Radiographic Positioning of the Knee Patella Views (2022)

Radiographic Positioning of the Knee Patella Views (1)

This article for the Radiologic Technologist (X-Ray Tech) discusses radiographic positioning of the knee for patella views.

Patella PA

Purpose and Structures Shown To show the patella in PA projection. This view shows greater detail in the patella due to the decreased OID (object to image receptor distance).

Radiographic Positioning of the Knee Patella Views (2)

Position of patient Prone position with the legs extended. Place one sandbag under the thigh and another under the leg to relieve pressure on the patella, if needed.

Radiographic Positioning of the Knee Patella Views (3)

Position of part Center the IR to the patella. Adjust the leg so that the patella is parallel with the plane of the IR. This usually requires the heel to be rotated 5 to 10 degrees laterally.

Central ray Perpendicular to the IR and the midpopliteal area, exiting at the patella. Collimate closely to the patellar area.

Technical factors Visualization of soft tissues and sharp trabecular markings in the distal femur as well as a clear outline of the patella indicate optimal exposure without motion. Adequate penetration is necessary to see the patella through the superimposing femur. No rotation should be present.

Patella Lateral

Purpose and Structures Shown Patella in lateral profile and patellofemoral joint space.

Radiographic Positioning of the Knee Patella Views (4)

Position of patientLateral recumbent position.

Radiographic Positioning of the Knee Patella Views (5) Radiographic Positioning of the Knee Patella Views (6)

Position of part Ask the patient to turn onto the affected hip. A sandbag may be placed under the ankle for support. Flex the affected knee about 5-10 degrees. Increasing flexion reduces the patellofemoral joint space. Femoral epicondyles should be perpendicular to the IR.

Central ray Perpendicular to the IR, entering the knee at the patella. Collimate closely to the patellar area.

Insall-Salvati RatioThis is a ratio that is used to evaluate the position of the patella. It is the ratio of the longest diagonal length of the patella to the length of the patellar tendon on a lateral radiograph. This measurement is relatively independent of the degree of knee flexion. A ratio of less than 0.8 is indicative of patella alta (high-riding patella).

(Video) How to perform Patella X-ray procedure (Tangential sunrise view)

Insall-Salvati ratio patella

Radiographic Positioning of the Knee Patella Views (7)

Insall-Salvati ratio measurement to assess the position of the patella.

Patella PA Oblique Lateral Rotation

Purpose and Structures Shown Medial margin of the patella superimposed over the femur and also the lateral aspect of patella free of the femur.

Radiographic Positioning of the Knee Patella Views (8)

Position of patientProne position.

Radiographic Positioning of the Knee Patella Views (9)

Position of part Flex the knee 5-10 degrees. Externally (laterally) rotate the knee 45 -55 degrees from prone position.

Central ray Perpendicular to the IR, exiting the palpated patella. When the patella is being imaged, collimation should be to the mid-knee area.

Patella PA Oblique Medial Rotation

Purpose and Structures ShownMajority of the medial patella without the femur.

Radiographic Positioning of the Knee Patella Views (10)

Position of patientProne position.

Radiographic Positioning of the Knee Patella Views (11)

Position of part Flex the patient’s knee about 5-10 degrees. Medially rotate the knee 45-55 degrees from the prone position.

Central ray Perpendicular to the IR, exiting the palpated patella. Collimate closely to the patellar area.

(Video) Skyline view knee/patella (Ep-41) | knee joint skyline view | patella skyline view

Patella PA Axial Oblique Kuchendorf Method

Purpose and Structures Shown Majority of the patella is seen free of superimposition by the femur. This projection is more comfortable for patients with an injured patella as it does not place any pressure on the patella.

Radiographic Positioning of the Knee Patella Views (12)

Position of patient Prone position. Elevate the hip on the affected side by 2 or 3 inches. Place a sandbag under the ankle and foot. Adjust it so that the knee is slightly flexed (approximately 10 degrees) to relax the muscles.

