Back of the leg

ByProf. Saeed Abuel Makarem

Muscles of the back of the leg• It is divided into • 2 groups:• Superficial: 3 muscles,• Gastrocnemius.• Plantaris.• Soleus.• Deep: 4 muscles,• Popliteus.• Flexor digitorum longus.• Flexor hallucis longus.• Tibialis posterior.

Gastrocnemius Origin: 2 heads Med: popliteal surface of

the femur above medial condyle.

Lat: lateral aspect of lateral condyle of femur.

Insertion: through the tendo calcaneus to post surface of calcaneus.

Nerve: Tibial nerve. Action: Flexion of knee joint Planter flexion of the foot.

PlantarisPlantaris• Small fusiform muscle.• May be absent or doubled• Homologues to palmaris longus• Origin: lateral supracondylar

ridge of the femur.• Insertion: long ribbon- like

tendon descends between Gastrocnemius & soleus.

• then on medial side of tendo Achillesto t he back of the calcaneus.

• Nerve: Tibial nerve.• Action: assists in• Flexion of the knee.• Planter flexion of the foot.

Soleus It is a broad flat muscle It forms the main bulk of the

calf. Origin: inverted V-shaped from

soleal line of tibia, upper ¼th of back of the fibula & fibrous arch between tibia and fibula.

Insertion: tendo calcaneus Nerve: Tibial nerve. Action: Planter flexion of ankle. Main forward propulsive force

in walking & running with Gastrocnemius & plantaris

Deep Group Popliteus• Origin: lateral surface of lateral

condyle of the femur• It is intra capsular, it takes partial

origin from the lateral semilunar cartilage.

• Insertion: post. surface of the tibia above the soleal line.

• Nerve: Tibial nerve.• Action:• Unlocking of the knee joint• Flexion of the knee.• NB. tendon of popliteus separates

between lateral meniscus and lateral collateral ligament of the knee

Flexor digitorum longus

• Origin: medial part of back of the tibia below the soleal line.

• Insertion: terminal phalanges of lateral four toes.

• Each slip pierces the tendon of flexor digitorum brevis of the sole.

• Nerve: Tibial nerve• Action:• Planter flexion of the terminal

phalanx of the lateral 4 toes.• Assists in planter flexion of the

foot

Flexor hallucis longus• Origin: lower 2/3rd of the posterior surface of the fibula

• Insertion: Base of the distal phalanx of the big toe.

• Nerve: Tibial nerve.• Action: Planter flexion of the

distal phalanx of big toe• Assists in planter flexion of

the foot.• Maintenance of medial

longitudinal arch of the foot.

TIBIALIS POSTERIOR• Origin:• Back of interosseous membrane.• Back of tibia lateral to vertical line• Back of fibula medial to medial crest• Insertion:• All tarsus except talus.• The main insertion into tuberosity of the

navicular bone.• It is also inserted into the base of 2nd,3rd& 4th

metatarsal bones.• Nerve: Tibial nerve• Action:• Planter flexion• Inversion • Maintain the medial longitudinal arch.

Posterior tibial artery One of the two terminal

branches of popliteal artery Begins at level of the distal

border of popliteus muscle Passes downward deep to

Gastrocnemius & soleus It descends on posterior

surface of tibialis posterior Its lower part lies on back

of tibia covered by skin & fascia

It passes behind the medial malleolus to the sole

TD

AVN

HH

Tome: Tibialis posteriorDoes: Flexor digitorum longus A: Posterior tibial arteryV: Posterior tibial veinN: Posterior tibial nerveHat: Flexor hallucis longus

• Branches of posterior tibial artery (PTA):

• 1- Peroneal artery:• Arises close to the origin of

PTA.• Gives nutrient artery to the

fibula & descends behind it.• Gives muscular branches• Shares in anastomosis around

the ankle• 2- Muscular branches• 3- Nutrient artery to tibia• 4-Medial planter artery• 5- Lateral planter artery

Tibial Nerve• Larger of the 2 terminal branches of sciatic nerve in the lower 1/3 of back of thigh

• It bisects the popliteal fossa• It passes deep to the Gastrocnemius

and soleus• It lies on posterior surface of tibialis

posterior• It accompanies the posterior tibial

artery.• It passes behind the medial

malleolus to reach the sole• Branches:• Muscular branches.• Medial calcaneal branch to • Articular to ankle joint• Medial & lateral planter nerves

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Sciatic Nerve Injury• The sciatic nervesciatic nerve (L4 and 5 and S1, 2, & 3)

curves laterally and downward through the gluteal region.

• It leaves the pelvis through the greater sciatic foramen below the piriformis.

• situated at first midway between the post. superior iliac spine and the ischial tuberosity.

• Then, it lies midway between the tip of the greater trochanter and the ischial tuberosity.

• Then it passes downward in the midline on the posterior aspect of the thigh and dividesdivides into the common peronealcommon peroneal and tibial nerves,tibial nerves, at a variable site above the popliteal fossa.

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TraumaThe sciatic nervesciatic nerve is sometimes injured by:

• penetrating wounds, • fractures of the pelvis, or • dislocations of the hip joint.

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• The sciatic nerve is most frequently injuredmost frequently injured by…?

- badly placed - badly placed intramuscular injections intramuscular injections in the gluteal region.in the gluteal region.

• To avoid this injury, injections into the gluteus maximus or the gluteus medius should be made…

• ….well forward on the upper outer upper outer quadrant of the buttock. quadrant of the buttock.

• Most nerve lesions are incomplete,Most nerve lesions are incomplete, and in in 90% of injuries, the common peroneal 90% of injuries, the common peroneal part of the nerve is the most affected.part of the nerve is the most affected. Why? - The common peroneal nerve fibers lie most superficialmost superficial in the sciatic nerve.

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The following clinical features are present:

Motor: Motor: • The hamstring muscles are The hamstring muscles are

paralyzed,paralyzed, but weak flexion of the weak flexion of the knee is possible. knee is possible. Why? - because of the action of the sartorius (femoral nerve) and gracilis (obturator nerve).

• All the muscles below the knee are paralyzed, and the weight of the foot causes it to assume the plantar-plantar-flexed position,flexed position, or foot drop.

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Sensory: Sensory:

• Sensation is lost below below the knee,the knee, except for a except for a narrow area down the narrow area down the medial side of the lower medial side of the lower part of the legpart of the leg and along the medial border of the foot as far as the ball of the big toe, which is supplied by the saphenous nerve (femoral nerve).

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Sciatica• Sciatica describes the

condition in which patients have pain along pain along the sensory distribution the sensory distribution of the sciatic nerve. of the sciatic nerve.

• Thus the pain is experienced in the posterior aspect of the thigh, the posterior and lateral sides of the leg, and the lateral part of the foot.

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Sciatica can be caused by: • prolapse of an intervertebral disc, with

pressure on one or more roots of the lower lumbar and sacral spinal nerves,

• pressure on the sacral plexus or sciatic nerve by an intrapelvic tumor, or

• inflammation of the sciatic nerve or its terminal branches.

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