Lecture 13: Anterior and Posterior Leg Flashcards
What are the bones of the lower leg and what holds them together?
Tibia and fibula
Held together by interosseous membrane
What important anatomical structures are included in the superficial fascia of the leg?
Saphenous veins = great saphenous v. and lesser saphenous v.
Where do the saphenous veins arise from?
Dorsal venous plexus of the foot
Describe the path of the great saphenous v. as it arises from the dorsal venous plexus of the foot
Ascends anteriorly to the medial malleolus, up the medial leg, becomes a tributary to the femoral v. in the femoral triangle
Describe the path of the lesser saphenous v. as it arises from the dorsal venous plexus of the foot
Ascends posteriorly to the lateral malleolus and then continues on the back of the leg to become a tributary to the popliteal v.
What 5 nerves provide cutaneous innervation to the lower leg?
Posterior femoral cutaneous n. Saphenous n. Superficial peroneal n. Lateral sural cutaneous n. Medial sural cutaneous n.
What is the deep investing fascia of the leg?
Crural fascia
Where does the crural fascia attach to the leg?
Anterior and medial borders of the tibia
2 intermuscular septa also extend from the crural fascia to the fibula (anterior + posterior)
What divides the lower leg into 3 compartments?
Interosseous membrane + 2 intermuscular septa formed by crural fascia
In general, what action is performed by the contents of the anterior compartment of the leg?
Anterior compartment contains the dorsiflexors of the ankle
What innervates all muscles of the anterior compartment of the leg, and what is this a terminal branch of?
All muscles are innervated by the deep peroneal n., which is a terminal branch of the common peroneal n.
What is the blood supply to the anterior compartment of the leg, and what is this a terminal branch of?
Anterior tibial a., which is a terminal branch of the popliteal a.
What are the muscular contents of the anterior compartment of the leg?
Tibialis anterior m.
Extensor digitorum longus m.
Peroneus tertius m.
Extensor hallucis longus m.
Origin of tibialis anterior
Upper 2/3 of lateral shaft of tibia + interosseus membrane
Insertion of tibialis anterior
Medial side of medial (1st) cuneiform + base of 1st metatarsal
Action of tibialis anterior
Dorsiflexion and inversion of foot
Origin of extensor digitorum longus
Anterior surface of fibula + interosseus membrane
Insertion of extensor digitorum longus
Middle and distal phalanges of toes 2-5 (by way of dorsal expansions)
Action of extensor digitorum longus
Extension of toes, dorsiflexion and eversion of foot
Origin of peroneus tertius
Distal fibula + interosseus membrane
Insertion of peroneus tertius
Base of 5th metatarsal
Action of peroneus tertius
Dorsiflexion and eversion of foot
Origin of extensor hallucis longus
Middle of 1/2 of anterior fibula + interosseus membrane
Insertion of extensor hallucis longus
Base of distal phalanx of big toe
Action of extensor hallucis longus
Extension of big toe, dorsiflexion of foot
Origin/insertion/action:
Tibialis anterior m.
Origin: upper 2/3 of lateral shaft of tibia + interosseus membrane
Insertion: medial side of medial (1st) cuneiform + base of 1st metatarsal
Action: dorsiflexion and inversion of foot
Origin/insertion/action:
Extensor digitorum longus m.
Origin: anterior surface of fibula + interosseus membrane
Insertion: middle and distal phalanges of toes 2-5 (by way of dorsal expansion)
Action: extension of toes, dorsiflexion and eversion of foot
Origin/insertion/action:
Peroneus tertius m.
Origin: distal fibula + interosseus membrane
Insertion: base of 5th metatarsal
Action: dorsiflexion and eversion of foot
Origin/insertion/action:
Extensor hallucis longus m.
Origin: middle of 1/2 of anterior fibula + interosseus membrane
Insertion: base of distal phalanx of big toe
Action: extension of big toe, dorsiflexion of foot
What compartment of the leg contains 2 muscles that serve to evert the foot?
Lateral compartment
What supplies innervation to the lateral compartment of the leg and what is this a terminal branch of?
Superficial peroneal n., which is a terminal branch of the common peroneal n.
