Download Chapter 8 Hip Joint Hip Structure Pelvic Girdle Hip Flexors

Hip Joint
Chapter 8
Biomechanics of the Human
Lower Extremity
• Ball and socket joint
• Head of the femur articulates with the
concave acetabulum
• More stable than the shoulder because
– Bone structure
– # muscles and ligaments
– Strength of muscles and ligaments
Pelvic Girdle
Hip Structure
• Includes 2 ilia and the sacrum
• Can be rotated to optimize positioning of the hip
• Integrity of the hip is enhanced by the strong
ligaments crossing the joint
– Forward
– Backward
– Laterally
Hip Flexors
Hip Movements are Facilitated by
Pelvic Tilt
Pelvic Tilt
Femoral Movement
• Posterior
• Flexion
• Anterior
• Extension
• Lateral
• Abduction
• Iliacus
• Psoas Major
• Assisted by:
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Pectineus
Rectus Femoris
Sartorius
Tensor Fascia Latae
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Muscle Contributing to Hip
Extension
Hip Abductors
• Gluteus Maximus
• Hamstrings
– Biceps femoris
– Semimembranosus
– Semitendinosus
• Gluteus Medius
• Assisted by:
– Gluteus Minimus
Hip Adductors
Tibiofemoral Joint
• Dual condyloid articulation between
– Medial and lateral condyles of tibia and femur
• Adductors
– Magnus
– Longus
– Brevis
• Main hinge joint considered the knee
Knee Structure
• Bony structure of the tibiofemoral joint
Patellofemoral Joint
• Articulation between the patella and the femur
• Purpose
– Improves mechanical advantage of the knee
extensors by up to 50%
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Menisci
• Cartilaginous discs located between the tibial
and femoral condyles
• Structures that distribute the load
• Help absorb shock
Major Knee Ligaments
• Collateral Ligaments
– Cross the medial and lateral aspects of the knee
• Cruciate Ligaments
– Cross each other in connecting the anterior and posterior
aspects of the knee
Popliteus
• Contributes to flexion
Knee Flexors
• Hamstrings
• Laterally rotates the femur
relative to the tibia
• Assisted by:
• “unlocks” fully extended
knee
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Gracilis
Sartorius
Popliteus
Gastrocnemius
Knee Extensors
Tibiotalar Joint
• Hinge joint
• Quadriceps
–
–
–
–
Rectus Femoris
Vastus Lateralis
Vastus Medialis
Vastus Intermedius
– Convex surface of the
superior talus articulates
with the concave surface
of the distal tibia
• Considered Ankle Joint
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Distal Tibiofibular Joint
• Syndesmosis
– Dense fibrous tissue binds the distal tibia and
fibula together
Ankle Dorsiflexors
• Tibialis Anterior
• Extensor Digitorum
Longus
• Peroneus Tertius
• Assisted by:
– Extensor Hallucis
longus
Ankle Plantarflexors
Subtalar Joint
• Gastrocnemius
• Soleus
• Assisted by:
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–
–
–
–
–
Tibialis posterior
Plantaris
Peroneus longus
Flexor hallucis longus
Peroneus brevis
Flexor digitorum
longus
Tarsometatarsal and
Intermetatarsal Joints
• Anterior and posterior facets of the talus
articulate with sustencalculum on the the
superior calcaneus
Plantar Arches
• Nonaxial joints that permit only gliding
movements
• Enable the foot to function as a semirigid
unit and to adapt flexibly to uneven
surfaces during weight bearing activity
• Medial and lateral longitudinal arches stretch
from the calcaneus to the metatarsals and
tarsals
• Transverse arch is formed by the bases of the
metatarsal bones
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Plantar Fascia
Foot Inversion Muscles
• Tibialis posterior
• Tibialis anterior
• Thick bands of fascia covering the plantar
aspect of the foot
• Stores mechanical energy during weight bearing
actiity
• Releases energy to assist push-off of foot
Foot Eversion Muscles
Foot Pronation
• Peroneus longus
• Peroneus brevis
• Assisted by:
– Peroneus tertius
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