of flexor digitorum longus and flexor hallucis
longus ms. the tibial nerve divides deep to the flexor retinaculum into
medial and lateral planter nerves.
Branches in the leg:
1- muscular branches to the tibialis posterior, flexor digitorum longus,
flexor hallucis longus and deep part of soleus m.
2- cutaneous branches include medial calcanean nerve (S1) arise in
the ankle pierce the flexor retinaculum supply the skin on the
posterior and lower part of the heel.
3- Small articular branch to the capsule of the ankle joint.
The posterior tibial artery
It is the direct continuation of the popliteal artery, supply the
muscles of the back and it is the main artery of the foot begin at the
lower border of the popliteus m. then descend with the tibial nerve
and two venae commitants deep to the gastrocnemius, soleus and the
transverse intermuscular septum of the leg. it runs first laterally to
give the peroneal artery then it inclines medially passes behind the
medial malleolus, ends by dividing into medial and lateral planter
arteries deep to the flexor retinaculum.
Branches in the leg:
1- peroneal artery it is the largest branch, arises from the posterior
tibial artery 2-3 cm below the lower border of the popliteus
muscle, descend obliquely along the back of fibula deep to the
flexor hallucis m. and ends in branches to the ankle and heel. it
gives:
a- muscular branches to the muscles of the lateral compartment of the
leg.
b- Nutrient branch to the fibula.
c- Perforating artery which pierces the distal end of the interosseous
membrane
The peroneal artery ends by giving post. lateral malleollar branch
to the lateral side of the back of the heel
2- circumflex fibular artery runs around the neck of the fibula
3- Nutrient artery to the tibia.
4- Muscular branches to the deep muscles of the back of the leg
5-Posterior medial malleolar to the posterior part of the medial
malleolus.
6- medial and lateral planter art.