The anterior forearm is the _________ side.

flexor

The _______ forearm is the extensor side

posterior

If the tendon of a muscle attaches towards the thumb, it will have ______ in the name and will at least ________ the wrist

radialis; abduct

If the tendon of a muscle attaches toward the __________, it will have ulnaris in the name and will at least _______ the wrist

pinky; adduct

If the tendon of a muscle attaches to the thumb, it will have _______ in its name

pollicis

If the tendons of a muscle attach to digits 2-5, the muscle will have _____ in its name

digitorum

How are the muscles of the arm organized?

There is an anterior and posterior compartment. Each compartment has superficial and deep groups of muscles

How many muscles total are in the anterior forearm?

Eight

How many muscles are in the superficial layer of the anterior forearm?

Five

How many muscles are in the deep layer of the anterior forearm?

Three

Name the muscles of the superficial anterior forearm

Pronator teres, Flexor carpi radialis, Palmaris longus, Flexor carpi ularis, and flexor digitorum superficialis

Which is the deepest muscle of the superficial forearm muscles?

flexor digitorum superficialis

O A I INN of pronator teres

O ulnar head: coronoid process of ulna

humeral head: medial epicondyle of humerus

I lateral surface of radius

A pronates the forearm, flex the elbow

Inn median n

O A I INN of flexor carpi radialis

O medial epicondyle of humerus

I base of second metacarpal

A flexes the wrist, abducts the wrist

Inn median n

O A I INN of palmaris longus?

O medial epicondyle of humerus

I palmar aponeurosis and distal half of flexor retinaculum

A flexes wrist and tenses palmar aponeurosis

Inn median n

O A I INN of flexor carpi ulnaris longus

O olecranon and posterior border of ulna via aponeurosis

I pisiform, hook of hamate, and fifth metacarpal

A flexes write, adducts wrist

Inn ulnar n

What are the four MOST superficial anterior forearm muscles, from lateral to medial

pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris

O I A INN of flexor digitorum superficialis

O medial epicondyle

I middle phalanges 2-5

A flexes digits 2-5

Inn median n

Which nerve innervates all superficial anterior forearm muscles except one? What is the exception and what is it innervated by?

median n; flexor carpi ulnaris; ulnar n

flexor carpi ulnaris is most medial muscle of this group

Which muscle of the superficial anterior forearm is innervated by the ulnar nerve?

flexor carpi ulnaris longus

O I A INN of flexor digitorum superficialis

O humero-ulnar head: medial epicondyle of humerus and coronoid process of ulna

radial head: oblique line of radius

I middle phalanges 2-5

A flex wrist, flex pip joints of digit 2-5 and flexes MTP joints

Inn median n

What are the three deep anterior forearm muscles?

flexor digitorum profundus, flexor pollicis longus, pronator quadratus

Describe the innervations of the deep anterior forearm muscles

all innervated by median n. half of flexor digitorum profundus is innervated by the ulnar n

O I A Inn of flexor digitorum profundus

O anterior proximal 3/4 of ulna and interosseus membrane

I distal phalanges 2-5

A flexes digits 2-5 at DIP joints ; flexes wrist

Inn to digits 2 and 3: median nerve (anterior interosseous branch)

to digits 4 and 5 ulnar nerve

O I A Inn of flexor pollicis longus

O The middle 2/4 of the anterior surface of the radius and the adjacent interosseus membrane.

IThe base of the distal phalanx of the thumb

A flex pollux at MTP and IP joints; flex wrist

Inn anterior interosseous nerve from median n

O I A INN of pronator quadratus

O distal anterior ulna

I distal anterior radius

A pronates forearm; deep fibers bind radius and ulna together

Inn anterior interosseous nerve from median nerve

Muscles found within the posterior forearm compartment are responsible for _______.

extension of the fingers

Which of these muscles is an intrinsic hand muscle that moves the thumb (i.e. the first digit)?

