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Rad2012
Pelvic Girdle
Question | Answer |
---|---|
What does the head of the proximal femur articulate with? | The acetabulum of pelvis to form the hip joint |
What is the fovea capitius? | A depression or pit located in the center of the femoral head; allows for the attachment of a ligament |
Where is the greater trochanter located? | Superiorly and Laterally; can be palpated as a landmark |
Lesser trochanter | smaller than the greater and located more medially and posteriorly than the greater trochanter |
What is the intertrochanteric line or crest? | A thick ridge of bone that joins the two trochanters together posteriorly |
What is the angle from the neck to the shaft of the proximal femur on an average person? | Approximately 125 degrees; a person with long legs and narrow pelvis would probably have an angle 15 degrees less; a shorter person with a wider pelvis would have an angle 15 degrees more. |
The femur lies in the thigh at an angle of approximately _____ degrees from vertical; this would increase more (____) if a person is short and has a wide pelvis. | *10 *15 degrees |
The head of the femur articulates with the pelvis at an anterior angle of _______ degrees. | 15-20 |
How many bones make up the pelvis? What are they? | *4 *2 innominate bones (hip bones), 1 sacrum, 1 coccyx |
How many bones make up the pelvic girdle? | 2 hip bones |
What are the three divisions that make up each hip bone? | ilium, ischium, and pubis |
The three divisions of the hip bone are separate bones, but fuse together in the _____ years in the area of the ______. | *middle teen *acetabulum |
What is the acetabulum? | the deep, cup shaped fossa that articulates with the femoral head to form the hip joint |
Where is the body of the ilium located? | More inferior and includes the upper two fifths of the acetabulum |
What is the ala (wing)? | the thin, flared portion of the upper ilium |
Iliac crest | upper curved area of the ala that extends from the ASIS to the PSIS; one of the most palpable bony landmarks used for abdominal positioning; usually only use the top or most superior portion |
ASIS | Anterior superior iliac spine- bony prominence located anteriorly at the anterior end of the iliac crest; also used as a landmark for positioning |
PSIS | Posterior superior iliac spine- bony prominence located posteriorly at the end of the iliac crest; not used for positioning |
AIIS | Anterior inferior iliac spine- small prominence located inferior to the ASIS |
PIIS | Posterior inferior iliac spine- small prominence located inferior to the PSIS |
Where is the body of the ischium located? | upper body forms the posteroinferior two fifths of the acetabulum; lower portion of body projects caudally and medially from the acetabulum |
Ischial tuberosity | rough, rounded area located at the end of the lower body; area in which our body rests when in a seated position; may be used as a bony landmark when performing prone abdomen projections |
Ramus | projects anteriorly from the ischial tuberosities |
Ischial spine | Posterior to the acetabulum; cannot be palpated; may see a small portion of this projection in an AP pelvis projection |
Greater sciatic notch | deep notch located directly above the ischial spine |
Lesser sciatic notch | smaller notch located directly below the ischial spine |
Where is the body of the pubis located? | Anteriorly and inferiorly to the acetabulum and includes the anteroinferior one fifth of the acetabulum. |
Superior ramus | extends anteriorly and medially for the body; the two meet at the midline to form the symphysis pubis joint |
Inferior ramus | extends downward and posterior from the symphysis pubis to joint the ramus of the ischium |
Obturator foramen | largest foramen or opening in the body;formed by the ischium and the pubis |
How is the ASIS used as a positioning landmark? | By placing each ASIS equal distances to the tabletop, it will confirm that the patient is in a true AP position and will not be rotated. Also used to help identify the location of the femoral head and neck |
How is the greater trochanter used as a positioning landmark? | Upper margin may be palpated in the upper thigh; lies approximately at the same horizontal level as the upper margin of the symphysis pubis or 1 and 1/2 inch superior. |
How is the ischial tuberosities used as a landmark for positioning? | usually lies 1 and 1/2 to 2 inches below the level of the symphysis and may be used to assist in positioning of the prone abdomen; not frequently utilized due to embarrassment and modesty |
How is the symphysis pubis used as a postioning landmark? | corresponds to the lowest level of the abdomen; used in conjuction with the ASIS to locate the head and neck of the femur |
Pelvic brim | defined by the upper margin of the symphysis anteriorly and by the prominent portion of the sacrum posteriorly; and imaginary plane drawn through this area allows for the location of a cavity above and beneath |
Greater or false pelvis | refers to the cavity that lies above the pelvic brim; it is formed by the iliac wings of the hip bones and contains lower abdominal organs as well as the fetus in a pregnant female. |
Lesser or true pelvis | refers to the cavity that lies beneath the pelvic brim; surrounded by bony structures; forms the actual birth canal in the female. |
Inlet or superior aperture | the area of the true pelvis defined by the pelvic brim |
Cavity | area located between the inlet and the outlet |
Outlet or inferior aperture | The area defined by the two ischial tuberosities and the coccyx; during birth, the fetus travels first through the inlet, then the cavity, and exits the outlet of the true pelvis |
Cephalopelvimetry | radiographic exams performed in the past to measure the baby's head in relation to the inlet and outlet of the mother's pelvis; ultrasound is the most common method used today and produces no ionizing radiation risks |
Female pelvis characteristics | usually wider and more flared in the area of the iliac wings; angle of the pubic arch is obtuse or greater than 90 degrees; shape of inlet or pelvic brim is usually larger and more round in appearance |
Male pelvis characteristics | usually more narrow and deep (tall) and less flared in the area of the iliac wings; angle of the pubic arc is acute or less than 90 degrees; shape of the inlet or pelvic brim is usually more narrow and heart shaped |
Sacroiliac joints | Synovial/Amphiarthrodial |
Symphysis pubis | Cartilaginous/Amphiarthrodial |
Union of the acetabulum | Cartilaginous/Synarthrodial for adults |
Hip joint | Synovial/Diarthrodial- ball and socket movement or spheroidal |
Location of the femoral head and neck | determine an imaginary line from the ASIS and the upper margin of the symphysis pubis; locate the midpoint of that line and proceed inferior 1 and 1/2 inches to locate the femoral head and 2 and 1/2 inches to locate the femoral neck |
Internal rotation of the leg | in order to obtain a true AP view of the proximal femur, you must internally rotate the entire leg 15 to 20 degrees; this action places the femoral head and neck parallel to the image receptor and prevents foreshortening |
True or False. If rotaion of the leg is successful, the lesser trochanter of the femur will not be visible on the completed radiograph. | true. this is necessary due to the head of the femur articulating with the acetabulum at an anterior angle of 15-20 degrees |
Evidence of hip fractures | Hip is a common fracture site, especially for elderly patients; a typical sign is the external rotation of a foot or leg; never rotate a patient's leg internally if this sign is present or if the patient is in pain from a traumatic injury |
What is the largest and strongest bone in the body? | Femur |
A small depression located in the center of the femoral head is called the ______. | Fovea capitius |
The lesser trochanter is located on the ____ (medial or lateral) aspect of the proximal femur. | Medial |
The lesser trochanter projects _____ (anteriorly or posteriiorly) from the junction between the neck and the shaft. | Posteriorly |
Because of the alignment between the femoral head and pelvis, the lower limb must be rotated _____* internally to place the femoral neck parallel to the plane of the IR to achieve a true AP projection. | 15-20* |
True/False: According to Grey's Anatomy reference textbook, the terms pelvis and pelvic girdle are not synonymous. | True |
What are the two important radiographic landmarks found on the ilium? | ASIS and the iliac crest |
Which bony landmark is found on the most inferior aspect of the posterior pelvis? | ischial tuberosity |
What is the name of the joint found between the superior rami of the pubic bones? | Symphysis pubis |
