Comprehensive Study Notes: Upper Extremity Anatomy and Radiographic Procedures

Osteology and Articulations of the Upper Extremity

• Digits and Hand Anatomy:
  • Phalanges:
    • There are a total of 14 phalanges in each hand.
    • Phalanges compose the digits, which are numbered 1 through 5 laterally (thumb) to medially (little finger).
    • Digits 2 through 5 each contain three phalanges: distal phalanx, middle phalanx, and proximal phalanx.
    • The first digit (thumb) contains only two phalanges: distal phalanx and proximal phalanx.
    • Each phalanx is named by its location and digit number (e.g., distal phalanx of the third digit).
    • Bone classification: Long bones.
  • Metacarpals:
    • Metacarpals compose the palm of the hand; there are 5 metacarpals in each hand, identified by numbers 1 through 5 laterally to medially.
    • Anatomical divisions: Distal head (articulating with the proximal phalanges), Body (shaft), Neck, and Proximal base (articulating with the carpal bones).
    • Bone classification: Long bones.
  • Carpals:
    • There are 8 carpal bones in each wrist, arranged in two transverse rows of four bones each.
    • Bone classification: Short bones.
    • Proximal Row (lateral to medial):
      1. Scaphoid
      2. Lunate
      3. Triquetrum
      4. Pisiform
    • Distal Row (lateral to medial):
      1. Trapezium
      2. Trapezoid
      3. Capitate
      4. Hamate
    • Mnemonic Aid ("Steve Left The Party To Take Carol Home"):
      • Steve = Scaphoid
      • Left = Lunate
      • The = Triquetrum
      • Party = Pisiform
      • To = Trapezium
      • Take = Trapezoid
      • Carol = Capitate
      • Home = Hamate

• Articulations of the Hand and Wrist:
  • Interphalangeal (IP) Joints:
    • Articulations formed between adjacent phalanges.
    • Digits 2 through 5 contain Distal Interphalangeal (DIP) joints and Proximal Interphalangeal (PIP) joints.
    • The first digit (thumb) contains a single Interphalangeal (IP) joint.
    • Classification: Synovial, diarthrotic, hinge-type joints.
  • Metacarpophalangeal (MCP) Joints:
    • Articulations between the distal heads of the metacarpals and the bases of the proximal phalanges.
    • Identified numerically from first to fifth MCP joint.
    • Classification: Synovial, diarthrotic, ellipsoidal-type joints.
  • Carpometacarpal (CMC) Joints:
    • Articulations between the proximal bases of the metacarpals and the carpal bones.
    • First CMC joint: Synovial, diarthrotic, saddle-type joint.
    • Second through fifth CMC joints: Synovial, diarthrotic, gliding-type joints.
  • Intercarpal Joints:
    • Articulations between adjacent carpal bones.
    • Classification: Synovial, diarthrotic, gliding-type joints.
  • Radiocarpal Joint:
    • Articulation between the distal articular surface of the radius and the scaphoid and lunate carpals.
    • Classification: Synovial, diarthrotic, ellipsoidal-type joint.

Osteology of the Forearm, Elbow, and Humerus

• Forearm Anatomy:
  • Consists of two long bones: the Ulna (positioned medially) and the Radius (positioned laterally).
  • Ulna Landmarks:
    • Olecranon process: Located proximally and posteriorly.
    • Coronoid process: Located proximally and anteriorly.
    • Trochlear notch: Concave depression between olecranon and coronoid process.
    • Radial notch: Lateral surface of coronoid process articulating with radial head.
    • Ulnar body (shaft).
    • Head of ulna: Located distally.
    • Ulnar styloid process: Distal projection from ulnar head.
  • Radius Landmarks:
    • Radial head: Disk-shaped proximal end articulating with capitulum and radial notch of ulna.
    • Radial neck: Constricted area below radial head.
    • Radial tuberosity: Prominence located proximally on anteromedial side.
    • Radial body (shaft).
    • Radial styloid process: Prominent projection on distal lateral border.

• Elbow Joint Complex:
  • Comprises three individual articulations housed inside a single joint capsule:
    1. Proximal Radioulnar Joint.
    2. Humeroulnar Joint.
    3. Humeroradial Joint.

• Humerus Anatomy:
  • Long bone composing the upper arm.
  • Proximal Humerus Landmarks:
    • Head: Smooth, hemispherical proximal articulation with glenoid cavity.
    • Anatomic neck: Narrow groove directly surrounding humeral head.
    • Surgical neck: Constriction distal to greater and lesser tubercles (common fracture site).
    • Greater tubercle: Prominent lateral process.
    • Lesser tubercle: Anterior process.
    • Intertubercular (bicipital) groove: Deep groove separating tubercles.
  • Distal Humerus Landmarks (Humeral Condyle):
    • Medial epicondyle: Prominent projection on medial side.
    • Lateral epicondyle: Projection on lateral side.
    • Trochlea: Smooth, spool-shaped medial process articulating with trochlear notch.
    • Capitulum: Smooth, rounded lateral process articulating with radial head.
    • Coronoid fossa: Anterior depression receiving coronoid process during flexion.
    • Radial fossa: Anterior depression receiving radial head during flexion.
    • Olecranon fossa: Deep posterior depression receiving olecranon process during extension.

General Radiographic Procedural Guidelines

• Patient Preparation:
  • All radiopaque artifacts must be removed from the region of interest prior to imaging:
    • For digits, hand, wrist, forearm, and elbow: Remove watches, rings, bracelets.
    • For humerus procedures: Remove watches, rings, bracelets, and bra/clothing with metal fasteners or buttons.
• Patient Positioning Protocols:
  • Ambulatory Patients: Seated at the end of the radiographic table with the affected limb resting on the Image Receptor (IR) on tabletop.
  • Non-ambulatory Patients: Adjust technique and position to image patient comfortably in bed or on a stretcher in a supine position.
  • Joint Alignment: Place shoulder, elbow, and wrist joints in the same horizontal plane for forearm and elbow procedures.
• Technical Standards:
  • Source-to-Image Receptor Distance (SID): Standard SID is $40\,\text{inches}$ ($102\,\text{cm}$).
  • IR Field Sizes:
    • $10 \times 12\,\text{inches}$ ($24 \times 30\,\text{cm}$)
    • $14 \times 17\,\text{inches}$ ($35 \times 43\,\text{cm}$)
  • ID Markers: Place physical radiopaque Right ($\text{R}$) or Left ($\text{L}$) side markers inside the collimated field margin without superimposing anatomy of interest. Digital annotation markers must be avoided.
  • Radiation Protection: Utilize close collimation boundaries, optimal exposure technical factors, and gonadal shielding according to regulatory rules or to reduce patient anxiety.
  • Breathing Instructions: Digits, hand, wrist, forearm, and elbow require the patient to maintain absolute immobility during exposure. Suspended respiration is mandated for humerus procedures.

Radiographic Positioning of the Digits (2 to 5)

• PA Projection (Digits 2 to 5):
  • Positioning: Patient seated at table end. Extended digit placed with palmar surface flat against center of IR. Align long axis parallel to IR. Separate adjoining digits slightly.
  • Central Ray (CR): Perpendicular to IR, entering the Proximal Interphalangeal (PIP) joint of the affected digit.
  • Collimation: $1\,\text{inch}$ ($2.5\,\text{cm}$) field margin on all sides of digit, including $1\,\text{inch}$ ($2.5\,\text{cm}$) proximal to the MCP joint.
  • Evaluation Criteria: Entire digit shown from fingertip to distal portion of adjoining metacarpal; open IP and MCP joints; equal soft tissue margins and bilateral body concavity (no rotation).

