ANAT: Lower Limb (leg) Flashcards
common peroneal (fibular) nerve:
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- L4-S2
- motor: common branch supplies short head of biceps femoris, superficial branch supplies lateral compartment, deep branch supplies anterior compartment
- sensory: lateral aspect of lower leg, dorsal aspect of foot
- runs laterally down the posterior leg, splits into deep and superficial branches (superficial is @ risk of damage inferior to knee joint)
- deep branch runs over dorsum of foot and branches into medial and lateral cutaneous nerves of the foot
tibial nerve:
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- roots: L4-S3
- motor: hamstrings (except short head of biceps femoris), hamstring part of adductor magnus and posterior compartment of leg
- sensory: posterolateral lower leg, plantar surface of the heel
- runs posteriorly down the middle of the leg, goes posterior to medial malleolus
- emerges on plantar surface of foot and divides into medial and lateral plantar nerve
where does the dorsals pedis a. run?
- in between the 1st and 2nd toes
superficial veins of the leg
- great/long saphenous vein: starts @ dorsum of foot, over medial malleolus, runs posterior to knee, emerges into medial thigh and drains into femoral v. in femoral triangle
- small/short saphenous vein: starts on lateral foot, runs up posterior leg, drains into popliteal vein in popliteal fossa
describe the deep veins of the leg + thigh
- basically same as arteries
describe the arterial supply of the leg
- popliteal artery: emerges down from popliteal fossa and divides into anterior tibial artery
- anterior tibial artery runs thru proximal aperture in interosseous membrane
- posterior division divides further into the peroneal (anterior) and posterior tibial artery
- posterior tibial artery goes down and passes medially into the foot > divides into lateral and medial plantar arteries > deep plantar arch
- peroneal artery runs along fibula and ends laterally at the foot
- anterior tibial artery runs along interosseous membrane and turns into dorsalis pedis (b/n 1st and 2nd toes)
what do the tibial and fibular arteries supply?
- anterior tibial: anterior compartment of lower leg + dorsal aspect of foot
- posterior tibial: posterior compartment of lower leg + plantar aspect of foot
- fibular: lateral compartment of lower leg
difference between medial and lateral condyles of the tibia
- medial: larger, raised and lifted up (complete fossa)
- lateral: smaller, smooth, sloped away on the posterior side
what are A, B, C, D?
- A = lateral epicondyle
- B = lateral condyle
- C = adductor tubercle
- D = medial epicondyle
what are E, F, G, H, I?
- E = medial condyle
- F = intercondylar line
- G = medial supracondylar line
- H = lateral supracondylar line
- I = intercondylar fossa
what are A, B, C, D?
- A = tibial tuberosity
- B = lateral condyle
- C = intercondylar eminences (lateral + medial)
- D = medial condyle
structure and function of the knee menisci (general)
- S = wedge-shaped fibrocartilage attached to the tibial intercondylar eminence, inner surface is avascular, outer surface is vascular
- F = deepens articular space, disperses force and synovial fluid
how do the medial and lateral menisci differ?
- ends of the medial meniscus are attached further apart (larger), whereas lateral = closer together (smaller)
- medial = attached to joint capsule (less mobile, more prone to injury) whereas lateral = free from joint capsule (more mobile and LESS prone to injury)
4 ligaments of the knee joint
- ACL
- PCL
- MCL
- LCL
where do the ACL and PCL attach?
- ACL: goes from lateral aspect of lateral condyle (femur) to medial portion of intercondylar eminence (tibia - same place as medial meniscus attachment)
- PCL: goes from lateral aspect of medial condyle (femur) to lateral portion of intercondylar eminence (tibia)
when can the patella track laterally?
- doing lots of repetitive action where the knee is not fully extended e.g. running/cycling
- lateral quads get stronger than medial > patella is pulled laterally
- bones rub together where they shouldn’t
- wear away meniscus and joint
function of ACL and what movement will damage it?
- prevents posterior displacement of the femur on a fixed tibia
- prevents anterior displacement of the tibia on a fixed femur
- (damaged in hyperextension)
function of PCL and what movement will damage it?
- prevents anterior displacement of the femur on a fixed tibia
- prevents posterior displacement of the tibia on a fixed femur
- (damaged w/ hyperflexion)
MCL and LCL differences
- when are they most tight?
