Anatomy of the Leg: Nerves and Muscles
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Questions and Answers

What is the primary function of the flexor digitorum longus muscle?

  • Support of the medial longitudinal arch of foot only
  • Plantarflection of the foot
  • Flexion of toes 2-5 and inversion of the foot (correct)
  • Flexion of the hallux and foot

    • Which artery is the larger terminal branch of the popliteal artery?

  • Posterior tibial artery (correct)
  • Anterior tibial artery
  • Medial malleolar artery
  • Fibular artery

    • Which muscle primarily assists in the flexion of the big toe?

  • Tibialis posterior
  • Soleus
  • Flexor hallucis longus (correct)
  • Flexor digitorum longus

    • What is the main function of the tibialis posterior muscle?

    <p>Plantar flexion and inversion of the foot</p> Signup and view all the answers

    What type of branches does the fibular (peroneal) artery have?

    <p>Muscular branches, nutrient a. to fibula, and communicating branches</p> Signup and view all the answers

    What is the primary function of the gastrocnemius muscle?

    <p>Plantar flexion of the foot and leg</p> Signup and view all the answers

    Which nerve innervates the gastrocnemius muscle?

    <p>Tibial nerve</p> Signup and view all the answers

    Where does the small saphenous vein drain into?

    <p>Popliteal vein</p> Signup and view all the answers

    Which structure acts as a support for the tendons of the deep layer muscles in the posterior compartment?

    <p>Flexor retinaculum</p> Signup and view all the answers

    Which muscle is considered the most superficial in the posterior crural compartment?

    <p>Gastrocnemius</p> Signup and view all the answers

    What connects the medial malleolus to the calcaneus?

    <p>Flexor retinaculum</p> Signup and view all the answers

    Which layer of the posterior compartment contains the plantaris muscle?

    <p>Superficial layer</p> Signup and view all the answers

    Which muscle originates from the lateral condyle of the femur?

    <p>Popliteus</p> Signup and view all the answers

    What is the primary function of the flexor hallucis longus muscle?

    <p>Flexion of the hallux and foot</p> Signup and view all the answers

    What is the innervation of the tibialis posterior muscle?

    <p>Tibial nerve</p> Signup and view all the answers

    Which structure is NOT a branch of the posterior tibial artery?

    <p>Dorsalis pedis artery</p> Signup and view all the answers

    Where does the flexor digitorum longus muscle primarily insert?

    <p>Distal phalanges of toes 2-5</p> Signup and view all the answers

    Which function is associated with the fibular (peroneal) artery?

    <p>Muscular branches to lateral compartment of the leg</p> Signup and view all the answers

    What is the function of the flexor retinaculum in the posterior compartment of the leg?

    <p>Holds the deep group muscle tendons in place</p> Signup and view all the answers

    Which nerve is responsible for innervating the soleus muscle?

    <p>Tibial nerve</p> Signup and view all the answers

    Which of the following muscles is not part of the deep layer in the posterior compartment?

    <p>Soleus</p> Signup and view all the answers

    Which structure pierces the roof of the popliteal fossa and is involved in venous drainage?

    <p>Small saphenous vein</p> Signup and view all the answers

    What muscle group do the gastrocnemius and soleus muscles together form?

    <p>Triceps surae muscle group</p> Signup and view all the answers

    Which statement about the sural nerve is correct?

    <p>It is formed from both the tibial and common fibular nerves</p> Signup and view all the answers

    Where do the deep group muscles of the posterior compartment primarily insert?

    <p>Calcaneus</p> Signup and view all the answers

    What role does the interosseous membrane play in the leg?

    <p>Separates the anterior and posterior compartments</p> Signup and view all the answers

    Which muscle is responsible for performing flexion of toes 2-5?

    <p>Flexor digitorum longus</p> Signup and view all the answers

    What is the primary function of the tibialis posterior muscle?

    <p>Plantar flexion and inversion of the foot</p> Signup and view all the answers

    Which artery branches from the posterior tibial artery and supplies the fibula?

    <p>Fibular (peroneal) artery</p> Signup and view all the answers

    The flexor hallucis longus muscle originates from which of the following?

    <p>Lower part of the post surface of the fibula</p> Signup and view all the answers

    Which of the following muscles does NOT assist in plantar flexion of the foot?

    <p>Rectus femoris</p> Signup and view all the answers

    Which nerve is primarily responsible for innervating the muscles in the superficial layer of the posterior compartment of the leg?

    <p>Tibial nerve</p> Signup and view all the answers

    What anatomical structure divides the leg into three compartments?

    <p>Deep fascia of leg</p> Signup and view all the answers

    What is the primary function of the plantaris muscle?

