Joints of the Hip Complex Flashcards
What does each component of hip bone help form?
The acetabulum
Which 3 bones comprise the hip bone?
Ischium, ileum and pubis
How is the congruence of the hip joint?
Good
Which parts of the acetabulum are not articular?
Lunate surface is weight-bearing, acetabular notch & fossa are non-articular.
What is the anatomical neck of the femur the site of?
The epiphysis
What attaches around the site of the growth plate at the epiphysis?
Joint capsule
What structures sit within the hip joint?
Fat pads, labrum and synovial fluid.
What is the non-articular site on the head of the femur?
Fovea
What inserts to the fovea?
Ligamentum teres
What types of epiphyses are the greater and lesser trochanters?
Traction epiphyses
What is the intertrochanteric line/crest?
The crest/line between the greater and lesser trochanters. Intertrochanteric line on anterior side, crest on posterior side.
What is a traction epiphysis?
A secondary center of ossification forming at the attachment site of a tendon.
What is a pressure epiphysis?
A secondary center of ossification that forms at the articular end of a long bone.
What shape is the head of the femur?
2/3 of a sphere.
How is the head of the femur directed?
Upwards, medially & forwards
Which part of the femoral head lies outside of the acetabulum and joint?
Anterior part
What is exposed anterior part of the femoral head protected by?
Psoas bursa – sits just below tendon of psoas major
What does the head of the femur articulate with?
Roof of acetabulum (thickest cartilage)
What does the neck of the femur do to allow a greater RoM?
The mid-region of the femoral neck is narrower than circumference of the head - greater ROM w/o contacting rim of acetabulum.
What are the 2 intra-articular structures of the hip joint?
Labrum and ligament of head of femur.
What does the labrum do?
Bridges acetabular notch, deepens cup & increases surface area - often torn in hip injury
What does the ligament of the head of femur do?
Has no supporting role - directs branch of obturator artery to femoral head (regresses after puberty)
What are the 2 systems of trabeculae that interesect in the femur?
Super and inferior.
What are the superior trabecula?
Vertical and articulate trabeculae formed due to compression through the head and neck.
What are the infeerior trabeculae?
Medial and lateral trabeculae that form in response to muscle pulls on greater and lesser trochanters.
Where does the line of gravity pass in relation to the hip joint?
Posterior
Where does the line of gravity pass in relation to the knee joint?
Anterior
Where does the line of gravity pass in relation to the ankle joint?
Anterior
What is the position of greatest stability at the hip joint?
Close packed position: extension, abduction & medial rotation
Where does the hip joint capsule attach?
At base of the long neck
What are the 3 ligaments of the hip joint?
Strong iliofemoral ligament in front, weaker behind (pubofemoral & ischiofemoral ligaments – blend with capsule with no direct attachment to femur)
When is the hip joint at maximum stability?
In extension
What is the hip joints maximum stability at extension primarily due to?
Iliofemoral ligament - spirals & tightens with hip extension
Do the ligaments of the hip joint attach to the femur?
No, they blend with the joint capsule.
What is the hip joint capsule lined internally by?
Ring of fibres – ‘zona orbicularis’
How is the posterior hip joint capsule different to the rest?
Does not extend as far distally –no limit to extension
What are the retinacular fibres of the hip joint?
Reflections of fibrous tissue from capsule to femoral neck contain ‘retinacular’ vessels
What do the retinacular vessels do?
Critical blood supply to head of femur.
Which movements occur at the hip joint?
- Flexion/extension (F – 120 deg; E – 10-20 deg)
- Abduction/adduction
- Medial/lateral rotation
- Medial rotation occurs with extension (‘screw- home’) – joint ‘locked’. Reverse in flexion
- Medial rotation in stance, lateral rotation in swing
What is the hip joint surrounded by?
Cuff of ‘fixator’ muscles to stabilise head of femur in acetabulum.
What are all fixator muscles of the hip?
External/lateral/outward rotators of the hip
What is the principle role of the fixator muscles of the hip?
To pull head of femur into socket
How do the tendons and fibres of the hip joint fixator muscles run?
Parallel to the neck of the femur
When is gluteus maximus recruited?
Only recruited for extreme contractions/power.
What is the role of gluteus medius and minimus?
Abduct the hip but primarily maintain position of pelvis in coronal plane (i.e. act from below)
What is gluteus medius capable of?
Both flexion & extension
What is the Trendelenberg gait?
Injury to gluteus medius and minimus results in failure to abduct the hip that’s involved in the swing phase.
When are the adductor muscles of the hip most powerful?
When adducting from an abducted position.
Where is groin pain and pathology related to the adductor muscles common?
At the bony attachment (osteitis pubis)
Which adductor muscle is especially known as a common source of groin pain and pathology?
Adductor longus
What is Hilton’s law?
Joint receives pain & proprioceptive fibres from branches to muscles that move the joint – also pass to overlying skin
What is the hip joint innervated by?
Articular branches of femoral & obturator nerves
What does referred pain from hip travel via?
Obturator nerve
Where does referred pain to the hip travel from?
Lumbar spine and sacroiliac joint.
Which spinal cord segments flex the hip?
L2/L3
Which spinal cord segments extend the hip?
L4/L5
Which spinal cord segments flex the knee?
L5/S1
Which spinal cord segments extend the knee?
L3/L4
Which spinal cord segments extend the ankle joint?
L4/L5
Which spinal cord segments flex the ankle joint?
L1/L2
Which spinal cord segments flex the toes?
L1/L2
Which spinal cord segments extend the toes?
L5/S1
Where does the hip joint get its blood supply?
Via anastomoses between branches of medial (primarily) & lateral femoral circumflex arteries (normally off profunda femoris)
Where does a small amount of blood supply to the hip joint come from?
Artery of head of femur (regresses after puberty)
Where do retinacular vessels pass?
Across femoral neck, bound down by ‘retinacular’ fibres (from capsule)
When are vessels supplying the hip joint susceptible to fracture?
In a fractured neck of femur
Where does the sciatic nerve pass?
Beneath piriformis and through greater sciatic foramen.
What is dislocation of the hip joint often associated with?
Fractured posterior lip of acetabulum
What is endangered in a dislocation of the hip joint?
Sciatic nerve
What is important in dislocation of the hip joint?
Early re-articulation
When is the hip joint most susceptible to dislocation?
When the joint is adducted, internally rotated and flexed.
What happens tot he neck-shaft angle (angle of inclination) with development?
Angle greater in newborn (≥150°) reduces to approx. 135° in adult
Why is the female angle of inclination smaller?
Due to width of pelvis
What does the angle of inclination enable?
Enables femur to swing free of the pelvis in locomotion.
What does the stability of the hip override?
Other joints of the lower limb
What is coxa valga?
A pathological increase in the angle of inclination
What is coxa vara?
A pathological decrease in the angle of inclination
Which pathology will result in the leg being further away from the midline?
Coxa valga (valga = outwards)
Which pathology will result in the leg being closer to the midline?
Coxa vara
What does coxa vara in adolescence result in?
- Increased stress on femoral neck.
- Increased shear forces on femoral head may cause proximal femoral epiphysis to ‘slip’ – ‘slipped capital femoral epiphysis’
In a fractured neck of the femur, what will muscle spasm cause?
External rotation & shortening of limb
What are the 2 different causes of dislocation of the hip joint?
Congenital or traumatic
What strengthens the anterior aspect of the hip joint?
Iliofemoral ligament
