Anatomy of the leg Flashcards
What is the purpose of the fibula?
Provide area for muscle attachments
Interosseous membrane
Connects tibia and fibula
Has an opening to allow blood vessels into lower leg
What nerves provide cutaneous innervation of the leg
- Saphenous nerve
- Medial sural cutaneous nerve
- Lateral sural cutaneous nerve
- Sural communicating nerve
- Sural nerve
- Superficial peroneal nerve
Characteristics of saphenous nerve
- L3, L4 branch of femoral nerve
- Supplies skin on medial, posterior, and anterior part of leg
- Supplies part of the foot
What nerve is the medial sural cutaneous nerve a branch of?
tibial nerve
Characteristics of lateral sural nerve
- Branch of common peroneal nerve
- Supplies skin of lateral leg
- Becomes the sural communicating nerve
Characteristics of sural communicating nerve
- Branch of lateral sural cutaneous nerve
2. Joins with medial sural cutaneous nerve to make the sural nerve
Characteristics of the sural nerve
- Formed by the medial sural nerve and communicating sural nerve
- Gives off branches to the lower leg
- Important for the foot
Characteristics of superficial peroneal nerve
- Branch of common peroneal
- Courses through lateral compartment
- Supplies skin of anterolateral distal leg and dorsum of foot
Small saphenous vein discription
- begins lateral side of foot
- ascends along posterior medial leg
- Drains into popliteal vein posterior to knee joint
What is the crural fascia of the leg?
Deep fascia that is a continuation of the fascia lata
Attached to the anterior and medial borders of tibia
What septa does the crural fascia give rise to?
All attached to the fibula
- anterior intermuscular crural septum
- Posterior intermuscular crural septum
- Transverse intermuscular crural septum
What retinaculum does the crural fascia give rise to?
- Superior extensor retinaculum
- Inferior extensor retinaculum
- Flexor retinaculum
Where is the superior extensor retinaculum?
Goes from medial malleolus to lateral malleolus
What is the purpose of retinaculum?
Stops tendons from bow-stringing across the ankle
Where is the inferior extensor retinaculum?
Y goes across dorsal part of foot
What is the main action of the muscles in the anterior compartment of the leg?
- Dorsiflexors of the ankle
- Extensors of the toes
- Muscles are in the leg but action is in the foot
What muscles are in the anterior compartment of the leg?
- Tibialis anterior
- Extensor compartment:
- Peroneus tertius
The anterior compartment is also called the….?
Dorsiflexor (extensor) compartment
Characteristics of tibialis anterior muscle?
Part of anterior compartment O: tibia and IO membrane I: medial cuneiform and 1st metatarsal bone A: eversion, extend the ankle joint Shin splints occur here Strongest dorsiflexor
What muscles are in the extensor compartment of the anterior compartment?
- Extensor hallucis longus
2. Extensor digitorum longus
Extensor hallucis longus O and I
Part of anterior compartment
O: fibula and IO membrane
I: distal phalanx of 1st toe
Extensor digitorum longus O and I
Part of anterior compartment
O: tibia, fibula and IO membrane
I: Middle and distal phalanges of toes 2-5
Goes below extensor retinaculum to give off tendons to 4 lateral toes
Peroneus tertius muscle O and I
O: fibula and IO membrane
I: 5th metatarsal bone
Attaches to extensor digitorum longus
It has its own tendon that does not go down to the toes but to the 5th metatarsal
What nerve innervates the muscles of the anterior compartment?
Deep peroneal nerve = branch of the common peroneal nerve
Artery of the anterior compartment of the leg?
Anterior tibial artery
What artery is the anterior tibial artery a branch of?
Popliteal artery
What branches does the anterior tibial artery give off?
- Tibial recurrent artery
- Anterior medial and lateral malleolar artery
- Dorsalis pedis artery
What does the anterior tibial artery change its name to at the ankle joint?
dorsalis pedis to supply the foot
What is compartment syndrome?
-The deep fascia of the leg has no give to it ergo when an injury occurs and swelling, bleeding, etc happen the compression increases and causes more blood vessels to break and can lead to nerve damage
What happens if the common peroneal nerve is damaged?
Paralysis of all anterior and lateral compartment muscles
What are the main actions of the lateral compartment of the leg?
- Everter compartment
- raise the foot off the ground and it goes inward
Characteristics of the lateral compartment of the leg
Muscles have their own retinaculi = peroneal retinacula
These muscles are easily over used
What muscles are in the lateral compartment
- peroneus longus
2. peroneus brevis
Peroneus longus muscle O and I
O: lateral fibula
I: Base 1st metatarsal and medial cuneifrom
Tendon goes to the groove of the cuboid bone and forms a sling for the foot
Peroneus brevis muscle O and I
O: lateral fibula
I: Tendon goes to 5th metatarsal
What nerve supplies the lateral compartment?
Superficial peroneal nerve = branch of common peroneal
What arteries supply the muscles in the lateral compartment?
- branches of peroneal artery- from posterior compartment
2. branches of anterior tibial artery- from anterior compartment
What are the main actions of the posterior compartment of the leg?
- Plantar flexion
- inversion of the foot
Known as the flexor compartment
What muscles are in the deep posterior compartment?
- Tibialis posterior
- Flexor digitorum longus
- Flexor hallucis longus
What muscles are in the superficial posterior compartment?
- Gastrocnemius
- Soleus
- Triceps surae
- Plantaris muscle
Characteristics of gastrocnemius muscle
Part of posterior compartment
O: lateral and medial condyles of the femur (2 heads of origin)
I: calcaneus
1. Crosses the knee joint = flexes the knee
2 Plantar flex the foot
3. Raise the heel off the ground for walking
What is the blood supply to the gastrocnemius muscle?
Posterior tibial artery that is a dead end artery
Characteristics of the soleus muscle
Part of posterior compartment O: fibula, soleal line of tibia I: calcaneus 1. Tendinous arch at top of muscle that forms a tunnel for tibial nerve and posterior tibial artery 2. Anti-gravity muscle
What is the action of the soleus muscle?
- Crosses the ankle joint = plantar flexion
2. Raise the heel of the ground
What makes the triceps surae?
2 heads of the gastrocnemius and the soleus muscle
Characteristics of plantaris muscle
Part of the posterior compartment
O: lateral supracondylar line of femur
I: calcaneus via “freshman nerve”- plantaris tendon
Action: proprioception
Characteristics of popliteus muscle
Part of posterior compartment
O: lateral condyle of femur
I: Superior to soleal line of tibia
Action: weak knee flexion and laterally rotate remur on tibia 5 degrees to unlock knee joint
Characteristics of flexor hallucis longus muscle
Part of posterior compartment
O: fibula and IO membrane
I: base of 1st distal phalanx
Characteristic of flexor digitorum longus
Part of posterior compartment
O: tibia inferior to soleal line
I: bases of distal phalanages of toes 2-5
Characteristics of tibialis posterior
Part of posterior compartment
O: tibia, fibula, and IO membrane
I: navicular, cuneiform’s, cuboid, bases of 2-4 metatarsals
What nerve innervates the muscles of the posterior compartment?
Tibial nerve
What artery supplies the posterior compartment?
Posterior tibial artery- branch of popliteal artery gives off many branches
What does the calf pump do for veins?
- Muscles pump blood up and valves stop the blood from going down
- Blood goes up the superficial veins into the deep veins
- deep veins have big muscles to pump the blood up to the trunk
What causes varicose veins?
Valves don’t work properly.
- Blood flows from deep veins back to superficial veins
- incompetent valves
- superficial veins don’t have much support
