Ankle And Foot Muscles Flashcards
What are the four compartments that the lower leg is divided into?
What are they divided by?
Anterior compartment
Posterior, deep and superficial compartments
Lateral compartment
Divided by - interosseous membrane
Two intermuscular septa (pass between fibula and deep fascia surround)
Direct attachment of the deep fascia to the periosteum of the anterior and medial borders of the tibia
What muscles make up the anterior compartment of the lower leg?
What are the innovated by?
Blood supply:
Tibias anterior
Extensor hallucis Longus
Extensor digitorium longus
Peroneus tertius (fibularous tertius)
Deep peroneal nerve (L4-S1) - dorsiflexors
Anterior tibial artery
What will happen if muscles of the anterior compartment are not innovated?
Foot drop
Anterior compartment
Tibialis anterior:
Proximal - upper 2/3’s lateral shaft of tibia
Adjacent Interosseous membrane
Distal - medial and inferior surfaces of medial cuneiform and base of metatarsal I
Never supply - deep peroneal nerve (L4/5)
Actions - dorsiflexion of the foot
Inversion of foot (intertarsal joint)
Dynamic support of medial arch of foot
Anterior compartment
Extensor hallucis longus -
Proximal - middle one half medial surface of fibula
Adjacent surface interosseous membrane
Distal - dorsal surface of base of distal phalanx of great toe
Nerve supply - deep peroneal nerve (L5/S1)
Actions - extension of great toe
Dorsiflexion of foot
Anterior compartment
Extensor digitorium longus -
Proximal - proximal one half medial surface fibula and related surface of lateral tibial condyle
Distal - via dorsal expansions into bases of distal and middle phalanges of lateral four toes
Nerve supply - deep peroneal nerve (L5/S1)
Actions - extension of lateral four toes
Dorsiflexion of foot
Extensor hoods -
What makes up an extensor hood? What ligaments are involved? And main function of it -
Tendons of extensor digitorium longus, extensor digitiorium brevis and extensor hallucis longus pass into dorsal aspect of the digits and expand over the proximal phalanges to form extensor hoods
Each is triangular in shape, apex attaches to the distal phalanx
Corners of the hoods attach mainly to the deep transverse metatarsal ligaments
Many intrinsic muscles of foot insert into extensor hood which allows forces of these muscles to be disrupted over the toes to cause flexion of the metatarsal phalangeal joints, simultaneously with extension of the inter-phalangeal joints
Anterior compartment
Peroneus (fibularis) tertius -
Proximal - distal part of medial surface of fibula
Distal - dorsomedial surface of base of metatarsal V
Nerve supply - deep peroneal nerve (L5/S1)
Actions - dorsiflexion of foot
Eversion of foot
*this muscle is so small that it can be considered a part of extensor digitorium longus.
What muscles make up the superficial posterior compartment ?
Function and nerve innovation -
Gastrocnemius
Soleus
Plantaris
All Innervation by tibial nerve S1-2
All plantarflex the foot
All insert into calcaneus via calcaneal tendon (Achilles).
Superficial posterior compartment
Gastrocnemius -
Proximal: medial head - posterior aspect of medial femoral condyle
Lateral head - posterior aspect of lateral femoral condyle
Distal - via calcaneal tendon to posterior surface of calcaneus
Nerve supply - tibial nerve S1-2
Actions - plantarflexion of the foot
Flexion of the knee
Superficial posterior compartment
Soleus -
Large flat muscle deep to gastroc
Proximal - soleal line and medial border of tibia
Posterior aspect fibula head and adjacent surfaces of neck and proximal shaft
Tendinous arch between tibial and fibular attachments
Distal - via calcaneal tendon to posterior surface of calcaneus
Nerve supply - tibial nerve S1-2
Action - plantarflexion of foot. Active when - knee flexion and go onto tip toes
Cannot palpate
Superficial posterior compartment
Plantaris -
Small muscle belly and long, thin tendon
Proximal - inferior part of lateral supracondylar line of femur
Oblique popliteal ligament of knee
Distal - via calcaneal tendon to posterior surface of calcaneus
Nerve supply - tibial nerve S1-2
Actions - plantarflexion of foot
Flexion of knee
Often used as a graft in surgeries as its so small
What muscles make up the deep posterior compartment of the lower leg?
Innervation and action -
Popliteus (acts on knee)
Flexor hallucis longus
Flexor digitorium longus
Tibialis posterior
Innervation by tibial nerve L4-S3
All expect poplietus contribute to plantarflexion of the foot
Deep posterior compartment
Popliteus -
Smallest and most deep
Proximal - lateral femoral condyle
Distal - posterior surface of proximal tibia about soleal line
Nerve supply - tibial nerve L4-S1
Actions - stabilises knee joint (resits lateral rotation of tibia on femur)
Unlocks knee joint (laterally rotates femur on fixed tibia) to begin movement
Deep posterior compartment
Flexor hallucis longus -
Proximal - lower 2/3’s posterior surface of fibula and adjacent interosseous membrane
Distal - plantar surface of base of distal phalanx of great toe
Nerve supply - tibial nerve S2/3
Actions - flexes great toe
Contributes to plantarflexion of the foot at ankle joint
Deep posterior compartment
Flexor digitorium longus -
Proximal - medial side of posterior surface of tibia
Distal - divides into four tendons which go to plantar surfaces of bases of distal phalanges of the lateral four toes
Nerve supply - tibial nerve S2/3
Actions - flexes lateral four toes
Contributes to plantarflexion at ankle joint
Contributes to gripping the ground
Deep posterior compartment
Tibialis posterior -
Proximal - posterior surface of tibia and fibula and interosseous membrane
Distal - tuberosity of navicular and adjacent region of medial cuneiform
Nerve supply - tibial nerve L4/5
Actions - inversion and plantarflexion of foot
Support of medial arch of foot during walking
What muscles make up the lateral compartment of the lower leg?
Innervation by -
Peroneus longus
Peroneus brevis - both of these perform eversion
NOTE, Peroneus used interchangeably with fibularis
Innervated by surperfical peroneal nerve L5-S2
Lateral compartment
Peroneus longus -
Proximal - upper lateral surface of fibula
Head of fibula
Distal - under surface and lateral sides of medial cuneiform and base of metatarsal I
Nerve supply - superficial peroneal nerve L5-S2
Actions - eversion and plantarflexion of foot
Supports arches of foot
Lateral compartment
Peroneus brevis -
Sits deep to Peroneus tertius
Proximal - lower 2/3’s of lateral surface of shaft of fibula
Distal - lateral tubercle at base of metatarsal V
Nerve supply - superficial peroneal nerve L5-S2
Actions - eversion of the foot
Intrinsic muscles - dorsum of the foot (top)
Extensor digitorium brevis -
Proximal- superolateral surface of the calcaneus
Distal - lateral sides of tendons of extensor digitorium longus of toes II and Iv via extensor hoods
Nerve supply - deep peroneal nerve S1/2
Actions - extension of toes
What are the other intrinsic muscles to be aware of?
Lumbricals - muscle bellies sitting between flexor digitorium longus
Abductor hallucis
Interossi dorsal and plantar
Contents of the tarsal tunnel: (from top to bottom)
Located on medial side of foot
Tibialis posterior
Flexor digitorium longus
Tibial artery and vein
Tibial nerve
Flexor hallucis longus
Attachments of the flexor retinaculum -
Proximal - medial malleollus
Distal - inferno medial margin of calcaneus