Muscles of forearm Flashcards
Which muscles are included in the superficial layer of the anterior forearm?
-Pronator teres
-Flexor carpi radialis
-Palmaris longus
-Flexor carpi ulnaris
Which muscles are included in the intermediate layer of the anterior forearm?
-Flexor digitorum superficialis
Which muscles are included in the deep layer of the anterior forearm?
-Flexor digitorum
-Flexor pollicis longus
-Pronator quadratus
What attachment site do all superficial muscles of the anterior forearm share?
The medial epicondyle of the humerus
What nerve innervates the pronator teres muscle?
Median nerve (passes through PT)
What does the median nerve pass through as it descends into the forearm?
Pronator teres
What are the attachments for the pronator teres muscle?
Medial epicondyle and mid-radius
What is the action of the pronator teres muscle?
Pronates forearm (palm facing down) with elbow in extension
Which nerve innervates the flexor carpi radialis?
Median nerve
What are the attachments for the flexor carpi radialis muscle?
Medial epicondyle and 2nd metacarpal
What is the action of the flexor carpi radialis muscle?
Flexion and radial deviation of the wrist
What nerve innervates the palmaris longus muscle?
Median nerve
What are the attachments for the palmaris longus muscle?
Medial epicondyle & blends into the connective tissue of the wrist/hand (palmar carpal ligament and palmar aponeurosis)
What is the action of the palmaris longus muscle?
Flexion of the wrist and hand
What is the only muscle in the anterior superficial forearm layer that is innervated by the ulnar nerve?
Flexor carpi ulnaris muscle
What are the attachments for the flexor carpi ulnaris?
Medial epicondyle and 5th metacarpal
What is the action of the flexor carpi ulnaris?
Flexion and ulnar deviation of the wrist
What nerve innervates the flexor digitorum superficialis?
Median nerve
What are the attachments for the flexor digitorum superficialis?
Medial epicondyle and gives off 4 tendons which land on the middle phalanges of each finger
The flexor digitorum superficialis (FDS) tendon forms a Y shape to let which tendon pass through?
The flexor digitorum profunda (FDP) tendon
As the flexor digitorum superficialis descends through the carpal tunnel, it exhibits what pattern?
2x2 pattern (2 stacked on top of each other)
What is the action of the flexor digitorum superficialis muscle?
Flexion of PIP joints in the fingers
The flexor digitorum profunda is innervated laterally by which nerve?
Anterior interosseous nerve (AIN)
The flexor digitorum profunda is innervated medially by which nerve?
Ulnar nerve
What are the attachments of the flexor digitorum profunda?
Ulna/interosseous membrane and sends 4 tendons down to connect to the fingers the distal phalanges
What do the flexor digitorum profunda tendons pass through to reach the distal phalanges of the fingers?
The flexor digitorum superficialis (pops out of the Y shape of the FDS)
What is the action of the flexor digitorum profunda?
Flexion of DIP joints in the fingers
What nerve innervates the flexor pollicis longus?
The anterior interosseous nerve (AIN)
What are the attachments of the flexor pollicis longus?
Radius/interosseous membrane and sends a tendon to the distal phalange of the thumb
What is the action of the flexor pollicis longus?
Flexion of the IP joint in the thumb
What nerve innervates the pronator quadratus?
The anterior interosseous nerve (AIN)
What are the attachments of the pronator quadratus?
Distal radius and ulna
What is the action of the pronator quadratus?
Pronation of the forearm
What muscles of the anterior forearm are known as the “wrist flexors”?
Flexor carpal radialis, Flexor carpi ulnaris, Palmaris longus
What muscles of the anterior forearm are known as the “long finger flexors”?
Flexor digitorum superficialis, flexor digitorum profundus, Flexor pollicis longus
What muscles of the anterior forearm are known as the “pronators”?
Pronator teres, Pronator quadratus
Which muscles of the anterior forearm are innervated by the median nerve?
All muscles of the superficial and intermediate layers except the Flexor carpi ulnaris
Which muscles of the anterior forearm are innervated by the ulnar nerve?
Flexor carpi ulnaris and medial 1/2 of Flexor digitorum profundus
Which muscles of the anterior forearm are innervated by the AIN of the median nerve?
All muscles of the deep layer except medial 1/2 of Flexor digitorum profundus
What is the palmer carpal ligament of the anterior wrist?
Connective tissue that crosses the wrist joint
What does the palmer carpal ligament contain?
