Foot & Ankle Radiographical Positioning Lecture 1 PDF

Foot & Ankle Radiographical positioning Lec.1 DR.SARKAW T S.KAKAI KHCMS (ORTHO. & TRAUMA) Positioning terminology Dorsal surface: the superior surface of the foot is known as the dorsal surface and slopes downwards, at a variable angle, from the ankle to the toes and from medial to lateral Plantar a...

Foot & Ankle Radiographical positioning Lec.1 DR.SARKAW T S.KAKAI KHCMS (ORTHO. & TRAUMA) Positioning terminology Dorsal surface: the superior surface of the foot is known as the dorsal surface and slopes downwards, at a variable angle, from the ankle to the toes and from medial to lateral Plantar aspect: the inferior surface of the foot is known as the plantar aspect Medial aspect: the surface nearer the midline of the body is the medial aspect Lateral aspect: the surface further from the midline of the body is the lateral aspect Medial rotation: the lower limb is rotated inwards, so that the anterior surface faces medially. This will produce internal rotation of the hip joint Lateral rotation: the lower limb is rotated outwards, so that the anterior surface faces laterally. This will produce external rotation of the hip joint Ankle flexion: (‘dorsiflexion’) of the ankle joint occurs when the dorsal surface of the foot is moved in a superior direction Ankle extension: (‘plantar flexion’) of the ankle joint occurs when the plantar surface of the foot is moved in an inferior direction Inversion: inversion of the foot occurs when the plantar surface of the foot is turned to face medially – with the limb extended Eversion: eversion of the foot occurs when the plantar surface of the foot is turned to face laterally – with the limb extended Radiographical anatomy Radiological considerations There are numerous possible accessory ossicles around the foot and ankle, and these must not be confused with fractures. The base of the 5th metatarsal ossifies from an accessory ossification center, which is orientated parallel to the long axis of the bone. Common Radiographic Views: A. Weight-bearing views: Provide a functional assessment of the foot and ankle and are crucial for detecting weightrelated pathologies such as arthritis or fractures. 1. Anterior-Posterior (AP) weight-bearing view 2. Lateral weight-bearing view B. Non-weight-bearing views: Useful for evaluating bony anatomy and detecting certain conditions without the influence of weight. 1. Anterior-Posterior (AP) non-weight-bearing view 2. Lateral non-weight-bearing view 3. Oblique views for specific anatomical details Special Considerations: A. Pediatric patients: Adjust techniques to account for smaller anatomy and the potential need for additional care to keep young patients still during imaging. B. Trauma cases: Adapting positioning for trauma patients may be necessary to obtain diagnostic images while minimizing patient discomfort. Special Views: Mortise View: Offers a clear assessment of the ankle joint, especially the tibiofibular clear space. The patient's foot is internally rotated 15-20 degrees to visualize the mortise joint space. Oblique View: Useful for visualizing bone relationships and detecting subtle fractures. The foot is angled 45 degrees to capture this view effectively. Proximal Tibio-Fibular Joint Imaging Dr.Sarkawt S.Kakai KHCMS (Ortho. & Trauma) Photos provided by Pexels Tibia Anatomy Proximal Extremity of Tibia The proximal extremity consists of condyles, tibial tuberosity, and the tibial plateau for the articulation with the femur. Body The body, also known as the shaft, is the long portion of the tibia between the two extremities. Distal Extremity of Tibia The distal extremity ends in the medial malleolus and has a flattened, triangular bular notch for articulation with the fibula. Photos provided by Pexels Fibula Anatomy Proximal Extremity of Fibula Body Details the expansion into a head that articulates with the lateral aspect of the posteroinferior surface of the lateral condyle of the tibia. Describes the long and slender portion of the fibula between the two extremities. Distal Extremity of Fibula Highlights the enlarged distal end of the fibula, known as the lateral malleolus, and its location at the lateral aspect of the ankle joint. Photos provided by Pexels Photos provided by Pexels Antero-Posterior (AP) Tibia/Fibula Patient Positioning and Image Receptor The limb is rotated medially until the medial and lateral malleoli are equidistant from the receptor. Direction and Location of X-ray Beam The collimated beam is centred to the mid-shaft of the tibia with the central ray at right-angles to both the long axis of the tibia and an imaginary line joining the malleoli. Photos provided by Pexels Lateral Tibia/Fibula Patient Positioning and Image Receptor From the supine/seated position, the patient rotates onto the affected side. Direction and Location of X-ray Beam The collimated beam is centred to the mid-shaft