Exam 2 Flashcards
Study of mechanics as it relates to the function and anatomy of biological systems
Biomechanics
Mechanical variables that describe the characteristics of a motion in time and space (things we can see with our own eyes)
Kinematics
vector
direction and magnitude
scalar
distance
The vector change in position of an object in a 2 or 3 dimensional space
Displacement
Rate of change of displacement with respect to time
velocity
rate of change of velocity with respect to time
acceleration
Mechanical variables representing the forces responsible for causing changes in kinematics, resulting in movements (things we can’t see)
Kinetics
Newtons first law
a body in motion tends to remain in motion at a constant velocity unless acted upon by an external force
Newtons second law
net force applied to a body will act to accelerate the object in the direction of force
newtons third law
for every action, there is an equal and opposite reaction
may propel the body or associate with the absorption of an impact.
Acts to change the kinematics of the human body
ground reaction force
a shear force expressed between two surfaces
friction
expression of forces that cause angular motion
torque
to produce torque what 2 components are needed
- axis of rotation (joint center)
- Force applied at a perpendicular distance away from the joint center
1st class lever
effort force and resistance force are located on opposite sides of the lever
2nd class lever
the effort force and resistance force are located on same side of lever. effort force is located further away from the axis
3rd class lever
the effort force and resistance force are located on same side of lever. effort force is located closer to axis
main contributions to human movement in the foot and ankle
- foot and ankle apply forces to the ground and receive ground reaction forces
- disperse body weight and GRFs across bone and soft tissue
What are the two arches that help to distribute impact forces, maintain balance, and propel the body forward in gait
Longitudinal arch (medial and lateral)
Transverse arch
Characteristics of the medial longitudinal arch
- highly elastic
- assists in distributing forces through the foot
- assists in propelling the body forward in gait
Characteristics of the lateral longitudinal arch
- Rigid (good for stability)
- Assists in maintaining balance
- Assists in distributing forces through the foot
Characteristics of the transverse arch
- assists in distributing forces through the foot
- assists in propleling the body forward in gait
what gives arches their elasticity in the foot
helps stabilize the longitudinal arches
plantar fascia
what is the order of body weight transfer from the tibia and down
tibia to talus to calcaneus
Bone that is wider on the anterior side with provides more ankle stability when the foot moves into doriflexion vs plantar flexion
Talus
What are the 5 tarsals in the foot
Navicular
3 cuneiforms (medial, intermediat, lateral)
cuboid
these act as pulleys for muscles wrapping around posteriorly on the tibia and fibula
Lateral and medial malleoli
Skeletal muscle insersions in the foot
- Inner surface of medial cuneiform
- basses of all metatarals
- superior and inferior surfaces of distal phalanxes
- posterior calcaneus
Talocrural joint
Articulation
Motion
articulation - talus tibia and fibula
motion- plantarflexion (20 degrees from neutral) and dorsiflexion (50 degrees from neutral)
internal and external rotation
Subtalar and Transverse tarsal joints
Articulation
motion
articulation - talus and calcaneus (subtalar) Navicular, cuneiforms, cuboid and calcaneus (transverse tarsal)
Motion - inversion (30 degrees) and eversion (15 degrees)
High ankle sparin
distal interosseous membrane can be sprained. Usually from inversion of the ankle while positioned in dosriflexion
What is injured during a lateral ankle sprain with neutral foot alignment
Calcaneofibular ligament
What is injuring during a lateral ankle sprain with planar flexed alignment
Anterior talofibular ligament
What joint helps with foot clearance
knee joint
what muscles work together to take stress off the knee joint
