Chapter 7 -- Femur and Pelvic Girdle

head of femur

neck of femur

common area for injury

femur

longest and strongest bone of the body

greater trochanter

body or shaft of femur

lesser trochanter

located on posterior side

intertrochanteric crest

located on posterior side

fovea capitis

serves as an attachment for ligaments

neck to shaft angle (A)

~125^o

longitudinal angle (C)

~10^o

anterior angle (B)

~ 15 to 20^o

taller pt angles of proximal femur

femur is more vertical (smaller longitudinal angle) with more of an angle of neck to shaft

shorter pt angles of proximal femur

femur is more medial with more of an longitudinal angle and less of a neck to shaft angle

hip bones, ossa coxae, or innominate bones

made up of 3 parts (ilium, pubis, ischium) to form the acetabulum

sacrum

coccyx

ilium

pubis

ischium

acetabulum

iliac crest

important positioning marker

ala or wing

can help determine rotation

body of pelvis

anterior superior iliac spine (ASIS)

anterior inferior iliac spine

posterior superior iliac spine (PSIS)

posterior inferior iliac spine

upper body of ischium

ramus of ischium

ischial tuberosity

lower body of ischium

lesser sciatic notch

ischial spine

greater sciatic notch

superior ramus

inferior ramus

symphysis pubis

obturator foramen (p. foramina)

helps to determine direction of obliquity

body of pubis

bony landmarks of pelvis

crest of ilium, ASIS, symphysis pubis, greater trochanter, ischial tuberosity

greater or false pelvis

brim or inlet of pelvis

lesser or true pelvis

outlet of pelvis

male pelvis

• general shape: narrower, deeper, less flared, pelvis inlet is more oval or heart shaped

• smaller or narrow angle of pubic arch ( <90^o) - acute angle

• shape of outlet is smaller

• ischial spines have more of a protrusion into pelvic inlet

female pelvis

• general shape: wider, more shallow, more flared, pelvic inlet rounder

• larger or wide angle of pubic arch (>90^o) -obtuse angle

• shape of inlet is larger

• ischial spines have less of a protrusion into pelvic inlet

sacroiliac joint

• classification: synovial

• mobility type: limited movement

• movement type: irregular gliding

symphysis pubis joint

• classification: cartilaginous

• mobility type: amphiarthrodial

• movement type: limited

union of acetabulum joint

• classification: cartilaginous

• mobility type: synarthrodial (for adults)

• movement type: nonmovable

hip joint

• classification: synovial

• mobility type: diarthrodial

• movement type: ball and socket (spherodial)

radiographic positioning considerations

• exposure factors: 80 to 90 kVp

  • consider ages — osteoporosis, etc.

• grid may be used (10cm or above)

• physical marker required

• collimation

hip localization method

• to estimate location of hip

• head is 1 ½ inches from ASIS to groin crease (right in the center of crease)

• neck is 2 ½ inches from head

anatomic position

lesser trochanters visible

external position, relaxed position

lesser trochanters in profile

true AP projection

• lesser trochanters not visible

• 15 to 20 degree internal rotation of lower legs

evidence of hip fracture

• asymmetric rotation

• affected limb with lesser trochanter in profile

shielding guidelines

male gonadal shielding

• small contact shield, top boarder at inferior margin of symphysis pubis

abdominal and pelvic shielding

female gonadal shielding

• ovarian shield for hips and proximal femora

positioning for AP (mid and distal femur)

• rotate leg 5 degrees internally for true AP

• CR perpendicular to femur and midpoint of IR; (lower IR margin should be approximately 2 inches [5cm] below knee joint or light field @ apex of patella)

evaluation criteria for AP (mid and distal femur)

• knee joint included

• distal two-thirds of distal femur

• no rotation

• optimal exposure factors

  • kVp range: 75-85

positioning for lateral (mid and distal) femur

• true lateral

• CR perpendicular to femur and midpoint of IR; (lower IR margin should be approximately 2 inches [5cm] below knee joint or light field @ apex of patella)

trauma lateromedial (mid and distal) femur

• support under affected leg/knee and support foot/ankle in true AP position

• place IR on edge against medial aspect pf thigh to include knee, with horizontal x-ray bea, directed from lateral side

evaluation criteria for lateral (mid and distal) femur

• knee joint included (minimum)

• in true lateral position, medial and lateral femoral condyles superimposed

• no rotation

• optimal exposure factors

positioning for lateral (mid to proximal) femur

• proximal femur not superimposed by opposite limb

• true lateral position

• CR perpendicular to femur and directed to midpoint of IR (top of light field at ASIS)

• suspend breathing during exposure

evaluation criteria for lateral (mid and proximal) femur

• proximal one-half to two-thirds of proximal femur, including the hip joint to be shown

• in true lateral position with superimposition of the greater and lesser trochanter by the femur exists with only a small part of the trochanters visible on medial side

  • most of greater should be superimposed by the neck of the femur

• optimal exposure factors

  • kVp range: 75-85

positioning for AP pelvis

• separate legs and feet, then internally rotate entire lower limb 15 to 20 degrees (non-trauma)

• align midsagittal plane of patient to centerline of table and CR

• CR perpendicular/center to IR, directed midway between level of ASIS and the pubic symphysis

  • approximately 2 inches [5cm] inferior to level of ASIS

• suspend breath during exposure

evaluation criteria for AP pelvis

• entire pelvis and proximal femora included

• no rotation of pelvis evidenced by symmetric appearance of the iliac alae, or wings

• lesser trochanters not visible

• optimal exposure factors

  • kVp: 80-90