Joints of the Hip Complex Flashcards
(39 cards)
Which is the only surface on the hip joint that is weight bearing?
Only the luneat surface is weight bearing, and articular with a rim of cartilage around it
What kind of joint is the hip joint & what is the socket called?
The hip joint is aball and socket joint & the fossa is called the acetabumulum
Anatomical neck, what occurs here?
Line of growth plate + capsular attachment
Attachment of capsule to the hip joint?
Anteriorly attaches to intratrochanteric line
Posteriorly it attaches to the itnratrochanteric crest
Ossification centres are what type of epiphysis?
Pressure & Traction epiphyses
- Traction is pull of muscle or ligaments on greater / lesser trochanter
- Pressure = dependent on adequate blood supply to head of femur ( capital epiphysis)
What is perthe’s disease
Poor blood supply to head of femur, causing avascular necrosis.
Note the orientation of the head of the femur, what is it protected by anteriorly?
Head of the femur is directed upward, medially and forwards. The anterior part protrudes outside the joint space and is protected by the psoas bursa.
How is the Psoas Bursa irritated? Clinical Question
The Psoas muscle attaches to the lesser trochanter, lots of hip flexion can irritate the bursa.
What induces improved range of motion of the hip joint i.e. thick about the shape of the neck and head?
Femoral head circumference is greater than that of the neck, thus the head can rotate without the neck touching the rim of the acetabulum.
What does the trabecular system do in the head of femur? name the two, and describe their action?
Clinical Implications
Trabecular system is designed to resist weight in the hip joint.
Superior system = the Arcuate bundle + medial bundle
It resists vertical forces & bending
Inferior system = MEdial + Lateral ( Bundles) , it resists teh pull of muscles on the lesser and greater trochanters
(in the middle of the inferior system is a point of weakness in osteoporotic pateints and post menopausal women, commonly affects the elderly
Femur Neck Angle
In normal its about 125 degrees, babies begin at 150 and reduce 1 degree per year until the end of adolescnce. Pathological
- Decrease = Cox Vara
- Patologycal increase = Cox Valga
What is femurs angle of torsion? What happens if the angle of torsion increases, what is the pathology Describe
The femur normally sits 10-15 degrees in front of the horizontal anteriorly.
If this angle increases pathologically, the lower limbs try to compensate, there is medial rotation of tibia, there is stresses on medial part of the knee and when the foot is pronated.
Capital Epiphysis Slip
If there is cox vara, this increases the shear forces pushing down on the head of femur
- Normally head of femur sits squarely on the femoral neck
- Increased shear stress and subsequent abnromal movement causes a slip
- The ephysis remains in the acetabulum, whilst the metaphsysis the end of the femur moves in an anterior direction with external rotation.
Where does line of gravity pass through the hip joint & what are the implications?
Line of gravity passes behind, so the capsule must be quite enforeced in front
Describe the close packed position of the hip
Extension, abduction and medial rotation
Describe loose packed position
Flexion, adduction and external rotation of the hip
What is the Iliofemoral ligament? What is its function
Located anteriorly. It originates from the ilium, immediately inferior to the anterior inferior iliac spine.The ligament attaches to the intertrochanteric line in two places, giving the ligament a Y shaped appearance. It prevents hyperextension of the hip joint. Re inforces the capusle.
- Stablishes the hip joint in extension, causes joint capsule to tighten.
- Posterior capsule doesnt extend as far distaly, extends to intratrochanteric crest, so this ligament limits movement in extension.
Pubofemoral LIgament
Located anteriorly and inferiorly. It attaches at the pelvis to the iliopubic eminance and obturator membrane, and then blends with the articular capsule.
It prevents excessive abduction and extension.
- They blend with the capsule and not directly to the femur
Ischiofemoral
Located posteriorly. It originates from the ischium of the pelvis and attaches to the greater trochanter of the femur. It prevents excessive extension of the femur at the hip joint.
Labrum? Function of the labrum? And pathology?
Labrum is like a fat pad, which increases in surface area for head of femur , making the socket deeper and increases stability by applying a negative pressure (suction effect)
When there is posterior dislocation of the hip, bits of it can break off and lodge elsewhere
Ligament of head of femur? Purpose? Pathology?
It is a direct extension of a brach of the obturator artery to supply blood to femoral head during development. Altough it regresses after puverty disruption to joint can cause it to bleed.
Retinaculum what is it?
Fibres from the hip joint capsule, supplied by retinacular vessels, susceptible to neck of femur fracture injuries.
What is the illiopsoas & what is its purpose?
Illiopsoas is a combination of the illiacus muscle and the psoas major at its inferior end, it is the primary hip flexor
What is the primary extensor of the hip?
The gluteus maximus
