Elbow, wrist, and hand

Question 1

Elbow complex

Answer 1

Humeroulnar joint - primary
Humeroradial joint
Proximal radioulnar joint

Question 2

What movements do the humeroular and humeroradial joints do?

Answer 2

Flexion and extension in the sagittal plane

Question 3

In the humeroulnar and humeroradial joint, stability is provided by…

Answer 3

Bony geometry

Ligamentous support

Question 4

Elbow motions

Answer 4

Primarily involved movement between articular surfaces of the humerus and ulna.
Radial head has a relatively small amount of contact with the capitulum of the humerus.
As the elbow reaches full extension, the olecranon process is received by the olecranon fossa.
Increased joint stability when it is fully extended.

Question 5

Radioulnar articulations

Answer 5

Include proximal and distal radioulnar joints with 1 degree of freedom.
Creates supination and pronation - motion in the transverse plane.
Classified as a trochoid synovial joint.
Annular ligament maintains radial head in its joint.
Shafts of radius and ulna are held tightly together between the proximal and distal articulations by an interosseous membrane.

Question 6

Carrying angle

Answer 6

AKA cubital valgus.
Created by intersecting of two lines - axis of humerus and axis of ulna.
Formed between the axis of movement of humeroulnar joint (which is not truly horizontal).
Allows the object carried in the hand to be away from the body.
More pronounced in females than males.

Question 7

Ligamentous support

Answer 7

Stability in flection - dependent on radial and collateral ligament and ulnar collateral ligament.

Question 8

Ulnar collateral ligament

Answer 8

Critical in providing medial support to prevent elbow from abducting when stressed in physical activity.
Many contact sports and throwing activities place stress on the medial aspect of the joint which results in injury.

Question 9

Radial collateral ligament

Answer 9

Provides lateral stability and is rarely injured.

Question 10

Annular ligament

Answer 10

Provides a sling effect around the radial head for stability.

Question 11

Limiting structures at the end of the ROM for elbow

Answer 11

Flexion: soft tissue
Extension: humeroulnar joint - the contact of olecranon process in the olecranon fossa

Question 12

Limiting structures the at the end of ROM for wrist

Answer 12

Dependent on position of hand - passive insufficiency.

Question 13

Anterior musculature in primary flexion and pronation

Answer 13

Biceps brachii
Brachialis
Brachioradialis
Pronator teres
Pronator quadratus

Question 14

Posterior musculature in primary extension and supination

Answer 14

Triceps brachii
Anconeus
Supinator

Question 15

In the wrist there are articulations between…

Answer 15

Radius/ulna and carpal bones
Carpal joints
Carpals and metacarpals

Question 16

Radiocarpal joint

Answer 16

Primary source of articulation at the wrist.

Most weight-bearing.

Question 17

Ulnocarpal joint

Answer 17

Ulna only articulates with TFDD and radius (aligned with lunate and triquetrum).
Maximum load os 20% of weight.
More muscular attachments.

Question 18

Carpals

Answer 18

Capitate - central position
Scaphoid - most commonly fractured
Lunate - most frequently dislocated
Pisiform - attatchment for flexor carpi ulnaris
Hammate - hook feature

Question 19

Carpal tunnel

Answer 19

Fibro-ossuous structure through which many anterior muscles cross the radiocarpal joint to reach the hand.
Formed by scaphoid, lunate, triquetrum, pisiform, and transverse carpal ligament.
In surgery, transverse carpal ligament is cut.
10 structures: median nerve, flexor pollicis longus, flexor digitorum, superficalis (4), flexor digitorum profundus (4).

Question 20

TFCC

Answer 20

Consists of disk, CT wedge and fibrous attachment.
Part of radioular joint and radiocarpal joint.
Suspends ulna off of lunate and triquetrum.
Acts as a space filler and shock absorber.

Question 21

The hand acts as a tool for…

Answer 21

Prehension
Sense organ - high innervation
Expression and nonverbal communication

Question 22

Carpometacarpal joints (2-5)

Answer 22

Metacarpal bases 2-5 articulate with one another.
Minimal motion of 2 and 3.
4 and 5 have significant motion.
3 is a stable pillar that the hand rotates on.
2nd metacarpal articulates with trapezoid.
3rd metacarpal articulates with capitate.
4-5th metacarpal articulates with hammate.

Question 23

Metacarpophalangeal joints

Answer 23

Condyloid joint with 2 degrees of freedom.
Cam achieve flexion/extension and abduction/adduction.
COnvex heads of the metacarpals 3 and 4 are covered with articulat cartilage.
Concave bases of phalanges are volar plates.

Question 24

Phalanges

Answer 24

Thumb - 2: proximal and distal.

Digits 2-5 - 3: proximal, middle, distal.

Question 25

Interphalangeal joints.

Answer 25

Digits 2-5: proximal interphalangeal and distal interphalangeal joints. Thumb has one interphalangeal joint. Hinge notion has one degree of freedom. Can achieve flexion/extension, while sliding is an accessory motion.

Question 26

Thumb

Answer 26

Highly mobile. Carpometacarpal joint is a sellar joint that enhances mobility. 9 muscles that facilitale positioning. MOtions: flexion/extension, abduction/adduction, opposition/reposition.

Question 27

Hand functions

Answer 27

Prehension | Powergrips

Question 28

Prehension

Answer 28

Grasping or taking hold of an object between and 2 surfaces in the hand. The thumb may or may not participate. The grip is used for accuracy and refinement - object manipulation.

Question 29

Power grips

Answer 29

Incorporate entire hand. Used for gross grasping activities. Involved in holding and object between partially flexed fingers and palm while the thumb provides a counter-perspective.

Question 30

Optimal positioning of wrist and hand

Answer 30

Wrist: slight extension and ulnar deviation MCP: flexed 45 degrees PIP: flexed 30 degrees DIP: slightly flexed