Muscles of the Forearm, Wrist & Hand Flashcards
What type of joint is the wrist joint?
The radiocarpal joint is a condyloid synovial joint.
What movements occur at the wrist joint?
The wrist joint allows for the following movements:
Flexion
Extension
Abduction (Radial deviation)
Adduction (Ulnar deviation)
What type of movements are possible at the MCP joints of the fingers?
The metacarpophalangeal (MCP) joints allow for:
Flexion
Extension
Abduction (moving fingers apart)
Adduction (bringing fingers together)
What movements occur at the PIP and DIP joints?
The proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints allow for:
Flexion
Extension
What type of joint is the thumb’s carpometacarpal (CMC) joint?
The CMC joint of the thumb is a saddle joint.
What are the unique movements of the thumb?
The thumb can perform:
Flexion (bringing the thumb across the palm)
Extension (moving the thumb away from the palm)
Abduction (lifting the thumb away from the palm)
Adduction (bringing the thumb back towards the palm)
Opposition (bringing the thumb to touch the fingers)
What muscles are in the superficial layer of the anterior compartment of the forearm?
Pronator Teres
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi Ulnaris
What is the action of Pronator Teres?
Pronator Teres pronates the forearm and assists in flexion of the elbow joint.
Which muscle is in the intermediate layer of the anterior compartment?
The Flexor Digitorum Superficialis.
What is the function of Flexor Digitorum Superficialis?
It flexes the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints of the fingers.
Which muscles are in the deep layer of the anterior compartment?
Flexor Digitorum Profundus
Flexor Pollicis Longus
Pronator Quadratus
What is the primary action of Flexor Digitorum Profundus?
Flexor Digitorum Profundus flexes the distal interphalangeal (DIP) joints of the fingers.
What muscles are in the superficial layer of the posterior compartment?
The muscles in the superficial layer are:
Brachioradialis
Extensor Carpi Radialis Longus
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Digiti Minimi
Extensor Carpi Ulnaris
Which muscle in the posterior compartment of the forearm acts as a flexor of the elbow joint?
The Brachioradialis acts as a flexor of the elbow joint.
What muscles are in the deep layer of the posterior compartment of the forearm?
The muscles in the deep layer are:
Supinator
Extensor Indicis
Abductor Pollicis Longus
Extensor Pollicis Brevis
Extensor Pollicis Longus
What is the action of Abductor Pollicis Longus?
Abductor Pollicis Longus abducts and extends the thumb at the carpometacarpal (CMC) joint.
Where do the muscles of the superficial layer of the anterior (flexor) compartment of the forearm originate?
They originate from the common flexor tendon attached to the medial epicondyle of the humerus.
What muscles originate from the common flexor tendon?
What muscles originate from the common flexor tendon?
Where do the muscles of the superficial layer of the posterior (extensor) compartment of the forearm originate?
A: They originate from the common extensor tendon attached to the lateral epicondyle of the humerus.
What muscles originate from the common extensor tendon?
The muscles that originate from the common extensor tendon are:
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Digiti Minimi
Extensor Carpi Ulnaris
Which tendon is most associated with tennis elbow (lateral epicondylitis)?
The common extensor tendon is most associated with tennis elbow
Which tendon is most associated with golfer’s elbow (medial epicondylitis)?
The common flexor tendon is most associated with golfer’s elbow.
What is the origin of the humeral head of the pronator teres?
Common flexor tendon (medial epicondyle)
What is the origin of the ulnar head of the pronator teres?
Coronoid process of the ulna
Where does the pronator teres insert?
Lateral mid-shaft of the radius
What is the primary action of the pronator teres?
Pronation of the forearm
Which nerve innervates the pronator teres?
Median nerve
What is the origin of the flexor carpi radialis?
Common flexor tendon (medial epicondyle)
Where does the flexor carpi radialis insert?
Base of the 2nd and 3rd metacarpals
What actions does the flexor carpi radialis perform?
Wrist flexion and radial deviation (abduction)
Which nerve innervates the flexor carpi radialis?
A: Median nerve
Which muscle group does the pronator teres belong to?
Anterior compartment of the forearm (superficial layer)
How does the action of flexor carpi radialis differ from that of pronator teres?
Flexor carpi radialis primarily flexes the wrist and aids in radial deviation, while pronator teres primarily pronates the forearm.
What is the origin of the flexor carpi ulnaris?
Common flexor tendon (medial epicondyle)
Where does the flexor carpi ulnaris insert?
Pisiform, hook of hamate, and 5th metacarpal
What actions does the flexor carpi ulnaris perform?
Wrist flexion and ulnar deviation (adduction)
Which nerve innervates the flexor carpi ulnaris?
Ulnar nerve
What is the origin of the palmaris longus?
Common flexor tendon (medial epicondyle)
Where does the palmaris longus insert?
Palmar aponeurosis of the hand
What are the actions of the palmaris longus?
Flexes the wrist and tenses the palmar aponeurosis
Which nerve innervates the palmaris longus?
Median nerve
Which muscle group do flexor carpi ulnaris and palmaris longus belong to?
Anterior compartment of the forearm (superficial layer)
How does the action of the flexor carpi ulnaris differ from that of the palmaris longus?
Flexor carpi ulnaris primarily functions in wrist flexion and ulnar deviation, while palmaris longus primarily flexes the wrist and tenses the palmar aponeurosis.
What is the origin of the flexor digitorum superficialis?
