S3_L1 Anatomy & Radiologic Evaluation of the Pelvis and Hip Flashcards
Identify the three ligaments that limit hip hyperextension
Iliofemoral (Y ligament of Bigelow), ischiofemoral, & pubofemoral ligaments
What are the normal values of the neck shaft angle / angle of inclination in adults?
125-135 degrees
NOTE: This angle is seen in the AP view as a medial angle
What is the normal value for the angle of anteversion in adults?
15 degrees
What is the value of the angle of inclination present at birth?
175 degrees
What is the value of the angle of anteversion present at birth?
40 degrees
What is the largest bursa in the body?
Iliopsoas bursa
NOTE: It can be viewed on the sagittal view
It is a horseshoe shaped structure where its center and inferior aspects are devoid of cartilage.
Acetabulum
The radiographic teardrop is a radiologic observation seen in the anteroposterior projection of the pelvis. It refers to the:
a. anterior and superior portion of the acetabulum
b. anterior and inferior portion of the acetabulum
c. posterior and superior portion of the acetabulum
d. posterior and inferior portion of the acetabulum
b. anterior and inferior portion of the acetabulum
NOTE: In total hip replacement, the radiographic teardrop is the marker or reference point and the acetabular cup must be in line with the radiographic teardrop.
Modified TF
A. The adult male pelvis is narrow, with an oval-shaped inlet and angle of pubic arch less than 90 degrees.
B. The adult female pelvis is broad, with a round inlet and angle of pubic arch greater than 90 degrees.
TT
Modified TF
A. The female pelvis has a wider anteroposterior diameter and pubic arch.
B. The male pelvis has a wider transverse diameter and narrow pelvic brim.
FF
A. The female pelvis has a wider transverse diameter and pubic arch.
B. The male pelvis has a wider AP diameter and narrower pelvic brim.
The greater trochanter appears at what ages?
4-5 years old
The lesser trochanter appears at what ages?
9-11 years old
Modified TF: Proximal Femur
A. The femoral head is ossified at birth.
B. On the other hand, the femoral shaft starts to ossify at 3-6 months.
FF
A. The femoral shaft is ossified at birth.
B. On the other hand, the femoral head starts to ossify at 3-6 months.
TRUE OR FALSE: All structures of the proximal femur (i.e., trochanters, head, shaft, neck) is ossified at an individual’s late teen years.
True
The tri-radiate cartilage fuses at [] years old and is fully fused by early [].
Tri-radiate cartilage: Fuses at 17 years old and is fully fused by early 20s
Modified TF
A. The pelvis is cartilaginous at birth and will not be seen on imaging at birth.
B. Its cartilaginous portion includes the lower ilium, lower end of the ischium, medial end of the pubis, and majority of the acetabulum (tri-radiate cartilage).
TF
B. Its cartilaginous portion includes the upper ilium, lower end of the ischium, medial end of the pubis, and majority of the acetabulum (tri-radiate cartilage).
TRUE OR FALSE: The shape of the pelvis in young boys and girls is similar until they reach puberty.
True, because after puberty, there will be differences in the pelvis of males and females.
Case: A 6 month-old infant was brought to USTH AMRC for medical consultation. Upon PE, dislocation of the hip was suspected. What diagnostic tool can be used to confirm and diagnose hip dislocation in this case?
a. CT Scan
b. X-ray
c. MRI
d. MSK US
d. MSK US
NOTE: As the pelvis is not fully ossified yet, a MSK US is more appropriate to use than a pelvic x-ray.
It is the keystone of the skeleton, linking the weight-bearing forces of trunk and upper body and the ground reaction force transmitted by the lower extremities.
