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Questions and Answers
What structure does the Peroneus Longus utilize as a pulley?
What structure does the Peroneus Longus utilize as a pulley?
Which muscle originates from the inferior 2/3rds of the lateral fibula?
Which muscle originates from the inferior 2/3rds of the lateral fibula?
What does the anterior tibial artery supply?
What does the anterior tibial artery supply?
What anatomical feature does the Dorsalis Pedis artery divide into?
What anatomical feature does the Dorsalis Pedis artery divide into?
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What supplies the lateral compartment of the leg?
What supplies the lateral compartment of the leg?
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Where is the Arcuate artery located in relation to other structures?
Where is the Arcuate artery located in relation to other structures?
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What do the metatarsal arteries connect with?
What do the metatarsal arteries connect with?
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Which muscle aids in extending the digits along with the extensor muscles on the dorsum of the foot?
Which muscle aids in extending the digits along with the extensor muscles on the dorsum of the foot?
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Which artery changes its name to Dorsalis Pedis at the ankle joint?
Which artery changes its name to Dorsalis Pedis at the ankle joint?
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What is the role of the Peroneus Longus and Brevis muscles?
What is the role of the Peroneus Longus and Brevis muscles?
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Which muscle in the anterior compartment is specifically responsible for extending the great toe?
Which muscle in the anterior compartment is specifically responsible for extending the great toe?
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What is the primary action of the muscles in the lateral compartment of the leg?
What is the primary action of the muscles in the lateral compartment of the leg?
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Which nerve innervates the anterior compartment of the leg?
Which nerve innervates the anterior compartment of the leg?
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What structure binds the tendons of the muscles in the leg around the ankle joint?
What structure binds the tendons of the muscles in the leg around the ankle joint?
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Which of the following muscles helps in dorsiflexion of the ankle?
Which of the following muscles helps in dorsiflexion of the ankle?
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What is the origin of the Extensor Digitorum Longus?
What is the origin of the Extensor Digitorum Longus?
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Which statement correctly describes the role of the peroneous (fibularis) longus muscle?
Which statement correctly describes the role of the peroneous (fibularis) longus muscle?
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Which compartment of the leg contains muscles that are primarily dorsiflexors?
Which compartment of the leg contains muscles that are primarily dorsiflexors?
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What is the primary function of the Tibialis Anterior muscle?
What is the primary function of the Tibialis Anterior muscle?
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Which part of the sciatic nerve innervates the lateral compartment?
Which part of the sciatic nerve innervates the lateral compartment?
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Which of the following structures is Y-shaped and binds tendons at the ankle?
Which of the following structures is Y-shaped and binds tendons at the ankle?
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How many muscles are primarily located in the anterior compartment of the leg?
How many muscles are primarily located in the anterior compartment of the leg?
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What is a common characteristic of the muscles that pass over the ankle joint?
What is a common characteristic of the muscles that pass over the ankle joint?
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Which muscle originates from the middle part of the anterior surface of the fibula?
Which muscle originates from the middle part of the anterior surface of the fibula?
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Study Notes
Anterior & Lateral Compartments of the Leg
- The leg is divided into 3 compartments by intermuscular septa, interosseous membrane, and bones.
- Compartments include: Anterior, Lateral, and Posterior.
- Deep and superficial muscles within each compartment share common functions and innervations.
Nerves Supply of Leg - From Sciatic Nerve
- Tibial nerve (purple) supplies the posterior compartment of the leg and sole of the foot.
- Common Peroneal nerve branches into superficial and deep branches.
- Superficial Peroneal nerve (blue) supplies the lateral compartment.
- Deep Peroneal nerve (green) supplies the anterior compartment.
Muscles of Anterior Compartment
- Key principles: Pass over the ankle joint; therefore, they are dorsiflexors. Long extensors pass along the dorsal aspect of the toes.
- Key muscles include Tibialis Anterior, Extensor Hallucis Longus, Extensor Digitorum Longus, and Peroneus (Fibularis) Longus.
- If you kick something, it goes from medial to lateral (THUD).
