LECTURE
What is the definition of open kinetic chain and closed kinetic chain?
Open kinetic chain: the distal aspect of the limb is free to move in space
Closed kinetic chain: the distal aspect of the limb is fixed
True or false: hamstrings and quadriceps are antagonistic pairs
True
What is the distal attachment of tibialis anterior?
1st cuneiform and base of 1st metatarsal
What are the actions of the talocrural and subtalar joint?
Talocrural joint: dorsiflexion and plantar flexion
Subtalar joint: inversion and eversion
What nerve comes out of the greater sciatic foramen?
Sciatic
What is the deep to superficial layering of the hip adductors?
Adductor magnus, adductor brevis, adductor brevis, adductor longus, gracilis and pectineus
Give an example of a single joint hip flexor, single hip extensor and a single joint knee extensor
Single joint hip flexor: iliacus or psoas major
Single joint hip extensor: gluteus maximus
Single joint knee extensor: any vastus muscle
Which muscles attach distally to the calcaneus?
Gastrocnemius (lateral and medial heads), soleus and plantaris
What are the 3 main contributers to plantar flexion?
Tibialis posterior, gastrocnemius and soleus
What is the innervation of the anterior, medial and posterior compartment of the leg?
Anterior compartment: femoral
Medial compartment: obturator
Posterior compartment: sciatic
What is the difference between active and passive insufficiency? (Give an example of each)
Active insufficiency: When a muscle reaches a point where it can't shorten any farther, occurs on the agonist, e.g. hamstrings can extend the hip and flex the knee, but can't do both
Passive insufficiency: When a muscle can't be elongated any farther without damage to the fibers, occurs on the antagonist, e.g. stretching issue of active straight leg raise vs. bent knee leg raise
What is the difference in actions of the gluteus minimus and medius? Also, explain how they rotate in terms relative to their attachment points.
Gluteus minimus: hip flexor and internal rotation. The anterior attachment point is on the greater trochanter, so when it shortens, it pulls the front aspect of the greater trochanter medially
Gluteus medius: hip extensor and external rotation. The attachment point is all over the greater trochanter, so when it shortens, it pulls the greater trochanter into external rotation
Which muscle attaches proximally to the distal half of the fibula?
Peroneus brevis
What are the 6 main hip external rotators?
Piriformis, gemellus superior, obturator internus, gemellus inferior, obturator externus and quadratus femoris
Which muscles are supplied by the superior gluteal and inferior gluteal arteries?
Superior gluteal: gluteus medius and minimus
Inferior gluteal: gluteus maximus
What is the importance of biarticular muscles in regards to energy?
It is important for energy transfer as it allows for proximal to distal sequencing and distal muscles to be smaller in size.
Biarticular muscles contract isometrically and thus, do not change in length. They transfer force from monoarticular muscle to distal monarticular muscle
In biarticular muscles, active and passive insufficiency do not work too well. Explain why.
They extend at one joint and flex at another, causing no movement. So, there must be a system that allows the muscle to influence one joint more than another joint
Which muscles have proximal attachments on the interosseous membrane?
Extensor digitorum longus, extensor hallucis longis, peroneus tertius, tibialis posterior and flexor hallucis longus
What are the 7 muscles that contribute to hip flexion?
Gluteus medius (anterior fibers), gluteus minimus, psoas major, iliacus, rectus femoris, tensor fasciae latae and sartorius
Describe the blood supply to the hamstrings (include the major arteries and landmarks it must pass through)
Abdominal aorta -> common iliac -> external iliac -> femoral
From the femoral artery, it travels superficially to the adductor muscles and beside the vastus medialis. It goes through the cirfumlex and perforating vessels through the adductor magnus to feed into the posterior compartment of the leg
Relate the concepts of Lombard's Paradox and biarticular muscles together
Biarticular muscle: muscles can produce two moments at two adjacent joints simultaneously
However, muscles don't know either to act on the hip or knee, so it depends on the force exerted on the attachment. The action that wins is the one with the greatest moment arm (biomechanically has better leverage). Two joints can work the same, but one must have a greater force.
Lombard's Paradox: when extension occurs at both ends of a multi joint muscle, but there must be better leverage where the muscle acts as an extensor.
How does the design of the rectus femoris muscle enable it to have a better mechanical advantage at knee extension?
Biomechanical advantage: the ability to create greater torque
Bony landmark: the patella creates a larger moment arm by shifting the moment arm away from the axis of rotation)
Breaking force: the distal joint at hip extensors slow down knee extension to prevent slamming of the two joints at forceful movements
What are the distal attachment points for the vastus lateralis, vastus intermedius and vastus medialis?
Vastus lateralis: lateral patella, anterior aspect of lateral tibial condyle and rectus femoris tendon
Vastus intermedius: inferior aspect of patella and tendons of vastus lateralis and medialis
Vastus medialis: medial tibial condyle, medial patella, medial aspect of rectus femoris tendon
If you have weak gluteus minimus and medius, what action does that affect and what does that weakness result in in terms of compensation?
Abduction
There must be enough strength to support the swing phase. If there isn't, the stride length becomes short. To compensate, a curvature in the spine occurs to put the centre of mass on the other side of the foot (Positive and Compensated Trendelenburg)
The sciatic nerve is cut halfway down your thigh. What muscles and movements are impacted?
Muscles: tibialis posterior, flexor digitorum longus, flexor hallucis longus, gastrocnemius, plantaris and soleus
Movements: plantar flexion and inversion of ankle, adduction of foot, flexion of knees and toes 1-5