Lippert: Chapter 12 Wrist Joint

Why is the ulna not considered part of the wrist joint?

Because an articular disk is located between the ulna and the proximal row of carpals

Generally speaking, you use wrist muscles when hammering. However, when extra force is needed, you may use elbow or even shoulder muscles. Why does this create greater force?

Because you are using a longer lever arm and using larger muscles.

The radiocarpal joint is also classified as what kind of joint? (How many directions?)

Biaxial (2), flexion & extension, radial deviation & ulnar deviation (combination is called circumduction, no rotation at wrist)

dorsal radiocarpal ligament

attaches from posterior surface of the distal radius to the same surface of the scaphoid, lunate, and triquetrum; limits flexion

articular disk

distal end of the ulna and articulates with the triquetrum and lunate bones; acts as shock absorber and as filler b/w distal ulna and adjacent carpal bones - the triquetrum and lunate

Which muscles cross the wrist on the ulnar side?

extensor carpi ulnaris and flexor carpi ulnaris

Which muscles attach on or close to the lateral epicondyle of the humerus?

extensor carpi ulnaris, extensor carpi radialis longus, extensor carpi radialis brevis

Which muscles attach on the medial epicondyle of the humerus?

flexor carpi ulnar, palmaris longus, flexor carpi radialis

The radial collateral ligament provides _____ support.

lateral

What is the name of the bony landmark just proximal to the lateral epicondyle?

lateral supracondylar ridge

The ulnar collateral ligament provides ________ support.

medial

Which muscles, if present, is very easy to identify but has little functional important

palmaris longus O: medial epicondyle I: palmar fascia (palmar aponeurosis) A: assistive in wrist flexion median nerve, C6, C7)

Describe the wrist joints: a. number of axes radiocarpal_________ intercarpal ________

radiocarpal - 2 intercarpal -0

Describe the wrist joints: b. shape of joint radiocarpal_________ intercarpal ________

radiocarpal - condyloid intercarpal - plane or irregular

Describe the wrist joints: c. joint motion allowed radiocarpal_________ intercarpal ________

radiocarpal - flexsion/extension, radial/ulnar deviation intercarpal - gliding

palmar fascia

relatively thick, triangular fascia located superficially in palm (palmar aponeurosis); covers tendons of extrinsic muscles and provides some protection

palmar radiocarpal ligament

thick, tough ligament that limits wrist extension; attaches from anterior surface of the distal radius and ulna to the capitate bone in the distal row(stronger than dorsal radiocarpal ligament)

The radiocarpal joint is classified as what kind of joint?

Condyloid, with the concave distal end of the radius and the articular disk articulating with the convex scaphoid, lunate, and triquetrum.

Identify the wrist joint position and the muscle group contracting isometrically. pushing down a stapler a. wrist position b. wrist muscle group

a. neutral/extension b. flexors

What does the radiocarpal joint consist of?

Distal end of the radius and the radioulnar disk proximally and the scaphoid, lunate, and triquetrum distally.

Which muscles cross the wrist on the radial side?

Extensor carpi radialis and flexor carpi radialis

What are the joint motions of the wrist?

Flexion, neutral position, extension, ulnar deviation, and radial deviation

Starting on the anterior surface of the ulnar side and moving in the direction of the radial side, name the wrist muscles that cross the wrist. Go completely around the wrist.

Flexor carpi ulnaris, palmaris longus (with flexor digitorum superficialis and profundus deep to it), flexor carpi radialis (abductor pollicis longus, extensor pollicis long and brevis, which are primarily thumb muscles but also cross the wrist), extensor carpi radialis longus, extensor carpi radialis brevis(extensor digitorum, a finger extensor), extensor carpi ulnaris

If you were shown a drawing of only a wrist joint, what landmarks could tell you if the drawing were a posterior or anterior view?

If the pisiform and "hook" of the hamate bone are visible, it would be the anterior side.

extensor carpi radialis brevis Origin: Insertion: Action: Nerve:

Origin: lateral epicondyle Insertion: base of 3rd metacarpal Action: wrist extension Nerve: radial (c6, c7)

flexor carpi radialis Origin: Insertion: Action: Nerve:

Origin: medial epicondyle Insertion: base of 2nd and 3rd metacarpals Action: wrist flexion, radial deviation Nerve: median (C6, C7)

palmaris longus Origin: Insertion: Action: Nerve:

Origin: medial epicondyle Insertion: palmar fascia Action: assistive in wrist flexion Nerve: median (C6, C7)

flexor carpi ulnaris Origin: Insertion: Action: Nerve:

Origin: medial epicondyle Insertion: pisiform and base of 5th metacarpal Action: wrist flexion, ulnar deviation Nerve: ulnar (C8, T1)

extensor carpi radialis longus Origin: Insertion: Action: Nerve:

Origin: supracondylar ridge Insertion: base of 2nd metacarpal Action: wrist extension, radial deviation Nerve: radial nerve (C6, C7)

extensor carpi ulnaris Origin: Insertion: Action: Nerve:

Origin:lateral epicondyle Insertion: base of 5th metacarpal Action: wrist extension, ulnar deviation Nerve: radial (c6, c7, c8)

Name the bones of the wrist joint, starting laterally on the proximal row of going medially. Use the same order for the distal row.

Proximal:Scaphoid, lunate, triquetrum, pisiform Distal: trapezium, trapezoid, capitate, hamate

What two joints make up the wrist joint?

Radiocarpal and midcarpal

What does the radial collateral ligament attach to?

The styloid process of the radius and to the scaphoid and trapezium bones.

What does the ulnar collateral ligament attach to?

The styloid process of the ulna and to the pisiform and triquetrum.

When hammering overhead, why are your wrist ulnar deviators working harder than when hammering at waist level?

You are working against gravity when hammering overhead and with gravity when hammering at waist level.

Which wrist motions occur in? a. the sagittal plane around the front axis? b. the frontal plane around the sagittal axis? c. the transverse plane around the vertical axis?

a. flexsion/extension b. radial/ulnar deviation c. none

Identify the wrist joint position and the muscle group contracting isometrically. holding a box from the bottom a. wrist position b. wrist muscle group

a. neutral b. flexors

Identify the wrist joint position and the muscle group contracting isometrically. Holding a cup of coffee. a. wrist position b. wrist muscle group

a. neutral or slight extension b. radial deviators

Identify the wrist joint position and the muscle group contracting isometrically. Typing on a conventional computer keyboard a. wrist position b. wrist muscle group

a. neutral or slight extension b. extensors

Identify the wrist joint position and the muscle group contracting isometrically. brushing long hair with a comb (w/ right hand brushing on left side) a. wrist position b. wrist muscle group

a. neutral or slight flexion b. flexors