American Registry of Radiologic Technologists Certification (ARRT) Radiographic Procedures and Anatomy Syllabus

For ribs above the diaphragm, what breathing phase and patient position are preferred?

Ribs above the diaphragm are imaged erect on full inspiration to depress the diaphragm and project the diaphragm low.

For ribs below the diaphragm, what breathing phase and position optimize visualization?

Imaged recumbent on full expiration to raise the diaphragm above the lower ribs.

For a sternum, why is the RAO projection (not LAO or AP) used for the frontal oblique?

The RAO rotates the sternum over the homogeneous density of the heart, providing uniform background and avoiding the spine superimposition; a slight oblique (15-20 degrees) is used.

What are the three divisions of the sternum?

Manubrium (superior), body (gladiolus), and xiphoid process (inferior).

Why is an AP abdomen (KUB) typically taken on expiration and supine?

Expiration relaxes the abdominal muscles and raises the diaphragm; supine position is the standard for evaluating the urinary tract, bowel gas pattern, and soft tissue without distortion.

What is the purpose of an erect or left lateral decubitus abdomen in an acute abdominal series?

To demonstrate free intraperitoneal air (under the diaphragm when erect, or along the right flank/liver on left lateral decubitus) and air-fluid levels indicating obstruction or perforation.

Which positions make up a typical 'acute abdomen' (three-way) series?

AP supine abdomen, AP erect abdomen (or left lateral decubitus if patient cannot stand), and a PA erect chest to check for free air under the diaphragm.

Name the soft-tissue airway structures evaluated on a soft-tissue lateral neck radiograph.

Nasopharynx, oropharynx, laryngopharynx, epiglottis, trachea, and the air column; useful for detecting epiglottitis, foreign bodies, or croup.

What radiographic sign suggests epiglottitis on a lateral soft-tissue neck image?

The 'thumb sign'—a thickened, rounded, enlarged epiglottis. (Croup classically shows the 'steeple sign' on AP airway.)

How many carpal bones are there, and name the proximal row from lateral to medial.

8 carpals. Proximal row (lateral/thumb side to medial): scaphoid, lunate, triquetrum, pisiform.

Which special wrist projection best demonstrates the scaphoid (navicular)?

The PA axial scaphoid (Stecher method) with ulnar deviation and/or CR angled 10-20 degrees proximally elongates and demonstrates the scaphoid free of foreshortening.

What does the carpal canal (tunnel) view (Gaynor-Hart method) demonstrate?

The carpal sulcus in an inferosuperior tangential projection with the wrist hyperextended; demonstrates the pisiform, hamulus of hamate, trapezium, and scaphoid for carpal tunnel evaluation.

For an AP elbow with proper positioning, how should the hand be placed and what should the epicondyles do?

Hand supinated and the humeral epicondyles parallel to the IR (no rotation), demonstrating the radial head, neck, and tuberosity slightly superimposed by the ulna.

What is demonstrated on an internal (medial) rotation AP shoulder, and what part is seen in profile?

The lesser tubercle is seen in profile medially; the humerus is in a lateral position. (External rotation shows the greater tubercle in profile and a true AP humerus.)

How many phalanges and metacarpals are in one hand?

14 phalanges (3 per finger, 2 in the thumb) and 5 metacarpals.

For an AP knee, how is the central ray angled and why does it vary by patient thickness?

CR is angled 0-5 degrees cephalad for average ASIS-to-tabletop measurement of 19-24 cm; 5 degrees caudad if thick/large thigh, 3-5 degrees cephalad if thin, to open the joint space and align with the tibial plateau.

What does the tunnel (intercondylar fossa) view of the knee demonstrate (e.g., Camp Coventry/Holmblad)?

The intercondylar fossa, intercondylar eminence, and tibial plateaus free of superimposition; used to detect loose bodies, osteochondritis dissecans, and joint mice.

Which projection best demonstrates the calcaneus, and how is the CR directed?

The axial (plantodorsal) calcaneus projection with CR angled 40 degrees cephalad to the long axis of the foot, demonstrating the calcaneus free of superimposition.

How many tarsal bones are there and which one is the largest?

7 tarsals; the calcaneus is the largest, and the talus articulates with the tibia and fibula at the ankle.

