Lecture 9: Anterolateral Leg Flashcards
The Crural Frascia thickens distally into what?
What does this structure do?
Extensor Retinaculum
-prevents bowstringing during dorsiflexion
Why do you often see edema in the legs of elderly people?
Their crural fascia is more lax, and thus their musculovenous pump is less effective
How does the musculovenous pump in the leg work?
The crural fascia is tight enough that when the muscles of the leg contract, they must expand inward instead of outward. This pushes blood up the veins of the leg, since they have valves that prevent blood from seeping down the leg.
How would you relieve intracompartmental pressure in the leg?
Fasciotomy
- Incise fascia to relieve pressure and prevent permanent injury
- Leg can stay open for a while
What muscles do you find in the anterior compartment?
- Tibialis Anterior Muscle
- Extensor Hallucis Longus Muscle
- Extensor Digitorum Longus
- Fibularis Tertius
Tibialis Anterior Muscle
What is its attachments?
Origin: Lateral Tibial Condyle
Insertion: Medial Surface of first cuneiform and first metatarsal base
Tibialis Anterior Muscle
What is its action?
- Inversion of Foot
- Dorsiflexion of Foot
Tibialis Anterior Muscle
What is its innervation and blood supply?
Innervation: Deep Fibular Nerve
Blood Supply: Anterior Tibial Artery
Extensor Digitorum Longus Muscle
What is its attachments?
Origin: Lateral Tibial Condyle and Medial Aspect of Fibula; Interosseus Membrane
Insertion: 2nd-5th intermediate and distal phalanges
Extensor Digitorum Longus Muscle
What is its action?
- Extends lateral four digits
- Dorsiflexion of Foot
Extensor Digitorum Longus Muscle
What is its innervation and blood supply?
Innervation: Deep Fibular Nerve
Blood Supply: Anterior Tibial Artery
Extensor Hallucis Longus Muscle
What is its attachments?
Origin: Anterior Aspect of Fibula; Interosseus Membrane
Insertion: Base of Distal Phalanx of Hallux
Extensor Hallucis Longus Muscle
What is its action?
- Extends hallux
- Dorsiflexion of Ankle
Extensor Hallucis Longus Muscle
What is its innervation and blood supply?
Innervation: Deep Fibular Nerve
Blood Supply: Anterior Tibial Artery
Fibularis Tertius Muscle
What is its attachments?
Origin: Anteroinferior Aspect of Fibula
Insertion: Dorsum of 5th metatarsal base
Fibularis Tertius Muscle
What is its action?
- Eversion
- Dorsiflexion of Ankle
Fibularis Tertius Muscle
What is its innervation and blood supply?
Innervation: Deep Fibular Nerve
Blood Supply: Anterior Tibial Artery
What muscle does the Fibularis Tertius tend to fuse with?
Extensor Digitorum Longus
Where does the common fibular nerve split into the superficial and deep branches?
Between the Fibula and Fibularis Longus Muscle
-Around the head of the fibula
What artery runs with the Deep Fibular Nerve?
The Anterior Tibial Artery
What does the Deep Fibular Nerve innervate?
- Anterior Compartment Muscles
- Ankle joint and metacarpal phlanageal joints
What are the terminal branches of the deep fibular nerve?
Medial and Lateral branches of the Deep Fibular Nerve at the dorsum of the foot
What is the function of the Lateral Branch of the Deep Fibular Nerve?
Innervates the intrinsic muscles of the dorsum of the foot
- Extensor Hallucis Brevis
- Extensor Digitorum Brevis
What is the function of the Medial Branch of the Deep Fibular Nerve?
Sensory innervation to the flip flop area
(medial branch innervates part of the medial two toes)
What artery supplies the anterior compartment?
Where does it come from?
Anterior Tibial Artery arises from Popliteal Artery and passes anteriorly via Interosseous Membrane
What is the terminal branch of the Anterior Tibial Artery?
Dorsalis Pedis
Ends at ankle between malleoli
What does “peroneal” mean?
Fibular
What structures do you find in the lateral compartment?
- Fibularis Brevis
- Fibularis Longus
- Superficial Fibular Nerve
Fibularis Longus Muscle
What is its attachments?
Origin: Head and Superior aspect of Fibula
Insertion: Base of 1st metatarsal and medial cuneiform
Fibularis Longus Muscle
What is its action?
- Eversion
- Plantar Flexion of Ankle
Fibularis Longus Muscle
What is its innervation and blood supply?
Innervation: Superficial Fibular Nerve
Blood Supply: Fibular Artery
What pulley structure on the calcaneus does the tendon of the fibularis longus muscle pass under?
Fibular trochlea (A ridge on the lateral surface of the calcaneus)
What bone has a specific groove for the fibularis longus?
The cuboid
Fibularis Brevis Muscle
What is its attachments?
Origin: Inferolateral aspect of Fibula
Insertion: Tuberosity of base of 5th metatarsal
Fibularis Brevis Muscle
What is its action?
- Eversion
- Plantar Flexion of Ankle
Fibularis Brevis Muscle
What is its innervation and blood supply?
Innervation: Superficial Fibular Nerve
Blood Supply: Fibular Artery
What provides sensation to the majority of the dorsum of the foot?
Superficial Fibular Nerve
Except flip flop spot (supplied by the Medial Branch of the Deep Fibular Nerve)
Where is the Common Fibular Nerve vulnerable to being struck?
What happens when it is injured?
Around the head of the fibula (the most superficial there)
Results in paralysis of all anterior and lateral leg muscles
- Loss of dorsiflexion and eversion
- Difficult to achieve heel strike
- Loss of sensation in anterolateral leg and dorsum of foot
What kind of gait accompanies damage to the common fibular nerve?
“High stepping gait”
What compartment of the leg contains no arteries?
The lateral compartment
What provides blood supply to the lateral compartment of the leg?
Perforating branches of the fibular artery
Fibular Artery runs in the posterior compartment
What vessel does the fibular artery come off of?
The Popliteal Artery
-Spits of into Posterior Tibial Artery and Fibular Artery
What muscle should we associate with shin splints?
Tibialis Anterior (due to repetitive microtrauma)
-Mild form of compartmental syndrome
What three muscles are responsible for eversion of the foot?
Fibularis Longus and Brevis
Fibularis Tertius
What two muscles invert the foot?
Tibialis Posterior and Tibialis Anterior Muscles
What might cause foot drop?
Injury to the common fibular nerve (in the case of loss of both dorsiflexion and eversion)
Injury to the deep fibular nerve (in the case of loss of just dorsiflexion, but not eversion)