Radiographic Positioning of the Knee Patella Views (13)

Position of part Center the IR to the patella. Laterally rotate the knee about 35-40 degrees from the prone position, which is more comfortable than the direct prone position. Place your index finger against the medial border of patella and press it laterally. Rest the knee on its anteromedial side to hold the patella in a position of lateral displacement.

Central ray Directed to the joint space between the patella and femoral condyles at an angle of 25-30 degrees caudad, entering the posterior surface of the patella.

Patella Tangential Projection Hughston Method

Purpose and Structures Shown Femoral condyles. This projection demonstrates subluxation of the patella and patellar fractures.

Position of patient Prone position with the foot resting on the table.

Radiographic Positioning of the Knee Patella Views (14)

Position of part Place the IR under the patient’s knee. Slowly flex the affected knee so that the tibia and fibula form a 50 to 60 degrees angle from the table. Rest the foot against the collimator or support it in position.

Radiographic Positioning of the Knee Patella Views (15)

Central ray Angled 45 degrees cephalad and inferior and directed through the patellofemoral joint.

Patella Tangential Projection Merchant Method

Purpose and Structures Shown Axial projection of the patellae and patellofemoral joints, seen as slightly magnified images.

Radiographic Positioning of the Knee Patella Views (16)

Position of patient Supine with both knees at the end of table. Support the knees and lower legs with an adjustable IR-holding device. Place pillows or a foam wedge under the patient’s head and back for comfort and to relax the quadriceps femoris.

Radiographic Positioning of the Knee Patella Views (17)

Position of part Using the “axial viewer” device, raise the patient’s knees about 2 inches to place the femur parallel with the tabletop. Adjust the angle of knee flexion to 40-45 degrees. Strap both legs together at calf level to control leg rotation and allow the patient to relax. Place the IR perpendicular to the CR and resting on the patient’s shins about 1 foot distal to the patellae. Ensure that the patient is relaxed. Relaxation of quadriceps femoris is significant for accurate diagnosis. If not relaxed, a subluxed patella may be pulled back into intercondylar sulcus, which will result in a false normal appearance. Record the angle of knee flexion for reproducibility during follow-up examinations.

(Video) Knee X-ray Positioning

Central ray Perpendicular to the IR. The beam is directed caudal and inferior. With 45 degrees knee flexion, angle the CR 30 degrees caudal from the horizontal plane (60 degrees from the vertical) to achieve a 30 degrees CR-to-femur angle. CR enters midway between patellae at the level of the patellofemoral joint.

Radiographic Positioning of the Knee Patella Views (18)

Patella Tangential Projection Settegast Method (Sunrise View)

Purpose and Structures Shown Provides information about the patella and patellofemoral articulation. It is an alternative method to obtain an axial image of the patella. A common technique is the inferosuperior projection. This projection involves acute flexion of the knee and should not be attempted until patellar fracture has been ruled out by other views.

Radiographic Positioning of the Knee Patella Views (19)

Position of patient Supine or prone (prone is preferred because the knee can usually be flexed to a greater degree and immobilization is easier). In the prone position the IR is placed under the knee and the knee is flexed 115 degrees from the horizontal axis.

Radiographic Positioning of the Knee Patella Views (20)
Radiographic Positioning of the Knee Patella Views (21)

If the patient is seated on the radiographic table, the patient must hold the IR securely in place behind the knee. In the supine position, the patient’s knee is flexed 40-45 degrees with a knee support in place.

Radiographic Positioning of the Knee Patella Views (22)
Radiographic Positioning of the Knee Patella Views (23)

Position of part Flex the patient’s knee slowly as much as possible or until the patella is perpendicular to the IR (if the patient’s condition permits). With slow, even flexion, patient the will be able to tolerate the position, whereas quick, uneven flexion may cause excessive pain. Loop a long strip of bandage around the patient’s ankle or foot if desired. Have the patient grasp the ends of the string over the shoulder to hold the leg in position. Gently adjust the leg so that its long axis is vertical.