Pelvis
Modified TF
A. The pelvis serves as protection for visceral organs and support for head, neck, and arms.
B. It is formed by two innominate bones, the sacrum, and the coccyx.
TT
The largest bone in the human body
Femur
Imaging Protocols
- Extends from the iliac crest to lesser trochanter
- Just above the most superior point of the ilium down to just below the most inferior point at the ischium
- (B) hips and the pelvis are imaged simultaneously
A. X-ray
B. CT Scan
C. MRI
- C
- B
- C
Imaging tool used to identify labral tears or femoroacetabular impingement disorders
A. X-ray
B. CT Arthrography
C. MR Arthrogram
D. Musculoskeletal Ultrasound
C. MR Arthrogram
Advanced Imaging Evaluation of MRI: Fluid-Sensitive Sequence
- Axial plane
- Coronal plane
- Sagittal plane
A. T2 with fat saturation
B. T2 with inversion recovery
- B
- A
- A
Fundamental Tenets of Musculoskeletal MRI
- Proton density
- T2 fat saturation
- Gradient echo
A. To define anatomy
B. To define abnormal fluid
- A
- B
- A
MRI Image Interpretation
The following are structures to view on the axial plane, except
A. Sacrum
B. Sacroiliac joints
C. Labrum
D. Superior aspect of acetabulum and cartilage
E. None of the above
D. Superior aspect of acetabulum and cartilage
This can be viewed in the sagittal plane
MRI Image Interpretation
The following are structures to view on the axial plane, except
A. Acetabulum
B. Femoral head and neck
C. Pubic symphysis
D. Ilium
E. None of the above
E. None of the above
MRI Image Interpretation
The following are structures to view on the axial plane, except
A. Greater trochanter
B. Pulvinar
C. Lesser trochanter
D. Alpha angle (on axial oblique view)
E. None of the above
E. None of the above
MRI Image Interpretation
The following are structures to view on the sagittal plane, except
A. Sartorius
B. Gluteus maximus
C. Sphericity of the femoral head
D. Superior aspect of acetabulum and cartilage
E. None of the above
E. None of the above
MRI Image Interpretation
The following are structures to view on the sagittal plane, except
A. Rectus femoris
B. Hamstrings
C. Vastus medialis
D. Iliopsoas
E. None of the above
E. None of the above
MRI Image Interpretation
The following are structures to view on the coronal plane, except
A. Ilium
B. Hip abductors
C. Proximal femurs
D. Hip joints
E. None of the above
E. None of the above
MRI Image Interpretation
The following are structures to view on the coronal plane, except
A. Hip adductors
B. Osseous structures
C. Gluteal muscles
D. Sacroiliac joints
E. None of the above
E. None of the above
Modified TF
A. The labrum is not viewed on CT scan unless it is enhanced with arthrography.
B. CT arthrography is done by injecting radiopaque dye to view the labrum.
TT
The following are conditions that warrant MRI, except
A. Evaluation post-treatment
B. For clarification and staging of conditions
C. For correlation of abnormal skeletal findings on other imaging studies
D. Osteonecrosis of the femoral head
E. None of the above
C. For correlation of abnormal skeletal findings on other imaging studies
This is an indication for x-ray/routine radiologic evaluation.
The following are conditions that warrant CT Scan, except
A. For assessment of alignment and displacement of fracture fragments
B. For follow-up studies
C. For evaluation of acetabulum or sacrum
D. For severe trauma
E. None of the above
B. For follow-up studies
This is an indication for x-ray/routine radiologic evaluation.
The following are conditions that warrant an X-ray, except
A. Pain
B. Osseous changes secondary to metabolic disease
C. Evaluation of soft tissue for suspected foreign body
D. Systemic disease or nutritional deficiencies
E. None of the above
E. None of the above
The following are conditions that warrant MRI, except
A. Athletic pubalgia
B. Marrow abnormalities
C. Femoroacetabular impingement
D. Staging tumors, neoplastic conditions
E. None of the above
E. None of the above
The following are conditions that warrant CT Scan, except
A. For accurate measurement of bone geometry
B. For identification of loose bodies in the joint
C. For evaluation of bony alignment
D. Measuring bone geometry in congenital hip dislocation, joint replacement
E. None of the above
E. None of the above
The following are conditions that warrant an X-ray, except
A. Infections
B. Acetabular labral tears
C. Arthropathies
D. Neoplasms
E. None of the above
B. Acetabular labral tears
This is an indication for MRI
The following are conditions that warrant an X-ray, except
A. Vascular lesions
B. Congenital syndromes and developmental disorders
C. Pre-operative and post-operative studies
D. None of the above
D. None of the above
The following are conditions that warrant MRI, except
A. Trauma
B. Sacral plexus abnormalities
C. Musculotendinous disorders and associated bursities
D. Legg-Calve-Perthes Disease
E. None of the above
A. Trauma
Trauma is an indication for x-ray, and in severe cases, CT scan
The following are conditions that warrant MRI, except
A. Slipped Capital Femoral Epiphysis
B. Radiographically occult fractures
C. Developmental Dysplasia of the Hip
D. Stress fracture of the femur, pelvis, sacrum
E. None of the above
E. None of the above
Pelvis
- Anterior 1/5 of acetabulum
- Posterior 2/5 of acetabulum
- Superior 2/5 of acetabulum
- Covers 50% of femoral head
A. Acetabulum
B. Ilium
C. Ischium
D. Pubis
- D
- C
- B
- A
TRUE OR FALSE: To inflict trauma or fracture to the pelvis requires a great high-velocity force because the pelvic ring is very stable.
