Forearm and Wrist Flashcards
Which distal end of the radius or ulna is larger?
Distal end of radius is larger than distal end of ulna
Which 2 carpal bones of the wrist does the radius articulate with?
Scaphoid
Lunate
What process on the distal radius articulates with the carpal bones?
Radius styloid process
Name the tubercle on the posterior side of the distal end of the radius
Dorsal tubercle
Name the notch on distal end of radius that articulates with the ulna
Ulnar notch
Name the notch on distal end of radius that articulates with the ulna
Ulnar notch
Which order of bones does force through the hand pass through?
Force will go through radius distally then pass through ulna (size of bone reflects where force is beared)
What joins the radius and ulna in the forearm?
Interosseous membrane
Does the ulna directly articulate with carpal bones?
No, it articulates with an fibrocartilage disc positioned above the carpal bones
Name the carpal bones of the hand
Trapezium
Scaphoid
Trapezoid
Capitate
Lunate
Hamate
Triquetrum
Pisiform
How many carpal bones are there?
8
How many metacarpals are there?
5
How many proximal phalanges are there?
5
How many middle phalanges are there?
4
How many distal phalanges are there?
5
Which carpal has a prominent hook?
Hamate
Which carpal bone articulates with the thumb?
Trapezium
Which carpal bone articulates with the fibrocartilage disc attached to the ulna?
Triquetrum
Through which carpal bone is most force of the hand transmitted through?
Scaphoid (little bit through lunate)
Which forearm bone crosses over in pronation?
The radius crosses over the ulna in pronation
All muscles involved in movement of the hand are _________ to the hand
Extrinsic
What does it mean if the muscle is extrinsic to the hand?
The main belly of the muscle is in the forearm, only tendons are sent to the hand
Why can the hand adduct more than it can abduct?
The radius styloid process is larger than the ulnar styloid process, so less movement is possible around the radius styloid process
What movement can the thumb do that the other digits cannot do?
Opposition (contact to other digits)
What movement can the thumb do that the other digits cannot do?
Opposition (contact to other digits)
What type of joint is the wrist joint?
Synovial joint - all carpal bones are contained in the same synovial membrane
Which bones are involved in the mid carpal joint
The proximal and distal row of carpal bones
Can all mammals carry out supination?
No, most 4 legged mammals are permanently pronated so that the digits face forwards
How are the anterior and posterior compartments of the arm displaced?
Anterior compartment displaces towards the ulna
Posterior compartment displaces towards the radius
What wrist action does the anterior compartment of the arm conduct?
Flexion and abduction
What wrist action does the posterior compartment of the arm conduct?
Extension and adduction
Which side of the arm conducts abduction?
Radial side
Which side of the arm conducts adduction?
Ulnar side
Which side of the arm conducts adduction?
Ulnar side
What nerve innervates the whole posterior compartment of the arm?
Radial nerve
How many muscles are present on the superficial layer of posterior compartment of forearm?
7 muscles
Name the 7 muscles of the superficial layer of the posterior compartment of forearm
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Anconeus
What is the origin of brachioradialis?
Lateral supraepicondylar ridge
What is the insertion of brachioradialis?
Lateral surface of distal radius
What innervates brachioradialis?
Radial nerve
What is the action of brachioradialis?
Flexion of elbow when arm is partially pronated
What is the action of brachioradialis?
Flexion of elbow when arm is partially pronated
What is the origin of extensor carpi radialis longus and brevis?
Lateral supraepicondylar ridge (longus)
Lateral epicondyle (longus and brevis)
What is the insertion of extensor carpi radialis longus and brevis?
Base of metacarpal 2 (longus and brevis)
Base of metacarpal 3 (brevis)
What innervates extensor carpi radialis longus and brevis?
Radial nerve
What is the action of extensor radialis longus and brevis?
Extension and abduction of the wrist
What is the origin of extensor digitorum?
Lateral epicondyle
What is the insertion of extensor digitorum?
Extensor hoods of digits 2-5
What innervates extensor digitorum?
Radial nerve
(Posterior interosseous nerve)
What is the action of extensor digitorum?
Extends digits 2-5 and the wrist
What is the origin of extensor digiti minimi?
Lateral epicondyle
What is the insertion of extensor digiti minimi?
Extensor hood of digit 5
What innervates extensor digiti minimi?
Radial nerve
(Posterior interosseus)
What is the action of extensor digit minimi?
Accessory extensor of digit 5
What is the origin of extensor carpi ulnaris?
Lateral epicondyle
What is the insertion of extensor carpi ulnaris?
Base of metacarpal 5
What innervates extensor carpi ulnaris?
Radial nerve
(Posterior interosseous)
What is the action of extensor carpi ulnaris?
Extension and adduction of the wrist
What is the origin of aconeus?
Lateral epicondyle
What is the insertion of aconeus?
Olecranon and posterior surface of ulna
What is the innervation of aconeus?
Radial nerve
What is the action of aconeus?
Abducts ulna to maintain position of the hand, stabilises elbow joint
How many muscles are in the deep layer of posterior compartment of forearm?
5
How many muscles are in the deep layer of posterior compartment of forearm?
5
Which 2 superficial muscles of posterior compartment of forearm do not cross the wrist joint?
Brachioradialis
Anconeus