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