• Lateral Projection (Digits 2 to 5):
  • Positioning:
    • Second and third digits: Extend affected digit with lateral surface resting on IR (mediolateral projection); flex unexamined digits into a fist.
    • Fourth and fifth digits: Extend affected digit with medial surface resting on IR (lateromedial projection); flex unexamined digits into a fist.
  • Central Ray (CR): Perpendicular to PIP joint of affected digit.
  • Evaluation Criteria: Fingertip to distal metacarpal; fingernail shown in profile; concave anterior surfaces of phalanges; open IP joint spaces; no superimposition of proximal phalanx or MCP joint by adjacent digits.

• PA Oblique Projection (Digits 2 to 5):
  • Positioning: Rest palmar surface on a $45^{\circ}$ foam wedge, or rotate hand so digits extend parallel to IR plane forming a $45^{\circ}$ angle; separate affected digit to eliminate tissue overlap.
  • Central Ray (CR): Perpendicular to PIP joint of affected digit.
  • Evaluation Criteria: Entire digit including distal metacarpal; concavity present on elevated side of phalangeal bodies indicating $45^{\circ}$ rotation; open IP and MCP joint spaces.

Radiographic Positioning of the First Digit (Thumb)

• AP Projection (First Digit):
  • Positioning: Seat patient at table. Internally rotate hand medially into extreme rotation, placing posterior surface of thumb flat on IR; align long axis parallel; hold extended fingers back using tape or opposite hand; verify true AP alignment.
  • Central Ray (CR): Perpendicular to MCP joint of thumb.
  • Collimation: $1\,\text{inch}$ ($2.5\,\text{cm}$) on all sides, extending $1\,\text{inch}$ ($2.5\,\text{cm}$) proximal to first Carpometacarpal (CMC) joint.
  • Evaluation Criteria: Distal tip of thumb to trapezium; no rotation (equal soft tissue margins and bilateral body concavity); open IP and MCP joints without overlap. PA projection shows magnification compared to AP.

• Lateral Projection (First Digit):
  • Positioning: Palmar surface resting on IR; align long axis parallel; center MCP joint to IR; rotate thumb until lateral surface rests against IR (mediolateral projection).
  • Central Ray (CR): Perpendicular entering MCP joint of thumb.
  • Evaluation Criteria: Tip of thumb to trapezium; true lateral projection with thumbnail in profile; concave anterior surface of proximal phalanx; open IP and MCP joint spaces.

• PA Oblique Projection (First Digit):
  • Positioning: Place palmar surface flat against IR; ulnar-deviate hand slightly; thumb naturally aligns in a $45^{\circ}$ PA oblique position; center MCP joint to IR.
  • Central Ray (CR): Perpendicular to MCP joint of thumb.
  • Evaluation Criteria: Distal tip of thumb to trapezium; oblique body concavity; open IP and MCP joints.

Radiographic Positioning of the Hand

• PA Projection (Hand):
  • Positioning: Forearm resting flat on table; palmar surface placed flat against IR; extend and separate digits slightly to prevent soft tissue superimposition; center third MCP joint to IR.
  • Central Ray (CR): Perpendicular entering third MCP joint.
  • Collimation: $1\,\text{inch}$ ($2.5\,\text{cm}$) margins on sides, extending $1\,\text{inch}$ ($2.5\,\text{cm}$) proximal to ulnar styloid process.
  • Evaluation Criteria: Fingertips to distal radius and ulna; no rotation (equal concavity of metacarpal shafts, equal distance between metacarpal heads); open MCP and IP joints.

• PA Oblique Projection (Hand):
  • Positioning: Forearm resting on table; rotate palm away from IR until MCP joints form a $45^{\circ}$ angle; support extended digits on a $45^{\circ}$ stepped sponge (or parallel to IR) to prevent foreshortening of phalanges; center MCP joints to IR.
  • Central Ray (CR): Perpendicular entering third MCP joint.
  • Evaluation Criteria: Anatomy from fingertips to distal radius and ulna; $45^{\circ}$ rotation shown by decreasing interosseous space between 2nd through 5th metacarpal bodies and partial superimposition of 3rd, 4th, and 5th metacarpal bases/heads; open MCP and IP joints.

