Flashcards in Hip STRUCTURE focus Deck (39):
What is the primary fxn of the hip joint?
To support the weight of HAT
The femur articulates directly with which surface?
The lunate surface, covered by hyaline cartilage. Femur has NO direct articulation with acetabular fossa.
The acetabulum is positioned
anteriorly and laterally
Normal fxn depends on femoral head coverage. Femoral head coverage is determined by
The labrum enhances joint stability by
providing a seal to maintain negative intra-articular pressure; increasing concavity, increasing congruency
What structure decreases force transmitted to the articular cartilage and provides proprioceptive feedback?
T or F The transverse acetabular ligament does NOT act as a load-bearing structure.
Angle of torsion occurs in what plane? Normal angle?
transverse plane - 15*
Angle of inclination occurs in what plane? Normal angle?
frontal plane - 125*
With a normal angle of inclination, the greater trochanter lies in line with
the center of the femoral head
In coxa valga, how does the increased angle of inclination change the weight bearing?
brings vertical weight bearing line closer to the shaft of the femur, diminishing force across the femoral neck.
In coxa valga, how does the increased angle of inclination influence biomechanics?
decreases MA of hip abductors; results in fxnally weak muscles
How does coxa valga influence femoral articular suface contact?
decreases contact area --> less stability!
Which deviation in hip inclination most often leads to dislocation?
Which deviation in hip inclination leads to decreased joint rxn force?
Which deviation in hip inclination is a predisposition to femoral neck fx?
coxa vara --> increased shear/bending force along femoral head and neck
Excess femoral anteversion often occurs with which hip inclination deviation?
Excess femoral anteversion reduces hip stability because femoral articular surface is exposed
How does excess femoral anteversion influence muscle biomechanics?
reduces MA for abduction
In supine position, anteverted femoral head will have what implication on IR and ER?
excessive IR and limited ER
(think about the anterior articular surface exposure!)
In standing, the anteverted femur may result in _______ femoral torsion, but depends on _______ position.
medial femoral torsion (TOE IN)
depends on femoral-tibial position!
In the NWB joint, what positioning increases articular contact?
flexion, aBduction, slight lateral rotation "frog-leg position"
In WB, what feature increases contact of the femoral head with the acetabulum?
elastic deformation of articular surface (most contact with anterior/superior/posterior articular surface)
When labral tear is present, the seal is broken. Results?
instability (negative intra-articular pressure is compromised!)
Increases stress on surrounding joint capsule
Pt presents with shallow acetabulum and valgus anteverted femur. How does this influence center-edge angle, femoral head exposure, stability, pathology?
DEC center-edge angle
INC femoral head exposure = DEC congruence
predisposition for labral pathology and OA
The predominant stress on the capsule occurs where?
The loosely attached capsule is located
Which structure is intracapsular but extrasynovial?
Describe the attachments of the ligamentum teres.
Edge of acetabular notch -> passes under/blends with transverse acetabular ligament -> attaches to fovea
Attachments of iliofemoral ligament? What does it limit?
LIMITS HYPEREXTENSION (resists both M and L rotation)
anterior inferior iliac spine --> 2 bands insert on the intertrochanteric line
Attachments of pubofemoral ligament? What does it limit?
LIMITS ABDUCTION and LATERAL ROTATION
anterior aspect of pubic ramus --> anterior intertrochanteric fossa
Of the hip joint ligaments, which part is the thickest and strongest?
superior band of the iliofemoral ligament
Attachments of ischiofemoral ligament? What does it limit?
LIMITS EXTENSION and MEDIAL ROTATION
posterior acetabula rim + acetabular labrum --> inner surface of greater torch
Which ligaments are posterior which are anterior?
anterior: iliofemoral, pubofemoral
What is the open-packed position for the hip joint?
Flexion with slight abduction and lateral rotation
What are the primary transmission of forces in trabecular systems?
Trabecular systems create strength in which bone regions?
both cancelous and cortical
Trabecular systems lead to weakness. What is this area called and implications?
"zone of weakness" in the femoral neck
site of fx susceptibility