Muscles of the Forearm Flashcards
Abductor pollicis longus innervation
radial nerve
Posterior compartment, deep
(C6-8)
Attachments of the abductor pollicis longus
from proximal posterior radius, ulna and interosseous membrane to the base of the 1st metacarpal & trapezium
Actions of the abductor pollicis longus
abducts and extends the thumb at the carpometacarpal joint and abducts hand at wrist (radial deviation)
Innervation of the brachioradialis
radial nerve
(C5-6)
(posterior compartment- superficial layer)
What is the only non-extensor muscle in the posterior compartment of the forearm (superficial layer)?
brachioradialis
Attachments of the brachioradialis
From the lateral supracondylar ridge of the humerus –> distal radius lateral to the styloid process
Actions of the brachioradialis
elbow flexion
extensor carpi radialis brevis (ECRB) INNERVATION
radial nerve (C6-8)
posterior compartment, superficial layer
Attachments of the extensor carpi radialis brevis
lateral epicondyle of the humerus (common extensor origin) –> base of the the 3rd metacarpal
Actions of the ECRB
Extends and abducts the hand at the wrist (radial deviation)
extensor carpi radialis longus innervation
radial nerve
C6-8
(posterior compartment of forearm, superficial layer)
Attachments of the extensor carpi radialis longus
lateral supracondylar ridge of the humerus–> base of the 2nd metacarpal
Actions of the extensor carpi radialis longus
extension and abduction of the hand at wrist (radial deviation) and assist in flexion of the elbow
Innervation of the extensor carpi ulnaris
radial nerve
(posterior compartment of the forearm, superficial layer)
C6-8
Attachments of the extensor carpi ulnaris
lateral epicondyle of the humerus (common extensor origin) to the base of the 5th metacarpal
Actions of the extensor carpi ulnaris
extends and adducts the hand at the wrist (ulnar deviation)
Actions of the extensor carpi ulnaris
extends and adducts the hand at the wrist (ulnar deviation)
Innervation of the extensor digitorum
Radial nerve (C6-8)
posterior compartment of forearm, superficial layer
Attachments of the extensor digitorum
lateral epicondyle of the humerus (common extensor origin) to the extensor expansions of digits 2-5
Actions of the extensor digitorum
extends phalanges (primarily at MCP, secondarily at interphalangeal) and extends hand at wrist
Innervation of the extensor digiti minimi
radial nerve (C7-8)
Posterior comartment, superficial
Attachments of the extensor digiti minimi
Lateral epicondyle of the humerus (common extensor origin) to the digital expansion of 5th digit
Actions of the extensor digiti minimi
extends 5th digit (MCP and IP joints)
Innervation of extensor indicis
radial nerve (C7-8)
DEEP layer of posterior compartment
Attachments of the extensor indicis
from the posterior surface of the ulna and interosseous membrane –> the digital expansion of the 2nd digit
Actions of the extensor indicis
extends 2nd digit (MCP & IP)
Innervation of the extensor pollicis brevis
radial nerve (C6-8)
posterior compartment, deep layer to the thumb
Attachments of the extensor pollicis brevis
posterior radial surface and interosseous membrane –> the base of the 1st proximal phalanx
Actions of the extensor pollicis brevis
extends the thumb at MCP and extends and abducts CMC joint
Innervation of the extensor pollicis longus
radial nerve
(C6-8)
(posterior compartment, deep muscles to the thumb)
Attachments of the extensor pollicis longus
middle 1/3rd of the posterior surface of the ulna and interosseous membrane –> the base of the 1st distal phalanx
Actions of the extensor pollicis longus
extends the thumb (CMC, MCP, and IP)
Innervation of the flexor carpi radialis
median nerve
(C6-8)
(anterior compartment, superficial)
Attachments of the flexor carpi radialis
the medial epicondyle (common flexor origin) to the palmar aspect of the base of the 2nd metacarpal
Actions of the flexor carpi radialis