Central ray Perpendicular to the joint space between the patella and the femoral condyles when the joint is perpendicular. If not, degree of CR angulation depends on degree of flexion of the knee. The angulation typically will be 15 to 20 degrees from the lower leg. Close collimation is recommended.

Radiographic Positioning of the Knee Patella Views (24)

Patella Skyline Laurin View

Purpose and Structures Shown This is an inferosuperior axial projection of the patella which is visualized free from superimposition by any bony structure. The patellofemoral joint is clearly seen. The skyline projection demonstrates fractures on the lateral aspect of the patella that may be missed on other views.

Skyline Laurin Patella

Radiographic Positioning of the Knee Patella Views (25)

Radiographic Positioning of the Knee Patella Views (26)

Position of patient Semi-recumbent on the examination table with a pillow or cushion behind the back to enable the patient to maintain the position. The patient holds the IR superior to the patella in landscape orientation. The position of the patient should be as close to the end of the table as possible.

Radiographic Positioning of the Knee Patella Views (27)

Position of part The knee is flexed 20-30 degrees. Ensure the patient’s feet are out of the primary beam.

Malpositioned Skyline Patella

(Video) SKYLINE VIEW (PATELLO-FEMORAL JOINT), ANATOMY & PHYSIOLOGY PART - 72

Radiographic Positioning of the Knee Patella Views (28)

Central rayThe beam is directed cephalad and superior, 160 degrees from the vertical axis or 30 degrees from the horizontal axis. The X-rays pass inferior to superior through the patella. The tube will need to be below the level of the table.

Suggested Reading

Radiography of the leg and knee: An overview of anatomy and pathology

Radiographic positioning of the leg

Radiographic positioning of the knee in AP views

Radiographic positioning of the knee in PA views

Radiographic positioning of the knee in lateral views

RLKA

Read more about this and other subjects and get 2 Category A ARRT CE Credits in the X-Ray CE Course “Radiography of the Leg, Knee, and Ankle”

Radiographic Positioning of the Knee Patella Views (29)

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Visit here to more about knee patella projections.

FAQs

What is the normal position of the patella? ›

The literature indicates that the normal patella is positioned laterally relative to the trochlea when the knee is fully extended. As such, a laterally positioned patella on MRI is often interpreted as normal.

What is skyline view of patella? ›

The knee skyline Laurin view is an inferior-superior projection of the patella. It is one of many different methods to obtain an axial projection of the patella.

What is the position of the patella to the IR? ›

Patella will be perpendicular to plane of the IR. For new or unhealed patellar fractures; knee should usually not be flexed more than 10 degrees. Check with your medical director. Knee flexion of 20 to 30 degrees is usually preferred – this position relaxes muscles and shows maximum volume of the joint cavity.

Where the patella should be positioned on the knee for the AP projection? ›

The femoral and tibial condyles should be symmetrical, the head of the fibula is slightly superimposed bit the lateral tibial condyle. The patella is resting on the superior portion of the image superimposing the distal femur.

What is sunrise view of knee? ›

View sunrise view. This is called the sunrise view because the patella appears to be rising over the horizon. This view is taken with the knee flexed. The radiograph is taken with the x-ray beam tangential to the patella parallel to the long axis of the lower extremity.

What is the patella in the knee? ›

The patella is a sesamoid bone: a round bone embedded in a tendon that shields and protects a joint. In the case of the patella, ligaments attach it to both the thigh muscles (quadriceps) and the shinbone (tibia).

