Hip, Knee, and Ankle Anatomy and Function

Posted on Oct 7, 2024 in Biology

Hip Joint

Articulation

The hip joint is a ball-and-socket joint (enarthrosis/spheroidal).

Joint Surfaces

  • Femur
  • Hip Bone

Muscles

Flexors

  • Iliopsoas
  • Rectus Femoris (Quadriceps)
  • Sartorius
  • Tensor Fascia Lata
  • Pectineus

Extensors

  • Hamstrings (Biceps Femoris, Semitendinosus, Semimembranosus)
  • Gluteus Maximus, Medius, and Minimus

Adductors

  • Adductor Brevis, Longus, and Magnus
  • Gracilis

Internal Rotators

  • Gluteus Medius and Minimus

External Rotators

  • Gluteus Maximus
  • Iliopsoas
  • Pectineus
  • Adductors (Brevis, Longus, Magnus)
  • Sartorius
  • Tensor Fascia Lata

Knee Joint

Articular Surfaces

  • Distal Femur (Condyles)
  • Proximal Tibia
  • Patella

Ligaments

  • Intracapsular (e.g., Cruciate ligaments)
  • Extracapsular (e.g., Patellar ligament, Collateral ligaments)

Muscles

Flexors

  • Hamstrings
  • Sartorius
  • Gracilis
  • Popliteus

Extensors

  • Quadriceps (Rectus Femoris, Vastus Lateralis, Vastus Medialis, Vastus Intermedius)

Internal Rotators

  • Sartorius
  • Semitendinosus
  • Gracilis
  • Popliteus

External Rotators

  • Biceps Femoris
  • Tensor Fascia Lata

Ankle Joint

Movements

  • Dorsiflexion (20-30°)
  • Plantarflexion (40-50°)

Muscles

Dorsiflexors

  • Tibialis Anterior
  • Peroneus Tertius

Plantarflexors

  • Triceps Surae (Gastrocnemius and Soleus)
  • Tibialis Posterior
  • Peroneus Longus and Brevis

Inversion

  • Tibialis Anterior and Posterior

Eversion

  • Peroneus Longus, Brevis, and Tertius

General Principle

Muscles acting against gravity produce the movement. Muscles acting with gravity oppose the movement.