The ______ of the pelvis is the largest foramen in the skeletal system. | Obturator foramen |
The upper margin of the greater trochanter is approximately ___ above the level of the superior border of the symphysis pubis, and the ischial tuberosity is about ____ below. | 1" , 1 and 1/2 to 2" |
An imaginary plane that divides the pelvic region into the greater and lesser pelvis is called the _____. | Pelvic brim |
List the alternate names for the greater and lesser pelvis. | greater= False ; lesser= True |
List the major function of the greater and lesser pelvis. | Greater- supports lower abdominal organs and fetus Lesser- forms the actual birth canal |
List the 3 aspects of the lesser pelvis, which also describe the birth route during the delivery process. | A. Inlet B. Outlet C. Cavity |
Ilium | Ala, Posterior superior iliac spine (PSIS), Anterior superior iliac spine (ASIS), Articulates with the sacrum to form the SI joints |
Ischium | Posses a large tuberosity found at the most inferior aspect of the pelvis, Lesser sciatic notch |
Pubis | Possesses a slighly movable joint, Forms the anterior, inferior aspect of the lower pelvic girdle |
In the past, which radiographic examination was performed to measure the fetal head in comparison with the maternal pelvis to predict possible birthing problems? | Cephalopelvimetry |
Which two bony landmarks need to be palpated for hip localization? | ASIS and symphysis pubis |
From the midpoint of the imaginary line created by the ASIS and the symphysis pubis, where would the femoral neck be located? | Approximately 2" below the midpoint of the line |
A second method for locating the femoral head is to palpate the ____ and go _____ inches medial at the level of ____ which is _____ inches distal to the orginial palpation point. | ASIS; 1 to 2"; symphysis pubis and/or greater trochanter; 3 to 4" |
To achieve a true AP position of the proximal femur, the lower limb must be rotated ____* internally. | 15-20* |
Which structures on an AP pelvis or hip radiograph indicate whether the proximal head and neck are in position for a true AP projection? | Lesser Trochanter should not be visible or should only be seen slightly visible on the radiograph |
Which physical sign may indicate that a patient has a hip fracture? | Foot rotated externally |
Which projection should be taken first and reviewed by a radiologist before attempting to rotate the hip into a lateral position (if trauma is suspected)? | AP pelvis |
Gonadal shielding should be used for all patients of reproductive age, unless ____. | It covers anatomic structures of primary interest |
Should a gonadal shield be used for a hip study on a young female? | Yes, use a shaped ovarian shield with top of shield at level of ASIS and bottom at symphysis pubis |
Should a gonadal shield be used for a hip study on a young male? If yes describe how it should be placed on the patient. | Yes, the top of the shield should be placed at the inferior margin of the symphysis pubis |
What is the advantage of using 90kV rather than 80kV range for hip and pelvis studies on younger patients? | It reduces patient dose approximately 30% |
What is the disadvantage of using 90kV for hip and pelvis studies, especially on older patients with some bone mass loss? | It reduces radiographic contrast |
Which condition is a common clinical indication for performing pelvic and hip examinations on a pediatric (newborn) patient? | Development dysplasia of hip (DDH) |
True/False: Geriatric patients are more prone to hip fractures because of their increased incidence of osteoporosis. | True |
Which imaging modalities can be used on a newborn to assess hip joint stability during movement of the lower limb? | Sonography |
Which imaging modalities is most sensitive in diagnosing early signs of metastatic carcinoma of the pelvis? | Nuclear medicine |
Metastatic carcinoma | Malignacy spread to bone via the circulatory and lymphatic systems or direct invasion |
Ankylosing spondylitis | A disease producing extensive calcification of the longitudinal ligament of the spinal column |
Congenital dislocation | Now referred to as developmental dysplasia of the hip |
Chondrosarcoma | A malignant tumor of the cartilage of hip |
Proximal hip fracture | Most common fracture in older patients because of high incidence of osteoporosis or avascular necrosis |
