Lower Limb Stability & Actions Flashcards
What are the 2 requirements for maintaining stability?
- The line of gravity passes through the supporting base
2. The line of gravity passes through the axis of rotation of each joint.
Gravity naturally causes ____ ____ which is resisted by the iliofemoral and ischiofemoral (HIP) ligaments. If COG is moved posteriorally, a person would resist with the hip flexors: _______ and ______.
If the COG is moved anteriorly, a person would resist with the _________.
Hip Extension.
Illiopsoas and rectus femoris
Hamstrings
Describe the meaning of a Gower’s Sign. What might a person do to compensate when walking?
Commonly seen in someone with weak gluteal muscles. Associated with Muscular Dystrophy. The person would walk up his or her legs using arms and stand with his shoulders thrown back, since he cannot lean forward.
Gravity naturally causes ______ at the knee. This is resisted by the posterior knee ligaments: ______ and _______. If the COG is placed posteriorly, one would resist with ________ (knee extensors). If COG is displaced anteriorly, resist with ________.
Extension;
Oblique Popliteal ligament, Posterior knee joint capsule
Quadriceps;
Hamstrings.
Gravity naturally causes _____ at the ankle. This is resisted by your plantar flexors: _____ and _____. If the COG is displaced posteriorly, the ______ resist. If COG is displaced anteriorly, the ______ resist.
Dorsiflexion;
Gastrocnemius and Soleus;
Tibialis anterior;
plantar flexors
Describe the Trendelenberg Test
Describes where a person stands on one leg to test lateral hip stabilizers, the gluteus medius and minimus. A positive sign shows an unbalanced pelvis shown as a slanted iliac crest towards the unsupported side. The abductors are too weak to resist gravity.
A positive Trendelenberg sign is indicated by…
The hips slanted towards the affected (weak) side of the gluteus minimus and medius, when a person stands on one leg. This can indicate an injury to the Superior gluteal nerve that innervates these muscles.
A slow descent during a squatting exercise which involves flexing the knee engages what lower limb muscle? What are these muscles function at the hip?
Hamstrings = hip extensors + knee flexors
A tribute dancer to Michael Jackson is performing “the Lean” move for “Smooth Criminal”. Anatomically his center of gravity has significantly been displaced _______. What muscles of the lower limb is the dancer using to stop himself from toppling over?
Anteriorly;
Plantar Flexors at the ankle: Gastrocnemius, Soleus;
Hamstrings at the knee: Semitendinosus, Semimembranosis, Biceps Femoris (short and long head)
Gravity naturally causes ________ at the hip, _______ at the knee and _________ at the ankle.
Extension @ hip;
Extension @ knee;
Dorsiflexion @ ankle
When standing on one leg, gravity acts as a hip _________. To resist falling over on the side, what hip abductors are working?
Gravity = hip adductor;
Resisted by Gluteus medius and minimus (hip abductors)
A young teenager is walking with a heavy backpack on his way to school. Because of this, his center of gravity is displaced __________. What muscles, attached to the hip, prevent him from falling backwards?
COG moved Posteriorly;
Iliopsoas and Rectus Femoris (hip flexors)
What ligaments work to stabilize the hips, when standing, for someone with a Gower’s sign?
Iliofemoral and Ischiofemoral ligaments resist movement with posterior displacement of COG
What ligaments stabilize the knee for someone leaning forward (anteriorly displaced COG)?
Posterior knee joint capsule + Oblique popliteal ligament
Both located posterior to the knee
What muscles provide resistance at the knee when someone is leaning back to sit down (posteriorly displaced COG)?
Quadriceps Femoris = knee extensors
