Hip (innominate) bone

• Fusion of 3 separate bones: ilium, ischium, pubis
• Socket that receives femur to form hip joint is called the acetabulum (acetabular fossa)
• Hole formed by the union between pubis and ischium is called the obturator foramen

Articulations

• Pelvis - 2 hip bones that articulate anteriorly via cartilaginous joint and the sacrum posteriorly via a synovial joint
• Sacroiliac joint and pubic symphysis are very limited so provide a stable structure for weight transfer and shock absorption

Bony features

• Iliac crest - top of ilium, curved
• Iliac fossa - depression on ilium
• Anterior superior/inferior iliac spine - bumps on ilium
• Pubic tubercle - sticky out bit on pubis
• Greater/lesser sciatic notch - curve on hip bone
• Ischial spine - bump on ischium

Hip joint

• Very stable joint supported by ligaments
• Thick and strong ligaments - limit movement
  

Femur

• Longest bone in body
• Articulates proximally with hip (hip joint) and distally with tibia (knee joint)
• Rounded condyles form a hinge joint with tibia

Proximal tibia

• Tibial plateau receives femoral condyles (epicondyles, epi - on top)
• Intercondylar ridge - attachment for cruciate ligaments
• Tibial tuberosity provides attachment for muscles

Knee joint

• Collateral ligaments prevent femur from tipping side to side on tibia
• Cruciate ligaments prevent femur from sliding forwards or backwards on tibia
• Rotation can occur

Distal leg

• Tibia is weight bearing
• Fibular - muscle and ligament attachment
• Distally both have bony projections called malleoli that form the receptacle for the talus in the talocrural joint
• Malleoli - provides ligament attachment

Talocrural joint

• Collaterals - prevent leg bones from tipping side to side
• Only flexion (plantar flexion) and extension (dorsiflexion) can occur

Subtalar joint

• Talus sits over calcaneous
• Rocks side to side (saddle joint)