Leg, Ankle and Foot (Week 5--Miller) Flashcards
Bones of the foot
Phalanges (14)
Metatarsus (5)
Tarsus (7–3 proximal and 4 distal)
7 tarsal bones
3 proximal: calcaneus, talus, navicular
4 distal: 3 cuneiform, cuboid
Joints of the foot
Interphalangeal (IP) joints
Metatarsophalangeal (MTP) joints
Tarsometatarsal (TM) joints
Intertarsal joints
Midtarsal joints
Anterior compartment of the leg
Extensor (dorsiflexor) compartment
4 muscles: tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus tertius muscle tendon (very small!)
Deep peroneal nerve
Anterior tibial artery
Lateral compartment of the leg
2 muscles: peroneus (fibularis) longus, peroneus (fibularis) brevis
Superficial peroneal nerve
NO ARTERY (just branches from fibular artery of posterior compartment and other arteries)
Common peroneal nerve
Not in the lateral compartment
However, wraps around neck of fibula posteriorly and is easily lacerated
2 branches are deep and superficial peroneal nerves so injury to common peroneal nerve can lead to loss of dorsiflexion (anterior compartment of leg) and eversion (lateral compartment of leg)
(loss of dorsiflexion results in foot drop during walking)
Superficial peroneal (fibular) nerve
Branch of common peroneal nerve
Lies deep to peroneus longus muscle and innervates both muscles of lateral compartment, thus controls eversion of the foot
After it innervates muscles of lateral compartment, becomes cutaneous (sensory) nerve
Posterior compartment of the leg
Flexor compartment
Deep layer muscles: popliteus, flexor hallucis longus, tibialis posterior
Superficial layer muscles: gastrocnemius, soleus, plantaris
Tibial nerve
Posterior tibial artery and fibular artery (looks like it was heading to lateral compartment but didn’t quite make it there!)
Superficial veins
Great and small saphenous veins
Are not subjected to forces from arteries and muscles forcing blood up the limb
Valves in perforating veins must prevent high pressure blood in deep veins from moving into superficial veins
When muscles within compartments relax, blood sucked from superficial into deep veins to be sent up to heart
Deep veins
Veins within compartments
Subjected to intermittent pressure from adjacent arteries and muscular action which forces blood up the limb
Sural nerve
Cutaneous (sensory) nerve
Made from tibial nerve after it is joined by branch from common fibular peroneal nerve (communicating sural)
Emerges from popliteal fossa in groove between heads of gastrocmenius
Accompanies small saphenous vein and supplies posterior leg
Crural fascia
Continuation of fascia lata in the leg
Posterior compartment of the leg superficial layer
Gastrocnemius
Soleus
Plantaris tendon
Neurovascular structures between superficial and deep layers of posterior compartment of leg
Posterior tibial artery (branch of popliteal artery)
Fibular artery (branch of posterior tibial artery)
Tibial nerve (branch of sciatic nerve)
Posterior compartment of the leg deep layer
Popliteus
Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus
Calcaneal tendon (achilles tendon)
Common tendon of superficial layer muscles (gastrocnemius, soleus, plantaris)
Inserts onto calcaneus bone
Ankle (talocrural) joint
Synovial joint (hinge-type)
Between distal tibia/fibula and superior part of talus
Main movements are dorsiflexion and plantar flexion
Joint capsule is reinforced laterally by lateral ligament and medially by deltoid (medial) ligament
3 ligaments of the lateral ligament
Anterior talofibular ligament
Posterior talofibular ligament
Calcaneofibular ligament
Note: lateral ligament resists inversion of the foot
Lateral ankle sprain
Usually caused by excessive inversion of the foot with plantar flexion of the ankle
Anterior talofibular ligament and calcaneofibular ligament partially torn (leads to pain and local swelling)
In typical lateral ankle sprain, USUALLY anterior talofibular ligament is involved
Deltoid (medial) ligament
Triangular in shape
Attaches superiorly to medial malleolus and inferiorly separates into 4 parts which attach to talus, calcaneus and navicular bones
Note: deltoid (medial) ligament resists eversion of the foot
Medial ankle sprain
Less common than lateral ankle sprain
Caused by excessive eversion
Because deltoid (medial) ligament so strong, usually causes deltoid ligament to pull off the tip of the medial malleolus (ouch…!)
