The document provides an overview of radiography of the lower limb, including positioning considerations and common pathologies. It describes the bones of the foot, leg, and femur in detail. Key points include dividing the foot into phalanges, metatarsals, and tarsals; describing joints like the subtalar and ankle; reviewing arches of the foot; and listing 18 common pathologies like fractures, osteoarthritis, and osteosarcomas along with their typical radiographic presentations.

1. Part I
Radiography of Lower Limb

2. Lower Limb
 Foot
 Leg – tibia & fibula
 Femur (distal and mid)

3. Foot
 Divided into three groups
1. Phalanges (toes/or digits) 14
2. Metatarsals (instep) 5
3. Tarsals 7
Total 26

4. Phalanges – Toes (Digits) and
Metatarsals

5. Joints

6. Tarsals
1. Calcaneus (os calcis)
2. Talus (astragalus)
3. Cuboid
4. Navicular (scaphoid)
5. 1st, 2nd, and 3rd cuneiforms

7. Calcaneus (Os Calcis)
 The largest and strongest bone in the
foot
 The posterior portion often called the
heel bone
 Inferoposteriorly it has a rough striated
process called tuberosity
 Tuberosity has two small rounded
processes at its widest points called the
lateral process (smallest) and medial
process (largest)

8. Calcaneus (Os Calcis)
 Articulations
 Articulate with two bones
 The cuboid anteriorly
 The talus superiorly
 Forms the subtalar (talocalcaneal) joint
 Three articulation facets
o Posterior articular facet (largest)
o Middle articular facet: it is the upper
portion of the sustentaculum tali
o Anterior articulation facet
 Calncaneal sulcus: a deep depression
b/w posterior and middle articular facets
which forms the sinus tarsi (tarsal
sinus) when combined with similar
depression of the talus

9. Talus (Astragalus)
 2nd largest tarsal bone
 Articulations
 Articulates with four bones
 Tibia and fibula superiorly
 Calcaneus inferiorly
 Navicular anrteriorly

10. Navicular (Scaphoid)
 Flattened oval-shaped
 Articulations
 Articulates with four bones
 Talus posteriorly
 Three cuneiforms anteriorly

11. Cuneiforms
 Wedge-shaped
 Three bones
1. Medial: largest
2. Intermediate: smallest
3. Lateral
 Articulations
 Medial cuneiform
 Articulated with four bones: navicualr
proximally; 1st and 2nd metatarsals distally;
Intermediate cuneiform laterally
 Intermediate cuneiform
 Articulates with four bones: avicular
proximally; 2nd metatarsal distally; medial
and lateral cuneiforms on each side
 Lateral cuneiform
 Articulates with six bones: navicular
proximally; 2nd, 3rd, and 4th metatarsals
distally; intermediate cunefirom medially;
cuboid laterally

12. Cuboid
 Articulations
 Articulates with four bones
 Calcaneus proximally
 Lateral cuneiform and navicular
(occasionally) medially
 Fourth and fifth metatarsals distally

13. Arches
 Two arches to provide a strong,
shock-absorbing support for body
weight
1. Longitudinal arch
 Springy
 Composes
 Medial component: cal., tal., nav., 1st
cun., and 1st MT
 Lateral component: cal., tal., and
cub.
 Most of the arch on the medial and
midaspects of the foot
2. Transverse arch
 Located primarily along the plantar
surface of the distal tarsals and the

14. Ankle Joint
 Formed by three bones: tibia, fibula, and talus
 Frontal view
 The inferior portions of the tibia and fibula
form a deep “socket” or thee-sided opening
called a mortise into which the upper talus
fits
 The entire three-part joint space of the ankle
mortise is not seen in a true AP projection b/c
of the overlapping of portions of the distal
fibula and tibia by talus. This caused by the
more posterior position of the distal fibula
 A 15o internally rotated AP projection, called
mortise position, is used to visualize this
mortise joint that should have an even space
over the entire talar surface
 The distal tibial surface forming the roof of
the ankle mortise joint is called the tibial
plafond (ceiling) (potential site of fx)

15. Ankle Joint
 Lateral view
 True lateral view shows that
the lateral malleolus is ~1 cm
posterior in relationship to the
medial malleolus

