4) Lateral Compartment of the Leg Flashcards
Lateral compartment of the leg
Formed by fibula and anterior/posterior IM septa
Muscles of lateral compartment characteristics
Attach proximally to LATERAL tibular shaft
Evertors (aid in plantarflexion)
Innervation to lateral compartment muscles
Superficial fibular nerve
Blood supply to lateral compartment muscles
Perforating branches from fibular artery and anterior tibial
(branches pierce IM septa)
no major artery in compartment
Tendons of muscles of lateral compartment
Visible at lateral ankle, posterior to lateral malleolus
retromalleolar groove
Origin of Fibularis Longus
Fibular head and proximal 1/2 of lateral fibular shaft
Crural fascia
Insertion of Fibularis Longus
Lateral/plantar aspect of medial cuneiform and 1st met (tuberosity)
Fibularis Longus path
Posterior to lateral malleolus WITHIN fibular groove
Deep to superior fibular retinaculum
Inferior to peroneal (fibular) trochlea, deep to inferior fibular retinaculum
Fibular sulcus and groove of cuboid (inf surface), crosses sole of foot to insert on medial side
Groove of cuboid
Converted to tunnel by long plantar ligament
Function of Fibularis Longus
Eversion
Plantarflexion
Pronation of subtalar and midtarsal joints
Helps support 1st met during propulsion
Origin of Fibularis brevis
Distal 1/2 of lateral fibular shaft
Crural fascia
Med and inf to Fib Longus
Ant to Fib Longus (as they pass around Lat Malleolus)
Insertion of Fibularis Brevis
Styloid process of 5th met
Fibularis Brevis Path
Post to Lat Malleolus (Ant to Fib Longus tendon)
Deep to super fib retinaculum
Superior to peroneal (fibular) trochlea, deep to inferior fib retinaculum
Heading anteriorly toward insertion
Fibularis Brevis tendon
Anterior to fibularis longus tendon at ankle
Function of Fibularis Brevis
Eversion
Plantarflexion
(pronation of Subtalar Joint)
Peroneus (Fibularis) Quartus characteristic
Common ACCESSORY muscle
Can cause overcrowding of retromalleolar region/fibular groove
Overcrowding by Peroneous (FIbularis) Quartus
Can cause degen/dislocation of Fibularis brevis
Origin of Peroneus (Fibularis) Quartus
Actual muscle belly of fibularis brevis or longus
Lateral fibular shaft between origins of fibularis longus and brevis
Insertion of Peroneus (Fibularis) Quartus
Retrotrochlear eminence (Cuboid and 5th met base)
Fibular Synovial Sheath path
Immediately superior to Lat Malleolus (4cm above)
Divides at fibular trochlea
Ends at level of cuboid
Tendons in the fibular synovial sheath
Share sheath proximally (passing post to lateral malleolus in retromalleolar groove)
Fibular Synovial Sheath divide at fibular trochlea
separated by fascial extensions of inferior fibular retinaculum that attaches to peroneal trochlea
Fibularis longus tendon’s synovial sheath
As it passes along plantar foot
May or may communicate with proximal fibular synovial sheath
Fibular (Peroneal Retinacula)
Thickening of crural fascia and deep fascia of the foot (pedis fascia)
Anchors tendons of lateral compartment
Superior Fibular Retinaculum
Continuous with superior extensor retinaculum (transverse crural ligament)
Superior Fibular Retinaculum attaches
Posterinferior lateral malleolus and retrotrochlear eminence
pulley for tendons as they pass posterior to lateral malleolus
Inferior Fibular Retinaculum
Continuous with stem of inferior extensor retinaculum (frondiform ligament)
Inferior Fibular Retinaculum attaches
Sinus tarsi
Peroneal trochlea and lateral calcaneus
Blood supply to Lateral compartment of the leg
Branches from fibular and anterior tibial arteries
penetrate through Ant and Post IM septa
Nerve supply to Lateral compartment of the leg
Common Fibular Nerve (L4-S2)
Common Fibular supply to Lateral compartment
From sciatic
Passes around fibular neck
Enters lateral compartment (through post IM septa)
Piereces through Fib Longus
Common fibular terminal branches
Deep fibular
Superficial fibular
Superficial fibular nerve
L4-S1
From common fibular in lateral compartment
Superficial fibular nerve path
Descends between fibularis muscles (supplies lat comp muscles)
Pierces anterolateral crural fascia in distal 1/3 of leg (cutaneous innervation to distal anterolateral leg, dorsum of foot)
Branches of superficial fibular nerve
Medial dorsal cutaneous nerve
Intermediate dorsal cutaneous
Medial dorsal cutaneous nerve
Supplies cutaneous to medial hallux and adjacent 2nd and 3rd digit
Branches give rise to 3 digital branches
Intermediate dorsal cutaneous
Supplies cutaneous to adjacent 3rd and 4th, 4th and 5th digits
Branches give rise to 4 digital branches
Is lateral side of 5th digit innervated by Medial or Intermediate dorsal cutaneous?
N O
Branches of medial and intermediate dorsal cutaneous nerve
ON PAPER (TOO COMPLICATED)
Lateral dorsal cutaneous nerve
After lateral malleolus
Continuation of sural
Supplies lateral foot border
Branch of lateral dorsal cutaneous
10th proper dorsal digital nerve (dorsolateral 5th toe)
Continuation of lateral dorsal cutaneous
Saphenous nerve
Supplies:
Medial midfoot/arch
Medial ankle
Medial dorsal cutaneous nerve
Crosses ankle centrally
Supplies dorsomedial foot
Intermediate dorsal cutaneous nerve
Anterior to lateral malleolus
Supplies dorsolateral midfoot