- MCL (tibial): attaches to medial meniscus
- LCL (fibular): not attached to lateral meniscus
- both are more taut in extension to prevent valgus and varus movement
where do the MCL and LCL attach?
- MCL: medial epicondyle of femur > tibia
- LCL: lateral epicondyle of femur > styloid process of head of fibula
what are the retinacula of the knee?
- medial + lateral
- fibrous tissue that provides stability
unhappy triad
- a blow to the lateral side of the knee (> valgus = bow-legged) can damage the MCL, medial meniscus and ACL
- b/c MCL attaches to medial meniscus and ACL also shares an attachment point w/ the medial meniscus on the joint capsule
impact of tearing ACL/PCL on synovial membrane
- (esp. ACL)
- likely to damage synovial membrane b/c it runs right around the ligaments
- leads to significant swelling
4 bursae and fat pad of the knee
- suprapatellar (quadriceps) bursa - under quadriceps tendon
- prepatellar (anterior to patella)
- infrapatellar (superficial + deep) - anterior and posterior to patellar ligament
- semimembranosus - between semimembranosus and gastroc (medial)
- fat pad is posterior to patellar tendon
describe the articular surfaces of the patella
- lateral facet is larger than the medial facet
describe the boundaries of the popliteal fossa (diamond shape)
- superomedial: semimembranosus + semitendinosus
- inferomedial: medial head of gastroc
- superolateral: biceps femoris
- inferolareral: lateral head of gastroc + plantaris
contents of the popliteal fossa
- popliteal artery (most medial)
- popliteal vein (saphenous vein drains into this)
- sciatic nerve: divides @ the apex of the fossa into tibial n. and common peroneal n. (most lateral)
compartments of the lower leg and what are they separated by?
- anterior
- superficial + deep posterior (separated by transverse intermuscular septum)
- lateral (bordered by the anterior and posterior crural septa)
muscles in the posterior superficial compartment and what movement are they responsible for?
- also what nerve innervates them?
- gastroc
- soleus
- plantaris
- plantar flexion
- tibial nerve
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- gastrocnemius (medial and lateral head) - posterior superficial
- origin: medial and lateral condyles (femur)
- insertion: calcaneal tendon
- innervation: tibial nerve
- movement: plantar flexion and knee flexion
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- soleus (deep to gastroc) - multipennate (anti-gravity) - posterior superficial
- origin: back of tibia and fibula
- insertion: calcaneal tendon
- innervation: tibial nerve
- movement: plantar flexion
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- plantaris - posterior superficial
- origin: lateral epicondyle of femur
- insertion: calcaneal tendon
- innervation: tibial nerve
- movement: weak plantar flexion
what muscles are in the deep posterior compartment and what nerve innervates them?
- Tom, Dick and Harry (+pop)
- tibialis posterior (deepest posterior muscle)
- flexor digitorum longus
- flexor hallucis longus
- popliteus
- tibial nerve
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- tibialis posterior - posterior deep
- origin: interosseous membrane
- insertion: goes behind medial malleolus, fans out underneath the foot
- innervation: tibial nerve
- movement: plantar flexion, inversion
what is this muscle?
- what is its origin and insertion?
- innervation?
- function?
- popliteus - posterior deep
- origin:
- insertion: half lateral meniscus, half lateral condyle of femur
- innervation: tibial nerve
- function: unlock the knee during walking (help it come out of extension)
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- flexor hallucis longus (lateral to flexor digitorum longus) - posterior deep
- origin: posterior fibula
- insertion: goes underneath foot (deep to flexor digitorum longus) and supplies big toe
- innervation: tibial nerve
- movement: big toe + plantar flexion + inversion
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- flexor digitorum longus - posterior deep (medial to flexor hallucis longus)
- origin: posterior tibia
- insertion: goes underneath foot and supplies little toes (superficial to flexor hallucis longus)
- innervation: tibial nerve
- movement: flexion of 4 digits + plantar flexion
which muscles are in the lateral compartment of the leg?
- which nerve innervates them?
- fibularis longus and brevis
- superficial peroneal nerve
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- fibularis longus (superficial to brevis) - lateral
- origin: proximal fibula
- insertion: behind lateral malleolus, onto plantar surface, inserts on base of 1st metatarsal
- innervation: superficial peroneal nerve
- movement: eversion, weak plantar flexion
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- fibularis brevis (deep to longus) - lateral
- origin: lateral distal fibula
- insertion: behind lateral malleolus, onto base of 5th metatarsal
- innervation: superficial peroneal nerve
- movement: eversion, weak plantar flexion
which muscles sit in the anterior compartment of the leg?