Flexor pollicis brevis Flexor digiti minimi Flexor pollicis longus Extensor pollicis longus Abductor digiti minimi

flexor pollicis brevis

What anterior forearm muscle typically has a dual innervation?

flexor digitorum profundus

What structures pass through the carpal tunnel>

four tendons of flexor digitorum profundus

four tendons of flexor digitorum superficialis

tendon of flexor pollicis longus

median n

The __________ muscle is absent on one or both sides in about 14% of people.

palmaris longus

Abduction of the thumb is when the thumb is moved __________. (Note: Remember to start from the anatomical position.)

anteriorly

What nerve innervates all posterior forearm muscles?

radial n

what are the main functions of the posterior forearm muscles?

supinate the forearm and extend the wrist and digits

name the seven superficial posterior forearm muscles

brachioradialis

extensor carpi radialis longus

extensor carpi radialis brevis

extensor digitorum

extensor digiti minimi

extensor carpi ulnaris

anconeus

where do all superficial posterior forearm muscles originate on or near?

lateral epicondyle of the humerus

O I A INN of brachioradialis?

O proximal 2/3 of lateral supraepicondylar ridge of humerus

I lateral surface of distal end of radius proximal to styloid process

A flexion of elbow when forearm is in midpronated position; supination and pronation

Inn radial nerve

which muscle is nicknamed the drinking muscle because it flexes elbow when hand is in netural position, as if holding a mug>

brachioradialis

does brachioradialis cross anterior or posterior to elbow joint?

anterior

O I A INN of extensor carpi radialis longus?

lateral supra-epicondylar ridge of humerus

dorsal aspect of base of second metacarpal.

extend wrist abduct wrist

radial n

O I A INN of extensor carpi radialis brevis?

O lateral epicondyle of humerus (common extensor origin)

I dorsal aspect of base of third metacarpal

A extend and abduct wrist joint during fist clenching

INN deep branch of radial nerve

O I A INN of extensor digitorum

lateral epicondyle of humerus (common extensor origin)

extensor expansions of medial four fingers

extends digits 2-5 at MTP and IP joints; extends wrist

posterior interosseous nerve, continuation of deep branch of radial n

O I A Inn extensor digiti minimi

O lateral epicondyle of humerus (common extensor origin)

I extensor expansion of fifth digit

A extends wrist joint; extends fifth digit ant MTP and IP joints

INN posterior interosseous nerve (continuation of deep branch of radial nerve)

O I A Inn extensor carpi ulnaris

lateral epicondyle of humerus and posterior border of ulna via shared aponeurosis

dorsal aspect of base of fifth metacarpal

extends wrist and adducts wrist

posterior interosseous nerve, continuation of deep branch of radial nerve

A I anconeus

extend elbow

radial n

Name the five deep posterior forearm muscles

supinator

abductor pollicis longus

extensor pollicis brevis

extensor pollicis longus

extensor indicis

Where do the deep posterior muscles of the forearm originate?

interosseus membrane, radius, or ulna

O I A INN of supinator

O lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa, crest of ulna

I lateral, posterior, and anterior surfaces of proximal third of radius

A supinates forearm; rotates radius to turn palm anteriorly or superiorly if elbow is flexed

Inn deep branch of radial nerve

O I A INN of abductor pollicis longus

O posterior surface of proximal halves of ulna, radius, and interosseous membrance

I base of first metacarpal

A extends wrist; abducts and extends thumb

Inn posterior interosseous nerve - continuation of deep branch of radial nerve

O I A INN of extensor pollicis brevis

posterior surface of distal third of radius and interosseous membrane

dorsal aspect of base of proximal phalanx of thumb

extends wrist and extends proximal phalanx of thumb at MTP joint and extends carpometacarpal joint

Inn posterior interosseous nerve (continuation of deep branch of radial nerve)

O I A INN of extensor pollicis longus

O posterior surface of middle third of ulna and interosseous membrane

I dorsal aspect of base of distal phalanx of thumb

A extends wrist; distal phalanx of thumb at IP joint. extends metacarpophalangeal joints and carpometacarpal joints

Inn posterior interosseous nerve continuation of deep branch of radial nerve

O I A INN of extensor indices

O posterior surface of distal third of ulna and interosseous membrane

A extensor expansion of second finger

I posterior interosseous nerve

A extends wrist joint; extends index finger (helping independent extension)