What three views make up the routine ankle series, and what does the AP mortise (15-20 degree internal oblique) show?

AP, lateral (mediolateral), and AP oblique (mortise). The mortise view, with 15-20 degrees internal rotation, demonstrates the entire ankle mortise joint space open.

What is the angle of the central ray for an AP axial 'outlet' (Taylor) or inlet pelvis projection, and what do they show?

Pelvic inlet: CR 40 degrees caudad showing the pelvic ring/inlet for AP displacement. Outlet (Taylor): CR 20-35 degrees cephalad (male) to show the pubic and ischial rami without foreshortening.

For an AP pelvis, how should the feet be positioned and why?

Feet/legs internally rotated 15-20 degrees to place the femoral necks parallel to the IR, overcoming anteversion and demonstrating the femoral necks in full profile.

What does the modified axiolateral (Danelius-Miller) hip projection demonstrate, and when is it used?

A lateral view of the femoral head, neck, and acetabulum using a horizontal/cross-table CR; used for suspected hip fracture or post-surgery when the leg cannot be moved.

Classify joints by function and give the radiographic significance of synovial joints.

Functional classes: synarthrosis (immovable), amphiarthrosis (slightly movable), diarthrosis (freely movable/synovial). Synovial (diarthrodial) joints have a joint cavity and are most often imaged for trauma and arthritis.

Give examples of the structural joint classifications: fibrous, cartilaginous, and synovial.

Fibrous (sutures of the skull, syndesmosis of distal tibiofibular), cartilaginous (symphysis pubis, intervertebral discs), synovial (knee, shoulder, hip - includes ball-and-socket, hinge, pivot, gliding, condyloid, saddle).

How many vertebrae are in each region of the vertebral column?

7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral, and 3-5 fused coccygeal (typically 4).

What does the AP open-mouth (odontoid) projection demonstrate, and what must be aligned?

It demonstrates C1 (atlas) and the dens/odontoid process of C2 (axis); a line from the lower incisors to the base of the skull (mastoid tips) must be perpendicular to the IR to avoid superimposing the teeth or occiput.

On which oblique do the cervical intervertebral foramina open, and at what CR angle?

Posterior obliques (RPO/LPO, 45 degrees) demonstrate the foramina farthest from the IR (upside) with CR 15-20 degrees cephalad; anterior obliques (RAO/LAO) demonstrate the side closest to the IR with CR 15-20 degrees caudad.

What is demonstrated on a 45-degree oblique lumbar spine, and what is the 'Scottie dog' sign?

The zygapophyseal (apophyseal) joints; the 'Scottie dog' is formed by the vertebral structures—a fracture/defect of the pars interarticularis (neck/collar) indicates spondylolysis.

For the lateral lumbar spine, why is the central ray sometimes angled, and what does the L5-S1 spot view (Ferguson/lateral) target?

CR may be angled 5-8 degrees caudad if the spine sags (or use support) to open intervertebral disc spaces; the L5-S1 lateral spot uses CR perpendicular or angled to demonstrate the lumbosacral junction and disc space.

What positioning lines/landmarks define the cranial base, and what is the OML?

The orbitomeatal line (OML) connects the outer canthus to the EAM; the cranial base/floor is divided into anterior, middle, and posterior cranial fossae. The IOML, GAL, and AML are other key positioning lines.

What does the SMV (submentovertical, Schuller) projection demonstrate?

The base of the skull, foramina (ovale and spinosum), sphenoid and ethmoid sinuses, mandible, and petrous pyramids; the IOML is placed parallel to the IR with CR perpendicular to it.

What does the parietoacanthial (Waters) projection best demonstrate for facial bones and sinuses?

The maxillary sinuses, orbital floors (blowout fractures), zygomatic arches, and maxillae; the petrous ridges are projected below the maxillary sinuses (OML 37 degrees to IR).

Which projection (and angle) best demonstrates the maxillary sinuses free of superimposition by the petrous ridges?

The parietoacanthial (Waters) projection—erect to show air-fluid levels—projects the petrous ridges below the maxillary sinus floors.

What does the PA axial Caldwell projection demonstrate for the sinuses/orbits?

The frontal and anterior ethmoid sinuses; with CR 15 degrees caudad to the OML, the petrous ridges are projected into the lower third of the orbits.

