Bones and Radiography of the Hand, Wrist, and Forearm Flashcards

Vocabulary flashcards covering anatomy, joint classifications, projections, special methods, and technique cast conversions for the hand, wrist, forearm, and elbow.

Total Bones in Each Hand and Wrist

There are 27 total bones in each hand and wrist, consisting of 14 phalanges, 5 metacarpals, and 8 carpals.

Phalanges

The 14 bones that form the digits (fingers and thumb) of the hand.

Metacarpals

The 5 bones that form the palm of the hand.

Carpals

The 8 bones that form the wrist.

Digit Numbering System

The digits are numbered 1 through 5, starting with the thumb as 1 and ending with the little finger as 5.

Tuft

The very tip of the finger phalanx.

Phalanges of the Thumb

The thumb (1st digit) contains 2 phalanges: proximal and distal.

Phalanges of Digits 2 through 5

Digits 2 through 5 each contain 3 phalanges: proximal, middle, and distal.

Anatomic Position of the First Metacarpal

The 1st metacarpal of the thumb is located on the lateral side in anatomic positioning.

Metacarpal Head

The round distal portion of the metacarpal bone.

Metacarpal Body (Shaft)

The long-curved portion of the metacarpal bone; its anterior surface is concave and its posterior (dorsal) surface is convex.

Metacarpal Base

The expanded proximal end of the metacarpal bone that articulates with the carpals.

Interphalangeal (IP) Joint

The single joint located between the two phalanges of the thumb.

Imaging Requirement for First Metacarpal

When imaging the thumb, the first metacarpal must be included in its entirety from the distal phalanx to the base of the first metacarpal.

Distal Interphalangeal (DIP) Joint

The most distal joint located between the middle and distal phalanges in digits 2 through 5.

Proximal Interphalangeal (PIP) Joint

The joint located between the proximal and middle phalanges in digits 2 through 5.

Metacarpophalangeal (MCP) Joint

The joint located between the head of the metacarpal and the base of the proximal phalanx.

Carpometacarpal (CMC) Joints

The joints located at the proximal end where the metacarpals articulate with the respective carpal bones.

Distal Row of Carpals

Trapezium, Trapezoid, Capitate, and Hamate (listed from lateral to medial).

Proximal Row of Carpals

Scaphoid, Lunate, Triquetrum, and Pisiform (listed from lateral to medial).

Navicular

Alternative name for the Scaphoid carpal bone.

Semilunar

Alternative name for the Lunate carpal bone.

Triangular or Cuneiform

Alternative names for the Triquetrum carpal bone.

Greater Multangular

Alternative name for the Trapezium carpal bone.

Lesser Multangular

Alternative name for the Trapezoid carpal bone.

Os Magnum

Alternative name for the Capitate carpal bone.

Unciform

Alternative name for the Hamate carpal bone.

Hamulus

The hook-like process located on the hamate bone, visible on anterior views.

Medial Boundary of Carpal Sulcus

Formed by the triquetrum, pisiform, and hamulus of hamate.

Lateral Boundary of Carpal Sulcus

Formed by the scaphoid, trapezoid, and trapezium.

Radial Deviation

Turning the wrist towards the radius.

Ulnar Deviation

Turning the hand toward the ulna; specifically used as the scaphoid view.

Anatomic Position of Radius

Located on the lateral side of the forearm.

Anatomic Position of Ulna

Located on the medial side of the forearm.

Styloid Processes

Projections located at the extreme distal ends of both the radius and the ulna.

Head of Ulna

Located near the wrist at the distal end of the ulna; easily felt on the little finger side when the hand is pronated.

Head of Radius

Located near the proximal end of the radius near the elbow joint.

Relative Forearm Bone Lengths

The ulna is the longer of the two forearm bones, and the radius is the shorter bone.

Beaklike Processes of Ulna

The olecranon and coronoid processes located on the proximal aspect of the ulna.

Trochlear Notch

Also called the semilunar notch, a large depression on the proximal ulna that articulates with the humerus.

Humeral Condyle

The expanded distal end of the humerus, divided into the trochlea and capitulum.

Trochlea

The medial condyle of the humerus (meaning 'pulley') that articulates with the ulna.

Capitulum

The lateral condyle of the humerus (meaning 'little head') that sits on the head of the radius.

Trochlear Sulcus

The groove that forms the first and smallest concentric arc visible on a true lateral elbow radiograph.

Three Concentric Arcs of Lateral Elbow

Visualized on a true 90-degree flexed lateral elbow: 1st is trochlear sulcus, 2nd is double lines of outer ridges of capitulum/trochlea, 3rd is trochlear notch of ulna.

IP Joints Classification

Ginglymus (hinge) movement type.

MCP Joints Classification

Ellipsoidal (condyloid) movement type.

2nd to 5th CMC Joints Classification

Plane (gliding) movement type.

Intercarpal Joints Classification

Plane (gliding) movement type.

1st CMC Joint Classification

Sellar (saddle) joint classification.

Radiocarpal Joint Classification

Synovial structural classification, diarthrodial mobility type, and ellipsoidal (condyloid) movement type.

Proximal Radioulnar Joint Classification

Pivot (trochoidal) movement type.

Elbow Joint Classification

Ginglymus (hinge) movement type encompassing humeroulnar and humeroradial articulations.

Complete Elbow Joint Composition

Consists of three joints enclosed within one articular capsule: humeroulnar, humeroradial, and proximal radioulnar joints.

Carpals Demonstrated by Ulnar Deviation

Best demonstrates the carpals on the lateral/radial side: scaphoid, trapezium, and trapezoid.

Most Frequently Fractured Carpal Bone

The scaphoid bone.

Carpals Demonstrated by Radial Deviation

Best demonstrates the carpal bones on the ulnar side: lunate, triquetrum, pisiform, and hamate.

Positioning to Prevent Forearm Crossover

The forearm is radiographed with the hand supinated (palm up) for an AP projection.

Hand Pronation Effect on Forearm

Pronating the hand (PA projection) causes cross-over between the radius and ulna.

AP Elbow (No Rotation) Radiographic Image

The radius and ulna are partially superimposed.

AP Elbow Lateral Rotation Radiographic Image

Results in separation of the radius and ulna.

AP Elbow Medial Rotation Radiographic Image

Results in superimposition of the radius and ulna.

Extrasynovial Fat Pads

Fat pads located outside the synovial sac but within the joint capsule.

Scaphoid Fat Stripe Location

Visualized on PA and PA oblique projections of the wrist on the radial aspect.

Pronator Fat Stripe Location

Visualized on the lateral wrist projection approximately 1/4 inch from the anterior surface of the distal radius.

Diagnostic Value of Scaphoid Fat Stripe

Absence or displacement may be the only indicator of a fracture on the radial aspect of the wrist.

Diagnostic Value of Pronator Fat Stripe

Displacement or obliteration of its plane indicates subtle fractures of the distal radius.

Anterior Fat Pad of Elbow

Visible on the lateral projection; elevates and distorts in shape with trauma or infection.

Posterior Fat Pad of Elbow

Located deep within the olecranon fossa; normally NOT visible on a negative exam. Visualization at 90-degree flexion indicates joint pathology.

Supinator Fat Stripe

A long, thin stripe anterior to the proximal radius that may indicate radial head or neck fractures.

Projection Required for Elbow Fat Pads

Elbow fat pads and stripes are visible ONLY on the lateral projection.

Finger Radiograph CR Placement

Central Ray (CR) is directed to the PIP joint.

Finger Radiograph Extent

Requires inclusion of 1/3 of the metacarpal for the digit being radiographed (except thumb).

PA Thumb CR Placement

CR centered to the first MCP joint (results in increased OID compared to AP).

PA 45° Oblique Thumb CR Placement

CR directed to the first MCP joint while thumb rests in its natural oblique position.

Modified Robert's Method

AP axial projection with CR angled 15° proximal (toward wrist) to the first CMC joint to rule out a Bennett fracture.

Lewis Modification

A modification of the AP axial thumb projection centering CR to the 1st MCP joint with a 10-to-15-degree proximal angle.

Folio Method

PA stress projection of bilateral thumbs to check for sprain or tearing of the ulnar collateral ligament at the MCP joint.

Skier's Thumb Injury

Sprain or tearing of the ulnar collateral ligament of the thumb at the MCP joint resulting from acute hyperextension.

PA Hand CR Placement

Central Ray (CR) directed to the third MCP joint.

Purpose of Support Block in PA Oblique Hand

Places digits parallel to the IR to prevent foreshortening of phalanges and obscuring of IP joints.

Oblique Hand Adaptation for Metacarpals

If metacarpals are the only interest, the image can be taken with thumb and fingertips touching the IR.

Flexion and Extension Lateral Hand Projections

Alternatives to fan lateral used for localization of foreign bodies and demonstration of anterior or posterior displaced metacarpal fractures.

Norgaard Method ('Ball-catcher')

AP bilateral oblique projection performed with hands in a 45° oblique position.

Clinical Indication for Norgaard Method

Evaluation of early arthritic changes at the joints of the hands and fingers, especially at the base of the phalanges.

Lateral Wrist Clinical Indications

Demonstrates fractures or dislocations of distal radius/ulna (Barton, Colles, or Smith fractures) and osteoarthritis in trapezium and 1st CMC joint.

Contraindication for PA Axial Scaphoid Projection

Do NOT perform with ulnar deviation angle if the patient has possible wrist trauma.

Modified Stecher Method

PA scaphoid projection performed with the hand elevated 20° and a perpendicular CR.

Bridgman Recommendation for Scaphoid

Recommends adding ulnar deviation in addition to elevating the hand 20° for less scaphoid superimposition.

Radial Deviation Wrist CR Placement

CR directed perpendicular to the midcarpals.

Gaynor Hart Method

Tangential inferosuperior projection of carpal canal with CR 25° to 30° to hand, and hand/wrist rotated 10° toward radius.

Clinical Indications for Gaynor Hart Method

Rules out abnormal calcification and bony changes in carpal sulcus that impinge on median nerve, as well as carpal tunnel syndrome.

Tangential (Carpal Bridge) Projection

Hand hyperflexed, CR 45° distally to forearm centered to midpoint of distal forearm 1.5 inches proximal to wrist.

Clinical Indication for Carpal Bridge Projection

Demonstrates calcification or other pathology of the dorsal (posterior) aspect of carpal bones.

Elbow Medial Oblique Projection

Elbow in 45° internal (medial) rotation; BEST visualizes coronoid process of ulna and trochlea in profile.

Elbow Lateral Oblique Projection

Elbow in 45° external (lateral) rotation; BEST visualizes radial head and neck of radius, and capitulum of humerus.

Radial Head Lateromedial Projections Purpose

Series of four projections with varying hand rotation performed for occult fractures of radial head or neck.

Small to Medium Dry Plaster Cast Conversion

Increase exposure factors by 5 to 7 kVp.

Large or Wet Plaster Cast Conversion

Increase exposure factors by 8 to 10 kVp.

Fiberglass Cast Conversion

Increase exposure factors by 3 to 4 kVp.