    <p>Plantar flexion of the foot</p> Signup and view all the answers

    Which muscle originates from the soleal line of the fibula?

    <p>Soleus</p> Signup and view all the answers

    What muscle is considered part of the deep layer of the posterior compartment?

    <p>Flexor digitorum longus</p> Signup and view all the answers

    Which structure anchors the tendons of the deep group muscles in the posterior compartment?

    <p>Flexor retinaculum</p> Signup and view all the answers

    The gastrocnemius muscle inserts into which structure?

    <p>Tendocalcaneus</p> Signup and view all the answers

    What is the origin of the popliteus muscle?

    <p>Lateral condyle of the femur</p> Signup and view all the answers

    Study Notes

    Cutaneous Nerves of the Posterior Aspect of the Leg

    • Saphenous nerve - branch of the femoral nerve
    • Posterior femoral cutaneous nerve - branch of the sacral plexus
    • Lateral cutaneous nerve of leg - branch of the common fibular (peroneal) nerve
    • Sural nerve - branch of the tibial nerve and the common fibular (peroneal) nerve

    Superficial Veins

    • Small saphenous vein - pierces the popliteal fossa roof and empties into the popliteal vein

    Deep Fascia of the Leg (Fascia Cruris)

    • Interosseous membrane and "crural intermuscular septa" divide the leg into three compartments:
      • Anterior comparment
      • Lateral compartment
      • Posterior compartment - consists of two muscle groups:
        • Superficial
        • Deep

    Posterior Compartment Muscles - Superficial Group

    • Gastrocnemius muscle
    • Soleus muscle
    • Plantaris muscle

    Posterior Compartment Muscles - Deep Group

    • Popliteus muscle
    • Flexor digitorum longus muscle
    • Flexor hallucis longus muscle
    • Tibialis posterior muscle

    Flexor Retinaculum

    • Broad band of deep fascia
    • Extends from the medial malleolus to the calcaneus
    • Function: holds deep group muscle tendons in their proper places

    Gastrocnemius Muscle

    • Most superficial muscle of the posterior crural compartment
    • Origin: Two heads - lateral and medial condyles of the femur, join at the inferior margin of the popliteal fossa
    • Insertion: Calcaneous through the "tendo calcaneus" (Achilles tendon)
    • Nerve: Tibial nerve
    • Function: Flexion (plantar flexion) of the foot and leg

    Soleus Muscle

    • Located deep to the gastrocnemius muscle
    • Origin: Soleal line and the upper part of the fibula
    • Insertion: Calcaneous through the "tendo calcaneus"
    • Nerve: Tibial nerve
    • Function: Flexion of the foot

    Plantaris Muscle

    • Small and variable in size and extend, may be absent
    • Origin: Lateral supracondylar area of the femur
    • Insertion: Medial part of the tendo calcaneus
    • Nerve: Tibial nerve
    • Function: Assists flexion of the leg, plantar flexion of the foot

    Popliteus Muscle

    • Thin and triangular
    • Origin: Lateral condyle of the femur and the arcuate popliteal ligament
    • Insertion: Posterior surface of the tibia
    • Nerve: Tibial nerve
    • Function: Flexion and medial rotation of the leg

    Flexor Digitorum Longus Muscle

    • Origin: Posterior surface of the tibia below the soleal line
    • Insertion: Bases of the distal phalanges of digits 2-5
    • Nerve: Tibial nerve
    • Function: Flexion of digits 2-5, flexion of the foot, inversion of the foot, maintains the medial longitudinal arch of the foot

    Flexor Hallucis Longus Muscle

    • Long, powerful, and the largest muscle of the deep layer
    • Origin: Lower part of posterior surface of the fibula, interosseous membrane
    • Insertion: Base of the distal phalanx of the hallux (big toe)
    • Nerve: Tibial nerve
    • Function: Flexion of the hallux and foot, assisting in maintaining the foot's normal position.

    Tibialis Posterior Muscle

    • The deepest muscle of the posterior crural compartment
    • Origin: Lateral part of the posterior surface of the tibia (below the soleal line), posterior surface of the fibula, interosseous membrane
    • Insertion: Navicular bone, talus, cuneiform bones, cuboid bone, 2-4 metatarsal bones
    • Nerve: Tibial nerve
    • Function: Plantar flexes and inverts the foot

    Posterior Tibial Artery

    • Begins at the distal border of the popliteus muscle
    • Largest terminal branch of the popliteal artery
    • Accompanied by the tibial nerve
    • Branches:
      • Fibular (peroneal) artery
      • Circumflex fibular artery
      • Medial malleolar artery
      • Calcaneal branches
      • Nutrient artery for the tibia
      • Lateral and medial plantar arteries

    Fibular (Peroneal) Artery

    • Branch of the posterior tibial artery
    • Has: muscular branches, nutrient artery for the fibula, perforating branch, communicating branch, lateral malleolar branches, calcaneal branches.

