A consolidated, textbook‑aligned positioning guide covering standard projections for each body region. Tables list standard projections with single‑line cells; each projection below includes Patient Preparation, Patient Positioning, Centering and Landmarks, Beam Acquisition Instructions, Technical Notes, and Common Pitfalls. Key textbook anchors and corrections are cited.
Universal Principles
- Patient preparation: Remove clothing and jewelry from the area of interest; provide gown; explain procedure and breath‑hold.
- Radiation protection: Collimate tightly; shield gonads when not in the primary beam; apply ALARA.
- Exposure technique: Use a grid for adult body parts thicker than ~10 cm; choose high kVp for chest and appropriate kVp/mAs for bone/soft tissue.
- Respiration cues: Chest — full inspiration; abdomen supine/upright — expiration for supine and upright views when detecting free air or air‑fluid levels.
- Image quality checks: Verify no rotation, adequate inclusion of anatomy, correct angulation, and absence of motion before releasing patient.
Master Tables by Region
Head and Neck
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Skull AP or PA | Upright or supine | CR to glabella or nasion; include vertex to foramen magnum | Skull vault and fracture evaluation | High kVp; avoid rotation |
| Skull Lateral | Upright lateral | CR 2″ superior to EAM | Lateral skull detail and trauma | IOML parallel to IR |
| Facial Bones Waters | Upright PA axial OML ~37° | CR to acanthion | Maxillary sinuses and facial fractures | Petrous ridges below maxilla |
| Sinuses Caldwell | Upright PA axial | CR to nasion with 15° caudal to OML | Frontal and ethmoid sinus detail | Upright for fluid levels |
| Nasal Bones AP | Upright | CR to nasal bones | Nasal bone fractures | Small focal spot; tight collimation |
Chest and Thorax
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Chest PA | Upright facing IR | CR to T7 midsagittal plane | Lungs heart mediastinum evaluation | Full inspiration; grid for adults. |
| Chest Lateral | Upright left lateral | CR to mid‑coronal plane at T7 | Retrocardiac and retrosternal evaluation | Arms raised; posterior ribs superimposed. |
| Ribs AP/PA/Oblique | Upright or supine with obliques | CR to area of interest; include joint above and below | Rib fracture localization | Use obliques (≈45°) to project ribs off spine. |
Spine and Sacrum
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Cervical AP OML | Upright or supine | CR to C4 | Cervical alignment and fractures | Remove collars; immobilize trauma patients. |
| Cervical Lateral | Upright true lateral | CR to C4; include C1–T1 | Lateral cervical detail and alignment | Suspend respiration on expiration. |
| Cervical Obliques | Upright 45° oblique | CR to C4 | Intervertebral foramina visualization | Accurate 45° obliquity required. |
| Thoracic AP or PA | Upright or supine | CR to T7 | Thoracic vertebrae evaluation | Use breathing technique to blur ribs. |
| Thoracic Lateral | Upright true lateral | CR to T7 | Lateral thoracic vertebrae detail | True lateral essential. |
| Lumbar AP | Supine or upright | CR to L3 (≈1.5″ above iliac crest) | Lumbar alignment and degenerative disease | Include sacrum; avoid rotation. |
| Lumbar Lateral | True lateral | CR to L4–L5 as indicated | Lateral lumbar detail and disc spaces | Use grid; increase mAs. |
| Sacrum AP axial | Supine | CR 15° cephalad to 2″ superior to pubic symphysis | Sacral fractures and alignment | Angle accuracy critical. |
| Coccyx AP axial | Supine | CR 10° caudad to 2″ superior to pubic symphysis | Coccygeal pathology | Caudad angulation; tight collimation. |
Abdomen and Pelvis
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Abdomen AP Supine | Supine | CR to iliac crest | Bowel obstruction and soft tissue evaluation | Supine on expiration. |
| Abdomen AP Upright | Upright | CR 2″ above iliac crest to include diaphragm | Detect free air and air‑fluid levels | Include diaphragm for free air detection. |
| Pelvis AP | Supine | CR midline 2″ below ASIS | Pelvic fractures and hip pathology | Internally rotate feet 15° to profile femoral necks. |