16. Ankle Joint
Axial view

17. Exercise
A
B
C
D

18. Leg – Tibia and Fibula

19. Femur (Distal and Mid)
 Anterior view

20. Femur (Distal and Mid)
 Posterior view

21. Femur (Distal and Mid)
 Lateral view

22. Femur (Distal and Mid)
 Axial view

23. Patella

24. Knee Joint
 Major knee ligaments

25. Knee Joint
 Menisci (articular disks)

26. Exercise
A B
C D
E
F

27. Radiographic Positioning
 Positioning considerations
 Radiographic examinations of lower limb below the
knee are generally done on a tabletop
 Distance = 100 cm
 Gonadal shielding
 Use lead vinyl-covered shield
 Shift the unused Bucky tray away from the field of x-ray to avoid
scattering
 Collimation
 Collimation borders should be visible on all four sides if the IR is
large enough too allow this without cutting off essential anatomy

28. Positioning Considerations
 General positioning
 Always place the long axis of the part being
radiographed // to the long axis of the IR
 If more than on projection is taken on the same
IR, the part should be // to the long axis of the
part of the IR being used
 All body parts should be oriented in the same
direction
 Exception: for leg radiograph in adults, the limb
should be oriented diagonally to include knee
and ankle joints
 Correct centering
 In general, the par t being radiographed should
be // to the plane of the IR
o

29. Positioning Considerations
 Exposure factors
 Lower-to-medium kV (50-70)
 Short exposure time
 Small FS
 Adequate mAs for sufficient density
 Optional technique for foot: an increase to 70-75 kV with
accompanying decrease in mAs will decrease contrast to result in a
more uniform exposure density b/w the phalanges and the tarsals
 Imaging receptors
 Detail screen in used with or without grid depending on part
thickness

30. Positioning Considerations
 Pediatric patients
 Patient motion should be restricted
 Use immobilization device such as sponge, tape, or sand bags
 Ask family for help  ensure protection for help
 Speak to child in a soothing manner and with language the child can
readily understand to ensure maximal cooperation
 Geriatric patients
 Provide clear and complete instructions
 Routine examination might be altered to accommodate the older
patient’s physical condition
 Use adequate immobilization device
 Exposure factors may need to be reduced

31. Positioning Considerations
 Placing of markers and patient ID information
 Always place it in the location least likely to
superimpose anatomy of interest for that projection
 Increase exposure with cast
TYPE OF CAST INCREASE IN EXPOSURE
Small to medium plaster cast Increase mAs 50%-60% or +5-7 kV
Large plaster cast Increase mAs 100% or +8-10 kV
Fiberglass cast Increase mAs 25%-30% or +3-4 kV

32. Positioning Considerations
 Digital imaging considerations:
1. Collimation: insures optimal quality
2. 30% rule: at least 30% of the IP should be exposed to ensure accurate exposure
index (or “S” number)
3. Lead masking: for multiple projections
4. Accurate centering: as in the FSR
5. Grid use with DR: acceptable
6. Evaluation of exposure index value: to verify that the exposure factors used were
in the correct range to ensure an optimum quality image with the least possible
radiation dose to the patient
7. Exposure factors:
 Wide exposure latitude
 Consider the ALARA principle: use highest possible kVp with lowest possible mAs
 Generally 60 kVp is the lowest factor used for any CR or DR procedures

33. Pathologic Indications
1. Bone cyst
 Benign neoplastic bone lesion filled
with clear fluid
 Most often occur near the knee joint
in children and adolescents
 Generally not detected on
radiographs until a pathologic fx
occurs
 When detected on radiograph they
appear as lucent areas with a thin
cortex and sharp boundaries
 Most common radiographic exam: AP
& lateral of affected limb
 Possible radiographic appearance:
well-circumscribed lucency

34. Pathologic Indications – cont’d
2. Chondromalacia patellae (runner’s
knee)
 Softening of the cartilage under the
patella → wearing of cartilage, pain, and
tenderness
 Cyclists and runners are vulnerable to
this condition
 Most common radiographic exam: AP &
lateral knee, tangential (axial) of
femoropatellar joint
 Possible radiographic appearance:
pathology of femoropatellar joint space,
possible misalignment of patella