    Posterior Aspect of the Leg

    • The saphenous nerve originates from the femoral nerve.
    • The posterior femoral cutaneous nerve originates from the sacral plexus.
    • The lateral cutaneous nerve of the leg originates from the common fibular (peroneal) nerve.
    • The sural nerve originates from the tibial nerve and common fibular (peroneal) nerve.
    • The small saphenous vein pierces the roof of the popliteal fossa and drains into the popliteal vein.

    Deep Fascia of the Leg

    • The deep fascia of the leg (fascia cruris), interosseous membrane, and crural intermuscular septa divide the leg into three crural compartments which are the anterior, lateral, and posterior compartment.
    • The posterior compartment contains two groups of muscles which are the superficial group and deep group.
    • Superficial muscles are the gastrocnemius, soleus, and plantaris muscles.
    • Deep muscles are the popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior muscles.

    Flexor Retinaculum

    • The flexor retinaculum is a band of deep fascia that passes from the medial malleolus to the calcaneus.
    • The flexor retinaculum holds the tendons of the deep group muscles in their proper places.

    Muscles

    • The superficial muscles of the posterior crural compartment are the gastrocnemius, soleus, and plantaris muscles.
    • The gastrocnemius muscle is the most superficial muscle in the posterior crural compartment.
      • It originates at the lateral and medial condyles of the femur, and they come together at the inferior margin of the popliteal fossa.
      • It inserts into the calcaneus via the tendo calcaneus (Achilles tendon).
      • It is innervated by the tibial nerve.
      • It is responsible for flexion (plantar flexion) of the foot and leg.
    • The soleus muscle is located deep to the gastrocnemius muscle.
      • It originates at the soleal line and the upper part of the fibula.
      • It inserts into the calcaneus via the tendo calcaneus.
      • It is innervated by the tibial nerve.
      • It is responsible for flexion of the foot.
    • The plantaris muscle is a small muscle that is variable in size and extent, and it may be absent.
      • It originates at the lateral supracondylar area of the femur.
      • It inserts into the medial part of the tendo calcaneus.
      • It is innervated by the tibial nerve.
      • It assists with flexion of the leg and plantar flexion of the foot.
    • The deep muscles of the posterior crural compartment are the popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior muscles.
    • The popliteus muscle is a thin, triangular muscle.
      • It originates at the lateral condyle of the femur and arcuate popliteal ligament.
      • It inserts into the posterior surface of the tibia.
      • It is innervated by the tibial nerve.
      • It is responsible for flexion and medial rotation of the leg.
    • The flexor digitorum longus muscle originates at the posterior surface of the tibia below the soleal line and inserts into the bases of the distal phalanges of the 2nd-5th toes.
      • It is innervated by the tibial nerve.
      • It is responsible for flexion of the toes, flexion of the foot, and inversion of the foot, and it also helps maintain the medial longitudinal arch of the foot.
    • The flexor hallucis longus muscle is the long, powerful, and largest muscle of the deep layer.
      • It originates at the lower part of the posterior surface of the fibula and the interosseous membrane.
      • It inserts into the base of the distal phalanx of the hallux (big toe of the foot).
      • It is innervated by the tibial nerve.
      • It is responsible for flexion of the hallux and the foot, and it is also important in holding the leg in the normal position of the foot.
    • The tibialis posterior muscle is the deepest muscle in the posterior crural compartment.
      • It originates at the lateral part of the posterior surface of the tibia below the soleal line, the posterior surface of the fibula, and the interosseous membrane.
      • It inserts into the navicular bone, talus, cuneiform bones, cuboid bone, and the 2nd-4th metatarsal bones.
      • It is innervated by the tibial nerve.
      • It is responsible for plantar flexion and inversion of the foot.

    Posterior Tibial Artery

    • The posterior tibial artery begins at the distal border of the popliteus muscle.
    • It is the larger terminal branch of the popliteal artery.
    • It is accompanied by the tibial nerve.
    • It has the following branches: fibular (peroneal) artery, circumflex fibular artery, medial malleolar artery, calcaneal branches, nutrient artery of the tibia, and lateral and medial plantar arteries.

    Fibular (Peroneal) Artery

    • The fibular (peroneal) artery is a branch of the posterior tibial artery.
    • It has muscular branches, nutrient artery to the fibula, perforating branch, communicating branch, lateral malleolar branches, and calcaneal branches.