of the tibia, with the central ray at right-angles to the long axis of the tibia and parallel to an imaginary line joining the malleoli. Photos provided by Pexels Photos provided by Pexels Photos provided by Pexels Lateral Oblique Projection Patient Positioning and Image Receptor The patient lies on the affected side (lateral knee position), with the knee slightly flexed. The other limb is brought forward in front of the one being examined and supported on a sandbag. The limb rotated laterally to project the joint clear of the tibial condyle (approximately 45° rotation from lateral position). Direction and Location of X-ray Beam The collimated vertical beam is centred to the head of the fibula. Photos provided by Pexels Photos provided by Pexels Antero-Posterior Oblique Projection Patient Positioning and Image Receptor The patient is either supine or seated on the X-ray table, with both legs extended The limb is rotated medially (approximately 10–20°) to project the tibial condyle clear of the joint. Direction and Location of X-ray Beam The collimated vertical beam is centred to the head of the fibula. Photos provided by Pexels Photos provided by Pexels Radiological Considerations Usefulness of Projections Although rarely requested, these projections can be useful in the initial assessment of the proximal tibio-fibula joint. Role of MRI MRI is increasingly used to evaluate the proximal tibio-fibula joint. Photos provided by Pexels Photos provided by Pexels Photos provided by Pexels Photos provided by Pexels Photos provided by Pexels Photos provided by Pexels Lec.3 Knee Joint BY Dr.Sarkawt S.Kakai KHCMS (Ortho. & Trauma) Anatomy Anatomy Basic Projections Two projections are taken routinely: an antero-posterior (AP) and a lateral. The AP projection is frequently obtained in the weightbearing/standing position as it provides more meaningful information on the condition of the joint when compared to the traditional (supine) non-weight-bearing technique. Antero-posterior – weight-bearing Position of Patient and Image Receptor The patient stands with their back against the vertical Bucky or DDR receptor. The patient’s weight is distributed equally. The knee is rotated so that the patella lies equally between the femoral condyles. Direction and Location of X-ray Beam The central ray at 90° to the long axis of the tibia Essential image characteristics The patella must be centralised over the femur. The image should include the proximal 1/3 of the tibia and fibula and distal 1/3 of the femur. Antero-posterior – supine Position of Patient and Image Receptor The patient is either supine or seated on the X-ray table or trolley, with both legs extended. The affected limb is rotated to centralise the patella between the femoral condyles, and sandbags are placed against the ankle to help maintain this position. Direction and Location of X-ray Beam The central ray at 90° to the long axis of the tibia Essential image characteristics The patella must be centralised over the femur. The image should include the proximal 1/3 of the tibia and fibula and distal 1/3 of the femur. Lateral (Basic) Position of Patient and Image Receptor The patient lies on the side to be examined, with the knee flexed at 45° or 90°. The other limb is brought forward in front of the one being examined and supported on a sandbag. Direction and Location of X-ray Beam The vertical beam is centred to the middle of the superior border of the medial tibial condyle, with the central ray at 90° to the long axis of the tibia Essential image characteristics The patella should be projected clear of the femur. The proximal tibio-fibular joint is not clearly visible. (Approximately 1/3 of the fibula head should be superimposed behind the tibia.) Skyline projections Used to 1.Assess the retro-patellar joint space for degenerative disease. 2.Determine the degree of any lateral subluxation of the patella with ligament laxity. 3.Diagnose chondromalacia patellae. 4.Confirm the presence of a vertical patella fracture in acute trauma. There are three methods of achieving the skyline projection: Supero-inferior – beam directed downwards. Conventional infero-superior. Infero-superior – patient prone Position of Patient and Image Receptor Conventional inferosuperior (Skyline) The patient sits on the X-ray table, with the knee flexed 30–45° and supported on a pad placed below the knee. The image receptor is held by the patient against the anterior distal femur Direction and Location of X-ray Beam The X-ray tube is lowered into the horizontal orientation. Avoiding the feet Essential image characteristics The retro-patellar space should be clearly seen without superimposition of the femur or tibia within the patellafemoral joint Femur Shaft Lec.4 Dr.Sarkawt S.Kakai Femur The femur is the longest and strongest bone in the body. The entire weight of the body is transferred through this bone and the associated