Radiographic Anatomy of Extremities

Shoulder & Proximal Humerus - Shoulder Showdown X-rays

• Key Bones & Landmarks:
  • Clavicle
  • Scapula: Glenoid, Coracoid, Acromion
  • Proximal Humerus: Head, Anatomical/Surgical Necks, Greater/Lesser Tuberosities
• Key Joints: Sternoclavicular (SC), Acromioclavicular (AC), Glenohumeral
• Standard Views & What They Show:
  • AP (Internal/External Rotation): General overview, tuberosities profile.
  • Grashey (True AP): Clear Glenohumeral joint space.
  • Axillary: Glenohumeral articulation, dislocations (anterior/posterior).
  • Scapular Y (Trauma view): Glenohumeral alignment, scapular body/processes, dislocations.
• Key Measurement:
  • Acromiohumeral Interval: Normal 7-11mm. ↓ suggests rotator cuff tear.
• Common Ossification Centers: Proximal humerus, coracoid, acromion (appear & fuse at various ages).

⭐ Anterior dislocation is the most common type of shoulder dislocation (~95%), often showing Hill-Sachs (posterolateral humeral head impaction) and Bankart (anteroinferior glenoid labrum) lesions.

Elbow, Forearm, Wrist & Hand - Elbow to Hand Exposé

• Key Bones:
  • Distal Humerus: Epicondyles, trochlea, capitellum.
  • Radius: Head, neck, styloid. Ulna: Olecranon, coronoid, styloid.
  • Carpals (📌 SLTPTTCH): Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate.
  • Metacarpals, Phalanges.
• Key Joints: Elbow (humeroulnar, humeroradial, proximal radioulnar), Distal radioulnar, Wrist (radiocarpal, midcarpal), Carpometacarpal (CMC), Metacophalangeal (MCP), Interphalangeal (IP).
• Standard Views:
  • Elbow, Forearm: AP, Lateral.
  • Wrist: PA, Lateral, Scaphoid view, Ulnar deviation.
  • Hand: PA, Oblique, Lateral.
• Important Lines/Signs:
  • Elbow: Anterior humeral line, Radiocapitellar line. Fat pad signs (posterior fat pad always abnormal).
  • Wrist: Gilula’s lines (carpal arcs), Terry Thomas sign (scapholunate dissociation).
• Ossification Centers (Elbow - 📌 CRITOE): Capitellum (1y), Radial head (3y), Internal (medial) epicondyle (5y), Trochlea (7y), Olecranon (9y), External (lateral) epicondyle (11y).

⭐ Fall on outstretched hand (FOOSH) is a common mechanism for scaphoid, Colles', or radial head fractures.

Pelvis, Hip & Proximal Femur - Hip Highlights Radiography

• Key Bones & Joints:
  • Pelvic Ring (Ilium, Ischium, Pubis), Acetabulum, Sacrum, Coccyx.
  • Proximal Femur: Head, Neck, Trochanters (Greater/Lesser).
  • Joints: Sacroiliac, Pubic Symphysis, Hip.
• Standard Views:
  • Pelvis AP.
  • Hip AP (internal rotation for femoral neck).
  • Frog-leg lateral / Cross-table lateral (trauma).
• Lines & Angles:
  • Shenton’s line, Iliofemoral line.
  • Klein’s line (for SCFE).
  • Femoral neck angle: 120-135°.
  • Pubic symphysis width: <10mm (adults, non-pregnant).
• Ossification Centers: Femoral head, trochanters, acetabular Y-cartilage.

⭐ Slipped Capital Femoral Epiphysis (SCFE) typically occurs in obese adolescents. Best diagnosed with frog-leg lateral views if Klein's line is equivocal on AP.

Knee, Ankle & Foot - Leg Landscapes Lowdown

• Bones:
  • Knee: Distal Femur, Patella, Tibia (plateaus, tuberosity), Fibula (head).
  • Ankle: Tibia (medial malleolus), Fibula (lateral malleolus), Talus.
  • Foot: 📌 Tarsals (Talus, Calcaneus, Navicular, Cuboid, Cuneiforms (3) - Talented CAlifornian NAval CUstoms CUnningly MAnipulate), Metatarsals, Phalanges.
• Joints:
  • Knee: Tibiofemoral, Patellofemoral, Proximal tibiofibular.
  • Ankle: Tibiotalar (Mortise), Subtalar.
  • Foot: Midtarsal (Chopart's), Tarsometatarsal (Lisfranc's).
• Views:
  • Knee: AP, Lat, Skyline, Tunnel.
  • Ankle: AP, Lat, Mortise.
  • Foot: AP/DP, Oblique, Lat.
• Lines/Angles:
  • Tibial plateau lines.
  • Patellar alignment: Insall-Salvati ratio (normal 0.8-1.2).
  • Boehler’s angle (calcaneus): normal $20-40°$.
  • Syndesmotic width, Talar tilt.
• Ossification: Patella, tibial tuberosity, distal femoral/proximal tibial epiphyses.

⭐ Ankle mortise view: key for syndesmosis integrity & subtle talar shift.

High‑Yield Points - ⚡ Biggest Takeaways

• Ossification centers & fusion ages are key for age determination.
• Salter-Harris fractures involve the physis; know their types (I-V).
• Identify accessory ossicles (e.g., os trigonum) to avoid misdiagnosing fractures.
• Sesamoid bones (e.g., patella) are common; note their typical locations.
• Know normal joint spaces & alignments (e.g., carpal arcs, Boehler's angle).
• Recognize soft tissue signs of bony injury (e.g., fat pad signs).
• Standard views (AP, Lateral); special views (e.g., scaphoid, mortise) for specific areas.