Which projection of the patella provides the Sharper recorded detail? ›

Knee and Femur Anatomy
QuestionAnswer
This acts as a shock absorber in the kneeMeniscus
In the AP projection of the proximal femur, the foot should usually be slightly rotated internally ________ degrees.15-20
Which projection of the patella provides sharper recorded detail, AP or PA?PA
48 more rows

What is the Settegast method? ›

A Settegast is a standard medical x-ray projection that presents a tangential view of the patella. To acquire such an image the patient is placed in a prone position with the knee flexed at least 90 degrees and the field of view centered on the patellofemoral joint space.

What projections demonstrate patellar pathology? ›

The knee series is a set of radiographs taken to investigate knee joint pathology, often in the context of trauma. It usually comprises an AP and lateral projection, although other non-standard, modified projections can be used for specific indications.

What is skyline view in radiology? ›

Skyline view is routinely used for the evaluation of patellofemoral abnormalities in general practitioner, orthopaedic and rheumatology patients but rarely forms part of the trauma radiographic series.

Why is Q angle important? ›

The Q angle formed by the vector for the combined pull of the quadriceps femoris muscle and the patellar tendon, is important because of the lateral pull it exerts on the patella. Any alteration in alignment that increases the Q angle is thought to increase the lateral force on the patella.

Where does the central ray Enter the knee for a lateral projection of the patella? ›

Rest the knee on its anteromedial side to hold the patella in a position of lateral displacement. Central ray Directed to the joint space between the patella and femoral condyles at an angle of 25-30 degrees caudad, entering the posterior surface of the patella.

What are the proper positioning guidelines for an AP axial knee? ›

Position of part Flex the affected knee by 40 to 50 degrees, enough to place the long axis of the femur at an angle of 60 degrees to the long axis of the tibia. Support the knee on sandbags. Place the IR under the knee, centered to the mid-knee joint area.

What is the degree of flexion of the knee for a tangential view of the patella? ›

tangential (axial or sunrise/skyline) projection, patella - pt prone, knee flexd 90 degrees, have pt hold gauze or tape to hold position if needed, CR 15-20 from lower leg.

Why must the central ray be angled 5 to 7 Cephalad for a lateral knee position? ›

Central ray Directed 5 to 7 degrees cephalad to the knee joint 1 inch (2.5 cm) distal to the medial epicondyle. Slight angulation of the CR will prevent the joint space from being obscured by a magnified image of the medial femoral condyle.

What does the PA axial view of the knee best demonstrate? ›

Knee PA Axial Holmblad Method

Purpose and Structures Shown This projection best demonstrates the intercondylar fossa of the femur, femoral condyles, tibial plateaus, and intercondylar eminence. It is useful in evaluating for bony or cartilaginous pathology and narrowing of the joint space.

What is the Q angle? ›

Introduction. The Q angle, which is also known as quadriceps angle, is defined as the angle formed between the quadriceps muscles and the patella tendon. It was described for the first time by Brattstrom in 1964 [1].

What is holmblad method? ›

Holmblad Method - Patient is kneeling on x-ray table and is patient standing, Holmblad Variation - The patient is partially standing with affected leg on a stool or chair.

What is the difference between patella and patellar? ›

Summary. The patella is a sesamoid bone that lies in the tendon of quadriceps femoris. The patellar tendon arises from the apex of the patella as well as its anterior and posterior surfaces. The patellar tendon inserts onto the tibial tuberosity.

What two bones attach to the patella? ›

The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint.
...
Patella
Pronunciation/pəˈtɛlə/
Originspresent at the joint of femur and tibia fibula
Identifiers
Latinpatella
7 more rows

Is the patella a bone or cartilage? ›

The kneecap (patella) is a small triangular bone. It is just one of the many parts that make up the knee joint. Some of the other parts are muscles, ligaments, and leg bones. The kneecap provides leverage for your muscles as they bend and straighten the leg.

Where is the patella located? ›

The patella is the largest sesamoid bone in the human body and is located anterior to knee joint within the tendon of the quadriceps femoris muscle, providing an attachment point for both the quadriceps tendon and the patellar ligament.