joints at each end. Therefore, these joints are a frequent source of pathology when trauma occurs. Proximal Femur The proximal femur consists of four essential parts, the head (1), neck (2), and greater (3) and lesser trochanters (4) Basic projections Two projections are taken routinely, preferably with both the knee and hip joints included on the image. The images are acquired using a large 35 - 43 cm CR cassette or alternatively within the field of view of a DDR detector. Antero-posterior (Basic) Position of patient and image receptor The patient lies supine on the X-ray table, with both legs extended and the affected limb positioned to the centre line of the table. The affected limb is rotated to centralize the patella over the femur. Sandbags are placed below the knee to help maintain the position. Direction and location of the X-ray beam The collimated vertical beam is centered to the mid-shaft of the femur, with the central ray at 90° to an imaginary line joining both femoral condyles. Essential image characteristics Ideally, the length of the femur should be visualised, including the hip and knee joints. This may be difficult to obtain, and an additional projection of the knee or hip joint may be required if coverage is not initially achieved The patella should be centralised to indicate rotation has been minimised. Lateral (Basic) Position of patient and image receptor From the antero-posterior position, the patient rotates on to the affected side with the knee is slightly flexed and the patient adjusted so that the thigh is positioned to the centre line of the table. The pelvis is rotated backwards to separate the thighs. Pads are used to support the opposite limb behind the one being examined. Direction and location of the X-ray beam The collimated vertical beam is centered to the middle of the femoral shaft, with the central ray parallel to the imaginary line joining the femoral condyles. Essential image characteristics The length of the femur should be visualized, including the hip and knee joints. Often, an additional projection of the hip joint using a grid, may be required Notes In cases of suspected fracture, the limb must not be rotated. If both joints are not included on one image, then a single anteroposterior projection of the joint distal to the fracture site must be taken. This ensures that no fracture is missed nd allows assessment of any rotation at the fracture site. Leg alignment In adults, this technique is undertaken with the patient erect and therefore weight-bearing and is described below for both digital CR and DDR. The full-length standing radiograph in the anteroposterior (AP) projection is the basic tool for the radiologic analysis of lower limb alignment. CR method Position of patient and image receptor The patient stands on a low step, with the posterior aspect of their legs against the cassette holder. The arms are extended and supported by the side of the trunk. The legs should be, as far as possible, in a similar relationship the pelvis, the patella of each knee facing forward. Direction and location of the X-ray beam The collimated horizontal central ray is directed towards a point midway between the knee joints. DDR method Position of patient and image receptor Positioning is similar to that described for the CR method but with the patient erect and facing the X-ray tube on the dedicated patient stand. Direction and location of the X-ray beam For DDR systems using movement of the X-ray tube and DDR detector to acquire a full imaging set, with multiple exposures Notes A vertical radiopaque ruler extending the full length of the vertical platform. Lower limb Alignment Dr.Sarkawt S.Kakai KHCMS (Ortho. & Trauma) Full-Length Anteroposterior Standing Radiograph Is the basic tool for the radiologic analysis of lower limb alignment. To correctly evaluate the alignment of the lower limbs in the frontal plane, the femoral condyles must be oriented parallel to the X-ray film. This is accomplished by directing the patellae forward while keeping both knee joints in a neutral position. Anatomic axes The anatomic axes of the femur and tibia coincide with the mid-diaphyseal line of each bone. They are defined by the midpoints of two lines drawn perpendicular to the shaft. The mechanical axis The axis passes through the center point of the hip joint (center of the femoral head) and through the center point of the ankle joint. The mechanical axis should pass just medial to the center point of the knee joint. The lateral or medial mechanical axis deviation (MAD) from the center of the joint is measured in millimeters (mm). Femoral neck-shaft angle The angle between the longitudinal femoral shaft axis and the femoral head-neck axis is measured. The axis of the femoral neck is defined by a line bisecting the femoral neck through the center of the femoral head. A known normal range of 125°-135° Coxa valga: >135° Coxa vara: