hip joint

acetabulum

· fusion of ilium, ischium, pubis

· Y-shaped physis

· one upper limb marked by iliopubic eminence

· other upper limb marked by ridge near greater sciatic notch

· stem passes through acetabular notch into obturator foramen

· deepened by peripheral acetabular labrum

· continued across acetabular notch as transverse ligament

· transverse ligament gives rise to ligamentum teres

· central non-articular part of acetabulum filled with fat

· Haversian fat pad

FEMUR

· neck narrower than head

· allows for increased ROM

· pit in nonarticular convexity

· fovea for ligamentum teres

capsule

Acetabulum

· attached circumferentially

· to labrum and transverse ligament

Femur

· attached to neck of femur

· in front all the way along neck to intertrochanteric line

· behind only halfway along neck (limited by obturator externus)

· fibres reflected back to articular margin

· as retinacular fibres

Ligaments

Iliofemoral

· syn. Y-shaped ligament of Bigelow

· stem

· lower half of AIIS

· limbs

· upper and lower ends of intertrochanteric line

· limits extension

· is fulcrum around which neck of femur rotates when hip dislocates

Pubofemoral

· from iliopubic eminence

· to inferior part of neck of femur

· limits abduction in extension

Ischiofemoral

· from posteroinferior acetabulum

· fibres

· pass lateral to capsule

· spiral upwards

· form fibres that run around neck of femur

· called zona orbicularis

· very few fibres reach femur

Synovium

· attached to articular margins

· lines all of capsule

· reflected over retinacular fibres

Relations

Anterior

· iliac bursa lies over capsule

· extends upwards into iliac fossa under iliacus

· iliacus lies between capsule and femoral n

· psoas major lies between capsule and femoral a

· pectineus lies between capsule and femoral v

Posterior

· obturator externus spirals around femoral neck

· piriformis and tricipital tendon lie between capsule and sciatic n

Medial

· obturator internus and obturator neurovascular structures lie medially

· ovary lies adjacent in female

neurovascular

Blood supply

· see other section

Nerve supply

· 3 nerves (Hilton’s law)

· femoral n

· n to rectus femoris

· sciatic n

· n to quadratus femoris

· obturator n

· anterior division

Movements

Flexion

· motors

· psoas and iliacus

· rectus

· sartorius and TFL

· pectineus

· limited by

· thigh touching abdomen

· hamstring tension

Extension

· motors

· gluteus maximus

· hamstrings

· limited by

· tension in iliofemoral ligament

Abduction

· motors

· gluteus medius and minimus

· piriformis

· limited by

· tension in adductors

· tension in pubofemoral ligament

Adduction

· motors

· adductor longus, brevis and magnus

· pectineus

· gracilis

· limited by

· contact with other leg

· tension in glutei

External rotation

· anything that passes across back of hip joint

· motors

· gluteus maximus

· gluteus medius and minimus (posterior fibres)

· piriformis, obturator externus and gamelli

· quadratus femoris

· limited by

· tension in pubofemoral ligament

Internal rotation

· anything that passes across front of hip joint

· motors

· gluteus medius and minimus (anterior fibres)

· psoas major and iliacus

· pectineus and adductor longus

· fractured NOF

· femur rotates about its own axis

· muscles that pass backwards along its medial side now cause external rotation

· esp. psoas

Stability

Bony

· very important

· head in socket

Ligaments

· important

· esp. iliofemoral

Muscles

· important

· esp. gluteus medius and minimus