Nerves of the leg (big picture)
Sciatic nerve branches into common peroneal and tibial divisions near popliteal fossa
Tibial nerve crosses knee posterior and enters posterior compartment of leg (tibial then turns into medial and lateral plantar nerves)
Common peroneal nerve wraps around lateral side of leg near neck of fibula then divides into superficial peroneal (fibular) nerve and deep peroneal (fibular) nerve; also gives off lateral cutaneous nerve
Superficial peroneal nerve dives deep to peroneus (fibularis) longus and becomes nerve of the lateral compartment
Deep peroneal nerve enters and becomes nerve of anterior compartment
Arteries of the leg (big picture)
External iliac artery turns into femoral which gives off deep femoral artery, then goes through adductor hiatus to become popliteal artery
Popliteal artery divides into anterior and posterior tibial artery at lower border of popliteus muscle
Anterior tibial artery pierces interosseus membrane to enter and become artery of anterior compartment, then crosses the ankle and is called dorsalis pedis artery, which then turns into arcuate artery
Posterior tibial artery continues inferiorly in posterior compartment and gives rise to fibular artery then continues to becomes medial and lateral plantar arteries
Posterior tibial artery terminates distal to flexor retinaculum by dividing into medial and lateral plantar arteries that supply muscles on the sole of the foot
Structures related posteriorly to medial malleolus
“Tom, Dick, ANd Harry”
Tibialis posterior tendon
Flexor Digitorum longus tendon
Posterior tibial Artery
Tibial Nerve
Flexor Hallucis longus tendon
Flexor retinaculum
Roof of tarsal tunnel (on medial malleolus)
Structures related posteriorly to lateral malleolus
Peroneus (fibularis) longus tendon
Peroneus (fibularis) brevis tendon
All the retinaculums of the foot
Superior extensor retinaculum (anterior compartment tendons)
Inferior extensor retinaculum (anterior compartment tendons)
Fibular retinaculum (lateral compartment tendons)
Flexor retinaculum (posterior compartment tendons)
Dorsum of the foot
Dorsal venous arch gives rise to great saphenous vein medially and small saphenous vein laterally
Superior and inferior extensor retinaculae bind down the extensor hallucis longus and extensor digitorum longus tendons
Dorsalis pedis artery gives rise to arcuate artery which arcs across base of metatarsal bones and gives rise to 2nd-4th dorsal metatarsal arteries (1st dorsal metatarsal artery arises directly from dorsalis pedis artery and gives rise to deep plantar artery which joins arterial arch on plantar surface of foot) and those give rise to dorsal digital arteries
2 intrinsic foot muscles: extensor hallucis brevis and extensor digitorum brevis
Swelling of which two foot muscles can be mistaken for ankle problem?
Extensor digitorum brevis and extensor hallucis brevis
(on dorsum of foot)
Plantar foot
Longitudinal arch and transverse arch
Plantar aponeurosis
Long plantar ligament, spring ligament, peroneus longus tendon, posterior tibialis tendon
Thenar, hypothenar, central and deep compartments
Lateral and medial plantar nerves
Lateral and medial plantar arteries
Plantar foot arches
Longitudinal arch: lateral and medial arches
Transverse arch
Arches act as shock absorbers for supporting weight of body and propelling it during movement
Plantar foot arch abnormalities
Pes planus (flat foot): longitudinal arch depressed or collapsed; congenital or acquired
Pes cavus (claw foot): medial longitudinal arch unduly high; most cases caused by muscle imbalance (results from poliomyelitis)
Which ligaments/tendons help support which arches?
Peroneus longus tendon helps maintain transverse arch
Long plantar ligament and spring ligament help maintain longitudinal arch
4 factors that maintenance of arches of the foot depend on
1) Shape of interlocking bones
2) Strength of ligaments
3) Plantar aponeurosis
4) Action of muscles through bracing action of their tendons
Plantar aponeurosis
Helps support arches of foot and protects deeper structures
Plantar digital nerves (cutaneous branches of lateral and medial plantar nerves) run deep to superficial transverse metatarsal ligament which is continuous with plantar aponeurosis
Central compartment of plantar foot superficial layer
Flexor digitorum brevis
Muscles of the foot innervation
Medial plantar nerve
Lateral plantar nerve
Both are branches of the tibial nerve, both course with their respective arteries
In central compartment
Send deep branches which course between central and deep compartment
Blood supply to plantar foot
Posterior tibial artery branches into medial and lateral plantar arteries
(Don’t have to know: which pass into space between central and deep compartments to form plantar arch (which anastomoses with deep plantar branch of dorsalis pedis artery))
Where do cutaneous nerves of lower limb come from?
Branches of:
Femoral nerve
Obturator nerve
Tibial nerve
Common peroneal nerve
Direct branches of lumbar plexus or sacral plexus
Cutaneous innervation of the thigh
Anterior thigh is innervated by branches of the femoral nerve (L2-4)
**Posterior** thigh is innervated by **posterior femoral cutaneous nerve**
Lateral thigh is innervated by lateral femoral cutaneous nerve (L2-3)
Medial thigh is innervated by obturator nerve (L2-4)