Muscles of Lateral Compartment
- Key principles: Pass lateral to the ankle; therefore, they are evertors (pull the foot out).
- Key muscles include Fibularis (Peroneus) Longus and Fibularis (Peroneus) Brevis.
Peroneus (Fibularis) Longus
- Origin: Head & superior 2/3rds of lateral fibula.
- Inserts: Base of 1st Metatarsal and Medial cuneiform.
- Most Superficial.
- Passes posterior to lateral malleolus using it as a pulley.
- Enters a groove on the anterior inferior aspect of the cuboid bone.
- Runs obliquely & distally to its attachment.
- Like a Stirrup.
Peroneus (Fibularis) Brevis
- Origin: Inferior 2/3rds of lateral fibula.
- Inserts: Dorsal tuberosity of lateral side of base of 5th metatarsal.
- Deeper of the two muscles.
- Passes behind lateral malleolus (using it as a pulley).
- Works with the longus to evert foot (helps to prevent excessive inversion).
Tibialis Anterior
- Origin: Lateral condyle & superior half of lateral tibia & interosseous membrane.
- Inserts: Medial & inferior surface of medial cuneiform & 1st metatarsal.
- Action: Dorsiflexion & inverts the foot.
Extensor Hallucis Longus
- Origin: Middle part of anterior surface of fibula & interosseous membrane.
- Inserts: Dorsal aspect of base of distal phalanx of great toe.
- Action: Extends Great Toe (helps dorsiflexion of ankle).
Extensor Digitorum Longus
- Origin: Lateral condyle of tibial & superior 3/4 of medial surface of fibula and interosseous membrane.
- Inserts: Middle & Distal phalanges of lateral 4 digits (extensor expansion).
- Action: Extends lateral 4 digits (helps dorsiflexion of ankle).
Peroneous (Fibularis) Tertius
- Part of Extensor Digitorum Longus; it's origin is on the more distal fibres along fibula.
- Inserts into the 5th metatarsal (not a phalanx).
- Often absent.
Extensor Retinacula
- The deep fascia of the leg is called crural fascia).
- Two thickenings bind the tendons of the muscles before and after the ankle joint.
Superior extensor retinaculum
- Strong, broad band of deep fascia.
Inferior extensor retinaculum
- Y-shaped band of deep fascia.
Blood Supply - Anterior Compartment
- Anterior Tibial Artery supplies the anterior compartment.
- The branch of the popliteal artery passes anteriorly through a gap in the interosseous membrane and descends.
- Joined with the deep peroneal nerve.
- Note: The neurovascular bundle has different vessels.
Blood Supply - Lateral Compartment
- The lateral compartment does not have its own blood supply.
- Perforating arteries supply this compartment.
- Proximally - perforating arteries of anterior tibial artery.
- Distally - perforating arteries of peroneal (fibular) artery.
Blood Supply - Dorsum of Foot
- Dorsalis Pedis passes into the first interosseous space, divides into deep plantar artery & 1st dorsal metatarsal artery.
- Deep plantar artery anastomoses with lateral plantar artery to form deep plantar arch.
Dorsum of Foot - Blood Supply (cont.)
- Dorsalis pedis gives off 2 branches: Lateral tarsal artery & Arcuate artery.
- These anastomoses to form arterial loop and give off metatarsal arteries, which further divide to give off dorsal digital arteries.
Dorsum of Foot - Blood Supply (cont.)
- Metatarsal arteries are also connected to the plantar arch & plantar metatarsal arteries via perforating arteries.
- The arch is usually hidden under extensor digitorum brevis.
Dissection Time
- Remove the skin over the leg.
- Identify & the muscles in anterior and lateral compartments.
- Try to find the neurovascular bundle (NVB).
- Dissection continues dorsally over the foot.
- Try to find dorsalis pedis.
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Description
Explore the anatomy of the leg with a focus on the anterior and lateral compartments. Learn about the key muscles, their functions, and the nerve supplies that innervate these areas. This quiz will deepen your understanding of leg compartmentalization and muscle functions.