What Groove does the patella sit in? ›

The V-shaped patella sits in a groove at the front of the femur of the knee, called the trochlear groove. Some people are born with a shallow trochlear groove (= trochlear dysplasia).

How does the patella move during knee flexion? ›

As the knee flexes, the patella glides medially and centers itself within the trochlear groove. During knee extension from 45 degrees to 0 the patella tilts medially 5–7 degrees from a laterally tilted position related to the geometry of the femoral trochlear groove.

Where does the patella lie on the femur when the knee is in full extension? ›

The primary function of the patella is during knee extension. The fact that the patella sits atop the anterior surface of the femoral condyles, increases the angle at which the quadriceps tendon pulls on the shaft of the tibia.

What is the posterior side of the patella called? ›

Answer and Explanation: If we are referring to the patella bone, the posterior side of the patella is called the posterior surface. It is a concave surface with a small ridge running vertically. To one side of the ridge is the media facet while the other side called the lateral facet.

What two bones attach to the patella? ›

The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint.
...
Patella
Pronunciation/pəˈtɛlə/
Originspresent at the joint of femur and tibia fibula
Identifiers
Latinpatella
7 more rows

Is the patella a bone or cartilage? ›

The kneecap (patella) is a small triangular bone. It is just one of the many parts that make up the knee joint. Some of the other parts are muscles, ligaments, and leg bones. The kneecap provides leverage for your muscles as they bend and straighten the leg.

What is Type 3 patella? ›

Patella geometry

The shape of the patella, however, does not always follow the groove exactly as demonstrated by Wiberg patella variations [17]. A type III patella, representing 25 % of all cases [15], has a small and convex medial facet, leaving only the lateral facet in contact with the trochlear.

What is patellar tilt? ›

The tilt angle is defined as the angle subtended by a line joining the medial and lateral edges of the patella and the horizontal. The radiograph (Merchant type) is taken with the foot pointing up, the lower edge of the film parallel to the ground, and the knee at 30 degrees flexion.

What are the two bands behind knee? ›

Knee ligaments are bands of tissue that connect your thigh bone to your lower leg bones. They can be classified into two main groups: collateral ligaments and cruciate ligaments.

How can I improve my patella tracking? ›

Nonsurgical treatment may include rest, regular stretching and strengthening exercises, taping or bracing the knee, using ice, and short-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) . Quadriceps strengthening is the most commonly prescribed treatment for patellar tracking disorder.

What is grasshopper eye patella? ›

Physical Examination

Knee Bent: With patella alta, when the knee is bent to 90 degrees (a right angle), the kneecaps point upwards instead of forwards and may be externally tilted and rotated, twisted round to the outer side of the knee. This is known as a positive “grasshopper eyes sign”.

What is Q angle? ›

Introduction. The Q angle, which is also known as quadriceps angle, is defined as the angle formed between the quadriceps muscles and the patella tendon. It was described for the first time by Brattstrom in 1964 [1].

Where does the patella lie on the femur when the knee is in full extension quizlet? ›

Where does the patella lie on the femur when the knee is in full extension? The patella lies slightly lateral and proximal to the trochlea.

Where does the patella articulate with the femur? ›

It articulates with the lower end of the femur at the patellofemoral joint, which is generally considered to be a part of the knee joint.

What is a patella alta? ›

Patella alta is a positional fault defined most simply as the superior displacement of the patella within the trochlear groove of the femur. Patella alta has been shown to be associated with chondromalacia on the articular surface of the patella and pain.

Videos

1. Knee Additional vws
(Scott Wimer)
2. Knee AP, Lat, Tunnel, Sunrise. X-ray positioning
(Tetiana Soloviova)
3. Sunrise of the Knee Part 1
(dominoesxp)
4. Radiographic Positioning of Lower Leg and Knee (A)
(RadTechEd)
5. Sunrise and Settegast views for Patella
(Jeffrey Jobe)
6. Skyline position of knee
(Dr. R.K Mishra)

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