How many total intrinsic hand muscles are there?

twenty

How many intrinsic hand muscles are innervated by ulnar n and how many by median n?

five by median nerve and fifteen by ulnar n

what are the intrinsic muscles of the hand?

muscles of the thenar eminance (3)

msucles of the hypothenar eminance (3)

lumbricals (4)

adductor pollicis m

palmar and dorsal interosseus muscles (8)

palamris brevis

Name the hypothenar eminance muscles

abductor digiti minimi

flexor digiti minimi brevis

opponens digiti minimi

Name the thenar eminence muscles

Opponens pollicis

Flexor pollicis brevis

Abductor pollcis brevis

O I A INN of abductor digiti minimi

O pisiform

I medial side of base of proximal phalanx of fifth finger

A abducts fifth finger and assists in flexion of proximal phalanx\

Inn deep branch of ulnar nerve

mnemonic for remembering which hand muscles are innervated by the median n

FOAL

flexor pollicis brevis
opponens pollicis

abductor pollicis brevis

lateral two lumbricals

*all pollicis, more lateral*

O I A Inn of flexor digiti minimi brevis

O hook of hamate and flexor retinaculum

I medial side of base of proximal phalanx of fifth digit

A flexes proximal phalanx of fifth digit

Inn deep branch of ulnar nerve

O I A INN of opponens digiti minimi

O hook of hamate and flexor retinaculum

I medial border of fifth metacarpal

A draws fifth metacarpal anterior and rotates it for opposition with thumb

Inn deep branch of ulnar nerve

O I A Inn of abductor pollicis brevis

O flexor retinaculum and tubercles of scaphoid and trapezium

I lateral side of base of proximal phalanx of thumb

A abducts thumb and helps with opposition

Inn recurrent branch of median nerve

O I A Inn of flexor pollicis brevis

O flexor retinaculum and tubercles of scaphoid and trapezium

I lateral side of base of proximal phalanx of thumb

A flexes thumb

Inn superficial head: recurrent branch of median nerve

deep head: deep branch of ulnar nerve

Opponens pollicis O I A INN

O flexor retinaculum and tubercles of scaphoid and trapezium

I lateral side of first metacarpal

recurrent branch of median nerve

draws first metacarpal medially to center of palm and rotates it medially (opposition)

lumbricals one and two are innervated by the _________; lumbricals 3 and 4 are innervated by the ________

median n; deep branch of ulnar n

what are the actions of the lumbricals?

flex at the metacarpal phalangeal joint and extend at the interphalangeal joint

O I A INN of adductor pollicis?

O oblique head: bases of 2nd and 3rd metacarpals, capitate, adjacent carpals

transverse head: anterior surface of shaft of third metacarpal

I medial side of base of proximal phalanx of thumb

A adducts thumb toward lateral border of palm

Inn deep branch of ulnar nerve

How many palmar interosseus muslces are there?

three

O I A and Inn of palmar interosseus muscles?

O palmar surfaces of second, fourth and fifth metacarpals (unipennate)

I bases of proximal phalanges; extensor expansions of 2nd fourth and fifth fingers

A adduct 2nd fourth and fifth digits; assist lumbricals

Inn deep branch of ulnar nerve

how many dorsal interossei are there?

four

O I action and INN of dorsal interossei

O adjacent sides of two metacarpals (bipennate)

I bases of proximal phalanges; extensor expansions of 2nd-4th fingers

A abduct 2nd through 4th fingers from axial line; assist lumbricals

Inn deep branch of ulnar nerve

O I A Inn of palmaris brevis

O Flexor retinaculum (medial) and palmar aponeurosis

I palm

A wrinkles skin

Inn superficial branch of ulnar nerve

Origin and insertion of lumbricals one and two?

Origin and insertion of lumbricals three and four?

O 1 & 2 - lateral two tendons of of flexor digitorum profundus (as unipennate muscles)

O 3 & 4 - medial three tendons of flexor digitorum profundus (as bipennate muscles)

Common insertion - lateral sides of extensor expansions of 2nd through 5th fingers