Functional Joints of the Foot (Part 2) Flashcards
Midtarsal joint
- Transverse Tarsal Joint
- Chopart’s Joint
- Two separate anatomical joints
- Two common axes of motion
- Joints move together
Two anatomical joints of the midtarsal joint
- Talonavicular
- Calcaneocuboid
Talonavicular joint
- Panarthrodial
- The long axis
- Highly adjustable in stance
Calcaneocuboid joint
- Saddle shaped
- The oblique axis
- “Locks” the lateral column
- Anterior medial overhang of distal calcaneus
- Inferomedial process of the cuboid
Bifurcate/Chopart’s ligament
- Y-shaped originating from anteromedial corner of sinus tarsi
Medial portion of bifurcate ligament
- Calcaneonavicular ligament
Lateral portion of bifurcate ligament
- Calcaneocuboid ligament
Ankle sprains with bifurcate ligament
- May cause avulsion of anterior superior process of calcaneus with inversion ankle injuries
Plantar calcaneonavicular (spring) ligament attachments
- Runs from sustentaculum tali to the navicular tuberosity to support the talar head
Plantar calcaneonavicular (spring) ligament
- Possesses a thick fibrocartilaginous layer dorsally
- Helps to maintain integrity of medial longitudinal arch
Plantar calcaneocuboid (short plantar) ligament
- Short, wide and very strong!
- Supports the lateral longitudinal arch
Plantar calcaneocuboid (short plantar) ligament attachments
- Runs from plantar surface of calcaneus to plantar surface of cuboid
Long plantar ligament
- Helps to provide the floor of the canal the peroneus longus passes through
Long plantar ligament attachments
- Runs from plantar surface of calcaneus and cuboid, in front of the tuberosity, to the bases of the second, third and fourth metatarsal base
Midtarsal joint longitudinal axis
- Allows frontal plane movement of the forefoot
- Comprised of the talonavicular joint
- Dictates movement of the medial column of the foot
- Pronatory/supinatory
Midtarsal joint oblique axis
- Allows sagittal and transverse plane movement of the forefoot
- Comprised of the calcaneocuboid joint
- Dictates movement of the lateral column of the foot
- Pronatory/supinatory
Longitudinal axis of MTJ anatomy
- Ball and socket joint
- Almost parallel to the long axis of the foot
Longitudinal axis of MTJ positioning
- 9° from the sagittal plane
- 15° from transverse plane
- Predominantly frontal plane motion
Longitudinal axis of MTJ range of motion
- Minimum: 4 - 6°
- Average: 8°
- Pronatory/supinatory axis
Longitudinal axis of MTJ runs
- From MAD
- Lateral, posterior and plantar to:
- Medial, Anterior and Dorsal
Oblique midtarsal joint anatomy
- Saddle joint
- Among the least mobile joints of the foot
- High degree of angulation from transverse and sagittal planes
Oblique midtarsal joint axis positioning
- 52° from sagittal plane
- 56° from transverse plane
- Predominantly sagittal and transverse plane motion
Axes of MTJ and their ROM
- Oblique Axis – 22° average ROM
- Longitudinal Axis – 8° average ROM
Neutral position of midtarsal joint
- “Locked” midtarsal joint
- Maximally pronated position
- There should be NO sagittal plane motion when the heel comes off the ground
- Enables the foot to function as a second class lever
Neutral position of midtarsal joint lever components
- Fulcrum – metatarsal-phalangeal joint axis
- Effort – gastrocsoleus complex
- Load – rearfoot and weight bearing load of body
Locking mechanism of the OMTJ
- Osseous mechanism
- Ligamentous mechanism
Osseous portion of OMTJ locking mechanism
- Concave-convex OMTJ
- Rotation of cuboid on calcaneus
- Pronation
Pronation of osseous mechanism of OMTJ locking involves
- Dorsal movement
- “Packing” of the joint
- Dorsal lateral aspect of calcaneus limits movement
Parallelity of axes