hamstrings and quadriceps (dynamic stabilizers)
what allows the feet to push into the ground with more force
the knee joint transferring muscle force from the large muscles of the thigh and core to the lower leg
two major rigid structures supporting the knee joint
femur and tibia
these articulate to form the knee joint
femoral and tibial condyles
why is the medial femoral condyle larger than the lateral femoral condyle
the long axis of the femur runs slightly toward the midline of the body (q line)
does the fibula have articulation with the knee
no
sesamoid bone that pushes the quadriceps muscle force further away from the joint center
patella
Key bony landmarks in the knee
superior/inferior poles of patella
tibial tuberosity
gerdys tubercle
medial/lateral femoral epicondyles
upper anteromedial surface of tibia
head of fibula
gliding joint that increases the mechanical advantage of the quadriceps muscle group
patellofemoral joint
When the knee is flexed 30 degrees what motion can it also do
internal and external rotation
Static stability in the knee
bony stability
strong ligaments
menisci
dynamic stability in the knee
activation of skeletal muscles acting primarily in the sagittal plane
where are the menisci thicker
on the medial knee (q angle)
Commonly injured in sport play during foot planting, cutting, or when an external force is applied to the posterior aspect of the tibia
ACL
What to focus on for neuromuscular triaing for ACL prevention
- Frontal plane knee stability
- landing and cutting biomechanics
- core strength
- extremity strength imbalances
injured when an external force is applied to the anterior aspect of the tibia
PCL
Commonly injured when an external force is applied to the lateral aspect of the tibia
MCL
lateral ligament of the knee
LCL
What does having a strong core do
makes humans more effective at transmitting force from the large muscles of the hip and thigh to the feet, where they can be applied to the ground
Q angle
formed from ASIS to midline of patella
Locate femur femoral head and greater trochanter
femur- long bone
femoral head- round end that connects hip joint
greater trochanter- most superior point that is lateral
What does the pelvic girdle consist of
right and left pelvic bones that are joined together posteriorly by the sacrum
What does each pelvic bone consist of
ilium, ischium and pubis
Key bony landmarks in anterior pelvis
- iliac crest
- Anterior superior iliac spine
- Anterior inferior iliac spine
Key bony landmarks in the posterior pelvis
- iliac crest
- sacrum/coccyx
- ischial tuberosity
- pubis
Where is the pubic sympysis and what type of joint is it
inferior joint between pelvic bones
amphiarthrodial
Where is the sacroiliac joints and what type of joint is it
connects the lower appendicular skeleton to the axial skeleton
amphiarthodial
diarthrodial ball and socket joint that permits movement in all 3 planes
acetabulofemoral
Static stabilization of the acetabulofemoral joint
strong, dense ligaments help prevent dislocation and extreme ROM
Iliofemoral ligament
prevents anterior dislocation and may restrict hip extension
pubofemoral ligament
prevents anterior dislocation and may restrict hip extension and abduction
ischiofemoral ligament
prevents posterior dislocation and may restrict internal rotation
What movements occur in the sagittal plane of the hip joint with ROM
Flexion- 120 degrees from neutral
extension - 30 degrees from neurtral
What movements occur in the frontal plane of the hip joint with ROM
abduction - 45 degrees from neutral
adduction - 20 degrees from neutral
What movements occur in the transverse plane of the hip joint with ROM
internal rotation - 35 degrees from neutral
External rotation - 45 degrees from neutral
Horizontal abduction of the hip
frontal plane
abduction of a flexed hip
60 degrees from neutral
Horizontal adduction of th hip
Frontal plane
adduction of a flexed hip
40 degrees from neutral
Pelvic girdle sagittal plane movement
Anterior rotation
Posterior rotation
Pelvic girdle frontal plane movement
Right lateral rotation
Left lateral rotation
Pelvic girdle transverse plane movement
Right transverse rotation