- which nerve innervates them?
- Tom, Dick and Harry (+ tertius=traitor b/c anterior instead of lateral)
- tibialis anterior
- extensor digitorum longus
- extensor hallucis longus
- fibularis/peroneus tertius
- deep peroneal nerve
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- tibialis anterior - anterior
- origin: lateral tibia and interosseous membrane
- insertion: 1st cuneiform and 1st metatarsal (ends medially)
- innervation: deep peroneal and recurrent genicular nerves
- movement: dorsiflexion, inversion
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- extensor hallucis longus (deep to extensor digitorum longus) - anterior
- origin: interosseous membrane + fibula
- insertion: big toe
- innervation: deep peroneal nerve
- movement: dorsiflexion of ankle and big toe
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- extensor digitorum longus (superficial to extensor hallucis longus) - anterior
- origin: fibula
- insertion: 4 little toes
- innervation: deep peroneal nerve
- movement: dorsiflexion (inc little toes)
what is this muscle?
- what is its origin and insertion?
- innervation?
- movement?
- fibularis tertius - anterior
- origin: fibula
- insertion: 5th toe
- innervation: deep peroneal nerve
- movement: eversion, dorsiflexion
MCL and LCL of the ankle/talocrural joint (tibia, fibula, talus)
- LCL (prevents inversion): calcaneofibular ligament, anterior + posterior talofibular ligaments
- deltoid (MCL - prevents eversion): tibionavicular, anterior + posterior tibiotalar ligaments
describe the articulation of the other joints in the foot and what movements do they do?
- subtalar (talocalcaneal - plane/gliding): inversion, eversion
- talocalcaneonavicular
- talonavicular: pronation and supination
- calcaneocuboid: pronation and supination
what are A, B, C, D, E?
- A = cuneiforms (medial, intermediate, lateral)
- B = navicular
- C = talus
- D = cuboid
- E = calcaneus (the shelf on the left is called the sustentaculum tali)
ligaments which support the subtalar and TCN joints
- calcaneonavicular (spring) ligament
- long and short plantar ligaments
- cervical ligament
- bifurcate ligament
- interosseous talocalcaneal ligament
- calcaneofibular ligament
3 arches of the foot and what bones make them up?
- medial longitudinal (higher): talus, navicular, cuneiforms, metatarsals I-III
- lateral longitudinal: calcaneus, cuboid, metatarsals III-V
- transverse: from medial to lateral (cuneiforms, cuboid, bases of metatarsals I-V)
function of the foot arches
- act as a spring for weight bearing + shock absorption
which muscles support the medial and lateral arches of the foot?
- medial: FHL, EHL, FDL, EDL, tibialis anterior and posterior
- lateral: lateral compartment of leg (flat foot = less lateral arch)
which arch is the fibularis longus tendon the most important for?
- transverse arch
what are A, B, C, D?
- A = styloid process (for LCL)
- B = head of fibula (biceps femoris tendon - lateral)
- C = neck of fibula
- D = lateral malleolus
what are A, B, C?
- A = medial malleolus
- B = articular surface for talus
- C = fibular notch
what types of joints are the proximal and distal tibiofibular joints?
- proximal = plane/gliding (lined by hyaline cartilage)
- distal = syndesmosis (not lined by hyaline cartilage or a joint capsule, technically a ligament )
ligaments of the proximal and distal tibiofibular joints
- proximal: anterior superior tibiofibular, posterior superior tibiofibular, LCL
- distal: anterior inferior tibiofibular, posterior inferior tibiofibular
function of the interosseous membrane (tibia and fibula)
- transmits force/absorbs shock
- therefore a blow to one bone could damage the other
- contains a hole (aperture) at the proximal and distal end for neurovasculature
is the gastroc or soleus more likely to be injured?
- test for injured achilles
- gastroc b/c crosses 2 joints and can undergo eccentric contraction
- soleus injury is low risk but can still occur
- thompson test: lie prone w/ foot hanging off bed, squeeze gastroc
compartment syndrome + Sx
- bleeding of a particular artery can cause pressure > blockage of blood flow and poor perfusion of muscles in that particular compartment
- Sx: muscle tightness, agonising pain, paraesthesia, suspected Fx
which ligaments may be damaged by eversion and inversion?
