Chapter 6: Toes, Foot, Ankle Flashcards
1
Q
Bones of the foot
A
- 14 Phalanges
- 5 Metatarsals
- 7 Tarsals
- 26 total
2
Q
Base of 5th metatarsal has a
A
tuberosity (common facture site)
3
Q
Talus
A
2nd largest tarsal, transmits weight
4
Q
Longitudinal Arch: Supports weight, comprised of medial and
A
Lateral plantar surface, higher on medial side
5
Q
Transverse Arch: Along the distal tarsals & TMTJ,
A
Comprised of the cuneiforms & cuboid
6
Q
Distal portions of tib/fib along with superior talus form the mortise
A
Formed by a 15-20º posterior rotation of the fibula
7
Q
Lateral view of ankle joint: Distal fibula is located approximately 1cm
A
Posterior in relation to distal tibia. Important when evaluating a “true lateral”
8
Q
Interphalangeal (IP) joints
A
Ginglymus (hinge)
9
Q
Metatarsophalangeal (MTP) joint
A
Modified ellipsoidal (condyloid)
10
Q
Tarsometatarsal & intertarsal joints:
A
Plane (gliding)
11
Q
Ankle joint
A
Saddle (sellar) dorsiflexion & plantar flexion only
12
Q
Jones fracture- occurs at the
A
base & shaft of the 5th MT (tuberosity)
13
Q
Pott fracture- complete fracture of distal fibula with major injury to ankle joint,
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Including ligament damage and frequently fractured distal tibia
14
Q
Gout- a form of arthritis in which uric acid appears in excessive
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quantities in the blood & joints (common in 1st MTP)
15
Q
Helix valgus (bunion)-bunion usually refers to the prominent medial portion of the
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First metatarsal head and especially to the bursa or a bursa plus osteophyte
16
Q
AP/AP Axial Projection- Entire Forefoot
A
- IR 8x10, 40 SID, 60-62 kVp, 1.2-2mAs
- Pt seated or supine flex knee rest plantar surface on IR
- CR perpendicular or 10-15º angle posteriorly entering 3rd MTP (CR perpendicular if 15º wedge sponge is used, or joints are not area of interest) (axial recommended when joints are of interest)
- Collimate 1” on all sides of the toes to include distal ends of metatarsals
- Anatomy: Demonstrates 14 phalanges of the toes.
- Position: Toes separated from each other. No rotation of phalanges, ST width & equal mid-shaft concavity. Open IP & MTP on axial view
17
Q
AP/AP Axial Projection-Toe
most often done AP Axial to open up joint spaces. If AP perpendicular beam is used, toes must be elevated on a 15º wedge sponge
A
- IR 8x10 portrait, 40 SID
- Pt supine or seated on table, knee flexed, plantar surface in IR. Center MTPJ of affected digit to IR.
- CR: angle 10-15º toward the calcaneus entering MTPJ in question. Collimation to all four sides, including part of the digits adjacent to one being imaged.
Include distal half of MT, unless protocol is to include all - Position: Digits should be separated with no overlapping. Long axis of foot is aligned to long axis of portion of IR being exposed. No rotation demonstrated by equal concavity of phalanges & distal MT. If rotation occurs, side with concavity represents elevated side. Open IP & MTP joints without distortion
- No motion: sharp cortical margins, boney trabecular detail, soft tissue structures
*Increasing flexion of knee can help a patient apply plantar surface flat on IR - Post annotation of digit imaged on radiograph
18
Q
AP Oblique Projection-Toes(Medial or Lateral Rotation)
A
- IR 8x10 portrait (landscape for multiple exposures), 40 SID, 50-55 kVp
- Pt supine or sitting on table, plantar surface on IR, align long axis of digit to long axis of CR & IR. Center MTP of digit in question to CR. Rotate leg 30-45º medially for 1st-3rd digits. 30-45º laterally for digits 4 & 5. Use 45º sponge for support if necessary.
- CR perpendicular to MTP in question. Collimate on all four sides to include adjacent digits and distal portion of MT of affected digit
- Anatomy: Distal portion of MT & digit without overlap. Long axis of foot aligned with long axis of IR being exposed
- Position: Correct obliquity evident by increased concavity on one side of shafts (elevated side) and by overlapping of ST of digits. Heads of MT should appear directly side by side with minimal to no overlap
- No motion by sharply defined cortical margins of bone and boney trabecular detail
19
Q
Lateral Projections-Toes(Mediolateral & Lateromedial)
Lateromedial for digits 1-3,
Mediolateral for digits 4-5
A
- IR 8x10 portrait (landscape for more than one image), 40 SID, 50-55 kVp
- Pt supine or seated. Rotate affected leg and foot. Adjust IR to center and align long axis of affected toe to CR & long axis of IR being exposed. Use tape/gauze, or tongue depressor to separate & flex unaffected toes to prevent superimposition.