• Lateral Projection (Hand):
  • Positioning: Forearm flat on table with elbow flexed $90^{\circ}$; rest hand on medial (ulnar) surface (thumb side up; lateromedial projection); radial and ulnar styloids superimposed perpendicular to IR.
    • Extension Position: Digits 2 through 5 extended and superimposed; first digit abducted at a right angle. Best position for localizing foreign bodies and metacarpal displacement.
    • Fan Lateral Position: Digits fanned individually into a stair-step shape on a foam support. Best position for demonstrating individual phalanges without superimposition.
  • Central Ray (CR): Perpendicular entering second MCP joint.
  • Evaluation Criteria: Fingertips to distal radius/ulna; superimposed metacarpals and superimposed distal radius/ulna.

Radiographic Positioning of the Wrist

• PA Projection (Wrist):
  • Positioning: Axilla in contact with table; elbow flexed $90^{\circ}$; center wrist joint to IR; flex digits slightly (cupping hand) to place carpal region flat against IR.
  • Central Ray (CR): Perpendicular entering midcarpal area.
  • Collimation: $2.5\,\text{inches}$ ($6\,\text{cm}$) proximal and distal to wrist joint, $1\,\text{inch}$ ($2.5\,\text{cm}$) on sides.
  • Evaluation Criteria: Distal radius and ulna, carpals, and proximal half of metacarpals; no wrist rotation; open radioulnar and intercarpal joint spaces.

• Lateral Projection (Wrist):
  • Positioning: Elbow flexed $90^{\circ}$; forearm and wrist resting on ulnar/medial surface (lateromedial projection); styloid processes superimposed perpendicular to IR.
  • Central Ray (CR): Perpendicular entering radiocarpal joint.
  • Evaluation Criteria: Superimposed distal radius and ulna; superimposed metacarpals; proximal metacarpals through distal forearm visible.

• PA Oblique Projection (Wrist):
  • Positioning: From pronated position, rotate palmar surface away from IR until wrist forms a $45^{\circ}$ angle; support with a $45^{\circ}$ wedge sponge.
  • Central Ray (CR): Perpendicular entering midcarpal area, just distal to radius.
  • Evaluation Criteria: Carpals on lateral side (trapezium and distal scaphoid) shown free of superimposition; slight interosseous space between 3rd, 4th, and 5th metacarpal bodies.

• AP Oblique Projection (Wrist):
  • Positioning: Center dorsal surface of wrist to IR; rotate wrist medially (internally) until coronal plane forms a $45^{\circ}$ angle with IR; support with a $45^{\circ}$ wedge sponge.
  • Central Ray (CR): Perpendicular to midcarpal area (entering anterior surface midway between medial and lateral borders).
  • Evaluation Criteria: Pisiform separated from adjacent carpals; triquetrum and hook of hamate in profile free of superimposition.

• PA Projection in Ulnar Deviation:
  • Positioning: Elbow flexed $90^{\circ}$; wrist centered on IR; turn hand outward toward ulnar side to extreme deviation without moving forearm.
  • Central Ray (CR): Perpendicular entering scaphoid bone.
  • Evaluation Criteria: Scaphoid bone shown clearly with adjacent articulations open.

• PA Axial Scaphoid — Stecher Method:
  • Positioning: Wrist centered on IR; elevate finger end of IR $20^{\circ}$ on a support wedge. Alternatively, place wrist flat with ulnar deviation and angle CR $20^{\circ}$ proximally toward elbow.
  • Central Ray (CR): Perpendicular to table entering scaphoid bone.
  • Evaluation Criteria: Scaphoid projected clearly without foreshortening and with surrounding joint spaces open.

• Tangential Carpal Tunnel — Gaynor-Hart Method:
  • Positioning: Hyperextend wrist placing long axis of hand vertical; hold digits back with opposite hand; rotate hand slightly toward radial side.
  • Central Ray (CR): Angled $25^{\circ}\text{ to }30^{\circ}$ toward palm of hand (elbow), entering $1\,\text{inch}$ ($2.5\,\text{cm}$) distal to base of third metacarpal.
  • Evaluation Criteria: Carpal bones in arch formation; pisiform in profile free of superimposition; hamulus of hamate projected clearly.

