Midtarsal joint Flashcards
Midtarsal joint composed of 2 joints
- Talonavicular
2. Calcaneocuboid
Midtarsal joint composed of 2 axes
- Longitudinal midtarsal joint axis (LMJA)
2. Oblique Midtarsal Joint Axis (OMJA)
Midtarsal joint is —————-and each axis is ————–
Biaxial
Triplanar
LMJA is ———from the transverse plane
15º
LMJA is———-from the sagittal plane
9º
LMJA is ———-from the frontal plane
75º
LMJA provides primarily ———plane motion
Frontal
OMJA is located ——–from the transverse plane
52º
OMJA is located ———-from the Sagittal plane
57º
OMJA is located ———-from the frontal plane
38º
Primary motion at the OMJA is
dorsiflexion/ platarflexion ( Sagittal plane)
with equal amount of abduction/adduction (transverse plane)
The OMJA is sometimes referred to as
secondary ankle joint
The OMJA is sometimes referred to as secondary ankle joint because
The OMJA can provide dorsiflexion.
The range of motion of the midtarsal joint is highly dependent upon the position of
subtalar joint
As the subtalar joint pronates
The axis becomes more parallel and we get increased ROM
As the axis becomes more oblique
we get decreased ROM
The relationship of the axis determines
what kind of motion is available
What is Elftman’s theory?
- As the subtalar joint becomes pronated, the 2 axes become more parallel, increasing the mid tarsal range of motion available
- As the subtalar joint supinates, the 2 axes become more divergent, causing decreased range of motion available at the midtarsal joint .
pronation of mid-tarsal joint , causes
increase in midtarsal joint range of motion
Supination of midtarsal joint, causes
decrease in midtarasl joint range of motion
Elfman’s theory suggests that if the subtalar joint is in neutral position, the maximally pronated position of the forefoot
should be perpendicular to the calcaneal bisection
If the subtalar joint is maximally supinated,the maximally everted (pronated)position of midtarsal joint (forefoot relative to the rear foot)
may be inverted relative to the calcaneal bisection
If the subtalar joint is maximally pronated, the maximally everted (pronated) position of the midtarsal joint
may demonstrate an everted position of the forefoot relative to the rearfoot (Calcaneal bisection)
for these make sure you look at the pictures
when subtalar joint pronates
the OMJA and the LMJA are parallel to each other
For measuring the midtarsal joint,
you want the subtalar joint in the neutral position and midtarsal maximally pronated
For each subtalar joint position how many positions are available at the midtarsal joint?
- Maximally supinated
- Supinated
- Maximally pronated
In off-weight bearing (OKC) the ——-joint effects the ————joint position and ROM
Subtalar
midtarsal
The ———–joint DOES NOT effect ———–joint in OKC
Midtarsal
Subtalar
What is the “locked” position of midtarsal joint?
Maximally pronated position
Locked position of midtarsal joint provides
Stability of the foot during gait
If the midtarsal joint is not maximally pronated
it is supinated
Midtarsal joint locking occurs as a result of
- cuboid rotating until its dorsal border touch the anterior overhang of the calcaneus
- soft tissue effects
- Although ligaments contribute to the stability the Peroneus longus and Posterior tibial muscles are important as well
Fibularis longus acts to
- stabilize the 1st ray
- Resisting inversion force of the midtarsal joint
- Stabilize the 1st ray against the lesser tarsus
The tibialis posterior applies
an adduction moment to the lesser tarsus
Tibialis posteior and Fibularis longus function together or against each other to
prevent excessive motion at the midtarsal joint
What is the dominant plane of the midtarsal joint and why?
Because the LMJA is so close to the transverse and sagittal planes, dominance other that frontal plane is unlikely
it is basically saying that there is more angulation to the frontal plabe
What are dominant plane(s) at OMJA?
Transverse and Sagittal planes -mostly sagittal though (because they almost have equal angulations)
changes from normal will very likely produce dominant motion in one plane.
Sagittal plane dominance ~Motion at the OMJA will be increase in the ———-plane , particularly in the direction of ———–
Sagittal plane
Dorsiflexion
Transverse plane dominance ~
————sagittal plane motion will be available making the OMJA less likely to compensate for —————
Less
Ankle joint equinus
Transverse plane dominance ~
———–transverse plane motion will be available, which is ————to control clinically
More
More difficult
What is Equinus?
Equinus is a condition in which the upward bending motion of the ankle joint is limited
LMJA can readily compensate for
pronatory deformities at the subtalar joint
LMJA is unable to compensate for
inverted rearfoot deformities
If we have a pronated foot what will be the motion at the mid-tarsal joint?
inversion
LMJA undergoes
Supination
OMJA undergoes
Pronation