- CR perpendicular directed to IPJ of 1st digit & PIP for digits 2-5
- Anatomy: Phalanges of affected digit seen laterally and free of superimposition of other digits if possible. Minimum of distal phalanx
- Position: True lateral of digit demonstrated increased concavity along the anterior surface of distal phalanx & posterior surface of proximal phalanx.
- No motion evident by sharply defined cortical edges and ST bony trabecular detail
Lateromedial for digits 1-3,
Mediolateral for digits 4-5
20
Q
Tangential Projection-Toes(Sesamoid)
A
- IR 8x10 portrait, 40 SID, 50-55 kVp
- Lateral 1st digit in dorsiflexion may be used to demonstrate sesamoids. Place Pt prone, dorsiflex affected foot so the plantar surface of the foot forms a 15-20º angle from vertical.
Dorsiflex 1st digit and rest on IR to maintain position. Ensure long axis of foot is not rotated. Supine, dorsiflex foot, rest heel on IR, use support to hold foot in dorsiflexion (less desirable due to OID). - CR perpendicular to IR, directed tangentially to posterior aspect of 1st MTPJ (slight tube angle may be needed if patient is unable to fully dorsiflex). Collimate to 1-3rd distal MT.
- Anatomy: Sesamoids should be seen in profile free of superimposition. A minimum of the 1st 3 MT seen in profile, indicating correct dorsiflexion of foot. Collimation field at the posterior portion of the first MTP joint.
- Positioning: Centering & CR angle are correct if sesamoids are free of bony superimposition & open joint space between sesamoids and 1st MT
- No rotation. No motion evidenced by sharp bony cortical margins, bony trabecular detail & ST (contrast & brightness) without sesamoids appearing overexposed
21
Q
AP Axial Projection- Foot(Dorsoplantar Projection)
Clinical indications for foot: location and extent of fractures & fragment alignments, joint space abnormalities, ST effusions, location of FB.
A
- IR 10x17 portrait( may need 14x17 if large foot or bilateral), 40 SID.
- Pt supine or sitting. Extend (plantar flex) foot, place plantar surface flat on IR. Align and center long axis of foot to CR & long axis of IR. Use sandbags if necessary to prevent slipping.
- CR angled 10º posteriorly directed to base of 3rd MT (15º for upright). Collimate to outer margins of foot on 4 sides (about 1” field light).
- Anatomy: Entire foot demonstrated including all phalanges & MT, navicular, cuneiforms & cuboid. No rotation evidenced by nearly equal distance between 2nd-5th MT.
- Position: Bases of 1st & 2nd are usually separated, bases of 2nd-5th MT are overlapping. Intertarsal joint space between 1st & 2nd cuneiforms demonstrated (open).
- No motion, sharp borders and trabecular markings of distal phalanges and tarsals distal to talus. Sesamoid bones visualized through head of 1st MT
22
Q
AP Oblique Projection-Foot(Medial & Lateral Rotation)
A
- IR 10x12 portrait, 40 SID, 60-65 kVp
- Pt supine or sitting, flex knee with plantar surface on table with body turned slightly away from side of injury. Align and center ling axis of foot to CR & long axis of IR. Rotate foot medially to place plantar surface 30-40º to plane of IR. The general plane of the dorsal surface of foot should be parallel to IR & perpendicular to CR. Use sandbags or sponge for support if necessary
- CR perpendicular to 3rd MT base. Collimate to outer margins of ST on 4 sides (approx. 1” each side)
Medial oblique: - Anatomy: Entire foot demonstrated from distal phalanges to posterior calcaneus & proximal talus.
- Position: Long axis of foot should be aligned to long axis of IR. Correct obliquity demonstrated when 3rd-5th MT’s free of superimposition. 1st & 2nd MT bases superimposed only at bases. 5th MT tuberosity seen in profile and well visualized. Joint spaces around cuboid and sinus tarsi open.
- Optimal density (brightness), no motion, visualize sharp borders and trabecular markings of phalanges, MT, tarsals.
