Exam 2- Lower Extremities

• The foot and ankle complex is made up of 26 bones, 30 synovial joints, 30 muslces, and over 100 ligaments
• The synovial joints with the most movement in the foot and ankle complex are the talocrual, transverse tarsal, and subtalar joints
• Functions of foot and ankle complex:• Provides stable base of support for body in different weight-bearing postures w/ minimal energy expenditure• Accommodation of varied terrainduring upright posture and gait• Shock absorption at ground contact during gait• Provides efficient push-off during gait
• The rear foot consists of the talus and calcaneus
• the mid-foot has the tarsals: navicular, cuboid, and cunieforms
• the fore-foot has the metatarsals and phalanges
• Tibialis anterior and extensor hallicus longus are responsible for inversion and dorsiflexion of the foot and ankle
• peroneus tertius and extensor digitorum longus are responsible for eversion and dorsiflexion of the foot and ankle
• peroneus longus and peroneus brevis are responsible for plantar flexion and eversion of the foot and ankle
• the tibialis posterior, flexor hallicus longus, and flexor digitorum longus are responsible for inversion and plantar flexion of the foot and ankle
• The soleus, gastrocnemius, and plantaris are all rsponsible for plantar flexion
• The lower leg is divided into four compartments: anterior, lateral, deep posterior, superficial posterior
• Gastrocnemius

  • origin is the medial and lateral condyle of the femur
  • insertion is the posterior calcaneus
  • actions include knee flexion and ankle plantar flexion
• anterior compartment consists of tibilalis anterior, extensor hallicus longus, and extensor digitorum longus
• lateral compartment consists of peroneus longus, peroneus brevis, and peroneus tertius
• deep posterior compartment consists of flexor digitorum longus, flexor hallicus longus, and tibialis posterior
• superficial posterior compartment consists of gastrocnemius, soleus, and plantaris
• the transverse tarsal consists of the calcaneocuboid joint and the talonavicular joint
• arthrokinematic motion is the manner in which adjoining joint surfaces move on each other during osteokinematic joint movement
• osteokinematic motion is the motion of the bones relative to the cardinal planes
• arthrokinematic motions include roll, slide, and spin
• Class 1 pulley is a fixed pulley that causes an improved muscle action comes from the muscle tendon passing over an external support, the external support serving as a pulley. An example of this pulley is the patella.
• Class 2 pulley is a fixed pulley where the action of the muscle at the joint is altered because of the pulley. This pulley can be bone (lateral malleolus), cartilage (trochela of the eye), or ligament (flexor retinaculum)
• Class 3 pulley is a fixed pulley in which the joint serves as the pulley. The sartorius is an ecample of this pulley.
• A class 4 pulley is a moveable pulley that causes a change in joint position due to movement. An example of this is the pronator teres changing throughout pronation.
• A class 5 pulley is a moveable pulley in which the muscle is its own pulley. Examples of this type include the biceps brachii/ brachialis relationship and the soleus/gastrocnemius relationship
• When a fixed concave surface articulates with a moving convex surface the proximal and distal ends move in opposite directions
• when a fixed convex surface articulates with a moving concave surface the proximal and distal ends move in the same direction
• a close packed joint usually occurs at one extreme ROM where the ligaments are at their most stable position. It allows for a position of maximal congruency.
• A loose packed joint has minimal congruency between articular surfaces and supporting ligaments are lax.
• The type of external loading that ligaments go under the most is tension
• force is a push or pull on the body in only a linear motion
• external forces include ground reaction force, weight, friction, and fluid resistance
• internal forces include joint reaction force and muscular force
• Newton's first law of motion or law of inertia decribes an object's resistance to a change in motion unless acted upon by an opposing force
• Newton's second law of motion or law of acceleration describes when a force acts on an object it will cause the object to accelerate. Force is equal to mass times acceleration.
• Newton's third law of motion or law of reaction states that every action has an equal and opposite reaction.
• First class levers have an axis between the force and resistance (FAR)
• The functions of a 1st class lever are balance 2 or more forces, change the direction of an applied force, mechanical advantage for speed/ROM, and mechanical advantage for force.
• A second class lever is defined as resistance between an axis and a force (ARF)