Lecture 10 - Midtarsal & Ankle Joints Flashcards
Which joints make up the Midtarsal Joint?
What are it’s 2 axes?
Talonavicular & Calcaneocuboid joint
Function via 2 axes: longitudinal & oblique
Describe the anatomical structure of Midtarsal joint
TN joint: ball & socket more motion
CC joint: saddle shaped, provides stability to lateral column
List ligaments of MTJ
- plantar calcaneocuboid
- long plantar
- calcaneonavicular (spring)
- bifurcate ligaments
List the MTJ axes of motion
Longitudinal Axis = 9° from SP, 15° from TP (average motions)
- Mostly frontal plane motion
- Absorbs rearfoot rotation, generally functions opposite to STJ; LA pronates when STJ supinates
- 10° of motion
• Oblique Axis = 57° from SP & 52° from
TP (average motions)
- 10° motion
- Mostly sagittal plane & transverse plane motion
List relationship of the STJ to MTJ
Elftman described interrelationship of MTJ axes;
- When parallel (to eachother) have maximal motion (pronation)
- When convergent have less motion (supination)
STJ pronation increases MTJ motion = foot flexible (unlocks foot)
STJ supination decreases MTJ motion = foot rigid
In ‘Normal’ foot, fully pronated MTJ at both axes does what?
Locks forefoot on rearfoot, with the plantar surface of Ffoot parallel // to Rfoot
Traditional Thinking/ Theory of MTJ?
ROM impossible to measure clinically
Categorise into normal, hypermobile or restricted (subjective to clinician)
Recent MTJ research indicates?
- Calcaneocuboid & Talonavicular joints should be classifies as separate joints
- Axes continually moving in gait, average motion similar to averages reported
- Motion between cuboid & navicular could be significant
- STJ, CC & TN cannot be separated functionally
- Single axis of motion may be more kinematically sound
Which structures for the ankle joint?
Articulation between talus, distal tibia & fibula form ‘ankle mortice’
List medial ligaments of ankle joint
Deltoid (tibionavicular, tibiospring & deep posterior tibiotalar)
List lateral ligaments of the ankle joint
Anterior & posterior talo-fib & calcaneo-fib
Axis of motion of AJ?
8° from FP & 15° from TP
Axis moves during gait like wobbly axle on a wheel
Action of AJ?
Plantarflexion/ Dorsiflexion with small adduction & abduction
Minimum AJ ROM required for gait?
10° dorsiflexion & 20° plantarflexion
List motion of AJ in gait
- Heel contact
- Starts to PF from a 5° DF position to 10° PF position midway through contact. From here it DF
- Midstance
- At start of midstance, AJ is 5° PF & DF until 10° DF at end of phase
- Propulsion
- As heel lifts, PF occurs until 20° PF at toe off
- Swing phase
- Rapid DF to a 5° DF position to allow for foot clearance in swing phase