Anatomy

• Hip joint:

  • Ball and socket synovial joint
  • Formed by an articulation between the pelvic acetabulum and the head of the femur
  • Forms a connection from the lower limb to the pelvic girdle - so is designed for stability and weight bearing
• Articulating surfaces:

  • Articulation between the head of femur and acetabulum of the pelvis
  • Acetabulum is a cup like depression located on the inferolateral aspect of the pelvis - cavity is deepened by the presence of a fibrocartilaginous collar - acetabular labrum
  • The head of femur is hemispherical and fits completely into the concavity of the acetabulum
  • Both the acetabulum and the head of femur are covered in articular cartilage
• Ligaments:

  • Intracapsular - ligament of head of femur - encloses a branch of the obturator artery (artery to head of femur)
  • Extracapsular - iliofemoral, pubofemoral and ischiofemoral ligaments
  • Iliofemoral ligament is the strongest of the 3 ligaments and supports the joint anteriorly - hip most likely to dislocate posteriorly
• Vascular supply:

  • Largely via the medial and lateral circumflex femoral arteries
  • The medial circumflex femoral artery is responsible for the majority of the arterial supply - damage can result in avascular necrosis of the femoral head
• Nerve innervation:

  • Innervated primarily by the sciatic, femoral and obturator nerves
  • Same nerves innervate the knee - why pain can be referred to the knee from the hip and vice versa