ANA 211 Lower limb 3 Compartments of the leg Flashcards
Interosseous membrane
A thin & strong membrane, that binds the interosseous borders of tibia & fibula.
It binds the two bones and provides attachment for muscles.
What is the weight bearing bone of the leg and is therefore much larger
the tibia
Which takes part of the knee joint
tibia
compartments of the leg
The leg is divided into anterior (extensor), posterior (flexor), and lateral (fibular)
the compartments of the leg are divided by
Two Intermuscular Septa
Anterior border of fibula (Anterior fascial septum)
Posterior border of fibula (Posterior fascial septum)
the medial and lateral malleolus are formed by
tibia and fibula respectively
Action of muscles in the anterior compartment of leg
dorsiflex the ankle, extend the toes, and invert the foot.
Action of muscles in the posterior compartment of the leg
plantarflex the ankle, flex the toes, and invert the foot.
Action of muscles in the lateral compartment of the leg
evert the foot
Why is the proximal end of the tibia is large?
The proximal end of the tibia is large because its medial and lateral condyles articulate with the large condyles of the femur.
Describe the superior surface of the tibia
The superior surface of the tibia is flat, forming a tibial plateau consisting of the medial and lateral tibial condyles and an intercondylar eminence.
This eminence of the tibia fits into the intercondylar fossa between the femoral condyles.
Describe the shaft of tibia
The shaft of tibia is triangular in cross-section and has anterior, interosseous, and medial borders ;
a medial, lateral, and posterior surface
the anterior and medial borders, and the entire anterior surface are subcutaneous and easily palpable;
the lateral border is connected, by the interosseous membrane, along its length to the interosseous margin of the fibula;
the posterior surface is marked by an oblique line (the soleal line).
What is the soleal line?
The soleal line descends across the bone from the lateral side to the medial side where it merges with the medial border.
In addition, a vertical line descends down the upper part of the posterior surface from the midpoint of the soleal line.
It disappears in the lower one-third of the tibia.
Which part of the tibia support the body’s weight at the knee and ankle joints.
shaft
Describe the distal part of the tibia
The posterior surface of the distal end of the tibia is marked by a vertical groove, which continues inferiorly and medially onto the posterior surface of the medial malleolus.
The groove is for the tendon of the tibialis posterior muscle.
The lateral surface of the distal end of the tibia is occupied by a deep triangular notch (the fibular notch), to which the distal head of the fibula is anchored by a thickened part of the interosseous membrane.
Describe the shaft of the fibula narrow?
The fibula is not involved in weight bearing and as a result the shaft is much narrower than the shaft of the tibia and except for the end it is mainly for muscle attachment.
Like the tibia, the shaft of the fibula is triangular in cross-section and has three borders and three surfaces for the attachment of muscles, intermuscular septa, and ligaments.
The interosseous border faces and is attached to the lateral border of the tibia by the interosseous membrane.
Describe the distal end of the fibula
At its distal end, the fibula enlarges to form the lateral malleolus, which is more prominent and posterior than the medial malleolus and extends approximately 1 cm more distally.
The posterior surface of the lateral malleolus is marked by a shallow groove for the tendons of the fibularis longus and fibularis brevis muscles.
The Interosseous membrane is also known as
the middle tibio-fibular ligament
The tibial tuberosity allows for the attachment of what
the patellar ligament
the anterior crest of the tibia allows for the attachment of what?
the deep fascia
Origin of the Gastrocnemius
Medial head-posterior surface of distal femur just superior to medial condyle;
lateral head-upper posterolateral surface of lateral condyle (of femur)
anatomical term for Achilles heel
calcaneal tendon
Insertion of Gastrocnemius
Via calcaneal tendon, to posterior surface of calcaneus
Innervation of Gastrocnemius
Tibial nerve [S1,S2]
Action of Gastrocnemius
Plantarflexes foot and flexes knee
Origin of Plantaris
Inferior part of lateral supracondylar line of femur and oblique popliteal ligament of knee
insertion of Plantaris
Via calcaneal tendon, to posterior surface of calcaneus
(above the gastronemius)
Innervation of Plantaris
Tibial nerve [S1,S2]
Action of Plantaris
Plantarflexes foot and flexes knee
Origin of the Soleus
Soleal line, medial border of tibia, head of fibula, posterior border of fibula
Insertion of the Soleus
Via calcaneal tendon, to posterior surface of calcaneus
Innervation of Soleus
Tibial nerve [S1,S2]
Action of Soleus
Plantarflexes the foot
Origin of Popliteus
Posterior surface of proximal tibia
Insertion of Popliteus
Lateral femoral condyle
Innervation of Popliteus
Tibial nerve [L4 to S1]
Action of Popliteus
Unlocks knee joint (laterally rotates femur on fixed tibia)
Muscles in the deep posterior compartment of leg
popliteus
flexor hallucis longus
flexor digitorum longus
tibialis posterior
Origin of Flexor hallucis longus
Posterior surface of fibula and adjacent interosseous membrane
Insertion of Flexor hallucis longus
Plantar surface of distal phalanx of great toe
Innervation of Flexor hallucis longus
Tibial nerve [S2,S3]
Action of Flexor hallucis longus
Flexes great toe
Origin of Flexor digitorum longus
Medial side of posterior surface of the tibia
Insertion Flexor digitorum longus
Plantar surfaces of bases of distal phalanges of the lateral four toes
Innervation of Flexor digitorum longus
Tibial nerve [S2,S3]
Action of Flexor digitorum longus
Flexes lateral 4 toes
Origin of Tibialis posterior
Posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula
Insertion of Tibialis posterior
Mainly to tuberosity of navicular and adjacent region of medial cuneiform
Innervation of Tibialis posterior
Tibial nerve [L4,L5]
Action of Tibialis posterior
Inversion and plantarflexion of foot; support of medial arch of foot during walking
What is the major blood supply to the leg and foot?