35. Pathologic Indications – cont’d
3. Chondrosarcomas
 Most common radiographic exam: AP & lateral of affected limb, CT, MRI
 Possible radiographic appearance: bone destruction with calcification in the cartilaginous
tumor
4. Encondromas:
 Most common radiographic exam: AP & lateral of affected limb
 Possible radiographic appearance: well-defined radiolucent tumor with thin cortex (often
result in pathologic fx with minimal trauma)
5. Ewing’s sarcoma
 Most common radiographic exam: AP & lateral of affected limb, CT, MRI
 Possible radiographic appearance: ill-defined are of bone destruction with surrounding
“onion peel” (layers of periosteal reaction)
6. Exostosis (osteochondroma)
 Most common radiographic exam: AP & lateral of affected limb
 Possible radiographic appearance: a projection of bone with cartilaginous cap; grows //
to shaft and away from nearest joint
7. Fractures

36. Pathologic Indications – cont’d
8. Gout
 Form of arthritis that my be hereditary
 Uric acid appears in excessive quantities in
the blood and may be deposited in the joints
and other tissues
 Common initial attacks occur in the 1st MTPJ
of the foot
 Later attacks may also occur in other joints
such as the 1st MCPJ of the hand, but
generally these are not seen
radiographically until more advanced
conditions develop
 Most cases occur in men, and first attacks
rarely occur before age 30
 Most common radiographic exam: AP (obl.)
& lateral of affected part (most common
initially in MTPJ of foot)
 Possible radiographic appearance: uric acid

37. Pathologic Indications – cont’d
9. Joint effusion
10. Multiple myeloma
 Most common radiographic exam: AP & lateral
of affected part
 Possible radiographic appearance: multiple
“punched-out” osteolyte lesions throughout
affected bone
11. Osgood Schlatter disease
 Inflammation of the bone and cartilage involving
the anterior proximal tibia
 Most common in boys ages 10-15
 Cause: an injury that occurs when the large
patellar tendon detaches part of the tibial
tuberosity to which it is attached
 Most common radiographic exam: AP & lateral

38. Pathologic Indications – cont’d
12. Osteoarthritis
 Most common radiographic exam: AP, obl. &
lateral of affected part
 Possible radiographic appearance:
narrowed, irregular joint spaces with
sclerotic articular surfaces and spurs
 Exposure factor adjustment: advanced stage
may require slight decrease (-)
13. Osteoclastomas (giant cell tumors)
 Benign bone lesions
 Occur in long bones of young adults
 Usually occur in the proximal tibia or distal
femur after epiphyseal closure
 Most common radiographic exam: AP &
lateral of affected part, CT, MRI
 Possible radiographic appearance: large

39. Pathologic Indications – cont’d
14. Osteogenic sarcomas (osteosracomas)
 Most common radiographic exam: AP & lateral
of affected part, CT, MRI
 Possible radiographic appearance: excessively
destructive lesion with irregular periosteal
reaction; classic appearance is sunburst pattern
that is diffuse periosteal reaction
15. Osteoid osteomas
 Benign bone lesions
 Usually occurs in teenagers or young adults
 Symptoms include localized pain that typically
worsens at knight but is relieved by over-the-
counter anti-inflammatory or pain medications
 The tibia and the femur are the most likely sites
of these lesions
 Most common radiographic exam: AP & lateral
of affected part
 Possible radiographic appearance: small,
round-oval density with lucent center

40. Pathologic Indications – cont’d
16. Osteomalacia (rickets)
 Means bone softening
 Caused by lack of bone mineralization b/c of the deficiency
in calcium, phosphorous, and/or vit. D in the diet or an
inability to absorb these minerals
 Bowing of the weight-bearing parts often results
 In children, this defect is known as rickets and more
commonly results in bowing of the tibia
 Most common radiographic exam: AP & lateral of affected
limb
 Possible radiographic appearance: decreased bone
density, bowing deformity in weight-bearing limbs
 Exposure factor adjustment: loss of bone matrix requires
decrease (-)
17. Paget’s disease (osteitis deformas)
 Most common radiographic exam: AP & lateral of affected
part/s
 Possible radiographic appearance: mixed areas of
sclerotic and cortical thickening and lytic or radiolucent

41. Pathologic Indications – cont’d
18. Reiter syndrome
 Affects the sacroiliac joint and lower
limbs of the young men
 Includes bilateral attack, arthritis,
urithritis, and conjunctivitis
 Caused by a previous infection of the
GIT, such as salmonella, or by a
sexually transmitted infection
 Most common radiographic exam: AP
& lateral of affected part
 Radiographic appearance: specific
area of bony erosion at the Achilles
tendon insertion on the
posterosupoerior margins of the