Radiographic Positioning and Anatomy of the Femur and Pelvic Girdle

Comprehensive vocabulary flashcards covering pelvic girdle and proximal femur radiographic anatomy, pathology, specialized projections, and positioning methods.

Pelvic Girdle

The skeletal ring consisting of the two hip bones (also called ossa coxae or innominate bones), which are classified as irregular bones.

Angles of Proximal Femur

The three anatomical angular relationships of the proximal femur: the neck-to-shaft angle ($\approx 125^\circ \pm 15^\circ$), the longitudinal angle ($\approx 10^\circ$, ranging from $5^\circ\text{ to }15^\circ$), and the anterior angle of the femoral head and neck ($15^\circ\text{ to }20^\circ$).

Fovea Capitis

A small depression located on the femoral head that serves as the site of insertion for the ligamentum capitis femoris (ligament of the femoral head).

Bones of the Pelvis

The four bones that comprise the complete bony pelvis: two hip bones (ossa coxae or innominate bones), one sacrum, and one coccyx.

Acetabulum Composition

The cup-shaped socket formed by the fusion of three bones: the ilium (upper $2/5$), the ischium (posterior-inferior $2/5$), and the pubis (anterior $1/5$).

Anatomy Review: Ilium

The anatomical structures of the ilium: A represents the acetabulum; B represents the anterior inferior iliac spine (AIIS); C represents the anterior superior iliac spine (ASIS); D represents the iliac crest; E represents the ala (wing); F represents the body; G represents the posterior superior iliac spine (PSIS); and H represents the posterior inferior iliac spine (PIIS).

Ischium

The posteroinferior part of the hip bone consisting of an upper body, lower body, ramus, ischial tuberosity, ischial spine, greater sciatic notch, and lesser sciatic notch.

Pubis (Pubic Bone)

The anteroinferior part of the hip bone consisting of a body, a superior ramus, an inferior ramus, the symphysis pubis, and contributing to the border of the obturator foramen.

Greater Pelvis (False Pelvis)

The flared portion of the pelvis situated above the pelvic brim that supports the lower abdominal organs and the fetus during pregnancy.

Lesser Pelvis (True Pelvis)

The area situated entirely below the plane of the pelvic brim that forms the birth canal, having an inlet, a cavity, and an outlet.

Pelvic Brim

The circular bony ridge along the inner aspect of the pelvis that demarcates the boundary separating the greater (false) pelvis from the lesser (true) pelvis.

Hysterosalpingography

A radiographic examination of the uterus and fallopian tubes using contrast media to evaluate patency, demonstrated by the spill of dye into the peritoneal cavity.

Pubic Arch Angle (Gender Differences)

The angle formed under the pubic symphysis, which is obtuse ($> 90^\circ$) in the female pelvis and acute ($< 90^\circ$) in the male pelvis.

Sacroiliac (SI) Joint

A bilateral pelvic articulation classified structurally as synovial and functionally as an amphiarthrodial joint with limited movement.

Hip Joint (Classification)

The articulation between the femoral head and the acetabulum, classified structurally as synovial and functionally as a diarthrodial spheroidal (ball-and-socket) joint.

Symphysis Pubis Joint

The midline anterior articulation uniting the two pubic bones, classified structurally as cartilaginous and functionally as an amphiarthrodial joint with limited movement.

Union of Acetabulum

The junction where the ilium, ischium, and pubis fuse in the acetabulum, classified structurally as cartilaginous and functionally as a synarthrodial (immovable) joint.

Hip Localization (Method One)

A localization method using a line drawn between the ASIS and pubic symphysis; the femoral head lies $1\frac{1}{2}\text{ inches}$ ($4\,\text{cm}$) along the perpendicular bisector, and the femoral neck lies $2\frac{1}{2}\text{ inches}$ ($6-7\,\text{cm}$) along it.

Hip Localization (Method Two)

A localization method where the femoral neck is located by finding a point $1-2\text{ inches}$ ($3-5\,\text{cm}$) medial to the ASIS and then extending $3-4\text{ inches}$ ($8-10\,\text{cm}$) distal.

True AP Projection of the Proximal Femur

A radiographic view attained by internally rotating the lower limb $15^\circ\text{ to }20^\circ$, placing the femoral neck parallel to the image receptor and obscuring the lesser trochanter.

Asymmetric Limb Rotation

A radiographic appearance where the affected lower limb lies in external rotation with the lesser trochanter in prominent profile, frequently indicating a hip fracture.

Ankylosing Spondylitis

A rheumatoid arthritis variant characterized by chronic inflammation and fusion of the sacroiliac joints and spine, resulting in loss of normal spinal curvature.

Congenital Hip Dysplasia

A developmental malformation of the acetabulum that results in superior and lateral displacement or dislocation of the femoral head.

Legg-Calvé-Perthes Disease

A condition characterized by ischemic necrosis and flattening of the femoral head caused by a disruption of blood flow.

Slipped Capital Femoral Epiphysis (SCFE)

A condition in which the proximal portion (head) of the femur becomes displaced or dislocated from the distal portion along the proximal epiphysis (growth plate).

AP Projection of the Pelvis

A supine projection with the feet and legs internally rotated $15^\circ-20^\circ$ and heels separated by $8-10\text{ inches}$ ($20-24\,\text{cm}$); the CR is perpendicular to $2\text{ inches}$ inferior to the ASIS or $2\text{ inches}$ superior to the pubic symphysis.

Lateral Projection of the Pelvis

A lateral recumbent or upright projection centered perpendicular to $2\text{ inches}$ above the greater trochanters, demonstrating the lumbosacral junction, sacrum, coccyx, and superimposed upper femora.