The popliteal artery
Course of the popliteal artery
The popliteal artery enters the posterior compartment of leg from the popliteal fossa behind the knee.
It passes into the posterior compartment of leg between the gastrocnemius and popliteus muscles.
At the deep region of the posterior compartment of leg it immediately divides into an anterior tibial artery and a posterior tibial artery.
The posterior tibial artery supplies the posterior and lateral compartments of the leg and continues into the sole of the foot.
In the leg, the posterior tibial artery has two major branches, the circumflex fibular artery and the fibular artery:
The nerve associated with the posterior compartment of leg is the ___________ a major branch of the sciatic nerve
tibial nerve
Branches of the tibial nerve
In the leg, the tibial nerve gives rise to:
branches that supply all the muscles in the posterior compartment of the leg
two cutaneous branches,
- the sural nerve which supplies skin on the lower posterolateral surface of the leg and the lateral side of the foot and little toe.
- medial calcaneal Nerve-nerve innervates skin on the medial surface and sole of the heel
the strongest dorsiflexor of the foot
tibialis anterior muscle
Origin of Tibialis Anterior
lateral surface of the tibial condyle and the superior two-thirds of the proximal shaft of tibia
Insertion of Tibialis Anterior
the medial cuneiform and the base of metatarsal I
Innervation of Tibialis Anterior
Deep fibular nerve
Action of Tibialis Anterior
Dorsiflexion and inversion of the foot
Origin of Extensor digitorum longus
the proximal half of the medial surface of fibula, the anterior surface of the lateral tibial condyle and the anterior surface of the interosseous membrane
Insertion of Extensor digitorum longus
Distal and middle phalanges of digits 2-5
Innervation of Extensor digitorum longus
Deep fibular nerve (L5, S1)
Action of Extensor digitorum longus
Extension of the lateral four toes, and dorsiflexion of the foot.
Origin of Extensor Hallucis Longus
Middle third of medial surface of fibula, interosseous membrane
Insertion of Extensor Hallucis Longus
Base of distal phalanx of great toe
Innervation of Extensor Hallucis Longus
Deep fibular nerve (L5, S1)
Action of Extensor Hallucis Longus
Extension of the great toe and dorsiflexion of the foot
Origin Fibularis Tertius
Medial surface (distal third) of fibula, interosseous membrane (anterior surface), anterior intermuscular septum
Insertion of Fibularis Tertius
Dorsal surface of base of metatarsal bone 5
Innervation of Fibularis Tertius
Deep fibular nerve (L5, S1
Action of Fibularis Tertius
Eversion and dorsiflexion of the foot.
The two muscles in the lateral compartment of the leg
the fibularis longus and brevis (also known as peroneal longus and brevis).
Origin of Fibularis Longus
Head of fibula, proximal 2/3 of lateral surface of fibula, intermuscular septa
Insertion of Fibularis Longus
Medial cuneiform bone, metatarsal bone 1
Innervation of Fibularis Longus
Superficial fibular nerve (L5, S1)
Action of Fibularis Longus
Eversion and plantarflexion of the foot. Also supports the lateral and transverse arches of the foot
Origin of Fibularis Brevis
Distal 2/3 of the lateral surface of fibula, anterior inermuscular septum
Insertion of Fibularis Brevis
Tuberosity of the 5th metatarsal bone
Innervation of Fibularis Brevis
Superficial fibular nerve (L5, S1)
Action of Fibularis Brevis
Eversion of the foot
Gastrocnemius strain (tennis leg)
is a painful acute injury resulting from partial
tearing of the medial belly of the gastrocnemius at or near its musculotendinous junction, often seen in individuals older than 40 years of age. It is caused by overstretching the muscle by concomitant full extension of the knee and
dorsiflexion of the ankle joint. Usually, the abrupt onset of stabbing pain is followed by oedema and spasms of the gastrocnemius.
Enumerate all ligaments of the knee
Anterior cruciate ligament
Posterior cruciate ligament
Lateral meniscus
Medial meniscus - firmly attached to the tibial collateral ligament
Transverse ligament
Fibular (lateral) collateral ligament
Tibial (medial) collateral ligament (not names on image)
Enumerate all arteries of the knee
the genicular branches of the
femoral, popliteal, and anterior and posterior recurrent branches of the anterior tibial recurrent and circumflex fibular arteries
Enumerate all nerves of the knee