Lateral oblique (less common):
30º obliquity demonstrated the space between the 1st & 2nd MT’s and between 1st and 2nd cuneiforms. Navicular well visualized. - Weight bearing oblique’s require at 30º tube angulation from lateral foot towards medial, entering 3rd MT base.
23
Q
Lateral Projections-Foot(Mediolateral & Lateromedial)
A
- IR 10x12 portrait, 40 SID, 60-65 kVp (14x17 may be used if patient’s foot is large)
- Place patient in lateral recumbent position (left lateral recumbent for left mediolateral projection). Flex knee of affected limb about 45º, place opposite leg behind affected leg to prevent over-rotation. Dorsiflex foot to assist in positioning for a true lateral foot and ankle. Place leg and knee support so plantar surface is perpendicular to IR. (do not over-rotate). Align long axis of foot to long axis of IR center base of MT’s to IR.
- CR perpendicular to medial cuneiform (at level of 3rd MT base). Collimate to skin margins & 1” proximal to ankle joint (approx. 1” all sides).
- Anatomy: Entire foot aligned to the long axis of IR with 1” of distal tib/fib. Heads of MT superimposed with 5th MT tuberosity in profile
- Position: True lateral position shown when tibiotalar joint is open, distal fibula is superimposed by posterior tibia. Distal MT are superimposed (metatarsal heads)
- Optimal contrast and brightness, no motion. Lateromedial projection may be used if easier to obtain a true lateral position)
24
Q
Weight-Bearing Projections-Foot(AP/Oblique/Lateral)
A
- IR 10x12, or 14x17 (bilateral), 40 SID
AP axial- - Place patient erect with full weight evenly distributed on both feet. Feet directed straight ahead and parallel with each other
- CR angle 15º posteriorly to the midpoint between feet at level of the 3rd MT bases. (bilat.)
- Anatomy: Bilateral feet from ST surroundings of phalanges to distal talus.
- Position: Proper angulation is demonstrated by open TMTJ spaces and visualization of joint between 1st and 2nd cuneiforms. MT bases at center of CR with 4 sided collimation.
- Optimal brightness and density ST and bony borders of superimposed tarsals and MT, adequate penetration of midfoot region. ST bony trabecular details
Lateral Weight bearing Lateromedial to demonstrate longitudinal arch. - Have patient stand with affected foot lateral side to touch IR (IR size 14x17 crosswise) or 10x12 x-wise. Mediolateral projection.
- Stand on step stool or wood blocks and bear weight, make sure standing devise is higher than IR on bottom.
- CR through base of third MT ( medial cuneiform)
- Position: Distal fibula superimposed over posterior half of distal tibia, plantar surfaces of MT heads superimposed to demo no rotation. Longitudinal arch demonstrated in entirety.
4 sided collimation to include all ST and 1” of distal tib/fib. - Optimal density and contrast. No motion
25
Q
Plantodorsal (Axial) Projection(Calcaneus)
A
- IR 8x10 Portrait, 40 SID, 65-70 kVp
- Pt seated or supine with leg fully extended. Center and align ankle joint to CR and portion of IR being exposed. Dorsiflex foot so plantar surface is near perpendicular to IR.
- CR angle 40º cephalic to long axis of foot entering base of third MT exiting at level distal to lateral malleolus. Collimate close to region of calcaneus (increase angulation if plantar surface is not parallel to long axis of IR- closer to horizontal beam).
- Anatomy: Entire calcaneus visualized from tuberosity posteriorly to talocalcaneal joint anteriorly
- Position: No rotation demonstrated by portion of sustentaculum tali appearing medially in profile with proper 90º flexion, correct alignment and angulation of CR are evidenced by open talocalcaneal joint space- aka subtalar joint. No distortion of calcaneal tuberosity. Adequate elongation of the calcaneus.
- Contrast and density adequate through visualized talocalcaneal joint without overexposure of tuberosity
26
Q
Lateral Projection-Calcaneus(Mediolateral)
A
- IR 8x10 portrait, 40 SID, 65-75 kVp
- Pt in seated or lateral recumbent position ( rt. lateral recumbent for rt. side eval.) Place uninjured leg behind injured. Center calcaneus to CR and IR with long axis of foot parallel to plane of IR. Support knee and leg as needed to place plantar surface parallel to IR. Position ankle and foot for a true lateral, which places the lateral malleolus about 1cm posterior to posterior tibia. Dorsiflex foot so plantar surface is at a right angle to leg
- CR perpendicular to IR, directed to a point 1” inferior to medial malleolus. Collimate to include distal ankle joint and all of calcaneus.
