- When people look at others move, they usually view joint by joint motion/isolated joints rather than looking at how two bones of a joint move on each other in each plane of motion
- Injury occurs to the body when forces that the body can’t handle are presented
- According to the Gray Institute, occurs at Transformational Zones (TZ)
- TZ is a point in time when the body stops loading in one direction and begins to unload in another direction
- Every movement has at least 2 TZ’s. In the simplest form of gait there are 2 TZ’s:
- 1st TZ: Front foot hits the ground during walk - observe what happens at the big foot, mid foot, rear foot, ankle, knee, hip, lumbar, thoracic etc…
- 2nd TZ: Back foot pushes off preparing to walk forward - observe same jts as the 1st TZ
- What’s happening in all 3 planes of motion and all jts?
- 3 Step Process To Name Motion:
- What two bones make up the joint?
- Hip: Pelvis + Femur
- Knee: Femur + Tibia
- Are the bones moving in the same or opposite direction in each of the three planes of motion?
- Sagittal
- Frontal
- Transverse
- Which bone is moving faster, top or bottom?
- Same direction//same speed
- Same direction//top moves faster
- Same direction//bottom moves faster
- Opposite direction
KEY TAKEAWAY: No two bones of a joint ever stay still
- Before naming a joint, understand:
- Bottom Up Driver
= Bottom bone moves faster than top bone
- e.g. 1st TZ in gait (when the L foot hits the ground), L calcaneus everts, L talus dives down and in, L tibia follows along (but not as far or fast), L femur also follows along (but not as far or fast)
- Top Down Driver
= Top bone moves faster than bottom bone
- e.g. 2nd TZ in gait (when the R foot swings forward in prep for it’s 1st TZ), as the R foot swings forward, the pelvis rotates L in space. This L rotation drives the L femur to rotate L but not as far or fast as the pelvis, this creates L tibial rotation (but not as far or as fast)
- Bones spin in the:
- Sagittal plane = divides the body into R/L halves; bones spin clockwise or counter-clockwise on this “wall”
- Frontal plane = divides the body into front and back halves; bones spin clockwise or counter-clockwise on this “wall”
- Transverse plane = divides the body into top and bottom halves; bones spin clockwise or counter-clockwise on this “wall”
- *REMEMBER: One spin (clockwise or counter-clockwise) from each plane is always happening at the joints
- According to osteopathic lit,
- In extremities, we name the motion by what the distal bone does on a fixed proximal bone. Keep in mind that both bones are moving.
- Example: Knee at the 1st TZ of gait - Bottom Up Driver
- Which two bones make up the joint?
- Tibia and femur (patella is only there for the ride)
- Same or opposite direction?
- Sagittal: When the L foot hits the ground, L femur spins posteriorly in the pelvis, there is an anterior pelvic tilt, the L tibia is spinning anteriorly. Therefore, tibia and femur are spinning in opposite directions. As a result, knee feels flexion
- Frontal: Pelvis has a frontal plane shift, L knee dives down and in. Body has to control this motion. L femur is spinning on the wall counter-clockwise. L tibia is spinning opposite to the femur (clockwise on the wall). As a result, knee experiences ABD if we are basing this off osteopathic literature. You might think ADD since the knee is moving towards the midline - yes you are right - if you are looking at “the knee” as an “isolated region” - BUT, that is not how we name motion at the extremities - follow osteopathic lit - when the knee dives in towards the midline, the bottom of tibia relative to the bottom of the femur is outside of the midline - because motion is named based on what the distal bone is doing (the tibia is away from the midline) the knee feels ABD.
- Transverse: L foot hits the ground, L calcaneus everts, talus dives down and in. This makes the tibia rotate inwards and the femur rotate inwards; but the tibia does it faster than the top bone. Since they are moving in the same direction, move on to step 3 below.
- Which bone is moving faster?
- Drivers are important here - since it’s bottom up, the tibia moves faster than the femur. Therefore, the knee experiences IR in the sagittal plane
- IR is important for turning on glutes in the transverse plane. People who experience knee pain in the 1st TZ probably feel an ER moment instead of an IR moment at the knee because the tibia is not rotating faster than the femur - the knee feels ER causing the patella to smack into the lateral epicondyle and the VMO is “blamed”
- Example: Hip at 1st TZ of gait - Bottom Up Driver
- Two bones = Femur and pelvis
- Sagittal: L foot hits the ground, pelvis spins anterior on the “wall” of the sagittal plane. Femur spins posteriorly. Both bones are moving in the opposite direction. Therefore, hip feels flexion
- Frontal: L foot hits the ground, pelvis translates to the L, R side of pelvis drops down to the ground. When that happens, pelvis is spinning on the wall clockwise. Femur is spinning on the wall counterclockwise (opposite direction). Therefore, the hip is experiencing ADD. Looking in isolation, the hip region looks like it is ABD since it is outside the midline.
- Transverse: L foot hits the ground, IR occurs at knee. L Femur also experiences IR. Because the L femur is swinging in preparation for heel strike, the pelvis is rotates R in space causing the L femur to rotate R. Therefore, both bones are moving in the same direction - move on to step 3 - which bone is moving faster? Because the heel strikes the ground, the bottom bone (femur) should be moving faster. Therefore, hip feels IR
- Example: Hip at 2nd TZ of gait (back phase) - Top Down Driver
- Two bones = Femur and pelvis
- Sagittal: R foot swinging forward in space, pelvis translating forward in space, R femur also transfers forward in space. Since this is a top down driver, the pelvis translates faster. Fix the top, move the bottom: the hip feels extension
- Frontal: R foot hits the ground, pelvis translates R, spinning counter-clockwise on the wall, L femur spins the opposite direction. Therefore, hip feels ABD
- Transverse: R foot hits the ground, pelvis spins L, creates L rotation in L femur. Both bones are moving in the same direction - ER. Since they are moving in the same direction, ask which bone moves faster? Top down driver indicates the pelvis is moving faster than the L femur. Therefore, hip experiences IR
KEY TAKEAWAY: Bone can be moving one direction, but the joint might be feeling something completely different