Radiographic Positioning of the Forearm

• AP Projection (Forearm):
  • Positioning: Extended elbow; hand supinated; humeral epicondyles parallel and equidistant to IR; forearm aligned parallel to long axis of IR.
  • Central Ray (CR): Perpendicular entering midpoint of forearm.
  • Collimation: $2\,\text{inches}$ ($5\,\text{cm}$) distal to wrist joint and proximal to elbow joint; $1\,\text{inch}$ ($2.5\,\text{cm}$) on sides.
  • Evaluation Criteria: Entire forearm, wrist, and distal humerus; slight superimposition of radial head, neck, and tuberosity over proximal ulna; open radioulnar space.

• Lateral Projection (Forearm):
  • Positioning: Forearm resting on ulnar surface; elbow flexed $90^{\circ}$; hand in true lateral position (thumb side up); ulnar and radial styloids superimposed perpendicular to IR.
  • Central Ray (CR): Perpendicular entering midpoint of forearm.
  • Evaluation Criteria: Entire forearm in lateral profile; superimposed distal radius and ulna; superimposed humeral epicondyles; radial tuberosity facing anteriorly.

Radiographic Positioning of the Elbow

• AP Projection (Elbow):
  • Positioning: Extended elbow; hand supinated; lean patient laterally until humeral epicondyles are parallel with IR plane.
  • Central Ray (CR): Perpendicular entering mid-elbow joint.
  • Collimation: $3\,\text{inches}$ ($8\,\text{cm}$) proximal and distal to elbow joint.
  • Evaluation Criteria: Radial head, neck, and tuberosity slightly superimposed over proximal ulna; open elbow joint space; coronoid and olecranon fossae equidistant to epicondyles.

• Lateral Projection (Elbow):
  • Positioning: Elbow flexed $90^{\circ}$ (flex $30^{\circ}\text{ to }35^{\circ}$ if soft tissue injury present); resting on ulnar surface (thumb side up); epicondyles perpendicular to IR.
  • Central Ray (CR): Perpendicular to elbow joint.
  • Evaluation Criteria: Open elbow joint; olecranon process in profile; superimposed epicondyles; radial tuberosity facing anteriorly; fat pads evaluated in soft tissue.

• AP Oblique Projection — Medial Rotation Position:
  • Positioning: Extended elbow; medially (internally) rotate upper limb placing epicondyles at a $45^{\circ}$ angle to IR. Hand pronation alone is insufficient.
  • Central Ray (CR): Perpendicular entering elbow joint.
  • Evaluation Criteria: Coronoid process of ulna projected in profile; elongated medial epicondyle; olecranon process seated inside olecranon fossa.

• AP Oblique Projection — Lateral Rotation Position:
  • Positioning: Extended elbow; rotate limb laterally (externally) until posterior elbow forms a $45^{\circ}$ angle to IR (first and second digits touch table).
  • Central Ray (CR): Perpendicular entering elbow joint.
  • Evaluation Criteria: Radial head, neck, and tuberosity projected entirely free of ulnar superimposition; capitulum demonstrated.

• AP Partial Flexion Positions (Trauma/Inability to Extend):
  • Distal Humerus Projection: Posterior humerus flat on IR; support elevated forearm; CR perpendicular to humerus passing through elbow joint. Shows distal humerus without distortion; proximal forearm foreshortened.
  • Proximal Forearm Projection: Dorsal surface of forearm flat on IR; CR perpendicular to elbow joint and long axis of forearm. Shows proximal radius and ulna without distortion; distal humerus foreshortened.