What is the blood supply to the lateral compartment of the leg, and what does this branch off of?
Fibular circumflex aa. = branches of peroneal a.
What are the muscular contents of the lateral compartment of the leg?
Peroneus longus m.
Peroneus brevis m.
Origin of peroneus longus
Lateral shaft of head of fibula
Insertion of peroneus longus
Medial (1st) cuneiform + base of 5th metatarsal
Action of peroneus longus m.
Plantar flexion and eversion of foot, supports arch of foot
Origin of peroneus brevis
Lateral shaft of fibula
Insertion of peroneus brevis
Base of 5th metatarsal
Action of peroneus brevis
Plantar flexion of foot
Origin/insertion/action:
Peroneus longus m.
Origin: lateral shaft of head of fibula
Insertion: medial (1st) cuneiform + base of 5th metatarsal
Action: plantar flexion and eversion of foot; supports arch of foot
Origin/insertion/action:
Peroneus brevis m.
Origin: lateral shaft of fibula
Insertion: base of 5th metatarsal
Action: plantar flexion of foot
What provides innervation to the posterior compartment of the leg?
Tibial n.
What muscles are present in the posterior compartment of the leg?
Gastrocnemius (lateral + medial heads) Soleus Plantaris Popliteus Flexor hallucis longus Flexor digitorum longus Tibialis posterior
Origin of gastrocnemius
Just superior to lateral+medial epicondyles of femur
Insertion of gastrocnemius
Middle of posterior surface of calcaneus
Action of gastrocnemius
Flexion of leg, plantar flexion of foot
Origin of soleus
Upper posterior surface of fibula
Insertion of soleus
Middle of posterior surface of calcaneus (same as gastroc)
Action of soleus
Plantar flexion of foot
Origin of plantaris
Lower lateral supracondylar line + popliteal surface of femur
Insertion of plantaris
Calcaneus tendon
Action of plantaris
Insignificant/unknown
Origin of popliteus
Tendon just inferior to lateral epicondyle of femur
Insertion of popliteus
Posterior tibia above popliteal line
Action of popliteus
Flexion of leg, rotation of tibia medially
Origin of flexor hallucis longus
Lower 2/3 of posterior fibula + interosseus membrane
Insertion of flexor hallucis longus
Base of distal phalanx of big toe
Action of flexor hallucis longus
Flexion of distal phalanx of big toe
Origin of flexor digitorum longus
Posterior surface of tibia below popliteal line
Insertion of flexor digitorum longus
Plantar surface of base of distal phalanges of toes 2-5
Action of flexor digitorum longus
Flexion of distal phalanges of toes 2-5
Origin of tibialis posterior
Interosseous membrane and posterior shaft of tibia+fibula
Insertion of tibialis posterior
Tuberosity of navicular, cuboid, 3 cuneiforms, + bases of 2-4th metatarsals
Action of tibialis posterior
Inversion of foot; assists in plantar flexion
Origin/insertion/action:
Gastrocnemius m.
Origin: superior to epicondyles of femur
Insertion: calcaneus
Action: leg flexion, foot plantar flexion
Origin/insertion/action:
Soleus m.
Origin: upper posterior fibula
Insertion: calcaneus
Action: plantar flexion of foot
Origin/insertion/action:
Plantaris m.
Origin: lateral supracondylar line + popliteal surface of femur
Insertion: calcaneus tendon
Action: insignificant
Origin/insertion/action:
Popliteus m.
Origin: tendon just inferior to lateral epicondyle of femur
Insertion: posterior tibia above popliteal line
Action: flexion of leg, rotation of tibia medially
Origin/insertion/action:
Flexor hallucis longus m.
Origin: posterior tibia below popliteal line
Insertion: plantar surface of base of distal phalanges of toes 2-5
Action: flexion of distal phalanges of toes 2-5
Origin/insertion/action:
Tibialis posterior m.
Origin: interosseous membrane and posterior shaft of tibia+fibula
Insertion: tuberosity of navicular, cuboid, 3 cuneiforms, and bases of 2-4 metatarsals
Action: inversion of foot, assists in plantar flexion