- Subtalar joint cannot move independently of MTJ
- With pronated STJ…MTJ axes become more parallel
- Facilitates unlocking
- Mobile Adaptor role
Medial arch support in static stance involves
- Plantar fascia
- Long Plantar ligament
- Short Plantar ligament
- Spring ligament
Plantar fascia
- Originates from plantar calcaneal tubercles
- Divides into five slips to insert into bases of distal phalanges and plantar plates
- Receives some fibers from tendo achilles
Functions of the plantar fascia
- Supports the medial arch
- Bears 25 to 33% weight bearing load
- Aids in OMTJ pronation during propulsion
- Acts as a shock absorber
- Elevate the arch at heel off
- Windlass action of Hicks (passive action)
The first ray consists of
- First cuneiform
- First metatarsal
- Hallux
Flat joints of the first ray
- First cuneiform-navicular joint
- First cuneiform-first metatarsal joint
First ray motion
- Non-pronatory-supinatory axis of motion
First ray axis runs
- Medial-plantar-posterior to lateral-dorsal-anterior
First ray axis positioning
- 9° from transverse plane
- ~45° from sagittal and frontal planes
- Runs lateral, anterior and distal L-A-D
Motion of the first ray axis
- Nearly all motion in frontal and sagittal planes
- Very close to being a biplanar joint
First ray function/movements
- Non-pronatory/non-supinatory
- Inverts w/ dorsiflexion
- Everts w/ plantarflexion
First ray ROM
- 5 mm dorsiflexion
- 5 mm plantarflexion
- Start point: level of the second metatarsal
First metatarsophalangeal joint
- Articular facets of four bones within one synovial capsule
- First metatarsal head
- Proximal phalanx of hallux
- Tibial sesamoid
- Fibular sesamoid
- Condylar joints
First MTPJ
- Most complex of MTPJ
- Most important for propulsion
- “Dynamic acetabulum”
- Likened to a hammock
First MTPJ is likened to a hammock
- Metatarsal head rocks:
- Plantarly on the sesamoids and soft tissue
- Distally within the base of the proximal phalanx
Movement of the first MTPJ is primarily dorsifelxion and plantarflexion
- Minimum of 65 to 75º dorsiflexion required for toe off
- With elevation of first metatarsal, range of motion decreases
- Interphalangeal joint can provide up to 35º of motion
- Etiology for hallux limitus
Hubscher maneuver
- Evaluates first ray hypermobility (first ray and MTPJ position)
- With dorsiflexion of first ray, range of motion at MTPJ decreases
- “Jamming” occurs with MTPJ arthritic pain
- Good for evaluating orthotic control of medial column
First ray hypermobility
- Inability to stabilize first ray against the ground
- Peroneus longus has decreased plantarflectory vector
Congruent malalignment of first MTPJ
- Joint surfaces are parallel
Deviated malalignment of first MTPJ
- Joint surfaces intersect outside the joint
Subluxed malalignment of first MTPJ
- Joint surfaces intersect within the joint
- Stress reactions evident in lesser metatarsals
Metatarsal break angle
- Normal parabola: 2 > 1 > 3 > 4 > 5
- Angle second and fifth metatarsal heads - 62°
Metatarsal break angle (2-5)
- Toe off occurs about this axis (62°)
- Contributes to inversion of the rearfoot
- Abnormal parabola may cause uneven weight distribution during propulsion
Fifth ray
- Consists of fifth metatarsal only
Fifth ray axis (root)
- 20° from transverse plane
- 35° from sagittal plane
- Pronatory/supinatory
Fifth ray ROM
- May be evaluated as excursion
- 1-3 mm up to 10-12 mm
Fourth intermetatarsal angle (fifth ray)
- 6.5 – 8°
- Average 7.1°
Lateral deviation angle (fifth ray)
- Average 2.64°
MTPJ axes
- Pass perpendicular to the vertical axis of the MTPJ (strong abductors and adductors)
- Pass just below the transverse plane of the joint axis (very weak plantarflexors)
- Insert into the extensor expansion