Pelvic ring fracture | A fracture resulting from a severe blow to one side of the pelvis |
Osteoarthritis | A degenerative joint disease |
Which device will improve overall visibility of the proximal hip demonstrated on an axiolateral(inferosuperior) projection? | Compensating filter |
Which modality will best demonstrate a possible pelvic ring fracture? | CT |
True/False: Both joints must be included on an AP and lateral projection of the femur even if a fracture of the proximal femur is evident. | True. If an AP and lateral femur study is ordered, both joints must be demonstrated. |
Where is the central ray placed for an AP pelvis projection? | Midway between ASIS and symphysis pubis |
Which ionization chamber(s) should be activated when using AEC for an AP pelvis projection? | Upper right and left chambers |
Which specific positioning error is present when the left iliac wing is elongated on an Ap pelvis radiograph? | Rotation towards the left side |
Which specific positioning error is present when the left obturator foramen is more open than the right side on an AP pelvis radiograph? | Right rotation |
Traumatic | Danelius-Miller projection, Clements-Nakayama, Anterior pelvic bones |
Not traumatic | Unilateral frog leg, Modified Cleaves (bilateral frog-leg) |
Which projection is recommended to demonstrate the superoposteriorwall of the acetabulum? | PA axial oblique |
When gonadal shielding is not used, _____ receive a greater gonadal dose with an AP pelvis projection. | Females (nearly 3 times more) |
How many degrees are the femurs abducted (from the vertical plane) for the bilateral frog-leg projection? | 40-45* |
Where is the central ray placed for a unilateral frog-leg projection? | Midfemoral neck |
Which cassette size should be used for an adult bilateral frog-leg projection? | 14X17 crosswise |
Where is the central ray placed for an AP bilateral frog-leg projection? | 1" superior to the symphysis |
Which central ray angle is required for the "outlet" projection (Taylor Method) for a female patient? | 30-45* cephalad |
Which type of pathologic feature is best demonstrated with the Judet method? | Acetabular fractures |
How much obliquity of the body is required for the Judet method? | 45* |
What type of CR angle is used for a PA axial oblique (Teufel) projection? | 12* cephalad |
How is the pelvis (body) positioned for a PA axial oblique (Teufel) projection? | PA 35-40* toward affected side |
True/False: Any orthopedic device or appliance of the hip should be seen in its entirety on an AP hip radiograph. | True |
The axiolateral (inferosuperior) projection is designed for _______ (traumatic or nontraumatic) situations. | Traumatic |
How is the unaffected leg positioned for the axiolateral hip projection? | It is flexed and elevated to prevent it from being superimposed over the affected hip |
Which factor does not apply to an axiolateral projection of the hip on a male patient? | Use of gonadal shielding |
True/False: An AP pelvis projection using 90kV and 8 mAs results in a patient dose of approximately 30% less than a projection using 80kV and 12 mAs (for both males and females). | True |
True/False: During an axiolateral projection of the hip, a male patient receives more than 20 times the gonadal dose than a female. | True |
The modified axiolateral requires the CR to be angled _______* posteriorly from horizontal. | 15-20 |
Which special projection of the hip demonstrates the anterior and posterior rims of the acetabulum and the ilioischial and iliopubic columns? Which CR angle is used? | Posterior oblique projections of the acetabulum (Judet method) 0* (perpendicular) |
What is the name of the special AP axial projection of the pelvis is used to assess trauma to pubic and ischial structures? | AP axial outlet projection (Taylor method) |
Judet | Posterior oblique for acetabulum |
Taylor | AP axial for pelvic "outlet" bones |
Clements-Nakayama | Modified axiolateral |
Danelius-Miller | Axiolateral (inferosuperior) |
Teufel | PA axial oblique for acetabulum |
Modified Cleaves | Bilateral or unilateral frog-leg |
What is the optimal amount of hip abduction for the unilateral "frog-leg" projection to demonstrate the femoral neck without distortion? | 20-30* from vertical |
True/False: The Lauenstein/Hickey method for the unilateral "frog-leg" projection will produce distoration of the femoral neck. | true |