    Cutaneous Nerves

    • Saphenous nerve is a branch of the femoral nerve.
    • Posterior femoral cutaneous nerve is a branch of the sacral plexus.
    • Lateral cutaneous nerve of leg is a branch of the common fibular nerve.
    • Sural nerve is a branch of both the tibial nerve and common fibular nerve.

    Superficial Veins

    • Small saphenous vein pierces the roof of the popliteal fossa and drains into the popliteal vein.

    Crural Compartments

    • Deep fascia of the leg divides the leg into three compartments: anterior, lateral, and posterior.

    Posterior Compartment Muscles

    • Posterior compartment contains two groups of muscles: superficial and deep.
    • Superficial group:
      • Gastrocnemius muscle
      • Soleus muscle
      • Plantaris muscle
    • Deep group:
      • Popliteus muscle
      • Flexor digitorum longus muscle
      • Flexor hallucis longus muscle
      • Tibialis posterior muscle

    Flexor Retinaculum

    • It is a broad band of deep fascia that helps hold the tendons of the deep muscles in place.

    Superficial Layer Muscles

    • Gastrocnemius muscle:
      • Most superficial muscle in the posterior compartment.
      • Originates from the lateral and medial condyles of the femur.
      • Inserts onto the calcaneus via the calcaneal tendon (Achilles tendon).
      • Innervated by the tibial nerve.
      • Function: Flexion of the foot and leg.
    • Soleus muscle:
      • Located deep to the gastrocnemius.
      • Originates from the soleal line and upper part of the fibula.
      • Inserts onto the calcaneus via the calcaneal tendon.
      • Innervated by the tibial nerve.
      • Function: Flexion of the foot.
    • Plantaris muscle:
      • Small, variable muscle.
      • Originates from the lateral supracondylar area of the femur.
      • Inserts onto the medial part of the calcaneal tendon.
      • Innervated by the tibial nerve.
      • Function: Assists in flexion of the leg and plantar flexion of the foot.

    Deep Layer Muscles

    • Popliteus muscle:
      • Thin, triangular muscle.
      • Originates from the lateral condyle of the femur and the arcuate popliteal ligament.
      • Inserts onto the posterior surface of the tibia.
      • Innervated by the tibial nerve.
      • Function: Flexion and medial rotation of the leg.
    • Flexor digitorum longus muscle:
      • Originates from the posterior surface of the tibia below the soleal line.
      • Inserts onto the bases of the distal phalanges of the 2nd to 5th toes.
      • Innervated by the tibial nerve.
      • Function: Flexion of the toes 2-5 and foot, inversion of the foot, and helps maintain the medial longitudinal arch.
    • Flexor hallucis longus muscle:
      • Longest, most powerful muscle in the deep layer.
      • Originates from the lower part of the posterior surface of the fibula and the interosseous membrane.
      • Inserts onto the base of the distal phalanx of the hallux (big toe).
      • Innervated by the tibial nerve.
      • Function: Flexion of the hallux and foot, also helps hold the leg in normal foot position.
    • Tibialis posterior muscle:
      • Deepest muscle in the posterior compartment.
      • Originates from the lateral part of the posterior surface of the tibia below the soleal line, posterior surface of the fibula, and the interosseous membrane.
      • Inserts onto the navicular bone, talus, cuneiform bones, cuboid bone, and the 2nd to 4th metatarsal bones.
      • Innervated by the tibial nerve.
      • Function: Plantar flexes and inverts the foot.

    Posterior Tibial Artery

    • Begins at the distal border of the popliteus muscle.
    • Largest terminal branch of the popliteal artery.
    • Accompanied by the tibial nerve.
    • Branches:
      • Fibular (peroneal) artery
      • Circumflex fibular artery
      • Medial malleolar artery
      • Calcaneal branches
      • Nutrient artery of the tibia
      • Lateral and medial plantar arteries

    Fibular (Peroneal) Artery

    • Branch of the posterior tibial artery.
    • Branches:
      • Muscular branches
      • Nutrient artery to the fibula
      • Perforating branch
      • Communicating branch
      • Lateral malleolar branches
      • Calcaneal branches

    Support to the Foot

    • Foot support comes from both the medial and lateral sides of the posterior compartment.

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    Posterior Aspect of the Leg PDF

    Description

    Explore the fascinating anatomy of the leg, focusing on the cutaneous nerves, superficial veins, and deep fascia structures. This quiz will test your knowledge on the various muscles in the posterior compartment and their functions. Perfect for students studying human anatomy or medical professionals looking to refresh their understanding.

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