flexes & abducts hand at wrist (radial deviation) and
may assist in pronation of forearm & flexion of the elbow
Innervation of the flexor carpi ulnaris
ulnar nerve (C7-T1)
anterior compartment, superficial
Attachments of the flexor carpi ulnaris
from the medial epicondyle (common flexor origin) of the humerus and proximal ulnar shaft to the pisiform (medial carpal bone)
Actions of the flexor carpi ulnaris
flexes & adducts hand at wrist (ulnar deviation) and
assists in flexion of the elbow
Innervation of the palmaris longus
median nerve
(C7-8)
(ant compartment, superficial)
Attachments of the palmaris longus
medial epicondyle of the humerus (common flexor origin) to palmar aponeurosis
Actions of palmaris longus
flexes hand at wrist
tenses palmar fascia
Innervation of pronator teres
Median nerve (C6-7)
ant compartment, superficial
Attachments of the pronator teres
from the medial epicondyle and ulnar coronoid process (2 heads to this muscle) to lateral aspect of the radius
Actions of the pronator teres
pronates forearm
flexes forearm
Innervation of flexor digitorum superficialis
median nerve (C7-T1)
ant compartment, intermediate layer
Attachments of the flexor digitorum superficialis
from the medial epicondyle (common flexor origin) of the humerus –> the bodies (sides) of the middle phalanges of digits 2-5
Actions of flexor digitorum superficialis
flexion of digits (MCP & PIP),
flexion of hand at wrist
Innervation of flexor digitorum profundus
median (anterior interosseous nerve; 2nd & 3rd digits)
ulnar (4th & 5th digits) nerves (ULNAR NERVE TO FDP and FCU in anterior compartment)
(C7-T1)
(ant compartment, deep)
Attachments of the flexor digitorum profundus
from the anterior proximal two thirds of the ulna and interosseous membrane to the base of the distal phalanges of digits 2-5
Actions of flexor digitorum profundus
flexion of digits 2-5 (MCP, DIP, PIP) and flexion of hand at wrist
Innervation of the flexor pollicis longus
median nerve (anterior interosseous nerve)
C7-T1
(anterior compartment, deep)
What 3 muscles are innervated by the anterior interosseous nerve (from the median nerve)
flexor pollicis longus, pronator quadratus, flexor digitorum profundus (radial side)
Attachments of the flexor pollicis longus
from the anterior surface of the radius and interosseous membrane to the base of the distal phalanx of the thumb
Actions of the flexor pollicis longus
flexes thumb at MCP and IP joints
Innervation of the pronator quadratus
median nerve (anterior interosseous nerve) (C8-T1)
anterior compartment, deep
Attachments of the pronator quadratus
from the anterior surface of the distal ulna to the anterior surface of the distal radius
Actions of the pronator quadratus
pronates the forearm
Innervation of the supinator
radial nerve (C5-6)
posterior compartment, deep
Attachments of the supinator
from the lateral epicondyle of the humerus, radial collateral ligament and supinator crest of the ulna –> the lateral surface of the proximal radius
Actions of the supinator
supinates the forearm
What 4 extensor muscles do not attach at the lateral epicondyle (common extensor origin)?
extensor carpi radialis longus - lateral supracondylar ridge of the humerus
extensor indicis - from the posterior surface of the ulna & interosseous membrane
extensor pollicis brevis- from the posterior radial surface & interosseous membrane
extensor pollicis longus- from the middle 1/3rd of the posterior surface of the ulna & interosseous membrane
Do the extensor pollicis longus and the extensor pollicis brevis have proximal attachments on the same bone?
no
longus- ulna
brevis- radius
What flexor muscles/anterior forearm muscles do not attach at the medial epicondyle of the humerus?
flexor digitorum profundus- anterior proximal 2/3 of the ulna and interosseous membrane
flexor pollicis longus-
pronator quadratus
What muscle is not a forearm extensor but still attaches at the lateral epicondyle of the humerus?
the supinator