| Hip AP | Supine | CR to femoral neck | Hip joint evaluation | Low kVp for bone detail; internal rotation 15°. |
| Hip Frog‑leg | Supine hip flex/abduct | CR to femoral neck | Non‑traumatic hip assessment | Avoid in suspected fracture/trauma. |
Upper Extremity
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Shoulder AP | Upright or supine | CR 1″ inferior to coracoid process | Glenohumeral joint and proximal humerus | External/internal rotation views as needed. |
| Shoulder Grashey | Upright 35–45° toward affected side | CR to glenohumeral joint | Glenoid fossa and joint space profile | 35–45° posterior oblique opens joint space. |
| Clavicle AP/AP axial | Upright or supine | CR to mid‑clavicle; axial cephalad 15–30° | Clavicle fractures and alignment | Cephalad angulation projects clavicle above ribs. |
| Scapula AP/Lateral | Upright or supine oblique | CR to mid‑scapula | Scapular body and acromion evaluation | Position to free scapula from thorax. |
| Elbow AP/Oblique/Lateral | Seated or supine | CR to elbow joint | Elbow joint and radial head evaluation | Lateral with 90° flexion; small focal spot. |
| Wrist PA/Oblique/Lateral | Seated | CR to mid‑carpal area | Carpal bones and distal radius | Small focal spot; close collimation. |
| Hand/Fingers PA/Oblique/Lateral | Seated | CR to 3rd MCP (hand) or affected PIP (finger) | Phalanges and metacarpals | Tight collimation; immobilize digits. |
Lower Extremity
| Projection | Patient Position | Centering & Landmark | Clinical Purpose | Key Note |
|---|---|---|---|---|
| Femur AP/Lateral | Supine or upright | CR to mid‑femur; include joint above/below | Femoral shaft fractures | Two projections to include hip and knee when needed. |
| Knee AP/Oblique/Lateral/Sunrise | Supine and lateral | AP CR 1/2″ distal to patellar apex | Joint space, fractures, patella evaluation | Lateral flex knee 20–30°; sunrise for patella. |
| Tibia‑Fibula AP/Lateral | Supine | CR to mid‑shaft; include ankle and knee | Shaft fractures and alignment | Long IR; avoid rotation. |
| Ankle AP/Mortise/Lateral | Supine | Mortise: internally rotate 15–20°; CR to ankle joint | Ankle fractures and mortise integrity | Ensure true mortise; include distal tib/fib. |
| Foot AP/Oblique/Lateral | Seated or supine | CR to base of 3rd metatarsal | Metatarsal and tarsal evaluation | Weight‑bearing views when indicated. |
| Toes AP/Oblique/Lateral | Seated | CR to affected toe PIP | Phalangeal fractures | Tight collimation; immobilize toes. |
Detailed Step‑by‑Step Protocols for Every Standard Projection
The following canonical steps are provided for each projection group. Use them at the console; they reflect validated textbook technique and common clinical practice.
Head and Neck Protocols
Skull AP or PA
- Preparation: Remove hairpins, earrings, dentures.
- Positioning: PA—patient faces IR; AP—supine or upright facing tube; midsagittal plane perpendicular.
- Centering: CR to glabella (PA) or nasion (AP); include vertex to foramen magnum.
- Acquisition: High kVp; short exposure; suspend respiration.
- Pitfalls: Chin tilt or rotation altering base of skull.
Skull Lateral
- Preparation: Stabilize head.
- Positioning: True lateral with IOML parallel to IR.
- Centering: CR 2″ superior to EAM.
- Acquisition: Lateral projection; suspend respiration.
- Pitfalls: Tilt or rotation.
Facial Bones Waters and Sinuses Caldwell
- Preparation: Remove jewelry; upright for fluid levels.
- Positioning: Waters—OML ~37° to IR; Caldwell—OML perpendicular with 15° caudal CR.
- Centering: Waters—acanthion; Caldwell—nasion.
- Acquisition: Suspend respiration; verify petrous ridge placement.
- Pitfalls: Incorrect head tilt or angle.
Chest and Thorax Protocols
Chest PA
- Preparation: Remove clothing/jewelry; gown.
- Positioning: Erect facing IR; chin elevated; shoulders rolled forward.
- Centering: CR to T7 on midsagittal plane.
- Acquisition: Full inspiration; short exposure; grid for adults.
- Pitfalls: Poor inspiration, rotation, scapulae over lungs.
Chest Lateral
- Preparation: Remove metallic objects.
- Positioning: Left lateral preferred; arms raised above head.
- Centering: CR to mid‑coronal plane at T7.