Gull-Wing Sign

A radiographic sign demonstrated on a dorsal decubitus lateral projection of the pelvis (recommended by Berkebile, Fischer & Albrecht) in cases of acetabular rim fracture-dislocation and posterior femoral head dislocation.

Martz-Taylor Method

A radiographic procedure for congenital hip dislocation recommending two AP projections centered to the pubic symphysis: one with a perpendicular CR, and a second with a CR directed perpendicular to $45^\circ$.

Andrén-von Rosen Approach

A bilateral hip projection for diagnosing congenital hip dislocation in newborns, performed with both limbs forcibly abducted $45^\circ$ and the femora internally rotated.

Modified Cleaves Method (Bilateral Frog-Leg Position)

An AP oblique projection where the patient's hips and knees are flexed, thighs abducted $25^\circ-45^\circ$ from vertical, and soles placed together; the CR is perpendicular, entering $1\text{ inch}$ superior to the pubic symphysis.

Modified Cleaves Method (Unilateral Projection)

An AP oblique view of the affected hip flexed, thigh abducted $45^\circ$ laterally, and sole placed against the opposite knee; the CR is perpendicular, centered $1\text{ inch}$ superior to the femoral neck.

Original Cleaves Method

An axiolateral projection using the bilateral frog-leg position with the CR angled $25^\circ-45^\circ$ cephalad, centered $1\text{ inch}$ superior to the pubic symphysis.

AP Projection of the Hip

A supine radiographic view where the affected limb is medially rotated $15^\circ-20^\circ$ and the CR is directed perpendicular to the femoral neck to demonstrate the hip joint.

Lauenstein Method

A mediolateral lateral hip projection where the patient is rolled toward the affected side and the CR is directed perpendicular to the hip joint, superimposing the femoral neck over the greater trochanter.

Hickey Method

A mediolateral lateral hip projection where the CR is angled $20^\circ-25^\circ$ cephalad to the hip joint, projecting the femoral neck free of superimposition with the greater trochanter.

Danelius-Miller Method

An axiolateral cross-table projection for the hip where the unaffected limb is flexed and elevated, the affected limb is internally rotated $15^\circ-20^\circ$, and the horizontal CR is perpendicular to the femoral neck.

Clements-Nakayama Modification

A modified axiolateral hip projection for patients with bilateral hip trauma or limited mobility, performed with the IR tilted $15^\circ$ posteriorly and the CR angled $15^\circ$ posterior to the femoral neck.

Chassard-Lapine Method

An axial sitting projection where the seated patient leans forward $45^\circ$ and grasps the ankles; the CR is perpendicular to the lumbosacral region to assess the acetabulum, pelvic bones, pelvimetry diameters, or rectosigmoid.

Leonard-George Method

An axiolateral projection using a curved cassette and an elevated pelvis, where the CR is directed medially and inferiorly perpendicular to the depression superior to the greater trochanter.

Friedman Method

An axiolateral hip projection performed in the lateral recumbent position with the unaffected limb rolled $10^\circ$ posteriorly, using a CR angled $35^\circ$ cephalad directed to the femoral neck.

Hsieh Method

A PA oblique projection (RAO/LAO) with the unaffected side elevated $40^\circ-45^\circ$ and the CR perpendicular between the posterior iliac blade and femoral head to show posterior femoral head dislocations.

Teufel Method

A PA axial oblique projection (RAO/LAO) with the patient semiprone and MSP at $38^\circ$ from the table; the CR is angled $12^\circ$ cephalad entering the acetabulum to demonstrate the fovea capitis and superoposterior acetabular wall.

Judet Method (Internal Oblique)

An AP oblique projection ($45^\circ$ posterior oblique) with the affected hip up (LPO), centering $2\text{ inches}$ inferior to the affected ASIS to visualize the iliopubic column (anterior) and posterior rim of the acetabulum.

Judet Method (External Oblique)

An AP oblique projection ($45^\circ$ posterior oblique) with the affected hip down (RPO), centering perpendicular to the pubic symphysis to demonstrate the ilioischial column (posterior) and anterior rim of the acetabulum.

Rafert-Long Modification

A modification of the Judet method for trauma patients that uses a horizontal CR for the external oblique and a perpendicular/vertical CR for the internal oblique.

Taylor Method

An AP axial pelvic 'outlet' projection with the CR angled cephalad ($20^\circ-35^\circ$ for males, $30^\circ-45^\circ$ for females) entering $2\text{ inches}$ distal to the superior border of the pubic symphysis to image the pubic and ischial rami.

Bridgeman Method

A superoinferior axial pelvic 'inlet' projection where the CR is angled $40^\circ$ caudad entering at the level of the ASISs to visualize the pelvic ring.

Lilienfeld Method

A superoinferior axial projection where the seated-erect patient leans backward $45^\circ-50^\circ$ with an arched back, and the CR is directed perpendicular to $1.5\text{ inches}$ superior to the symphysis pubis.

Staunig Method

A PA axial pelvic inlet projection performed prone with the CR angled $35^\circ$ cephalad to the pubic symphysis to demonstrate the anterior pubic bones and pelvic ring.

AP Oblique Projection of the Ilium

An oblique view (RPO/LPO) with the unaffected side elevated $40^\circ$ to place the broad surface of the affected iliac wing parallel to the IR, centering perpendicular to the level of the ASIS.

PA Oblique Projection of the Ilium

An oblique view (RAO/LAO) with the unaffected side elevated $40^\circ$ to place the affected ilium perpendicular to the IR, centering perpendicular to the ASIS to show the ilium in profile and the femoral head within the acetabulum.