Muscles of the Posterior Forearm Flashcards
Group of muscles that are the extensors and supinators of the wrist and hand
Muscles of the posterior forearm
All muscles of the posterior forearm are innervated by the
Radial Nerve
4 of the 7 superficial muscles of the posterior forearm originate where?
Common extensor tendon from the lateral epicondyle of the humerus
The other 2 muscles of the posterior forearm originate where?
Slightly above the others on the lateral supracondylar ridge
All extensor muscle tendons that pass to the hand are held in place by
Extensor Retinaculum
Attaches the tendons to the phalanges on the posterior side of the fingers. A triangular hood like structure that covers the dorsal surface of each digit
Extensor expansion hood
The 7 muscles of the superficial posterior forearm
Anconeus Extensor Carpi Ulnaris Extensor Digiti Minimi Extensor Digitorum Extensor Carpi Radialis Brevis Extensor Carpi Radialis Longus Brachioradialis
Long thin muscle partly overlapped by the brachioradialis on posterior forearm
Extensor Carpi Radialis Longus
Where does the extensor carpi radialis insert?
Base of 2nd metacarpal
Actions of the extensor carpi radialis
Extends and abducts the wrist (makes a fist)
Origin of the extensor radialis longus
Lateral supracondyle ridge of the humerus
Innervated by
Radial nerve
Muscle that is slightly shorter than the extensor carpi radialis longus that lies deep to it
Extensor radialis brevis
Actions of the extensor radialis brevis
Extends and abducts the wrist
Origin of the extensor carpi radialis brevis
Lateral epicondyle of the humerus (common extensor tendon
Insertion of the extensor carpi radialis brevis
Base of the 3rd metacarpal
Innervated by
Radial Nerve
The muscle that is the main extensor of the four fingers
Extensor Digitorum
The insertion of the extensor digitorum that is a tent of connective tissue
The extensor expansion hood
Actions of the extensor digitorum
Extends the proximal phalynx of the digits
Middle and distal phalanges are extended
Extends hand at the wrist
Origin of the extensor digitorum
Insertion of the extensor digitorum
Nerve
Lateral epicondyle of the humerus
Extensor expansion hood
Radial nerve
Muscle that is a thin slip partially attached to extensor digitorum that goes to the little finger
Extensor Digiti Minimi
Actions of extensor digiti minimi
Extends proximal phalynx of fifth finger
Assists in extension of hand
Innervated by
Radial Nerve
Long band like muscle located along medial border of the forearm
Extensor Carpi Ulnaris
The actions of the extensor carpi ulnaris
Extends with carpi radialis and adducts the flexor carpi radialis
-(forms fist)
Origins of the extensor carpi ulnaris
Lateral epicondyle
Common extensor tendon
Fibers of posterior surface of the ulna
The five deep muscles of the posterior forearm
Supinator Abductor Pollicis Longus Extensor Pollicis Brevis Extensor Pollicis Longus Extensor Indicis
Deep muscle of the posterior forearm that wraps tightly around the upper 1/3 of the radius
Supinator
The origins of the supinator
Lateral epicondyle of the humerus
The ulna
Insertion of the supinator
The upper 1/3 of the radius
action of the supinator with the biceps brachii
Rotates the radius during supination
Muscle that is recruited when rapid forceful supination occurs
Biceps Brachii
A triangular depression on the dorso lateral side of the hand
Anatomical Snuffbox
Name the boundaries of the anatomical snuffbox
Tendons of the extensor pollicis longus
Extensor pollicis longus
Abductor pollicis longus
Muscle of the posterior forearm that originates deep to the superficial extensors and is the most lateral tendon of the snuff box
Abductor pollicis longus
Muscle that crosses the tendons of the extensor carpi radialis longus and brevis
Abductor pollicis longus
Action of the abductor pollicis longus
Abducts and extends the thub
Origination of abductor pollicis
Posterior radius and ulna,
Interosseous membrane
Insertion of abductor pollicis
Base of the first metacarpal
Innervation
Radial Nerve
Two muscles that exit obliquely from under the superficial muscle and cross over the extensor carpi radialis muscles
Extensor pollicis longus and brevis
Which of these two muscles is closely associated with the abductor pollicis longus?
Extensor pollicis brevis
Which of these two muscles hooks around a tubercle on the dorsum of the radius as a pulley?
Extensor pollicis longus
Actions of both the extensor pollices muscles
Extend the thumb
Abduct the hand
Origin of brevis
Dorsal Radius
Origin of longus
Ulna
Insertion of brevis
Proximal Phalynx of thumb
Insertion of longus
Distal phalynx of thumb
Movement of the thumb that bends the thumb medially
Flexion
Movement of the thumb that points the thumb laterally
Extension
Movement of the thumb that points anteriorly
Abduction
Movement of the thumb that brings it back posteriorly
Adduction
The deeply placed muscle covered by the extensor digitorum and inserts into the index finger
Extensor indicis
Origin of the extensor indicis
Posterior surface of the ulna
Interosseous membrane
Innervation of extensor indicis
Radial nerve
Action of extensor indicis
Extends the index finger
Inflammation of the common extensor tendon of the lateral epicondyle of the humerus, small area of origin and many muscles create high load per unit area
Lateral epicondylitis (Tennis Elbow)
Inflammation of the common flexor tendon on the medial epicondyle of the humerus
Medial epincondylitis (thrower’s elbow, golfer’s elbow, little league elbow)