Positioning Criteria-Wrist

Anatomists divide the bones of the upper extremity into what groups

hand, forearm, arm, shoulder girdle

•The hand consists of _____ bones, which are subdivided into the following groups:

27

•Phalanges: Bones of the digits (fingers and thumb)

•Metacarpals: Bones of the palm

•Carpals: Bones of the wrist

what is the correct practice when referring to the phalanges

digits

phalanges are what type of bones

long bones that consist of a cylindrical body and articular ends

how many phalanges have 2 articular ends

9

The distal phalanges are

small, flattened, and have a roughened rim around their distal anterior end; this gives them a spatula-like appearance.

The carpals have

2 rows of 4

• proximal and distal row

A triangular depression that is located on the posterior surface of the wrist and is visible when the thumb is abducted and extended is known as the

anatomic snuffbox.- tenderness in this area is a clinical sign suggesting a fracture of the scaphoid

What are the Carpal Bones Ossifcation times

•Capitate: 1-3 months

•Hamate: 2-4 months

•Triquetrum: 2-3 years

•Lunate: 2-4 Years

•Scaphoid: 4-6 Years

•Trapezium: 4-6 Years

•Trapezoid: 4-6 Years

•Pisiform: 8-12 Years

the scaphoid, the largest bone in the proximal carpal row

has a tubercle on the anterior and lateral aspect for muscle attachment and is palpable near the base of the thumb.

The lunate articulates with the

radius proximally and is easy to recognize because of its crescent shape.

•The triquetrum is approximately

pyramidal and articulates anteriorly with the hamate.

•The pisiform is a

pea-shaped bone situated anterior to the triquetrum and is easily palpated.

•Beginning at the distal row of carpals on the lateral side, the trapezium has

a tubercle and groove on the anterior surface. The tubercles of the trapezium and scaphoid constitute the lateral margin of the carpal groove.

•The trapezoid has a smaller surface

anteriorly than posteriorly.

•The capitate articulates with the

base of the third metacarpal and is the largest and most centrally located carpal.

•The ______-shaped hamate exhibits

wedge

the prominent hook of hamate, which is located on the anterior surface. The hamate and the pisiform form the medial margin of the carpal groove.

Wrist-carpal sulcus

•The anterior or palmar surface of the wrist is concave from side to side and forms the carpal sulcus.

• The flexor retinaculum, a strong fibrous band, attaches medially to the pisiform and the hook of hamate and laterally to the tubercles of the scaphoid and trapezium.

•The carpal canal or carpal tunnel is the passageway created between the carpal sulcus and the flexor retinaculum.

•The median nerve and the flexor tendons pass through the carpal canal. Carpal tunnel syndrome results from compression of the median nerve inside the carpal tunnel.

Common fractues of the hand/wrist

Bennett’s, boxer’s, torus or buckle

bennet’s

a fraucture at the base of the first metacarpal, often results from fist fights

boxer’s

fracrure of 5th metacarpal neck, often caused by direct force to a closed fist

torus/buckle

impacted fracture with buldgeing of periosteum- most common fracrtue of the distal radius and ulna in young children

Bone Age Study

•Helps doctors estimate the maturity of a child’s skeletal system

•Measured in years

•Children’s bones, such as those in the fingers and wrist, contain

growth plates

•Responsible for bones’ growth in length

•Softer bone that contain less mineral (Darker on x-rays)

•As kids grow, growth plates change in appearance on x-rays, eventually disappearing and growth plates close

•Growth plates look different at each age, allowing radiologists to determine the “bone age”

why is a bone age study done

–To determine:

• How much time a child will be growing

•When a child will enter puberty

•What the child’s ultimate height will be

–To monitor progress & guide treatment with growth affecting conditions in children

what is hositpal protocal for bone age studies

•Hospital routine varies slightly

•Most oftentimes is an x-ray of both wrists & hands, either on the same film (as shown below) or imaged separate or one separate image of the non-dominant hand

wrist/radiocarpal joint at level and just distal to

ulnar styloid

Scaphoid fat stripe

Soft tissue structures visible in a proper PA wrist.

It is convex in shape and is located just lateral to the scaphoid in an uninjured wrist. A change in the convexity of this stripe may indicate to the reviewer the presence of joint effusion or of a radial side fracture of the scaphoid, radial styloid process, or proximal first MC.

 

Failing to set the appropriate technical factors as described in Chapter 2 and to obtain a true PA projection may result in obscuring this stripe.

If the long axes of the forearm and 3rd MC are aligned

Wrist in natural position

Wrist lateral has a???

Pronator fat stripe

Lies parallel to the anterior surface of the radius

•Distortion of the pronator fat stripe is indicative of a radial fracture

On a good lateral projection, the anterior and the proximal cortical margins of these two carpals are aligned

Distal scaphoid and pisforn