Anterolateral Leg Flashcards
What does fascia do?
Cover the leg muscles
Describe how the fascia transitions as you move inferiorly down the lower extremity
Fascia lata in the thigh becomes the crural fascia in the leg which thickens around the ankle to form the superior and inferior extensor retinaculum
What are the 4 important septum that separate compartments in the leg?
Transverse septum, posterior septum, anterior septum, interosseus membrane
What does the interosseus membrane separate?
The anterior compartment and the posterior deep compartment
What does the transverse septum separate?
The posterior deep and posterior superficial compartments
What does the anterior septum separate?
The anterior and lateral compartments
What does the posterior compartment separate?
The lateral and posterior superficial compartments
What are the 4 muscles in the anterior leg?
Tibialis Anterior, Extensor hallucis longus, extensor digitorum longus, fibularis tertius
Origin, insertion, action and innervation of Tibialis Anterior
O: Lateral tibial condyle and superolateral 1/2 of tibia
I: Medial side of medial cuneiform and base of 1st metatarsal
Action: Dorsiflexion and inversion of the foot
Innervation: Deep fibular nerve
Origin, insertion, action and innervation of Extensor digitorum longus
O: Lateral tibial condyle, interosseus membrane and anterior fibular surface
I: Dorsum of 2nd-5th middle and distal phalanages
Action: Dorsiflexion and extension of 2-5 phalanges
Innervation: Deep fibular nerve
Explain the extensor expansion function of the extensor digitorum longus tendon
As the tendon attaches, it attaches to the middle and distal joints of the toes and provides a covering for them. At the proximal IP joint, it has one medial slip and at the distal IP joint it splits into 2 lateral slips
Origin, insertion, action and innervation of Extensor hallucis longus
O: Anteromedial fibular surface and interosseous membrane
I: Dorsum of base of 1st distal phalanx
Action: Dorsiflexion and extension of hallux
Innervation: Deep fibular nerve
Origin, insertion, action, and innervation of Fibularis Tertius
O: Anteroinferior aspect of fibular and interosseus membrane
I: Base of 5th metatarsal
Action: Dorsiflexion and eversion of the foot (lateral movement)
Innervation: Deep fibular nerve
Where is Fibularis Tertius in respect to the other fibularis muscles?
Anterior to fibula!
What is the nerve that innervates all of the anterior leg muscles?
Deep fibular nerve
Explain how the deep fibular nerve arises
Sciatic splits into tibial nerve and common fibular nerve, the common fibular nerve then runs anteriorly and splits into the deep fibular nerve and the superficial fibular nerve
Where does the deep fibular nerve run?
In between tibialis anterior and extensor hallucis longus
What all does the deep fibular nerve supply?
Anterior leg muscles, skin between the 1st and 2nd toe, ankle joint, dorsal foot muscles
What is the main arterial source for the anterior leg muscles?
Anterior tibial artery
What does the anterior artery become inferiorly?
Dorsalis Pedis at the malleoli
What are the lateral leg muscles?
Fibularis longus and fibularis brevis
What nerve innervates the lateral leg muscles?
Superficial fibular nerve
Origin, insertion, action, innervation of fibularis longus
O: Head of fibula and upper 2/3 of fibula
I: Medial cuneiform and 1st metatarsal (runs across dorsal foot via cuboid sulcus)
Action: Eversion of foot and plantar flexion
Innervation: Superficial fibular nerve
Origin, insertion, action, innervation of fibularis brevis
O: inferolateral fibula
I: 5th metatarsal base tuberosity
Innervation: superficial fibular nerve
Action: Eversion of foot and plantarflexion
What does the superficial fibular nerve supply?
Lateral leg muscles, cutaneous innervation of anteroinferior leg and almost entire dorsum of foot
What is the most commonly injured LE nerve?
Common fibular nerve
What results if the common fibular nerve is injured?
Paralysis of ALL anterior and lateral leg muscles!
How will a patient present if they have an injured common fibular nerve?
“Foot drop” with loss of dorsiflexion and eversion
Difficult to achieve heel strike, usually have some sort of stepping, waddling, or swing out gait
Foot will strike with “clop”
Loss of sensation of anterolateral leg and dorsum of foot
What is the one compartment that does not have its own artery that runs with the nerve?
LATERAL COMPARTMENT has NO distinct artery!
How does the lateral compartment of the leg receive blood?
The popliteus becomes the posterior tibial artery which then sends off a fibular artery branch that has perforating arteries that run anteriorly to lateral compartment
How may compartment syndrome arise?
Trauma of the leg may lead to hemorrage, edema, and inflammation within the fascia of the LE which causes an increase in pressure within the muscle compartment
What does the increase in pressure of compartment syndrome cause?
Ischemia - low oxygen delivery to the muscles
How do you fix compartmental syndrome?
Fasciotomy to relieve the pressure
What is a mild form of compartmental syndrome?
Shin splints (swelling of anterior tibialis)
What do shin splits hurt?
Repetitive microtrauma to the anterior tibialis and small tears to the overlying fascia