Left transverse rotation
Sagittal plane movement of the knee
flexion and extension
150 degrees from neutral
Transverse plane movement of the knee
Internal rotation (30 degrees)
external rotation (45 degrees)
What plexus innervates all lower extremity muscles
Lumbar and sacral plexuses
Posterior component of the ankle and foot muscles
Gastrocnemius
Soleus
Tibialis Posterior
Flexor Digitorum Longus
Flexor Hallucis Longus
Posterior component of the foot ank ankle major action
Plantar flexion
Toe Flexion
(secondary action, inversion)
Gastrocnemius
Major action
Assists with
Major action: Plantar flexion
Assists with: knee flexion
Soleus
Major action
Plantar flexion
Tibialis Posterior
Major actions
Plantar flexion
Inversion
Flexor digitorum longus
Major action
Assists with
Major action: flexion of toes 2-5
Assists with: plantar flexion and inversion
Flexor Hallucis Longus
Major action
Assists with
Major action: flexion of great toe (1)
Assists with: plantar flexion and inversion
Lateral compartment muscles of the ankle and foot
Peroneus Longus
Peroneus Brevis
Lateral compartment of the foot and ankle major action
Eversion
Peroneus longus
Major action
Assists with
Major action: eversion
Assists with:plantar flexion
Peroneus Brevis
major action
Assists with
major action: eversion
Assists with: plantar flexion
Anterior compartment muscles of the ankle and foot
Peroneus Tertius
Extensor Digitorum Longus
Extensor Hallucis Longus
Tibialis Anterior
Anterior compartment of the ankle and foot major actions
Dorsiflexion and to extension
Peroneus Tertius
Major action
assists with
Major action: dorsiflexion
Assists with: eversion
Extensor Digitorum Longus
Major action
Assists with
major action: extension of toes 2-5
Asists with: dorsiflexion and eversion
Extensor Hallucis Longus
Major action
assists with
Major action: extension of the great toe (1)
Assists with: dorsiflexion and inversion
Tibialis anterior
Major action
Assists with
Major action: dorsiflexion
Assists with: inversion
Anterior compartment of the knee major action
Extension
Rectus femoris
Major action in knee
Knee extension
Vastus Lateralis
Major action in knee
Knee extension
Vastus intermedius
Major action in knee
Knee extension
Vastus medius
major action in knee
Knee extension
Posterior compartment of knee major action
Flexion
Biceps femoris
Major action in knee
Knee flexion
Knee external rotation (when knee is flexed)
Semimembranosus
Major action in knee
Knee flexion
knee internal rotation (when knee is flexed)
Semitendinosus
Major action in knee
Knee flexion
Knee internal rotation
Sartorius
Major action in knee
Assists with
Major action: knee flexion
Assists with: knee internal rotation
Gracilis
assists with in knee
Knee flexion
Knee internal rotation
Popliteus
major action in knee
Knee flexion
Knee internal rotation
Rectus femoris
major action in hip and pelvis
Hip flexion
Anterior pelvic rotation
Sartorius
Major action in hip and pelvis
Hip flexion
Anterior pelvic rotation
External hip rotation
Gluteus medius
Major action in hip and pelvis
Assists with
Major action: hip abduction
Ipsilateral lateral pelvic rotation
Assists with: hip flexion, internal hip rotation, anterior pelvic rotation, hip extension, external hip rotation, posterior pelvic roation
Gluteus Minimus
Major action in hip and pelvis
Assists with
Major action: hip abduction, internal hip rotation
Assists with: hip flexion, anterior pelvic roation, ipsilateral lateral pelvic rotation
Gluteus Maximus
Major action in the hip and pelvis
Assits with
Major actions: hip extension, external hip rotation, posterior pelvic rotation, contralateral transverse pelvic rotation, ipsilateral lateral pelvic rotation
Assists with: hip abduction, hip adduction
Adductor magnus
Major actoin in hip and pelvis
Assists with
Major action: hip adduction, external hip rotation
Assists with: hip extension
Adductor longus
Major action in hip and pelvis
Assists with
Major action: hip adduction
assists with: hip flexion, anterior pelvic rotation
Tensor fascia latae
Major action in hip and pelvis
hip abduction
hip flexion
internal hip rotation
anterior pelvic rotation
ipsilateral lateral pelvic rotation