MSK Session 8 Flashcards
What bridges the acetabular notch?
Transverse acetabular ligament
What is in the acetabular fossa?
Fat pad covered by synovial membrane
What is the articular area of the acetabulum?
Lunate surface
What are the flexor muscles of the hip?
Iliopsoas Rectus femoris Sartorius Pectineus Adductor brevis and longus
Which muscles are the adductors of the hip?
Pectineus
Adductor brevis and longus
Adductor magnus
Obturator externus
Which muscles are the lateral rotators of the hip?
Piriformis Gluteus maximus Obturator internus Gemellin Quadratus femoris Obturator externus
Which are the extensors of the hip?
Gluteus maximus
Hamstrings
Adductor magnus
Which are the abductors of the hip?
Gluteus medius
Gluteus minimus
Which are the medial rotators of the hip?
Gluteus medius and minimus
What supplies blood to the hip joint?
Medial and lateral circumflex femoral arteries
Where do the circumflex femoral arteries arise from?
Usually profunda femoris artery
Occasionally femoral artery
Can the artery to the head of the femur support the hip joint alone?
No - will cause AVN
Where is the acetabulum not complete?
Inferiorly at the acetabular notch
What is the acetabular labrum?
Fibrocartilaginous rim attached to the margin of the acetabulum
What is the function of the acetabular labrum?
Increase articular contact area by 10% so more than half the femoral head fits in
What innervates the hip joint?
Anterior: femoral nerve
Inferior: obturator nerve
Posterior: nerve to femoris
Superior: superior gluteal
Where can pain in the hip be referred from?
Vertebral column
How does Hilton’s law apply to the hip joint?
Nerves supplying the muscles across the joint supply the joint too
What forms the joint capsule in the hip?
Loose external fibrous layer and internal synovial membrane
Where does the joint capsular of the hip attach?
Periphery of acetabular rim
Intertrochanteric line
Proximal to intertrochanteric crest
What path do most fibres of the joint capsule of the hip take?
Spiral
What forms the orbicular zone?
Deep fibres of the joint capsule passing circularly around the femoral neck
What restricts extension of the hip to 10-20 degrees beyond vertical?
Joint capsule of hip
What happens to the spiralling fibres in the joint capsule of the hip upon flexion?
Unwind
What pulls the femoral head medially into the acetabulum?
Muscles and ligaments
What is the structure of the iliofemoral ligament?
Anterior and superior
Y shaped
What is the function of the iliofemoral ligament?
Prevent hyperextension of the hip during standing by screwing femoral head into acetabulum
Which is the strongest ligament in the body?
Iliofemoral
What is the structure of the pubofemoral ligament?
Interior and inferior
Blends w/medial part of iliofemoral ligament
What is the function of the pubofemoral ligament?
Prevent overabduction of the hip by tightening during both extension and abduction
What is the structure of the ischiofemoral ligament?
Posterior
Spirals superolaterally to the femoral neck
Which of the three ligaments in the hip is the weakest?
Ischiofemoral
What is seen in congenital dislocation of the hip?
Femoral head superior
+ve Trendelenburg sign
Arthritis in adulthood
What is seen in acquired posterior hip dislocation?
Femoral head inferior and posterior on lateral surface of ilium
Shortened leg
Medial rotation
What is vulnerable to damage in acquired posterior dislocation of the hip?
Sciatic nerve
What is seen in acquired anterior hip dislocation?
Femoral head inferior to acetabulum
Acetabulum margin fracture
Which muscles make up the superficial layer of the buttock and gluteal region?
Gluteus maximus, medius and minimus
What is the main action of gluteus maximus?
Extension
Lateral rotation
Assist in rising from sitting
What is the main action of gluteus medius?
Abduction
Medial rotation
Pelvic stability
What is the main action of gluteus minimus?
Abduction
Medial rotation
Pelvic stability
What innervated gluteus maximus?
Inferior gluteal nerve
What innervates gluteus medius?
Superior gluteal nerve
What innervates gluteus minimus?
Superior gluteal nerve
What is the main action of piriformis?
Lateral rotation of extended thigh
Abduct flexed thigh
Steady femoral head in acetabulum
What innervates piriformis?
Branches of anterior rami of S1 and 2
What is the main action of obturator internus, superior gemelli, and inferior gemelli?
Laterally rotate extended thigh
Abduct flexed thigh
Steady femoral head in acetabulum
What innervates obturator internus?
Nerve to obturator internus
What innervates superior gemelli?
Nerve to obturator internus
What innervates inferior gemelli?
Nerve to quadratus femoris
What innervates quadratus femoris?
Nerve to quadratus femoris
What is the main action of quadratus femoris?
Laterally rotate thigh
Steady femoral head in acetabulum
What is the function of the superficial layer of buttock and gluteal region muscles?
Extension, abduction and medial rotation of femur
Prevent pelvic drop on opposite side to the flexed leg when walking
What is the general function of the deep layer muscles of the buttock and gluteal region?
Abduct flexed femur
Laterally rotate femur
Keep femur within joint
Main plain pelvic stability during walking
Which muscles form the deep layer of the buttock and gluteal region?
Piriformis Obturator internus Superior gemelli Inferior gemelli Quadratus femoris
Which muscle divides the greater sciatic foramen into two?
