RAD 155 Ch. 4 (Finger to Elbow)

Anatomy of the Upper Extremity

Study of the structure of the upper limb, including bones, joints, and muscles.

Bones in Hand

There are 27 bones in each hand, comprising phalanges, metacarpals, and carpals.

Phalanges (Fingers)

14 phalanges in each hand: 3 in digits 2-5 and 2 in the thumb.

Metacarpals

5 metacarpals form the palm of the hand.

Carpals

8 carpals in each wrist, divided into two rows.

Radius

One of the two forearm bones, located anteriorly.

Ulna

One of the two forearm bones, located posteriorly.

Distal Phalanx

The outermost phalanx bone of the fingers.

Middle Phalanx

The middle phalanx bone found in digits 2-5.

Proximal Phalanx

The innermost phalanx bone nearest the hand.

Naming Phalanges

Phalanges are named based on their location (e.g., distal phalanx of the third digit).

Role of Metacarpals

Contain metacarpal bones that form the palm of the hand.

Carpometacarpal Joint

Saddle-shaped joint at base of the thumb connecting trapezium to first metacarpal.

Proximal Row of Carpals

Arrangement includes scaphoid, lunate, triquetrum, pisiform.

Distal Row of Carpals

Arrangement includes trapezium, trapezoid, capitate, hamate.

Scaphoid

Largest carpal bone; most commonly fractured.

Lunate

Moon-shaped carpal bone that aligns with the radius.

Triquetrum

Triangular-shaped carpal bone that lies under the pisiform.

Pisiform

Small, pea-shaped carpal bone sitting atop the triquetrum.

Trapezium

Saddle-shaped carpal bone beneath the first metacarpal.

Trapezoid

Smallest bone in the distal row, located under the second digit.

Capitate

Largest carpal bone located under the third digit.

Hamate

Carpal bone shaped like a hook, situated between 4th & 5th digit.

Mnemonic for Carpals

"Steve Left The Party To Take Carol Home" helps remember carpal bone arrangement.

Common Hand and Wrist Fractures

Includes Bennett's fracture, Boxer's fracture, Colles' fracture, and Smith’s fracture.

Bennett's Fracture

Fracture of the first metacarpal at the base.

Boxer’s Fracture

Fracture of the fifth metacarpal, often caused by a punch.

Colles' Fracture

Distal radius fracture with posterior displacement; commonly from a fall.

Smith’s Fracture

Distal radius fracture with anterior displacement; typically from a flexed wrist fall.

Fat Pads

Soft tissue cushioning around joints to help protect bones and cartilage.

Carpal Tunnel

Passageway for the median nerve through the wrist.

Trochlear Notch

Indentation on the ulna where it articulates with the radius at the elbow.

Radial Notch

Shallow depression on the ulna allowing for radius rotation.

Coronoid Process

Process of ulna providing stability to the elbow joint.

Medial Definition

Direction towards the midline of the body.

Lateral Definition

Direction towards the sides of the body (outward).

Ulnar Deviation

Wrist movement resulting in outward bending towards the ulna.

Radial Deviation

Wrist movement resulting in inward bending towards the radius.

IP Joints

Interphalangeal joints between phalanges.

MCP Joints

Metacarpophalangeal joints connecting metacarpals and phalanges.

CMC Joints

Carpometacarpal joints at the bases of the metacarpals.

IR/Collimated Field Size

Sizes adjusted according to anatomy for radiation protection.

IR Size Hand

10 x 12 inches for fingers; 14 x 17 inches for the entire hand.

IR Size Wrist

10 x 12 inches size for wrist imaging.

IR Size Forearm

14 x 17 inches size for forearm imaging.

SID

Source-to-image distance; 40 inches used for upper limb imaging.

Patient Preparation

Remove artifacts and explain the imaging procedure to the patient.

Breathing Instructions for Imaging

Not required for digits, hand, and wrist procedures.

Kilovoltage Peak (kVp)

Controls the strength of the X-ray beam during imaging.

Hand & Finger kVp

Usually in the range of 50–60 kVp when taking X-rays.

Elbow kVp

Typically ranges from 60–70 kVp for elbow X-rays.

Essential Projections for Imaging Digits 2-5

Includes PA, PA oblique, and lateral projections.

Essential Projections for Thumb

Includes AP, PA oblique, and lateral projections.

Hand Projections

Requires PA, PA oblique, lateral, extension, and fan projections.

Wrist Projections

Includes PA, PA oblique, lateral, PA axial & Tangential Carpal Tunnel projections.

Forearm Anatomy

Comprises two long bones: ulna and radius.

Elbow Joint Projections

Only two: AP and lateral projections.

AP Elbow

Elbow extended with hand supinated; CR at midpoint.

Lateral Elbow

Lateromedial projection, elbow flexed at 90 degrees, CR at midpoint.

Monteggia Fracture

Fracture of the proximal ulna with dislocation of the radial head.

Supracondylar Fracture

Fracture of the distal humerus, common in children.

Practice Requirements for Test

Understanding anatomy and related procedures is crucial for exam success.

Preparation for Test

Includes understanding anatomy and related procedures from Chapters 4 & 5.

Cross Table Lateral

Elbow in true lateral position, done first in trauma imaging.

Fun Fact about Foot and Forearm

Your foot is the exact same size as your forearm.

Collimated Field Size for Elbow Imaging

3 inches proximal and distal to the elbow joint, and 1 inch on the sides.

Radiographic Procedures for Forearm

Requires essential projections AP and lateral.

Essential Projections for Humerus

AP, AP oblique (medial/lateral), and lateral projections.

Breath Instructions for Non-motion Procedures

Tell the patient not to move during digit, hand, and wrist procedures.