Chapter 8 Kinesiology

  • Hip Joint and Pelvic Girdle Overview
  • Relatively stable joint due to:
    • Bony architecture
    • Strong ligaments
    • Large supportive muscles
  • Functions in:
    • Weight bearing
    • Locomotion
  • Enhanced by a wide range of motion
    • Abilities include running, cutting, jumping, etc.
  • Anatomy of Bones
  • Ball and Socket Joint
    • Head of femur connects with acetabulum of pelvic girdle
  • Pelvic Girdle consists of:
    • Right and left pelvic bones connected posteriorly by the sacrum
    • Major bones: Ilium, Ischium, Pubis
  • Femur:
    • Longest bone in the body
  • Sacrum:
    • Extension of spinal column with five fused vertebrae
    • Inferiorly extends into the coccyx
  • Pelvic Bone Divisions
  • Upper two-fifths = Ilium
  • Posterior and lower two-fifths = Ischium
  • Anterior and lower one-fifth = Pubis
  • Collective term: Os Coxal or Innominate Bone
  • Bony Landmarks
  • Anterior Pelvis (Hip Flexors Origin):
    • Anterior iliac crest: Tensor fasciae latae
    • Anterior superior iliac spine (ASIS): Sartorius
    • Anterior inferior iliac spine (AIIS): Rectus femoris
  • Lateral Pelvis (Hip Abductors Origin):
    • Iliac crest (just below): Gluteus medius and minimus
  • Medially (Hip Adductors Origin):
    • Pubis and inferior ramus: Various adductor muscles
  • Posteriorly (Hip Extensors Origin):
    • Posterior iliac crest & sacrum/coccyx: Gluteus maximus
  • Proximal Thigh Anatomy:
    • Greater trochanter: Gluteal muscles, six deep external rotators
    • Lesser trochanter: Iliopsoas
    • Insertion for knee extensors located at proximal thigh
  • Joints
  • Anteriorly, pelvic bones joint at symphysis pubis (amphiarthrodial)
  • Sacrum forms sacroiliac joints with strong ligaments
  • Acetabulofemoral Joint:
    • Most mobile joint (excluding glenohumeral)
    • Multiaxial arrangement ensuring stability
    • Strong ligamentous capsule
  • Ligaments involved:
    • Iliofemoral ligament (prevents hyperextension)
    • Pubofemoral ligament (limits extension/abduction)
  • Joint Movements
  • Hip joint movement ranges:
    • Flexion: 0-130 degrees
    • Extension: 0-30 degrees
    • Abduction: 0-35 degrees
    • Adduction: 0-30 degrees
    • Internal Rotation: 0-45 degrees
    • External Rotation: 0-50 degrees
  • Pelvic rotation movements:
    • Results from movements at hip joints and lumbar spine
  • Types of pelvic rotations:
    • Anterior, posterior, left/right lateral, and transverse
  • Muscle Groups
  • Anterior Muscles (Hip Flexion)
    • Iliopsoas, Pectineus, Rectus femoris, Sartorius
  • Medial Muscles (Hip Adduction)
    • Adductor brevis, longus, magnus, Gracilis
  • Posterior Muscles (Hip Extension)
    • Gluteus maximus, Biceps femoris, Semitendinosus, Semimembranosus, External rotators
  • Lateral Muscles (Hip Abduction)
    • Gluteus medius, Gluteus minimus, External rotators, Tensor fasciae latae
  • Iliopsoas:
    • Major hip flexor, also participates in lumbar/femur rotation
  • Nerve Innervation
  • Lumbar Plexus:
    • Includes anterior rami of spinal nerves L1-L4
    • Innervates lower abdomen, anterior, medial portions of lower extremities
  • Major Lumbar Nerves:
    • Femoral nerve (anterior muscles)
    • Obturator nerve (medial thigh)
  • Sacral Plexus:
    • Formed by anterior rami of L4, L5, S1-S4
    • Innervates lower back, pelvis, perineum
  • Major Sacral Nerves:
    • Sciatic nerve (posterior thigh)
    • Superior and inferior gluteal nerves (gluteal region)
  • Muscle Actions
  • Hip Flexion Agonists: Psoas, Iliacus, Rectus Femoris, Pectineus, Sartorius
  • Hip Extension Agonists: Gluteus Maximus, Biceps Femoris, Semitendinosus, Semimembranosus
  • Hip Abduction Agonists: Gluteus Medius, Tensor Fasciae Latae
  • Hip Adduction Agonists: Adductor Brevis, Longus, Magnus, Gracilis
  • Hip Internal Rotation Agonists: Gluteus Minimus, Gluteus Medius
  • Hip External Rotation Agonists: Gluteus Maximus, Six Deep External Rotators
  • Conclusion
  • Understanding the anatomy and biomechanics of the hip and pelvic girdle is crucial for preventing injuries and optimizing performance in activities of daily living and sports.