Name two methods/projections used to demonstrate the temporal bone (petrous portion) and what each shows.

Axiolateral oblique (Law method) shows the mastoid air cells/TMJ region; posterior profile (Stenvers) and anterior profile (Arcelin) demonstrate the petrous pyramid, internal acoustic canal, and mastoid in profile.

What does the axiolateral oblique mandible projection demonstrate, and how is the head positioned for the body versus ramus?

It demonstrates the mandibular body, ramus, and angle; the head is positioned in a true lateral for the ramus, with varying rotation (e.g., 30 degrees toward IR) and CR 25 degrees cephalad to project the side of interest away from the cervical spine.

What is the contrast medium and patient prep difference between an upper GI (UGI) and a barium enema (BE)?

UGI uses orally ingested barium (NPO 8 hours) to study the esophagus, stomach, and duodenum; BE administers barium (and air for double-contrast) rectally after bowel-cleansing prep to study the large intestine.

In an upper GI series, which position fills the fundus of the stomach versus the body/pylorus with barium?

Recumbent/supine fills the fundus (posterior) with barium; prone (PA) fills the body and pylorus/duodenum with barium, while the fundus fills with air in double-contrast studies.

What does the RAO position demonstrate in an esophagram, and at what obliquity?

A 35-40 degree RAO places the esophagus between the vertebral column and the heart, demonstrating it free of superimposition during barium swallow.

What is the difference between an excretory urogram (IVU/IVP) and a retrograde pyelogram?

IVU/IVP injects iodinated contrast intravenously to assess function and anatomy of the renal collecting system (physiologic); retrograde pyelogram instills contrast directly via ureteral catheters during cystoscopy (non-functional, anatomic study).

During an IVU, why is ureteric compression sometimes applied, and what does the AP Trendelenburg/RPO/LPO demonstrate?

Compression over the distal ureters retains contrast in the renal pelves/calyces for better filling; obliques (30 degrees) demonstrate the kidney closest to the IR (upside ureter) and separate the kidneys from the spine.

What patient preparation and contrast route are used for an operative (immediate) cholangiogram versus an ERCP?

Operative/T-tube cholangiogram injects contrast directly into the biliary ducts (during or after gallbladder surgery via a T-tube/catheter); ERCP (endoscopic retrograde cholangiopancreatography) introduces contrast through an endoscope into the common bile and pancreatic ducts via the duodenal papilla.

What does a hysterosalpingogram (HSG) demonstrate, and what contrast route is used?

Contrast injected through the cervix outlines the uterine cavity and fallopian tubes to evaluate patency and uterine anatomy (commonly for infertility).

For mobile (portable) radiography, what is the cardinal radiation safety rule for the operator regarding distance?

Stand at least 6 feet (2 meters) from the patient, tube, and useful beam, at a 90-degree angle to the scatter source, and always wear a lead apron.

In surgical radiography with a C-arm, how does positioning the image intensifier versus the x-ray tube reduce operator dose?

Keep the x-ray tube under the table and the image intensifier on top/close to the patient; this reduces scatter to the operator's head/neck. Increasing tube-to-skin distance and minimizing fluoro time also lower dose.

What is the guiding principle for trauma radiography positioning when the patient cannot be moved?

Move the tube and IR (use cross-table/horizontal beam and CR angulation) rather than the patient; still obtain two projections 90 degrees apart, and never force a body part into position.

What special trauma cervical spine view must be obtained first and must include which vertebrae?

A cross-table (horizontal beam) lateral cervical spine that must demonstrate all 7 cervical vertebrae plus the C7-T1 junction before the collar is removed; a swimmer's (Twining) view may be needed to visualize C7-T1.

What exposure-factor adjustments are appropriate for pediatric radiography to reduce motion and dose?

Use short exposure times with higher mA (to minimize motion blur), appropriate kVp, tight collimation, gonadal shielding, and immobilization devices; follow ALARA and use the smallest field size.

What immobilization device is commonly used for pediatric chest/abdomen radiography, and what is a key concern with pediatric positioning?

The Pigg-O-Stat (with body clamps) holds infants erect for chest/abdomen imaging; key concerns are immobilization to prevent motion, careful gonadal shielding, and minimizing repeat exposures.