Hip STRUCTURE focus

Question 1

What is the primary fxn of the hip joint?

Answer 1

To support the weight of HAT

Question 2

The femur articulates directly with which surface?

Answer 2

The lunate surface, covered by hyaline cartilage. Femur has NO direct articulation with acetabular fossa.

Question 3

The acetabulum is positioned

Answer 3

anteriorly and laterally

Question 4

Normal fxn depends on femoral head coverage. Femoral head coverage is determined by

Answer 4

acetabular depth

Question 5

The labrum enhances joint stability by

Answer 5

providing a seal to maintain negative intra-articular pressure; increasing concavity, increasing congruency

Question 6

What structure decreases force transmitted to the articular cartilage and provides proprioceptive feedback?

Answer 6

labrum

Question 7

T or F The transverse acetabular ligament does NOT act as a load-bearing structure.

Answer 7

True.

Question 8

Angle of torsion occurs in what plane? Normal angle?

Answer 8

transverse plane - 15*

Question 9

Angle of inclination occurs in what plane? Normal angle?

Answer 9

frontal plane - 125*

Question 10

With a normal angle of inclination, the greater trochanter lies in line with

Answer 10

the center of the femoral head

Question 11

In coxa valga, how does the increased angle of inclination change the weight bearing?

Answer 11

brings vertical weight bearing line closer to the shaft of the femur, diminishing force across the femoral neck.

Question 12

In coxa valga, how does the increased angle of inclination influence biomechanics?

Answer 12

decreases MA of hip abductors; results in fxnally weak muscles

Question 13

How does coxa valga influence femoral articular suface contact?

Answer 13

decreases contact area –> less stability!

Question 14

Which deviation in hip inclination most often leads to dislocation?

Answer 14

coxa valga

Question 15

Which deviation in hip inclination leads to decreased joint rxn force?

Answer 15

coxa vara

Question 16

Which deviation in hip inclination is a predisposition to femoral neck fx?

Answer 16

coxa vara –> increased shear/bending force along femoral head and neck

Question 17

Excess femoral anteversion often occurs with which hip inclination deviation?

Answer 17

coxa valga

Question 18

Excess femoral anteversion reduces hip stability because femoral articular surface is exposed

Answer 18

anteriorly.

Question 19

How does excess femoral anteversion influence muscle biomechanics?

Answer 19

reduces MA for abduction

Question 20

In supine position, anteverted femoral head will have what implication on IR and ER?

Answer 20

excessive IR and limited ER

think about the anterior articular surface exposure!

Question 21

In standing, the anteverted femur may result in _______ femoral torsion, but depends on _______ position.

Answer 21

medial femoral torsion (TOE IN)

depends on femoral-tibial position!

Question 22

In the NWB joint, what positioning increases articular contact?

Answer 22

flexion, aBduction, slight lateral rotation “frog-leg position”

Question 23

In WB, what feature increases contact of the femoral head with the acetabulum?

Answer 23

elastic deformation of articular surface (most contact with anterior/superior/posterior articular surface)

Question 24

When labral tear is present, the seal is broken. Results?

Answer 24

instability (negative intra-articular pressure is compromised!)
Increases stress on surrounding joint capsule

Question 25

Pt presents with shallow acetabulum and valgus anteverted femur. How does this influence center-edge angle, femoral head exposure, stability, pathology?

Answer 25

DEC center-edge angle
INC femoral head exposure = DEC congruence
DEC stability
predisposition for labral pathology and OA

Question 26

The predominant stress on the capsule occurs where?

Answer 26

antero-superiorly (thick)

Question 27

The loosely attached capsule is located

Answer 27

postero-inferiorly

Question 28

Which structure is intracapsular but extrasynovial?

Answer 28

ligamentum teres

Question 29

Describe the attachments of the ligamentum teres.

Answer 29

Edge of acetabular notch -> passes under/blends with transverse acetabular ligament -> attaches to fovea

Question 30

Attachments of iliofemoral ligament? What does it limit?

Answer 30

LIMITS HYPEREXTENSION (resists both M and L rotation)
anterior inferior iliac spine --> 2 bands insert on the intertrochanteric line

Question 31

Attachments of pubofemoral ligament? What does it limit?

Answer 31

LIMITS ABDUCTION and LATERAL ROTATION

anterior aspect of pubic ramus –> anterior intertrochanteric fossa

Question 32

Of the hip joint ligaments, which part is the thickest and strongest?

Answer 32

superior band of the iliofemoral ligament

Question 33

Attachments of ischiofemoral ligament? What does it limit?

Answer 33

LIMITS EXTENSION and MEDIAL ROTATION

posterior acetabula rim + acetabular labrum –> inner surface of greater torch

Question 34

Which ligaments are posterior which are anterior?

Answer 34

posterior: ischiofemoral
anterior: iliofemoral, pubofemoral

Question 35

What is the open-packed position for the hip joint?

Answer 35

Flexion with slight abduction and lateral rotation

FROG LEG

Question 36

What are the primary transmission of forces in trabecular systems?

Answer 36

medial compressive

lateral tensile

Question 37

Trabecular systems create strength in which bone regions?

Answer 37

both cancelous and cortical

Question 38

Trabecular systems lead to weakness. What is this area called and implications?

Answer 38

“zone of weakness” in the femoral neck

site of fx susceptibility

Question 39

In the shaft (diaphysis), the medial cortical bone must resist __________ forces, while the lateral cortical bone must resist _________ forces. WHY?

Answer 39

medial: compressive forces
lateral: tensile forces

Because WB line (HAT) from center of rotation of femoral head and GFR causes bending force on shaft.