True
A fibro-fatty tissue pad found on the medial wall of the acetabulum. On MRI, specifically the axial plane, it gives off hypointense signals.
Pulvinar
What is the normal value of the alpha angle?
< 55 degrees (~42 degrees)
Modified TF
A. The alpha angle is an angle between the neck axis and the line connecting the center of the femoral head to the point at which the head sphericity ends.
B. This angle may indicate if a patient has a cam-type femoroacetabular impingement (cam lesion or pincer femoroacetabular impingement).
TT
Modified TF
A. The hallmark of the cam-type femoroacetabular impingement is a deep acetabular socket whereby more of the femoral head is covered by the socket.
B. The hallmark of the pincer-type femoroacetabular impingement is the osseous bump on the femoral neck.
FF
A. The hallmark of the pincer-type femoroacetabular impingement is a deep acetabular socket whereby more of the femoral head is covered by the socket.
B. The hallmark of the cam-type femoroacetabular impingement is the osseous bump on the femoral neck.
True about CT Arthrography, except
A. Used to evaluate labrum and joint cartilage
B. Contrast fills the folds of the joint capsule
C. Contrast media appears black on fluoroscopy
D. Contrast media appears black on CT
E. Alternative when MR Arthrography is contraindicated or unavailable
D. Contrast media appears black on CT
Correct answer: white on CT
Modified TF
A. Abnormally high signal on T2 at the muscle belly indicate the presence of muscle strain.
B. The pulvinar is a fibrofatty tissue pad that fills the acetabulum of children with DDH.
TT
Modified TF
A. The labrum is triangular in shape and is attached to the acetabular rim.
B. It has a dark signal in all MRI sequences and a bright signal would indicate a tear in the labrum.
TT
CT Scan Image Interpretation
The following are structures to view on the coronal plane, except
A. (B) comparison of hip joints
B. Greater and lesser trochanters
C. Sacrum
D. Acetabular roof
E. None of the above
D. Acetabular roof
This can be seen on the sagittal plane
CT Scan Image Interpretation
The following are structures to view on the coronal plane, except
A. Acetabulum
B. Femoral head, neck, and shaft
C. Ilium
D. Sacroiliac joints
E. None of the above
E. None of the above
CT Scan Image Interpretation
The following are structures to view on the axial plane, except
A. Anterior and posterior rim of acetabulum
B. Pubic ramus
C. Sacrum
D. Femoral head in acetabular fossa
E. None of the above
E. None of the above
CT Scan Image Interpretation
The following are structures to view on the axial plane, except
A. Medial wall of acetabulum
B. Greater trochanter
C. Lesser trochanter
D. Lateral wall of acetabulum
E. None of the above
D. Lateral wall of acetabulum
CT Image Interpretation
The following are structures to view on the sagittal plane, except
A. Acetabular roof
B. Iliopsoas muscle anterior to hip
C. Medial inclination of acetabular cup
D. Sacroiliac joints
E. Pubic symphysis
C. Medial inclination of acetabular cup
Correct answer: Anterior inclination of acetabular cup
CT Image Interpretation
TRUE OR FALSE: The greater trochanter is best viewed in the coronal plane.
True
The anteroposterior projection of the pelvis demonstrates the following, except
A. Entire pelvis, sacrum
B. Coccyx
C. Lumbosacral articulation
D. Both proximal femurs and hip joints
E. None of the above
E. None of the above
The lateral frog projection of the hip and proximal femur demonstrates the following, except
A. Greater trochanter
B. Lesser trochanter
C. Femoral head and neck
D. Proximal third femoral shaft
E. None of the above
E. None of the above
The anteroposterior projection of the hip and proximal femur demonstrates the following, except
A. Acetabulum
B. Femoral head and neck
C. Proximal third femoral shaft
D. Greater trochanter and whole lesser trochanter
E. Angle of inclination
F. None of the above
D. Greater trochanter and whole lesser trochanter
Correct answer:
Greater trochanter and part of lesser trochanter
NOTE: If you can see the entire LT, it means the hip is in ER and the x-ray was poorly taken.