• Axiolateral Projection — Coyle Method:
  • Indicated for trauma patients unable to extend elbow for standard oblique projections.
  • For Radial Head:
    • Elbow flexed $90^{\circ}$; hand pronated.
    • CR angled $45^{\circ}$ toward shoulder entering mid-elbow joint.
    • Evaluation: Open joint space between radial head and capitulum; radial head, neck, and tuberosity in profile free of superimposition.
  • For Coronoid Process:
    • Elbow flexed $80^{\circ}$; hand pronated.
    • CR angled $45^{\circ}$ away from shoulder entering mid-elbow joint.
    • Evaluation: Open joint space between coronoid process and trochlea; coronoid process elongated and shown in profile.

Radiographic Positioning of the Humerus

• AP Projection (Humerus):
  • Positioning: Standing, seated, or supine; top border of IR $1.5\,\text{inches}$ ($3.8\,\text{cm}$) above humeral head; hand supinated; epicondyles positioned parallel to IR.
  • Central Ray (CR): Perpendicular entering midportion of humerus. Suspended respiration.
  • Evaluation Criteria: Shoulder and elbow joints demonstrated; epicondyles in profile without rotation; greater tubercle shown in lateral profile; outline of lesser tubercle visible between head and greater tubercle.

• Lateral Projection (Humerus):
  • Non-Trauma Positioning: Top of IR $1.5\,\text{inches}$ ($3.8\,\text{cm}$) above humeral head; internally rotate arm, flex elbow $90^{\circ}$, rest palm on hip; epicondyles perpendicular to IR.
  • Trauma Positioning: Patient facing IR or Bucky; align body to position humerus into mediolateral orientation without moving injured arm.
  • Central Ray (CR): Perpendicular to midportion of humerus. Suspended respiration.
  • Evaluation Criteria: Shoulder and elbow joints demonstrated; superimposed epicondyles; lesser tubercle in profile medially; greater tubercle superimposed over humeral head.

Self-Assessment & Image Evaluation Identification Key

• Key Procedural Answers:
  • Articulation between middle and distal phalanges of second digit: DIP joint of second digit.
  • Carpal bone in proximal row between scaphoid and triquetrum: Lunate.
  • CR entry point for third digit PA projection: Third PIP joint.
  • Proximal collimation limit for AP first digit: $1\,\text{inch}$ ($2.5\,\text{cm}$) proximal to first CMC joint.
  • Projection requiring CR centered to third MCP joint: PA hand.
  • Proximal collimation limit for PA hand: $1\,\text{inch}$ ($2.5\,\text{cm}$) proximal to ulnar styloid.
  • Collimation margin proximal and distal to wrist joint for PA wrist: $2.5\,\text{inches}$ ($6\,\text{cm}$).
  • Carpal bone required on AP projection of thumb: Trapezium.
  • Portion of humerus articulating with radial head: Capitulum.
  • Lateral bone of forearm: Radius.
  • Projection showing olecranon process in profile: Lateral elbow.
  • CR angle and direction for radial head in axiolateral (Coyle) projection: Angled $45^{\circ}$ toward the shoulder.
  • Structure in profile on lateral side of proximal humerus on AP projection: Greater tubercle.
  • Projections requiring humeral epicondyles parallel to IR: AP forearm and AP elbow.
• Labeled Anatomical Structures Key:
  • Digit Radiograph Alignment:
    • A: Distal phalanx
    • B: Distal interphalangeal (DIP) joint
    • C: Middle phalanx
    • D: Proximal interphalangeal (PIP) joint
    • E: Proximal phalanx
    • F: Metacarpophalangeal (MCP) joint
    • G: Head of metacarpal
    • H: Metacarpal shaft
  • Wrist / Carpal Anatomical Map:
    • Scaphoid ($\text{S}$)
    • Lunate ($\text{L}$)
    • Triquetrum ($\text{T}$)
    • Pisiform ($\text{P}$)
    • Trapezium ($\text{G}$)
    • Trapezoid ($\text{M}$)
    • Capitate ($\text{C}$)
    • Hamate ($\text{H}$)
  • Forearm / Wrist Radiograph Map:
    • A: First metacarpal
    • B: Trapezium
    • C: Scaphoid
    • D: Capitate
    • E: Lunate
    • F: Radius
    • G: Ulna