8 - Hip Joint Flashcards
What type of joint is the hip joint?
Synovial ball and socket joint
What are the articulations of the hip joint?
Head of the femur and the acetabulum of the pelvis
What is the hip joint designed to be? What is sacrificed to achieve this?
A stable, weight bearing jointA large range of movement in exchange for stability is sacrificed to achieve this
What is the acetabulum?
A cup like depression on the lateral side of the pelvis
What are the head of the femur and acetabulum covered in? Where is it thicker?
Both covered in articular cartilage, which is thicker at points of weight bearing
What are the four ligaments that connect thefemur to the pelvis and increase stability?
Ligament of head of femurPubogemoral ligamentIliofemoral ligamentIschiofemoral ligament
What is the ligament of the head of femur attached to?
The acetabular fossa
What does the ligament of the head of femur enclose?
A branch of the oburator artery which contributes a small proportion of the blood supply to the hip joint
What is A?
The iliofemoral ligament
Where does the iliofemoral ligament attach and what is its function?
The intertrochanteric linePrevents hyperextension of the hip joint
What is B?
pubofemoral ligament
What does the pubofemoral ligament prevent?
Excessive abduction and medial rotation
What is C
Ischiofemoral ligament
What does the ischiofemoral ligament prevent?
Excessive medial rotation of the femur at the hip joint
What factors stabilise the hip joint? (4)
The structure of the acetabulum The fibrocartaliginous collar around the acetabulumThe iliofemoral, ischiofemoral and pubofemoral ligaments, along with thickened joint capsuleReciprocal support of muscles and ligaments
How does the structure of the acetabulum contribute to stability?
It is deep, and encompasses nearly all of the head of the femur. This decreases the probablity of the head slipping out of the acetabulum, and causing a dislocation.
How does the fibrocartaliginous collar around the acetabulum increase stability?
Increases the depth and articular surface of the acetabulum, and the stability of the joint
How do the iliofemoral, ischiofemoral and pubofemoral ligaments and the thickened joint capsule increase stability?
These ligaments have a unique spiral orientation; this causes them to become tighter when the joint is extended, which adds stability to the joint.Also means less energy is needed to maintain a standing position.
How do muscles and ligaments work in a reciprocal fashion at the hip joint?
Anteriorly, where the ligaments are strongest, the medial flexors (located anteriorly) are fewer and weaker. Posteriorly, where the ligaments are weakest, the medial rotators are greater in number and stronger - the effectively pull the head of the femur into the acetabulum
What movements can occur at hip joint?
flexion, extension, abduction, adduction and medial/lateral rotation
What does the degree to which the hip can flex depend on?
whether the knee is flexed, which relaxes the hamstrings, and increases the range of flexion
What is extension at the hip joint limited by?
The joint capsule, in particular the iliofemoral ligament. The structures become taut during extension to limit further movement