Modified TF: CT Scan
A. The joint capsule is evident if joint effusion is present.
B. Bursa is very light or slit-like but if it is inflamed, it is evident and balloon-like.
TT
- From inferior acetabular rim to inferior femoral neck
- AIIS to intertrochanteric line
- From ischial portion of acetabulum to superior femoral neck
- Found posteriorly, winds around hip
- Stabilizes pelvis on femur during standing
A. Iliofemoral ligament / Y Ligament of Bigelow
B. Ischiofemoral ligament
C. Pubofemoral ligament
- C
- A
- B
- B
- A
These two hip ligaments form a Z structure
- Iliofemoral
- Pubofemoral
Modified TF
A. In the pelvis AP projection, the central ray is perpendicular to the image receptor and directed midway between the levels of the ASIS and symphysis pubis.
B. The lower extremities are internally rotated 15-20º to place the femoral neck plane parallel to the image receptor.
TT
Modified TF
A. In the Hip and Proximal Femur AP projection, the central ray is perpendicular to the image receptor and passes through the femoral neck.
B. The lower extremities are positioned in 15-20º external rotation.
TF
B. The lower extremities are positioned in 15-20º internal rotation.
Modified TF
A. In the lateral frog leg projection, the central ray passes in a mediolateral direction through the femoral neck, striking the image receptor perpendicularly.
B. The patient’s hip is positioned in flexion, external rotation, and lateral abduction, rotating the femur 90º from the AP projection.
TT
Modified TF: AP pelvis projection
A. A narrowed iliac ala combined with a wider obturator foramen on the ipsilateral side can indicate internal rotation of the innominate bone.
B. A wider iliac ala combined with a narrower obturator foramen on the ipsilateral side can indicate external rotation of the innominate bone.
FF
A. A narrowed iliac ala combined with a wider obturator foramen on the ipsilateral side can indicate external rotation of the innominate bone.
B. A wider iliac ala combined with a narrower obturator foramen on the ipsilateral side can indicate internal rotation of the innominate bone.
TRUE OR FALSE: Proper positioning without hip rotation in the AP pelvis projection is evidenced by the equal size of the iliac alae and obturator foramina.
True
Modified TF
A. Angles of inclination less than 125º, looking more like a right angle, are varus deformities (coxa vara).
B. Angles greater than 135º, looking more like a straight line, are valgus deformities (coxa valga).
TT
Modified TF
A. In the AP pelvis projection, the femur should exhibit symmetrical angles of inclination from the femoral neck to the femoral shaft.
B. Asymmetry of the angles may be a sign of femoral fracture.
TT
Modified TF
A. The anterior acetabular rim represents the anterior margins of the acetabular cup.
B. The posterior acetabular rim represents the posterior cortical rim of the acetabular cup.
TT
Modified TF
A. The anterior column of the acetabulum is from the greater sciatic notch to the superior ramus of pubis.
B. The ilioischial line represents the limit of the anterior column of the acetabulum, and disruption of this line may indicate an abnormality of the anterior column.
TF
B. The iliopubic/iliopectineal/arcuate line represents the limit of the anterior column of the acetabulum, and disruption of this line may indicate an abnormality of the anterior column.
Modified TF
A. The acetabular roof represents the cortical aspect of the acetabular cup which corresponds to the major weight-bearing portion of the acetabulum.
B. The iliopubic line is a line from the sciatic notch to the pubic tubercle.
TT
Modified TF
A. The ilioischial line is a line from the iliac notch to the inner surface of the ischium.
B. It represents the anteromedial margin of the quadrilateral surface of the iliac bone and the limit of the posterior acetabular column.
TF
B. representing the posteromedial margin of the quadrilateral surface of the iliac bone and the limit of the posterior acetabular column.
Modified TF
A. Normally, the ilioischial line is tangential to or intersects the radiographic teardrop.
B. When there is an abnormality of this line, the posterior column of acetabulum is assumed to have a fracture.
TT
TRUE OR FALSE: Protrusio acetabuli can be a result of a complication in THR, where the cup went beyond the
ilioischial line and the surgery must be revised.
True
Modified TF
A. In the hip and proximal femur AP view, the greater trochanter is obscured by the femoral neck while the lesser trochanter can be clearly seen.
B. In the lateral frog projection, the lesser trochanter is obscured or only its tip is showing.
FF
A. In the lateral frog view, the greater trochanter is obscured by the femoral neck while the lesser trochanter can be clearly seen.
