What is the stance phase?
The period of time from when one foot hits the ground to when it leaves the ground
During the stance phase, what is a fxn of the quadriceps?
contract eccentrically to resist knee buckling and going into rapid flexion
What muscles advance the limb during the swing phase of gait (acceleration)?
Hip: flexors of the hip are active-iliopsoas is the most powerful flexor of the hip
Knee: flexors of the knee are active. knee must flex so foot can clear the ground-hamstrings
ankle: dorsiflexors of the ankle are active for acceleration of the limb to ensure the toes clear the ground-tibialis anterior
What muscles prepare the limb for contact (deceleratoin)?
When trying to slow down (decerlation) think of eccentric contraction. Think of when slowly lowering weight in a bicep curl.
Hip: extensors of the limb must eccentrically contract to prevent exess flexion of the hip-gluteus maximus
knee: the knee is now extending from momentum of the leg. therefore the knee flexors are active again, but this time eccentrically to slow the leg down-hamstrings
ankle: dorsiflexors are contracting isometrically to steady the foot for contact-tibialis anterior. roughly, the position of the ankle does not change
What is the ground rxn force? How is it related to quadricep contraction?
Our bodies apply a given amount of force to the ground through the foot each time we take a step. An equal and opposite force is then applied back to the body through the foot, known as the ground reaction force. When knee buckles during walking, is example of the ground reaction force working and the body not reacting appropriately. In OA, can occur due to pain, muscle weakness.
The GRF causes flexion of the knee when it is behind the knee (see slide 16). The quads contract eccentrically to prevent uncontrolled knee buckling. If have weak quads, have a shorter step bc do not want to spend a lot of time in single support of affected limb. can also hold leg really straight
The GRF also acts in the frontal plane. Discuss the significance of this as it pertains to the gluteus medius, minimus, and tensor fascia lata.
When GRF passes medial to the hip joint it creates a torque that adducts the hip. The gluteus medius, minimus and tensor fascia lata balance this moment to keep the pelvis level. If these muscles are weak, have Trendelenberg gait. In compensated Trendeleberg gait, pt can lean to other side to effectively shorten the affected limb
What muscles/nerves may be affected/lesioned with a patient who has difficulty standing or climbing stairs and why?
Pt may have a weak gluteus maximus muscle and/or lesioned inferior gluteal nerve. The gluteus maximus extends the thigh at the hip especially when the knee is flexed. It helps you perform these movements.
What muscles/nerves may be affected/lesioned with a patient who has weakness/loss of knee extension and why?
Pt may have weak quadriceps femoris muscles and/or lesioned femoral nerve. The quadriceps cause extension of the leg at the knee.
What muscles/nerves may be affected/lesioned with a patient who has foot drop (steppage gait)?
Pt may have weakness of the tibialis anterior and/or lesioned deep fibular or common fibular nerve. The tibialis anterior dorsiflexes the foot and if unable to, have foot drop. Pt has steppage gait to compensate so foot is not dragged.