How much is the cassette tilted for the modified axiolateral projection of the hip? | 15* from the vertical |
True/False: Gonadal shielding can be used for males for the axiolateral projection of the hip. | False |
AP Mid-Distal Femur | Patient is placed supine on exam table with legs extended; rotate the leg internally 5* for a true AP to place the femoral epicondlyes parallel to the IR. CR is perpendicular to mid-femur. Should demonstrate the distal 2/3 of the femur including the knee |
Lateral Mid-Distal Femur | Have the patient lying on affected side; affected knee should be flexed about 45* with the femoral epicondlyes perpendicular to the IR. CR is perpendicular to mid femur. Femoral condyles superimposed; lateral view of distal femur |
AP pelvis | Patient supine with their MSP in alignment w/the center of table; check for rotaion making sure the ASISs are equal distances from tabletop; patient should rotate feet and legs internally 15-20* in order to place the femoral necks parallel to IR |
AP pelvis | CR will be perpendicular to a point midway between the level of the ASISs and the symphysis pubis or 2" superior to the symphysis; top of IR will be about 1 to 1 and 1/2" above the iliac crest; 14X17 IR transverse; 40" SID |
AP pelvis | should demonstrate an AP projection of the pelvis including the head, neck, trochanters, and proximal third of the femurs; lesser trochanters should not be seen or barely visible on film |
AP pelvis | To check for rotation: obturator foramina and iliac wings should be symmetrical in appearance, if either is elongated, then the patient was rotated in that direction. |
AP Unilateral Projection (Affected Hip only) | Patient should be placed supine, no rotation, MSP in alignment with the center of table; internally rotate affected foot and leg 15-20*. CR is perpendicular to femoral neck; 10X12 IR lengthwise; 40" SID. |
AP Unilateral Projection (Affected Hip only) | AP view of the proximal 1/3 of the femur, hip joint, and acetabulum; lesser trochanter usually not demonstrated or barely visible |
AP Bilateral "Frog-leg" (Modified Cleaves) | Patient supine no rotation MSP to center of table have the patient flex their knees & draw their feet towards their body; w/the plantar surfaces of the feet together, the thighs should be abducted approx 45* from vertical; places femoral necks parallel IR |
AP Bilateral "Frog-leg" (Modified Cleaves) | CR perpendicular to 1 and 1/2" superior to the symphysis pubis (level of femoral heads); 14X17 IR transverse; 40" SID |
AP Bilateral "Frog-leg" (Modified Cleaves) | Should demonstrate the acetabulum, femoral neck and head, lesser trochanter seen on the medial side of the femur; femoral neck should have little superimposition of the greater trochanter |
Unilateral Frog-leg (separate modification- Lauenstein/Hickey) | Patient supine and have them flex knee of the affected side and abduct leg approx 45* (Places thigh at right angle to leg) the sole of foot should rest against opposite knee; pelvis may be rotated somewhat toward affected side |
Unilateral Frog-leg (separate modificaion- Lauenstein/Hickey) | CR perpendicular to femoral neck; 10X12 IR lengthwise; 40" SID. same as bilateral method, demonstrates greater trochanter superimposed over femoral neck |
Axiolateral Inferosuperior (Danelius/Miller) | patient supine; pelvis elevated to place the hip toward the center of IR; unaffected leg flexed until thigh is near vertical and placed out of CR path. |
Axiolateral Inferosuperior (Danelius/Miller) | the cassette should be positioned vertically along the crease of the iliac crest; this places the IR parallel to the long axis of the femoral neck; CR is perpendicular to the IR and femoral neck; 10X12 IR crosswise; 40" SID |
Axiolateral Inferosuperior (Danelius/Miller) | will demonstrate the acetabulum, femoral head, neck, and trochanters; ischial tuberosity will be demonstrated below the femoral head |
Modified Axiolateral Inferosuperior (Clements/Nakayama) | patient supine with affected side closest to edge of table; place the grid/IR at a level lower than hip and tilt the top backward approx 15*; the IR should be placed parallel to the femoral neck. CR 15* posteriorly to be perpendicular to femoral neck |
Modified Axiolateral Inferosuperior (Clements/Nakayama) | 10X12 IR crosswise with grid; 40" SID; hip joint with the acetabulum, femoral head, neck, and trochanters |