B. In the hip and proximal femur AP projection, the lesser trochanter is obscured or only its tip is showing.
Modified TF: Hip & proximal femur AP view
A. Narrowing of the hip joint space is associated with degeneration of the articular cartilage.
B. Widening of the joint space is associated with joint effusion.
TT
Destruction of normal joint congruity and ball-and-socket configuration may be caused by these pathologies, except
A. avascular necrosis
B. rheumatoid arthritis
C. degenerative joint disease
D. destructive tumors
E. none
E. none
Modified TF
A. Trabecular markings of the femoral head and neck are normally clear and sharp.
B. A washed-out or demineralized appearance may indicate the presence of an abnormal metabolic process.
TT
TRUE OR FALSE: Thinning or evaporation of the radiodense cortex of the femoral shaft indicates the presence of an abnormal metabolic process, such as osteoporosis.
True
Modified TF
A. On the MRI, serpentine high signal lines define margins between normal and avascular bone.
B. If there is no history of trauma, there may be avascular necrosis present in the area rather than a fracture.
FT
A. On the MRI, serpentine low signal lines define margins between normal and avascular bone.
Modified TF
A. On MRI, tumors or cysts may be seen in degenerative conditions.
B. Fractures appear as low signal lines and a history of trauma and pain may easily be concluded as a fracture.
TT
Intersection of a line drawn through the center of the femoral shaft and a line drawn through the center of the femoral neck.
A. Shenton’s hip line
B. Iliofemoral line
C. Femoral neck angle
D. Ischiofemoral line
C. Femoral neck angle
Curved line along the outer surface of the ilium that extends inferiorly along the femoral neck
A. Shenton’s hip line
B. Iliofemoral line
C. Femoral neck angle
D. Ischiofemoral line
B. Iliofemoral line
Curved line along the medial and superior surface of the obturator foramen to the medial aspect of the femoral neck.
A. Shenton’s hip line
B. Iliofemoral line
C. Femoral neck angle
D. Ischiofemoral line
A. Shenton’s hip line
TRUE OR FALSE: Disruptions in the iliofemoral and Shenton’s hip lines are associated with hip dislocation, femoral neck fracture, and slipped capital femoral epiphysis.
True
TRUE OR FALSE: In the hip and proximal femur AP view, the correct position of the femoral head in the acetabulum and correct alignment of the femoral head to the femoral shaft can be assessed by identifying the Shenton’s hip line, iliofemoral line, and femoral neck angle.
True
TRUE OR FALSE: Internal rotation of the lower extremities by 15-20º compensates for the normal anteversion of the femoral neck and allows the neck to be visualized parallel to the image receptor.
True
What projection is done for patients who cannot rotate a leg to do the frog leg position due to THR or a non-displaced femoral neck fracture?
axiolateral inferosuperior projection / groin-lateral projection / cross-table lateral / true lateral
Modified TF
A. The groin-lateral projection is done by flexing the uninvolved extremity up out of the way.
B. The central ray is directed through the femoral neck at an superoinferior angle.
TF
B. The central ray is directed through the femoral neck at an inferosuperior angle.
TRUE OR FALSE: In the pelvis AP view, the femoral necks are visible to their full extent as they are positioned in a plane parallel to the image receptor.
True
Modified TF
A. In the lateral frog projection, the femur is viewed from a medial-to-lateral aspect.
B. The lesser trochanter is now anterior, and the greater trochanter is now posterior.
TT
NOTE: The greater trochanter is superimposed behind the neck, and the lesser trochanter is superimposed in front of the neck and extends slightly below the medial border of the femur.
TRUE OR FALSE: The radiographic image of the acetabulum in the lateral frog view is unchanged from the AP view.
True
TRUE OR FALSE: On the pelvis AP view, the iliac alae are normally radiolucent at its anterolateral borders as the bony mass is thinner there.
True
TRUE OR FALSE: On the pelvis AP view, the interpubic cartilaginous disk of the symphysis pubis is shown as a radiolucent potential space.
True
What is the radiographic line on the pelvis or hip joint X-ray that passes through the tri-radiate cartilages?
A. Perkin’s Line
B. Hilgenreiner’s Line
C. Shenton’s Line
D. Center edge angle
B. Hilgenreiner’s Line
TRUE OR FALSE: The ilium makes up 1/5 of the superior aspect of the acetabulum.
False, 2/5
TRUE OR FALSE: In taking the AP view of the pelvis, the central ray is positioned midway between ASIS and symphysis pubis.
True
TRUE OR FALSE: Fluid sensitive sequence used for Axial plane cuts of the pelvis on MRI uses a T2 with Inversion Recovery sequence.
True
TRUE OR FALSE: The anterior acetabular rim on the AP view of the pelvis is located medial to the posterior rim of the acetabulum.
True