All flexor tendons crossing the wrist
What is the palmer carpel ligament a continuation of?
Extensor retinaculum (on the dorsal side of the wrist)
What are the muscles in the superficial layer of the posterior forearm?
-Brachioradialis
-Extensor carpi radialis longus
-Extensor carpi radialis brevis
-Extensor digitorum
-Extenson digiti minimi
-Extensor carpi ulnaris
What are the muscles in the deep layer of the posterior forearm?
-Extensor indices
-Outcropping muscles (Extensor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus)
-Supinator
Which muscle of the posterior forearm wraps around to land on the anterior forearm?
Brachioradialis
What nerve innervates the brachioradialis?
Radial nerve
What are the attachments of the brachioradialis?
Supracondylar ridge of the humerus and the distal radius
What is the action of the brachioradialis?
Flexion of the elbow
Which muscle is used to assess the C6 deep tendon reflex in a physical exam?
Brachioradialis
What nerve innervates the extensor carpi radialis longus?
Radial nerve
What nerve innervates the extensor carpi radialis brevis?
The deep branch of the radial nerve
What are the attachments for the extensor carpi radialis longus?
Supercondylar ridge of the humerus and 2nd metacarpal
What are the attachments for the extensor carpi radialis brevis?
Lateral epicondyle of the humerus and 3rd metacarpal
What is the action of the extensor carpi radilis longus?
Extension and radial deviation of the wrist
What is the action of the extensor carpi radilis brevis?
Extension and radial deviation of the wrist
What nerve innervates the extensor digitorum?
Posterior interosseous nerve(PIN)
What are the attachments for the extensor digitorum?
Lateral epicondyle of the humerus and digits 2-4 on the back of the hand (extensor expansion hood)
What is the action of the extensor digitorum?
Extension of the wrist
What nerve innervates the extensor digiti minimi?
Posterior interosseous nerve (PIN)
Which nerve innervates the extensor capri ulnaris?
Posterior interosseous nerve (PIN)
What are the attachments for the extensor carpi ulnaris?
Lateral epicondyle of the humerus and the 5th metacarpal on the back of the hand
What is the action of the extensor carpi ulnaris?
Extension and ulnar deviation of the wrist
What nerve innervates the supinator?
The deep branch of the radial nerve
The supinator is located deep to which muscles?
Extensor digitorum, Extensor carpi radialis brevis, Extensor capri radialis longus
What are the attachments for the supinator?
Starts at lateral epicondyle of the humerus/ulna (2 sites) and inserts in the proximal radius
Which muscle in the deep layer of the posterior forearm “wraps around the radius”?
Supinator
What is the action of the supinator?
Supination of the forearm
When the deep branch of the radial nerve reaches the lower forearm, what is it renamed?
Posterios interosseous nerve
What nerve innervates the extensor indices?
Posterior interosseous nerve (PIN)
Which muscles of the deep layer of the forearm are outcropping muscles?
Extensor pollicis longus, Extensor pollicis brevis, Abductor pollicis longus
What nerve innervates all of the outcropping muscles?
Posterior interosseous nerve (PIN)
What is the distal attachment of the extensor pollicis longus?
Distal phalange of thumb
What is the distal attachment of the extensor pollicis brevis?
Proximal phalange of the thumb
What is the distal attachment of the abductor pollicis longus?
Base of the 1st metacarpal
Which muscles of the posterior forearm are innervated by the radial nerve?
Brachioradialis and Extensor carpi radialis longus
Which muscles of the posterior forearm are innervated by the deep branch of the radial nerve?
Extensor carpi radialis brevis and Supinator
Which muscles of the posterior forearm are innervated by the posterior interosseous nerve?
All posterior forearm muscles distal (south) of the Supinator muscle
Which muscles of the posterior forearm are known as the “wrist extensors”?
Extensor carpi radialis longus, Extensor carpi radialis brevis, Extensor carpi ulnaris
Which muscles of the posterior forearm are known as the “finger extensors”?
Extensor digitorum, Extendor digiti minimi, Extensor indices
Which muscles of the posterior forearm are known as the “thumb extensors/abductors”?
Outcropping muscles (EPL, APL, EPB)
Where is the extensor retinaculum located?
Connective tissue on the posterior wrist
What does the extensor retinaculum contain?
All extensor tendons
What is the extensor retinaculum a continuation of?
Palmer carpal ligament (on palmer surface of the wrist)