- eversion: deltoid ligament (medial malleolus)
- inversion: lateral collateral ligament of ankle (lateral dorsum)
pes anserinus (“goose foot”) bursitis
- semitendinosus, gracilis and sartorius conjoin and insert together at the anteromedial proximal tibia
- looks like a goose foot
- the bursa underneath this tendon can get inflamed = common knee pain
intracapsular vs extracapsular NOF fractures
- intracapsular – can damage the medial femoral circumflex/retinacular arteries + and cause avascular necrosis of the femoral head
- extracapsular – blood supply to head of femur is intact > avascular necrosis is unlikely
why can’t we pronate and supinate our legs?
- tibiofibular joint is a fibrous joint = very stable but no movement
dorsal intrinsic foot muscles
- extensor digitorum brevis
- extensor hallucis brevis
plantar intrinsic foot muscles
- superficial: abductor digiti minimi, abductor hallucis, flexor digitorum brevis
- intermediate: quadratus plantae, lumbricals
- deep: flexor digiti minimi brevis, flexor hallucis brevis, adductor hallucis (2 heads), interossei
tarsal tunnel contents
- tibialis posterior tendon
- flexor digitorum longus
- posterior tibial artery
- posterior tibial vein
- tibial nerve
- flexor hallucis longus
- Tom, Dick And Very Nervous Harry (from anterior to posterior)
motor innervation of the foot
- deep fibular n. (dorsal)
- medial and lateral plantar nerves - branches of tibial n. (plantar)
sensory innervation of the foot
- dorsal: superficial fibular n.
- plantar: medial plantar nerve (medial 1/3) and lateral plantar nerve (lateral 2/3) - branches of tibial n.
Weber classification of ankle fracture + Tx
- type A: below syndesmosis (inversion) - Tx = CAM boot b/c syndesmosis still intact
- type B: @ syndesmosis (eversion)
- type C: above syndesmosis (eversion) - Tx = ORIF surgery b/c syndesmosis compromised
trimalleolar fracture
- fracture of medial, lateral and distal posterior tibia (posterior malleolus)
subtalar dislocation
- usually in medial direction during inversion, sometimes also during eversion
talus Fx
- commonly @ neck of talus, due to excessive dorsiflexion
ankle sprain
- grade 1, 2, 3 tear
- inversion most common
achilles tear
- occurs during excessive dorsiflexion
- presents as passive dorsiflexion and absent ankle jerk
flat feet
- pes planus (flat), pes cavus (high medial arch)
- spring ligament, connecting navicular to sustentaculum tali of calcaneus, fails
which nerve is involved in foot drop
- common peroneal nerve (L4-S2)
would there be more swelling in a knee ligament injury or meniscus injury?
- ligament injury b/c ACL and PCL are intracapsular > rupture will tear synovium which can cause swelling and bleeding into joint cavity
- whereas menisci are avascular
why are partial ligament tears more painful than complete ruptures?
- partial = nerve fibres are still intact so more perception of pain
- complete = severed nerve fibres = less pain
what does the sural nerve do?
- contributed by common peroneal and tibial n.
- purely sensory nerve
- sensory innervation to lateral leg and foot
identify the 4 membranes/septa which compartmentalise the leg
- interosseous membrane: joins tibia and fibula and separates anterior from posterior deep compartments
- anterior intermuscular septum: separates lateral and anterior compartments
- posterior intermuscular septum: separates lateral and posterior deep
- transverse intermuscular septum: separates posterior superficial and deep compartments
most common ankle ligaments to damage
- anterior talofibular ligament (ATFL) because it’s weakest
- also calcaneofibular ligament
- lateral ligaments weaker > inversion strains more common
pott fracture-dislocation
- inversion fracture to fibula
- lateral force > fracture of medial malleolus
oblique popliteal ligament function
- prevent hyperextension of knee
how to tell baker’s cyst vs popliteal aneurysm on palpation
- baker’s cyst = cold, non-pulsatile
- aneurysm = strong, pulsatile
positioning of femoral artery vs nerve in femoral triangle
- nerve = midpoint of inguinal ligament
- artery = 2/3 distance from pubic symphysis to ASIS
most common direction to dislocate patella
- laterally b/c quads tendon
which nerve is damaged in shaft vs head of fibula fractures
- head - common fibular n. damage
- shaft - deep fibular n. damage
