Bones & Muscles of the Forearm and Hand

Ulna

Forearm bone with the olecranon, trochlear notch, and styloid process

Olecranon

Bony projection at the most proximal part of the ulna

Trochlear notch

Curved depression of the ulna that wraps around the humerus

Styloid process of ulna

Process located at the distal end of the ulna

Radius

Forearm bone containing the radial tuberosity and a distal styloid process

Radial tuberosity

Attachment site on the radius for the biceps brachii

Styloid process of radius

Process located at the distal end of the radius

Anterior compartment of forearm

Contains pronator and flexor muscles

Pronation

Rotation of the radius across the ulna

Pronator teres

Superficial muscle that pronates the forearm

Pronator quadratus

Deep muscle that pronates the forearm

Pronator teres origin

Medial epicondyle of the humerus

Flexor retinaculum

Dense Regular Connective tissue at wrist that holds flexor tendons close to the bones

Flexors of the forearm

Flex the wrist, MP joints, and/or IP joints; originate from common flexor tendon on medial epicondyle

Common flexor tendon

Most forearm flexors originate from this tendon

Common flexor tendon location

Medial epicondyle of the humerus

Carpal tunnel syndrome

Inflammation of structures beneath the flexor retinaculum; causes pressure, pain, and “pins and needles” feeling

Carpal tunnel syndrome symptoms

Pressure, pain, and a 'pins and needles' feeling

Flexor carpi radialis

Flexes the wrist and abducts the hand

Palmaris longus

Flexes the wrist, tendon travels over flexor retinaculum, not everyone has this muscle

Palmaris longus tendon

Travels over/on top of the flexor retinaculum

Palmaris longus variation

Not everyone has this muscle

Flexor carpi ulnaris

Flexes the wrist and adducts the hand

Flexor digitorum superficialis

Intermediate forearm flexor that flexes the wrist and digits 2-5 at the MP and PIP joints, does not flex the DIP joints

Flexor digitorum superficialis digit action

Flexes digits 2-5 at the MP and PIP joints

MP joint

Metacarpophalangeal joint

PIP joint

Proximal interphalangeal joint

DIP joint

Distal interphalangeal joint

Flexor digitorum superficialis and DIP

Does NOT flex the DIP joints

Flexor digitorum profundus

Deep forearm muscle that flexes the wrist; flexes digits 2-5 at the MP, PIP and DIP joints, tendons attach to distal phalanx

Flexor digitorum profundus digit action

Flexes digits 2-5 at the MP, PIP, and DIP joints

Flexor digitorum profundus insertion

Tendons attach to the distal phalanges

Flexor pollicis longus

Deep muscle that flexes the wrist and MP joint and IP joint of thumb, tendons attach to distal phalanx

Flexor pollicis longus thumb action

Flexes the MP and IP joints of the thumb

Flexor pollicis longus insertion

Tendon attaches to the distal phalanx of the thumb

Posterior compartment of forearm

Contains supinator and extensor muscles

Supinator

Supinates the forearm

Biceps brachii and supination

Biceps brachii also supinates the forearm

Biceps brachii insertion

Radial tuberosity

Extensors of the forearm

Extend the wrist, MP joints, and/or IP joints

Extensor origin

Most forearm extensors originate from common extensor tendon on the lateral epicondyle of the humerus

Common extensor tendon location

Lateral epicondyle of the humerus

Extensor retinaculum

Connective tissue at wrist that holds extensor tendons down

Extensor carpi radialis longus

Extends the wrist and abducts the hand

Extensor carpi radialis brevis

Extends the wrist and abducts the hand

Extensor digitorum

Extends the wrist and digits 2-5 at MP, PIP, and DIP joints

Extensor digitorum digit action

Extends digits 2-5 at the MP, PIP, and DIP joints

Extensor digitorum insertion

Attaches to distal phalanges of digits 2-5

Extensor carpi ulnaris

Extends the wrist and adducts the hand

Extensor pollicis longus

Deep muscle that extends the thumb

Extensor pollicis brevis

Deep muscle that extends the thumb

Abductor pollicis longus

Deep muscle that abducts the thumb

Pollicis

Refers to the thumb

Intrinsic hand muscles

Muscles responsible for moving the fingers within the hand

Thenar muscles

Intrinsic hand muscles that move the thumb

Hypothenar muscles

Intrinsic hand muscles that move the little finger

Midpalmar muscles

Intrinsic muscles that move fingers 2-5

Midpalmar muscle shared action

Flex MP joints and extend PIP and DIP joints of fingers 2-5

Lumbricals

Four midpalmar muscles

Lumbricals action

Flex MP joints and extend PIP/DIP joints

Palmar interossei

Three muscles that adduct the fingers

Dorsal interossei

Four muscles that abduct the fingers

PAD

Palmar interossei ADduct the fingers

DAB

Dorsal interossei ABduct the fingers

Thumb abduction

Movement of the thumb away from the hand

Thumb adduction

Movement of the thumb toward the hand

Thumb extension

Straightening/moving the thumb posteriorly

Thumb flexion

Bending/moving the thumb across the palm

Abduction of hand

Movement of the hand toward the radial/thumb side

Adduction of hand

Movement of the hand toward the ulnar/little-finger side

Name circled part

Olecranon

Name circled part

Trochlear notch

Name circled part

Styloid Process (ulna)

Name upper blue part

Radial tuberosity

Name lower blue part

Styloid process (radius)

Name left label

Lateral epicondyle

Name right label

Medial epicondyle

Name blue label

Pronator teres

Name green label

Pronator quadratus

Name label with dot

Flexor retinaculum

Name purple label

Flexor carpi radialis

Name blue label

Palmaris Longus

Name green label

Flexor carpi ulnaris

Name yellow label

Flexor digitorum superficialis (intermediate group, anterior)

Name blue muscle

Flexor digitorum profundus (deep group, anterior)

Name green muscle

Flexor pollicis longus

Name muscle highlighted

Supinator

Name highlighted muscle

Extensor retinaculum (posterior)

Name blue muscle

Extensor carpi radialis longus

Name green muscle

Extensor carpi radialis brevis

Name yellow muscle

Extensor digitorum

Name purple muscle

Extensor carpi ulnaris

Name yellow muscle

Abductor pollicis longus

Name green muscle

Extensor pollicis brevis

Name blue muscle

Extensor pollicis longus

Name muscle

Lumbricals

Name muscle

Palmar interossei

Name muscle

Dorsal interossei