- Anatomy: Calcaneus demonstrated in profile with talus and distal tib/fib demonstrated superiorly and navicular and open talocalcaneal joint
- Position: Lateral malleolus superimposed over distal tibia and talus. Sinus tarsi and calcaneocuboidal joint space open. Collimation should include ankle joint proximally and talonavicular joint & base of 5th MT
- Optimal contrast and density. No motion.
27
Q
AP Projection- Ankle
A
- IR 10x12 IR landscape, 40 SID, 60-70 kVp
- Pt seated or supine, legs fully extended. Center ankle joint to CR and long axis of IR. DO NOT FORCE dorsiflexion, remain in natural position. Adjust foot and ankle to true AP projection, (ensure lower leg is not rotated). Intermalleolar line should not be parallel
- CR enters perpendicular to midpoint between malleoli. Collimate to lateral ST margins and include prox. MT and distal tib/fib
- Anatomy: Distal 1/3rd of tib/fib, lateral and medial malleoli , talus, and prox. half of MT demonstrated.
- Position: Long axis of leg should be aligned to collimation field and to IR. No rotation if the medial mortise joint is open and lateral is closed. Some superimposition of the distal fib by the distal tibia & talus exists. (tibia should be superimposing ½ of distal fibula) fibulotalar joint closed.
- Optimal exposure (talus must be penetrated). No motion
28
Q
AP Mortise Projection- Ankle(15-20 Degree Medial Rotation)
A
- IR 10x12 portrait, 40 SID, 60-70 kVp
- Place pt supine or seated with leg extended. Center and align ankle with CR and IR. Do not dorsiflex unless protocol of site or DR. preference. Internally rotate entire leg and foot about 15-20º until intermalleolar line is parallel with IR.
- CR perpendicular to IR midway between malleoli. Collimate to lateral ST and include distal tib/fib and prox. ½ MT
- Anatomy: Distal 1/3rd of tib/fib, tibial plafond involving the epiphysis if present, med and lat. malleoli, talus, prox. MT demonstrated
- Position: Entire ankle mortise should be open and well visualized. Proper obliquity demonstrated by open lateral and medial joint with malleoli in profile. Minimal superimposition of tibiofibular joint (anterior tubercle) (1/4th superimposition)
- No motion. Optimal exposure
29
Q
AP Oblique Projection- Ankle(45 Degree Medial Rotation)
A
Less common projection than mortise, may be used to demonstrate fx. of 5th MT tuberosity.
- Same pt positioning. Allow dorsiflexion if patients condition allows. If 5th MT is of interest, do not have patient dorsiflex. Plantar surface is 80-85º from IR. Rotate leg and foot medially 45º
- CR midway between malleoli. Collimate to ST, tib/fib MT
- Anatomy: 45º oblique demonstrates distal tibiofibular joint open, with no or minimal overlap
- Position: Lateral malleolus and talus joint should show no or slight superimposition. Medial malleolus and talus are partially superimposed. Ankle joint centered to CR and IR
- ST, MT, tib/fib included
30
Q
Lateral Projection- Ankle(Mediolateral or Lateromedial)
A
- IR 10x12 IR portrait, 40 SID, 60-70 kVp
- Center and align ankle with CR and IR (long axis). Place support under knee for true lateral. Dorsiflex foot so plantar surface is at a right angle to leg (or as much as patient can)
- CR perpendicular to medial malleolus (0.5” superior to lateral malleolus for lateromedial). Collimate to include distal tib/fib and mid MT area (include 5th MT tuberosity)
- Anatomy: Distal 1/3rd of tib/fib with distal fibula superimposed over posterior half of tibia. Tuberosity of 5th MT, navicular and cuboid well visualized
- Position: No rotation evidenced by distal fib over post tib. Tibiotalar joint open with uniform joint space. Superimposition of talar domes. Include distal 1/3rd of lower leg, calcaneus, tuberosity of 5th and ST
- No motion. Optimal exposure
31
Q
AP Stress Projections- Ankle(Inversion and Eversion positions)
A
- Dorsiflex foot, keep ankle in AP. Rotate inwards for inversion. Rotate outwards for eversion
- Anatomy: Ankle joint for evaluation of joint separation & ligament damage.
- Appearance of joint space may vary greatly depending on severity of ligament damage
