Forearm Flashcards
- Proximal and distal articulations of the radius
2. Proximal and distal articulations of the ulna
- Proximal= humerus at elbow joint and ulna at radioulna joint
Distal= scaphoid and lunate bones, and ulna at distal radioulna joint - Proximal= humerus at elbow joint and head of the radius at radioulna joint
Distal= articulates with radius at distal radioulna joint (does not take place in wrist formation)
Colles and smith fractures result from?
What does it cause
Difference between colles and smith
Fracture of the distal end of the radius from falling on an outstretched hand
Causes “dinner fork deformity” (posterior bump)
Colles and smith are reverse: colles= distal fragment is displaced anteriorly; smith= distal fragment is displaced posteriorly
What is the deep fascia that keeps the long flexor tendons in position at the wrist called?
Median nerve can be compressed at this level causing?
Deep fascia that keeps the extensor tendons in alignment is called?
Flexor retinaculum
Carpal tunnel syndrome
Extensor retinaculum
Pronator Teres
Origin
Insertion
Innervation
Action
Origin- medial epicondyle, medial border of coronoid process, and medial supracondylar ridge
Insertion- lateral surface of radial shaft (pronator tuberosity)
Innervation- median nerve
Action- pronation and flexion of forearm
Flexor carpi radialis
Origin
Insertion
Innervation
Action
Origin- medial epicondyle, adjoining deep fascia
Insertion- palmar surface of base of second and third metacarpal bones
Innervation- median nerve
Action- flexor of wrist, abduction of wrist
Palmaris longus
Origin
Insertion
Innervation
Action
Origin- medial epicondyle of humerus
Insertion- flexor retinaculum
Innervation- median nerve
Action- weak flexor of wrist
Flexor carpi ulnaris
Origin
Insertion
Innervation
Action
Origin- medial epicondyle of humerus, medial margin of olecranon process and 2/3 of posterior border of ulna
Insertion- pisiform bone, hook of hamate and 5th metacarpal bone
Innervation- ulnar nerve
Action- flexor of wrist, adduction of wrist
Flexor digitorum superificialis (intermediate layer)
Origin
Insertion
Innervation
Action
Origin- medial epicondyle, medial aspect of coronoid process, anterior oblique line of radius
Insertion- middle phalanx of medial four fingers
Innervation- median nerve
Action- flexion of middle phalanx at proximal interphalangeal joint, flexion of metacarpophalangeal joint and wrist joint (in prolonged contraction)
Flexor pollicis longus (deep flexor)
Origin
Insertion
Innervation
Action
Origin- anterior surface of shaft of radius below anterior oblique line; adjoining interossesous membrane
Insertion- palmer surface of base of distal phalanx of thumb
Innervation- median nerve
Action- flexor of thumb, flexor of hand at wrist joint
Flexor digitorum profundus (deep flexor)
Origin
Insertion
Innervation
Action
Origin- upper 3/4 of ulnar shaft
Insertion- palmar surface of base of distal phalanx of medial four fingers
Innervation- medial part of little and ring finger= ulnar nerve; lateral part of index and middle fingers= median nerve
Action- flexes distal phalanx of medial 4 fingers, flexes middle and proximal phalanges, and flexes hand at wrist joint
Pronator Quadratus
Origin
Insertion
Innervation
Action
Origin- lower 1/4 of ulna
Insertion- lower 1/4 of radius and adjoining anterior border of radius
(This muscle runs horizontally)
Innervation- median nerve
Action- pronates the forearm
- Ulna artery is deep to what muscle in the upper part of the forearm?
- Radial artery is covered by what muscle in the upper part of the forearm?
- Both heads of the pronator teres
2. Brachioradialis
- Median nerve rests on what muscle?
2. What 4 forearm muscles does the median nerve innervate? (Hint: all on flexor side)
- Brachialis
2. Pronator teres, flexor digitorum superficialis, palmaris longus, flexor carpi radialis
- Ulnar nerve enters the forearm by passing between both heads of what muscle?
- Ulnar nerve is accompanied by what for most of its course in the forearm?
- What two muscles does it innervate?
- Flexor carpi ulnaris
- Ulnar artery
- Flexor carpi ulnaris and medial half of the flexor digitorum profundus
Brachioradialis
Origin
Insertion
Innervation
Action
Origin- upper part of lateral supracondylar ridge of humerus
Insertion- base of styloid process of radius
Innervation- radial nerve
Action- flexion of forearm at elbow joint; supination of forearm
Extensor carpi radialis longus
Origin
Insertion
Innervation
Action
Origin- lateral supracondylar ridge of humerus
Insertion- posterior surface of base of second metacarpal bone
Innervation- radial nerve
Action- extension of hand at wrist joint; abduction of hand at wrist joint
Extensor carpi radialis brevis
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle of humerus
Insertion- posterior surface of base of third metacarpal bone
Innervation- deep branch of radial nerve
Action- extension of hand at wrist joint; abduction of hand at wrist joint
Extensor digitorum
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle of humerus
Insertion- middle and distal phalanges of medial 4 fingers
Innervation- deep branch of radial nerve
Action- extension of hand at wrist joint; extension of proximal, middle and distal phalanges of medial four digits
Extensor digiti minimi
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle of humerus
Insertion- extensor expansion of little finger
Innervation- deep branch of radial nerve
Action- extension of the hand at wrist joint; extension of proximal, middle, and distal phalanges of little finger
Extensor carpi ulnaris
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle; posterior border of the shaft of ulna
Insertion- base of 5th metacarpal bone
Innervation- deep branch of radial nerve
Action- extends and adducts hand at wrist
Anconeus
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle
Insertion- lateral surface of olecranon process of ulna; upper part of posterior surface of the shaft of ulna
Innervation- radial nerve
Action- extends elbow joint
Supinator
Origin
Insertion
Innervation
Action
Origin- lateral epicondyle; annular ligament of proximal radioulnar joint; and ulna
Insertion- neck and shaft of radius
Innervation- deep branch of radial nerve
Action- supination of forearm
Abductor pollicis longus
Origin
Insertion
Innervation
Action
Origin- posterior surface of shafts of radius and ulna
Insertion- base of first metacarpal bone
Innervation- deep branch of radial nerve
Action- abducts and extends the thumb
Extensor pollicis brevis
Origin
Insertion
Innervation
Action
Origin- posterior surface of shaft of radius
Insertion- base of proximal phalanx of thumb
Innervation- deep branch of radial nerve
Action- extends metacarpophalangeal joints of thumb
