Joints of the Lower Limb

ReferencesCornwall MW & McPoil TG (2002). Motion of the calcaneus, navicular, and first metatarsal during the stance phase of walking. J Am Pod Med Ass; 92: 67-76.Michaud TC (1997). Foot orthoses and other forms of conservative foot care. 2nd ed., pp.9-14.Valmassy RL (1996) Clinical biomechanics of the lower extremity, ch.1.

OutlineAnkle JointFirst RayLesser RaysFifth RayMTPJs

Ankle joint AnatomyMortise:Tibial plafond (distal articular surface)Distal articular surface of fibulaSuperior trochlear surface of talar dome

Ligamentous structure:Lateral collaterals (3)Medial collateral (deltoid)

Ankle joint axis of motionProjected medially, superiorly and anteriorly25° from frontal plane10° from transverse plane, but changes constantly as joint movesCan be visualised as running through the tips of the malleoli

Ankle joint motionPrimarily Dorsiflexion / PlantarflexionDF limited by anterior process of talus, triceps surae and posterior aspect of deltoid ligamentPF limited by posterior process of talus and anterior talo-fibular ligamentDF associated with ABD and EVPF associated with ADD and INV

Ankle joint range of motion

Muscles acting at ankle jointMain dorsiflexor: Tibialis anteriorMain plantarflexor: Gastroc-soleusDorsiflexors pass anterior to the axisPlantarflexors pass posterior to the axisOther muscles have little role in pure ankle joint function, but will affect joints distal to it

Ankle joint in gaitSlightly dorsiflexed at heel contactPlantarflexes to foot flat. This is a means of shock absorbance and is contolled by eccentric contraction of tibialis anteriorDorsiflexes as tibia moves over talus during forward progression. This is passiveEccentric contraction of gastroc-soleusPlantarflexes during propulsion under active contraction of gastroc-soleus groupDorsiflexes during swing for ground clearance

Ankle joint kinematics in gait

Ankle joint stabilityTalus wider anteriorly, so more stable in a dorsiflexed position

Deltoid ligament (medial) is stronger than lateral collateralsAnkle sprains: note role of joint axis, anterior widening of talus and relative weakness of lateral ligaments

First rayAnatomyfunctional unit consisting of 1st met. and medial cuneiformarticulates with navicular, middle (2nd) cuneiform and 2nd met.axis45° to frontal and sagittal planesvirtually parallel to transverse plane

Motiondorsiflexion with inversionplantarflexion with eversion

Major muscles acting at first raytibialis anterior (dorsiflexion) and peroneus longus (plantarflexion)

Motion during gaitDorsiflexes ~5° during contact (with STJ pronation) then plantarflexes by ~10° during midstance and propulsion to be ~5° plantarflexed at heel-off (STJ supination)Plantarflexion enables normal MTPJ dorsiflexion(Cornwall & McPoil, 2002)l

Lesser raysAnatomy2nd ray = 2nd met + intermediate cuneiform3rd ray = 3rd met + lateral cuneiform4th ray = 4th met

Axesmost likely in transverse and frontal planesLesser raysmotionvirtually pure plantarflexion/dorsiflexion

Major muscles acting at lesser raysinterossei and lumbricals

Motion during gaitlocked into dorsiflexion during stanceplantarflex during propulsion to enable normal MPJ dorsiflexion

Fifth rayAnatomy5th ray = 5th met alonearticulates with cuboid and 4th met

Axisprojected anteriorly, medially and superiorly20° to transverse plane35° to sagittal plane

Motiontriplanar pronation and supinationDorsiflexion with eversion (+abd)Plantarflexion with inversion (+add)total ROM <20°

Major muscles acting at fifth rayperoneus tertius and brevisboth produce dorsiflexion/eversion (as they insert superior to axis)Intrinsics and long flexors

act as plantarflexors?

Motion during gaithas not been studied

Metatarsophalangel Joints (MTPJs)anatomymet. head and base of proximal phalanx1st MPJ also articulates with sesamoidsaxestransverse axis (in transverse and frontal planes)vertical axis (in sagittal and frontal planes)

MotionDorsiflexion:

~65° required for normal walking. ~90° maximum non-weighbearing & weightbearing assessment

Plantarflexion:not required for normal walking10° maximum (?)

Adduction / abductionslight and insignificant (except in pathology)

Major muscles acting at MTPJs1st MTPJ: adductor and abductor hallucis, FHB, FHL, EHB, EHLlesser MTPJs: lumbricals, interossei, FDB, FDL, EDB, EDLmotion during gaittransverse plane motion is insignificant (in normal foot)~65° dorsiflexion required for normal propulsion

Relationship between first ray & first MTPJIf 1st ray is stationary, about 35° of hallux dorsiflexion can occur. For the hallux to dorsiflex to 65°, the 1st ray must plantarflex

ConclusionBy knowing the position of the joint axis you can determine the type of motion at a jointthe closer an axis is to a plane, the less motion available in that planeBy knowing the insertion of a muscle relative to the position of the axis, you can determine the effect that muscle has on joint motion