hip


BONY LANDMARKS




Pelvis




Innominate Bone (Hip Bone)



  • Made up of:

    • Ilium

    • Ischium

    • Pubis







Sacrum and Coccyx



  • Sacrum:

    • Base of spine

    • Articulates with ilium → sacroiliac joint


  • Coccyx:

    • Tailbone

    • Inferior to sacrum







Proximal Femur



  • Head of femur

  • Neck of femur

  • Greater trochanter

  • Lesser trochanter

  • Intertrochanteric line (anterior)

  • Intertrochanteric crest (posterior)

  • Shaft of femur

  • Gluteal tuberosity






THE HIP JOINT




Classification



  • Synovial

  • Ball and socket

  • Polyaxial (multi-directional movement)






MOVEMENTS AVAILABLE




Sagittal Plane



  • Flexion

  • Extension




Frontal Plane



  • Abduction

  • Adduction




Transverse Plane



  • Medial rotation

  • Lateral rotation




Combined



  • Circumduction






NORMAL RANGE OF MOVEMENT



  • Flexion: 100–120°

  • Extension: 15–20°

  • Abduction: 40–45°

  • Adduction: 15–30°

  • Lateral rotation: 45–60°

  • Medial rotation: 30–40°






HIP JOINT STABILITY



  • Deep acetabulum (socket)

  • Acetabular labrum (deepens socket)

  • Strong ligaments

  • Strong joint capsule

  • Vacuum effect (suction)

  • Oblique femoral neck angle

  • Surrounding powerful muscles






ARTICULAR SURFACES




Acetabulum



  • Cup-shaped socket

  • Lined with hyaline cartilage

  • Lunate surface:

    • Horseshoe-shaped

    • Thickest superiorly (weight-bearing)


  • Acetabular fossa:

    • Non-articular

    • Contains fat







Head of Femur



  • Spherical shape

  • Covered in hyaline cartilage

  • Thickest centrally

  • Thinner at edges




Fovea



  • No cartilage

  • Attachment for ligamentum teres






LIGAMENTS OF THE HIP



  • Iliofemoral ligament (anterior)

    • Prevents hyperextension


  • Pubofemoral ligament (anterior)

    • Limits abduction


  • Ischiofemoral ligament (posterior)

    • Limits medial rotation


  • Ligamentum teres (internal)

    • Connects femur to acetabulum

    • Minor blood supply role







SACROILIAC JOINT




Classification



  • Synovial plane joint




Features



  • Rough articular surfaces

  • Very limited movement




Movements



  • Nutation

  • Counter-nutation






SACROILIAC LIGAMENTS



  • Sacrospinous

  • Sacrotuberous

  • Interosseous sacroiliac

  • Ventral sacroiliac






PUBIC SYMPHYSIS




Classification



  • Secondary cartilaginous joint




Structure



  • Interpubic disc

  • Superior pubic ligament

  • Inferior (arcuate) ligament




Movement



  • Minimal






MUSCLES OF THE HIP




HIP FLEXORS



  • Psoas major

  • Iliacus

  • Sartorius

  • Rectus femoris

  • Pectineus

  • Gracilis




Limits



  • Soft tissue

  • Hamstrings






HIP EXTENSORS



  • Gluteus maximus

  • Adductor magnus (extensor part)

  • Biceps femoris

  • Semimembranosus

  • Semitendinosus




Limits



  • Ligaments

  • Close-packed position






HIP ABDUCTORS



  • Gluteus medius

  • Gluteus minimus

  • Sartorius

  • Tensor fasciae latae

  • Piriformis (when flexed)




Limits



  • Pubofemoral ligament

  • Iliofemoral ligament (medial band)






HIP ADDUCTORS



  • Adductor longus

  • Adductor brevis

  • Adductor magnus (adductor part)

  • Pectineus

  • Gracilis (weak)




Limits



  • Iliofemoral ligament (lateral band)

  • Ligamentum teres






HIP MEDIAL ROTATORS



  • Gluteus medius (anterior fibres)

  • Gluteus minimus (anterior fibres)

  • Tensor fasciae latae

  • Adductor magnus




Limits



  • Ischiofemoral ligament

  • Posterior capsule






HIP LATERAL ROTATORS



  • Gluteus maximus

  • Piriformis

  • Obturator internus

  • Obturator externus

  • Superior gemellus

  • Inferior gemellus

  • Quadratus femoris

  • Sartorius




Limits



  • Iliofemoral ligament (lateral band)






EXAM-IMPORTANT POINTS




Type of Hip Joint



  • Synovial

  • Ball and socket



(both needed for marks)





Articular Surfaces (3 marks)



  • Head of femur (convex)

  • Acetabulum (concave)

  • Hyaline cartilage






Hip Extension Muscles (4 marks)



  • Gluteus maximus

  • Semimembranosus

  • Semitendinosus

  • Biceps femoris






Normal Movement Values (common)



  • Extension: 15–20°

  • Adduction: 15–30°