HK 302 - lecture 5

knee/ankle/foot osteology/arthrology/myology continued

medial and lateral condyle (tibia)

attachment site for ligaments and musculature

medial and lateral plateau (tibia)

“shelf” for femur; medial side concave, lateral side convex

intercondylar eminence (tibia)

cruciate ligament attachment site

tibial tuberosity

attachment site for patella ligament/tendon, common site for traction injury

medial malleolus

distal projection at ankle, deltoid ligament attachment site

fibular head

large superior projection, close to peroneal nerve

fibular shaft

often site of fracture

lateral malleolus

inferior portion of bone that forms part of ankle; several ankle ligaments attach here

proximal tibiofibular joint

reinforced by anterior and posterior tibiofibular ligaments

distal tibiofibular joint

reinforced by anterior and posterior tibiofibular ligaments

syndesmosis

thick, fibrous connective tissue that spans the distance between tibia and fibula and supports both joints

tibia/fibula fracture

very rare!

maisonneuve fracture

• do not happen frequently

• fracture of proximal 1/3 of the fibula

• associated with “high ankle sprains” that disrupt the syndesmosis

• commonly missed on the initial evaluation of the ankle injury

tibialis anterior

origin: lateral condyle and proximal half of the lateral surface of the tibia

insertion: medial and plantar surface of medial cuneiform bone, base of first metatarsal

action: dorsiflexes the ankle; assists in the ankle inversion

innervation: deep peroneal nerve

tibialis posterior

origin: lateral portion of the posterior surface of the tibia

insertion: navicular tuberosity, sustentaculum tali

action: inverts the foot, assists with ankle plantar flexion

innervation: tibial nerve

peroneus longus

origin: lateral condyle of the tibia,, head and proximal 2/3 of the lateral surface of the fibula

insertion: lateral side of the base of the first metatarsal and medial cuneiform

action: eversion of the foot; assists in plantar flexion

innervation: superficial peroneal nerve

peroneus brevis

origin: distal 2/3 of the lateral surface of the fibula

insertion: base of the fifth metatarsal, lateral side

action: eversion of the foot; assists in ankle plantar flexion

innervation: superficial peroneal nerve

ankle sprain avulsion fracture

• occurs when the peroneus brevis is contracted and resisting ankle inversion while being forced beyond its physiological barrier

• tender on lateral foot over base of 5th metatarsal

soleus

origin: posterior surface of the head of the fibula and proximal 1/3 of its body, middle 1/3 of the medial border of the tibia

insertion: with the tendon of the gastrocnemius into the posterior surface of the calcaneus

action: ankle plantar flexion

innervation: tibial nerve

gastrocnemius

origin:

• medial head: proximal and posterior part of the medial condyle

• lateral head: lateral condyle and posterior surface of the femur

insertion: middle part of the posterior surface of the calcaneus

action: ankle plantar flexion; assists in knee flexion

innervation: tibial nerve

plantaris

origin: lateral supracondylar ridge of femur

insertion: via Achilles tendon to tuberosity of calcaneus

action: assist with plantarflexion of foot

innervation: tibial nerve

popliteus

origin: anterior part of the groove on the lateral condyle of the femur

insertion: triangular area proximal to the soleus on posterior surface of the tibia

action:

• medially rotates the knee in a NWB position

• in WB it laterally rotates the femur on the tibia

innervation: tibial nerve

compartments

the syndesmosis with other lower leg fascia divides the lower leg into compartments

• anterior: anterior tibialis, extensor hallicus longus, and extensor digitorum longus

• lateral: peroneus longus and brevis

• deep posterior: posterior tibialis, flexor digitorum longus, and flexor hallicus longus

  • posterior tibial artery

  • tibial nerve

• superficial posterior: gastrocnemius, soleus, plantaris

compartment syndrome

• increased pressure within the fixed space of the lower leg causing compression of the neural and vascular structures within a given compartment

• anterior compartment most frequently involved followed by deep posterior

• acute (traumatic - medical emergency!) vs. chronic (exertional)

• diagnosed by measurement of the intercompartmental pressure

  • positive if:

  • resting pressure > 15 mmHg

  • 1-minute post exercise 30 mmHg or greater

  • 5-minute post exercise 20 mmHg or greater

talus (rearfoot)

convex dome underneath the tibia; forms other half of the talocrural joint

calcaneus (rearfoot)

sits underneath the talus; insertion point for Achilles tendon and origin for plantar fascia; common site for pain

navicular (midfoot)

somewhat common stress fracture site due to location between mid and rearfoot

cuboid (midfoot)

mobile bone

cuneiforms (midfoot)

medial, middle, lateral; little clinical significance

metatarsals (forefoot)

total of 5, named medial to lateral; March fractures common in 2nd/3rd metatarsals, avulsion fractures common in 5th with an ankle sprain

phalanges (forefoot)

each toe has three phalanges - a proximal, intermediate and distal (except the big toe, which only has two phalanges)

talocrural joint

true “ankle” joint

• allows dorsiflexion and plantarflexion

• talus is wider anteriorly which limits dorsiflexion, but provides stability

• talus is narrower posteriorly which makes plantarflexion a less stable position

subtalar joint

inversion and eversion occur at this joint between the talus and calcaneus

anterior talofibular ligament

• talocrural & subtalar joint

• “3 o’clock” position; first torn in ankle sprain

calcaneofibular ligament

• talocrural & subtalar joint

• “6 o’clock” position; second torn

posterior talofibular ligament

• talocrural & subtalar ligament

• “9 o’clock” position; 3rd torn

deltoid ligament

• talocrural & subtalar joint

• medial side, very broad and strong structure

anterior/posterior tibiofibular ligaments

• talocrural & subtalar joint

• stabilize distal tib-fib; if torn know as a “high ankle sprain”

arches of the foot

functions: shock absorption; adapt to uneven terrain; provide space for structures

• pes planus (flat feet) vs. pes cavus (high arches)

plantar fascia (aponeurosis)

runs from calcaneal tubercle to the proximal phalanx of each digit; susceptible to development of heel pain

long plantar ligament

connects rearfoot to midfoot; placed under large amount of stress with pes planus foot

metatarsophalangeal (MTP)

joint between the foot and toes

proximal interphalangeal (PIP)

first joint of the toes, only on toes II-V

distal interphalangeal (DIP)

second joint of the toes, only on toes II-V