Hip joint Flashcards
What type of synovial joint is the hip
Ball and socket
Where is the articular cartilage thickest
Places of weight bearing
What makes up the hip bone
Ilium
Ischium
Pubis
What structures strengthen the hip joint
Acetabular labrum,
Joint capsule,
Ligaments,
Muscles
What is the Acetabular labrum
Fibrocartilaginous collar attached to margin of acetabulum and increases its depth
Where does the joint capsule attach
Intertrochanteric line (anteriorly)
What part of femur is extra capsular
Posterior lateral neck of femur
What is the intracapsular ligament
Ligament of head of femur
Attachments of ligament of head of femur
Acetabular fossa to fovea of femur
Which artery does the ligament of head of femur enclose
Branch of obturator artery
What are the extra capsular ligaments
Iliofemoral (anterior and superior protection, strongest in body)
Pubofemoral (anterior and inferior protection )
Ischiofemoral (posterior protection, weakest)
What’s the advantage of the orientation of the extra capsular ligaments
Spiral orientation so becomes tighter when joint is extended which increases stability and requires less energy to maintain standing position
Origin of iliofemoral ligament
Ilium, inferior to ASIS
Attachment of iliofemoral ligament
Intertrochanteric line in 2 places (Y shaped)
What does iliofemoral ligament prevent
Hyperextension
What does pubofemoral ligament prevent
Excessive abduction
Attachment of pubofemoral ligament
Iliopubic eminence and obturator membrane
What does ischiofemoral ligament limit
Extension at hip
Origin of ischiofemoral
Ischium
Attachment of ischiofemoral ligament
Greater trochanter
What is the strength of muscles and ligaments anteriorly
Ligaments are strongest
Medial flexors are fewer and weaker
What is the strength of muscles and ligaments posteriorly
Ligaments weakest
Medial rotators are greater in number and stronger
Muscles performing flexion
Iliopsoas,
Rectus femoris,
Sartorius
Muscles performing extension
Gluteus maximus,
Semimembranosus,
Semitendinosus,
Long head of biceps femoris
What determines degree of hip flexion
Whether knee is flexed - flexed increases range of hip flexion
Muscles performing abduction
Gluteus medius and minimus
Deep gluteals
Muscles performing adduction
Adductor longus, brevis and Magnus
Pectineus
Gracilis
Obturator externus
Muscles performing lateral rotation
Biceps femoris,
Gluteus maximus,
Deep gluteals
Muscles performing medial rotation
Gluteus medius and medialis
Semimembranosus
Semitendinosus
Articulation
Head of femur and acetabulum of pelvis
Innervation of HJ
Femoral nerve,
Obturator nerve,
Superior gluteal nerve,
Nerve to quadratus femoris
Blood supply to HJ
Majority by medial circumflex femoral artery,
Lateral circumflex femoral artery,
Obturator artery via ligament of head of femur (not enough to keep hip alive on own)
What separates the hip bones before age 15
Tri-radiate cartilage
When is fusion of hip bones complete
20-25
Where do the hip bones converge
Acetabulum
What are the extra capsular ligaments continuous with
Outer surface of joint capsule
Where do the medial and lateral circumflex femoral arteries anastomose
Base of femoral neck
What does the lateral circumflex femoral artery have to penetrate to reach the hip joint
Iliofemoral ligament
Therefore medial circumflex femoral artery provides most blood supply to HJ
What happens in hip replacement surgery
Plastic socket is cemented to hip bone to replace acetabulum
Stainless steel femoral stem and head to replace femur
When do surgical hip replacement take place
After traumatic injury
Degenerative diseases of joint
What are the bursae of hip joint
Trochanteric
Iliopsoas
Ischiogluteal
When do the bursa of hip joint become inflamed
repetitive strain or direct trauma
Where is the trochanteric bursa
Between gluteus maximus and greater trochanter
When can the trochanteric bursa be inflamed
In arthritis
What percentage of people have iliopsoas bursa communicating with HJ
15%
Where is the ischiogluteal bursa
Near ischial tuberosity
When can the ischiogluteal bursa become inflamed
Sitting down e.g. Horse riding and cycling
What are the types of hip dislocation
Acquired
Congenital
What percentage of congenital dislocations are bilateral
50%
How common are congenital hip dislocations
1.5 per 1000 births
8x more likely in girls
Cause of congenital hip dislocation
During development the femoral head is not placed within the acetabulum
Symptoms of congenital hip dislocation
Inability to abduct at hip
Affected limb is shorter
Positive trendelenburg sign
Consequence of congenital hip dislocation
Predisposes patient to arthritis of hip later in life
How common are acquired hip dislocations
Why
Uncommon
Joint is very strong and stable
Common cause of acquired hip dislocation
Traumatic accidents
Types of acquired hip dislocation
Anterior
Posterior
How are hip dislocations named
Position of femoral head in relation to acetabulum
What happens in posterior acquired hip dislocation
Femoral head tears through inferior and posterior part of joint capsule (weakest part)
Appearance of affected limb in posterior hip dislocation
Why does this occur
Shortened - extensors and adductors
Medially rotated - gluteus medius and minimus
Risk of posterior hip dislocation
Sciatic nerve can be damaged
Paralysis of hamstrings and muscles distal to knee
How do anterior hip dislocations occur
Excessive:
extension
abduction
lateral rotation
What often occurs in anterior hip dislocations
Femoral head pulls Acetabular labrum with it (anterior and inferior to acetabulum)
Where is margin of acetabulum incomplete
What strengthens this portion
Inferiorly (Acetabular notch)
Strengthened by transverse Acetabular ligament
What is a slipped upper femoral epiphysis
Fracture through epiphyseal growth plate
What age does a slipped upper femoral epiphysis usually occur
10-16
Displacement of fragments in slipped upper femoral epiphysis
Distal femur displaced superiorly and anteriorly in relation to growth plate
Location of iliopsoas bursa
Deep to iliopsoas
How does iliopsoas bursitis present
Swelling under inguinal ligament
