Lecture 11 Flashcards
Where is the line of gravity in relation to the hip, knee and ankle joints?
Posterior to hip, anterior to knee, very anterior to ankle.
What is happening to the hip while standing still?
The line of gravity is posterior to the joint, and “pushes” the joint into extension. The ligaments are tight, locking the hip joint so that no muscles are involved and no energy is spent. There are three capsular ligaments in the hip, which thicken the joint capsule. In flexion, ant. ligaments are loose, post. ligaments are tight. In extensions, ant. ligaments are tight, post. ligaments are loose.
What is happening to the knee while standing still?
The line of gravity is anterior to the knee. It pushes it into extension. The ligaments are tight, so no muscles are used and there is no energy expenditure.
What is happening to the ankle while standing still?
The line of gravity is anterior to the joint. It is pushed into dorsiflexion. The joint is not locked, and plantarflexors are needed to stabilise the ankle and oppose gravity. Because of this, energy is consumed, but the ankle is not locked so that it is efficient to start gait cycle.
What are the six phases in the gait cycle?
- early stance and heel strike
- mid stance
- late stance and toe off
- early swing
- mid swing
- late swing
What is happening to the hip, knee and ankle during early stance/heel strike? What are the agonists (include other 3 muscle roles where relevant)?
Hip:
- in flexion, moving to extension
- agonists = gluteus maximus + hamstrings
Knee :
- in extension (locked)
- stabilisers = quadriceps femoris, hamstrings, gastrocnemius (to prevent damage to knee)
Ankle :
- in dorsiflexion (best bony congruence and stable), but moving into plantar flexion
- agonist = triceps surae
- antagonist = tibialis anterior (to control rate of foot drop)
What is happening to the hip, knee and ankle during mid-stance? What are the agonists (include other 3 muscle roles where relevant)?
Hip :
- continuing to move into extension
- agonists = gluteus maximus + hamstrings
Knee :
- moving from extension into slight flexion
- agonists = hamstrings + gastrocnemius
Ankle:
- continuing to move into plantar flexion
- agonists = triceps surae
What is happening to the hip, knee and ankle during late stance/toe off? What are the agonists (include other 3 muscle roles where relevant)?
Hip:
- extension
- agonists = gluteus maximus + hamstrings
Knee:
- in extension
- agonists = hamstrings and gastrocnemius, contracting for next movement
Ankle:
- full plantarflexion
- agonists = triceps surae for strong propulsion
What is happening to the hip, knee and ankle during early swing? What are the agonists (include other 3 muscle roles where relevant)?
Hip:
- in extension, moving into flexion
- agonists = iliopsoas + rectus femoris
- antagonists = gluteus maximus and hamstrings
Knee:
- in flexion to lift foot off ground
- agonists = hamstrings and gastrocnemius
Ankle:
- in dorsiflexion to allow clearance of toes
- agonists = tibialis anterior
What is happening to the hip, knee and ankle during mid swing? What are the agonists (include other 3 muscle roles where relevant)?
Hip:
- in flexion
- agonists = iliopsoas and rectus femoris
- antagonists = gluteus maximus and hamstrings
Knee:
- in flexion to lift foot from ground
- agonists = gastrocnemius and hamstrings
Ankle:
- dorsiflexion so toes don’t drag
- agonists = tibialis anterior
What is happening to the hip, knee and ankle during late swing? What are the agonists (include other 3 muscle roles where relevant)?
Hip:
-in flexion
- agonists = iliopsoas and rectus femoris
Knee:
- moving from flexion to extension to prepare for heel strike
- agonists = quadriceps femoris
Ankle:
- in dorsiflexion for stability during heel strike
- agonist = tibialis anterior to pull into dorsiflexion
- stabilisers = triceps surae for ankle stability