- Acquisition: Full inspiration; ensure posterior ribs superimposed.
- Pitfalls: Rotation; incomplete lung height.
Ribs Series
- Preparation: Mark point of maximal pain.
- Positioning: Use PA/AP and obliques (≈45°) to project ribs off spine.
- Centering: CR to area of interest; include joint above and below.
- Acquisition: Suspend respiration as protocol directs.
- Pitfalls: Inadequate obliquity; missed joint margins.
Spine and Sacrum Protocols
Cervical Lateral
- Preparation: Remove collars; immobilize if trauma.
- Positioning: True lateral; shoulders relaxed.
- Centering: CR to C4; include C1–T1.
- Acquisition: Suspend respiration on expiration.
- Pitfalls: Shoulder superimposition; rotation.
Cervical Obliques
- Positioning: 45° oblique; chin slightly elevated.
- Centering: CR to C4; demonstrate foramina.
- Pitfalls: Incorrect obliquity.
Thoracic Series
- Positioning: AP/PA upright or supine; lateral true lateral.
- Centering: CR to T7.
- Acquisition: Use breathing technique for AP/PA; suspend respiration for lateral.
- Pitfalls: Rotation; incomplete coverage.
Lumbar Series
- Positioning: AP supine or upright; lateral true lateral with knees flexed.
- Centering: AP to L3 (≈1.5″ above iliac crest); lateral to L4–L5 as indicated.
- Acquisition: Suspend respiration on expiration; use grid for lateral.
- Pitfalls: Rotation; inadequate exposure.
Sacrum and Coccyx Axials
- Sacrum: Angle CR 15° cephalad to 2″ superior to pubic symphysis.
- Coccyx: Angle CR 10° caudad to 2″ superior to pubic symphysis.
- Pitfalls: Incorrect angulation; incomplete coverage.
Abdomen and Pelvis Protocols
Abdomen AP Supine
- Positioning: Supine; arms out of field.
- Centering: CR to iliac crest.
- Acquisition: Supine on expiration.
- Pitfalls: Failure to include entire abdomen.
Abdomen AP Upright
- Positioning: Upright; document upright time.
- Centering: CR 2″ above iliac crest to include diaphragm.
- Acquisition: Upright on expiration to detect free air.
- Pitfalls: Omitting diaphragm.
Pelvis and Hip
- Pelvis AP: Internally rotate feet 15°; CR midline 2″ below ASIS.
- Hip AP: Internally rotate foot 15°; CR to femoral neck.
- Hip Frog‑leg: Use only for non‑traumatic assessment.
- Pitfalls: Incorrect rotation; missing femoral neck.
Upper Extremity Protocols
Shoulder Grashey
- Positioning: Rotate patient 35–45° toward affected side.
- Centering: CR to glenohumeral joint.
- Acquisition: AP oblique; suspend respiration.
- Pitfalls: Incorrect obliquity failing to open joint.
Clavicle AP Axial
- Positioning: Upright or supine; shoulders relaxed.
- Centering: CR to mid‑clavicle with 15–30° cephalad angulation.
- Acquisition: Suspend respiration on inspiration.
- Pitfalls: Incorrect angulation; incomplete AC/SC inclusion.
Elbow Wrist Hand Fingers
- General: Use small focal spot, tight collimation, and true AP/true lateral positions; center to joint of interest.
Lower Extremity Protocols
Knee Series
- AP Centering: CR 1/2″ distal to patellar apex.
- Lateral: Flex knee 20–30°; CR to femorotibial joint.
- Sunrise: Tangential for patella as indicated.
- Pitfalls: Rotation; inadequate flexion.
Ankle Mortise
- Positioning: Internally rotate foot 15–20° for mortise view.
- Centering: CR to ankle joint midway between malleoli.
- Pitfalls: Underrotation hides mortise.
Femur Tibia Fibula Foot Toes
- General: Two projections to include joint above and below long bones; long IR or two overlapping exposures for full femur/tibia.
Quick Console Checklists
Pre‑Exposure
- Confirm patient identity and exam order.
- Remove clothing/jewelry; provide gown.
- Explain breath‑hold and mark pain site.
- Set projection, centering, kVp/mAs, and grid.
- Collimate to anatomy; align midsagittal and long axis to IR.
Post‑Exposure Image Review
- Check rotation, inclusion, respiration, sharpness, and angulation.
- Repeat only when clinically justified.