Piriformis
What is hip dysplasia?
abnormal relationship b/w femoral head and acetabulum
What can be abnormal in hip dysplasia?
Neck and shaft angle
Who is more affected by hip dysplasia?
Higher incidence in females
Which hip is more often affected in hip dysplasia?
Left
Why does hip dysplasia lead to dislocation at birth?
Abnormal forces experienced
What is the Ortolani test?
Forward pressure on femoral heads to move posteriorly dislocated into acetabulum
What does movement in the Ortolani test indicate?
Subluxation/dislocation that can be reduced
What is the Barlow test?
Backward pressure applied to femoral heads to feel for complete/partial displacement
What is the Galeazzi test used at 3-6 months?
Lie supine w/hips and knees flexed to 90 degrees and look for discrepancy in length and asymmetry
What are the treatments for hip dysplasia?
Harness if 6 months or harness ineffective
What is hip dysplasia often associated with in adulthood?
Arthritis
What is slipped upper femoral epiphysis?
Fracture through physis allowing femur to ride up and forward in relation to the epiphysis so the shaft moves superiorly but articulation with the hip is maintained
If slipped upper femoral epiphysis is not caught early what can develop?
Leg length discrepancy
Arthritis
What is the typical age of a patient presenting with slipped upper femoral epiphysis?
10-16 y.o.
What is the treatment for slipped upper femoral epiphysis?
Internal fixation w/single cannulated screw
Why should you look carefully for other injuries in acquired hip dislocation?
Due to stability of joint if dislocation is caused force must have been large and likely to have caused other damage
Which is the more common type of hip dislocation?
Posterior
What happens in posterior hip dislocation?
Femoral head forced posteriorly tearing through inferior and posterior joint capsule
What is anterior hip dislocation a consequence of?
Extension, abduction and lateral rotation
What is anterior hip dislocation associated with?
Fracture
What must occur for femoral neck fracture in a patient less that 40 y.o.?
High energy collision w/lower limb extension
If an elderly patient become confused following femoral neck fracture what is the associated mortality rate?
50%
Why are women >40 y.o. more likely to obtain femoral neck fracture than men?
Effects of osteoporosis
Why do femoral neck fractures often lead to femoral head AVN?
Intracapsular so main blood supply is likely to be disrupted
How does the limb often appear in femoral neck fracture?
Shortened
Laterally rotated
What does treatment depend of femoral neck fracture depend on?
Age and health - would replacement be more effective?
Why must you fix femoral neck fracture even in immobile patients?
To reduce mortality
What causes trochanteric fracture?
Direct impact or torsional force
Why is trochanteric fracture less likely to disrupt the blood supply than femoral neck fracture?
Extra-capsular
Who are trochanteric fractures most common in?
Elderly
What are the treatments for trochanteric fracture?
Dynamic hip screw
Cephalomedullary fixation
What is cephalomedullary fixation?
Rod down centre of bone to prevent excessive shortening
How does the impact of trochanteric fracture compare to that of femoral neck fracture?
Lower associated mortality rate
Likely to decrease mobility
What are the three bursae of the hip?
Trochanteric
Iliopsoas
Ischiogluteal
Which is the largest bursa of the hip?
Trochanteric
Where is the trochanteric bursa located?
B/w gluteus maximus and greater trochanter
Where is the iliopsoas bursa located?
Deep to iliopsoas
Which is the most powerful flexor of the hip?
Iliopsoas
In 15% of people what does the iliopsoas bursa communicate with?
Hip joint
How is iliopsoas bursa inflammation confused with hernia?
Can present as swelling below inguinal ligament
Where is the ischiogluteal bursa located?
Near ischial tuberosity
What causes inflammation of the ischiogluteal bursa?
Cycling/horse riding
What is the treatment for bursitis in the hip?
Rest and physiotherapy to increase length of corresponding muscle and tendon units to prevent further aggrevation
What can arthritis of the hip be due to?
Inflammation of the joint in synovium
Damage to cartilage
Combination of the two
What is earl y onset pain in arthritis usually due to and subsequently followed by?
Inflammation w/mechanical process later
What is the progression of osteoarthritis?
Cartilaginous damage –> compromised cartilage repair –> mechanical grinding causing pain –> increased mechanical load worsens effects
What can predispose to development of arthritis?
Previous joint injuries
Why do bone spurs form in osteoarthritis?
Narrowed joint space due to loss of cartilage so spurs form to counteract bone changes
What are the treatments for osteoarthritis?
NSAIDs
Muscle relaxants
Inter-articular corticosteroid injections
Modify lifestyle
What is the progression of rheumatoid arthritis?
Inflammation in synovium –> destruction of cartilage –> mechanical problems –> v.deformed bones –> bone ankylosis –> fusion of bones
What are the stages of rheumatoid arthritis development?
Syvonitis
Pannus
Fibrous ankylosis
Bony ankylosis
What happens in syvonitis?
Synovium inflamed and thickened
Bone and cartilage gradually eroded
What is pannus?
Layer of vascularised fibrous tissue that extends over an organ/structure
What happens during pannus formation in rheumatoid arthritis?
Exposed and pitted bones, no cartilage left
What happens in fibrous ankylosis during rheumatoid arthritis?
Fibrous CT invades
What happens in bony ankylosis in rheumatoid arthritis?
Bones fused