Humero-ulnar head: Common flexor tendon (medial epicondyle) and coronoid process
Radial head: Oblique line of radius (anterior proximal half)
Where does the flexor digitorum superficialis insert?
A: Middle phalanx of the medial 4 digits
What actions does the flexor digitorum superficialis perform?
Wrist flexion
Flexion of PIP joints of the medial 4 digits
Which nerve innervates the flexor digitorum superficialis?
Median nerve
To which muscle group does the flexor digitorum superficialis belong?
Anterior compartment of the forearm (intermediate layer)
How does the action of the flexor digitorum superficialis relate to finger movement?
It flexes the proximal interphalangeal (PIP) joints, allowing for flexion of the fingers.
What is the origin of the flexor pollicis longus?
Anterior radius and interosseous membrane
Where does the flexor pollicis longus insert?
Base of the distal phalanx of the thumb
What actions does the flexor pollicis longus perform?
Flexion of the MCP and IP joints of the thumb
Which nerve innervates the flexor pollicis longus?
Median nerve
What is the origin of the flexor digitorum profundus?
Proximal ¾ of the medial and anterior surfaces of the ulna and interosseous membrane
Where does the flexor digitorum profundus insert?
Base of the distal phalanx of the medial 4 digits
What actions does the flexor digitorum profundus perform?
Wrist flexion
Flexion of DIP joints of the medial 4 digits
Which nerves innervate the flexor digitorum profundus?
Ulnar nerve (medial half)
Median nerve (lateral half)
o which muscle group do the flexor pollicis longus and flexor digitorum profundus belong?
Anterior compartment of the forearm (deep layer)
What is the origin of the pronator quadratus?
Distal anterior ulna
Where does the pronator quadratus insert?
Distal anterior radius
What action does the pronator quadratus perform?
A: Pronation
Which nerve innervates the pronator quadratus?
Median nerve
What is the origin of the pronator teres?
Humeral head: Common flexor tendon (medial epicondyle)
Ulnar head: Coronoid process of ulna
Where does the pronator teres insert?
Lateral mid-shaft of radius
What action does the pronator teres perform?
Pronation of the forearm
Which nerve innervates the pronator teres?
Median nerve
What is the origin of the supinator?
Lateral epicondyle of humerus and supinator fossa of ulna
Where does the supinator insert?
Lateral surface of the proximal radius
What action does the supinator perform?
A: Supination of the forearm
Which nerve innervates the supinator?
Radial nerve
What is the origin of the brachioradialis?
Lateral supracondylar ridge of the humerus
Where does the brachioradialis insert?
Lateral distal radius
What action does the brachioradialis perform?
Flexion of the elbow in mid-pronation
Which nerve innervates the brachioradialis?
Radial nerve
What is the origin of the extensor carpi radialis longus?
Lateral supracondylar ridge of the humerus (distal to brachioradialis)
Where does the extensor carpi radialis longus insert?
Base of the 2nd metacarpal
What actions does the extensor carpi radialis longus perform?
Wrist extension and radial deviation (abduction)
Which nerve innervates the extensor carpi radialis longus?
Radial nerve
What is the origin of the extensor carpi radialis brevis?
Common extensor tendon (lateral epicondyle)
Where does the extensor carpi radialis brevis insert?
Base of the 3rd metacarpal
What actions does the extensor carpi radialis brevis perform?
Wrist extension and radial deviation (abduction)
Which nerve innervates the extensor carpi radialis brevis?
Radial nerve
What is the origin of the extensor digitorum?
A: Common extensor tendon (lateral epicondyle)
Where does the extensor digitorum insert?
Base of the middle and distal phalanges of the medial 4 digits via the extensor expansion
What actions does the extensor digitorum perform?
Extension of wrist, MCP, PIP, and DIP joints of the medial 4 digits
Which nerve innervates the extensor digitorum?
Radial nerve
What is the origin of the supinator?
Lateral epicondyle, radial collateral and annular ligaments, and supinator crest of ulna
Where does the supinator insert?
Lateral proximal 1/3 of radius
What action does the supinator perform?
Supination
Which nerve innervates the supinator?
Radial nerve
What is the origin of the extensor indicis?
Posterior distal 1/3 of ulna and interosseous membrane
Where does the extensor indicis insert?
Extensor expansion of the 2nd digit
What actions does the extensor indicis perform?
Extension of the wrist and index finger
Which nerve innervates the extensor indicis?
Radial nerve
What is the origin of the abductor pollicis longus?
Middle 1/3 of radius, ulna, and interosseous membrane
Where does the abductor pollicis longus insert?
Base of the 1st metacarpal
What actions does the abductor pollicis longus perform?
Abducts the thumb and extends the wrist and CMC joint
Which nerve innervates the abductor pollicis longus?
Radial nerve
What is the origin of the extensor pollicis brevis?
Posterior radius and interosseous membrane
Where does the extensor pollicis brevis insert?
Base of the proximal phalanx of the thumb
What actions does the extensor pollicis brevis perform?
Extends the proximal phalanx of the thumb at the 1st MCP joint, and extends the wrist and CMC joint
Which nerve innervates the extensor pollicis brevis?
Radial nerve
What is the origin of the extensor pollicis longus?
Posterior ulna and interosseous membrane
Where does the extensor pollicis longus insert?
Base of the distal phalanx of the thumb
What actions does the extensor pollicis longus perform?
Extends the distal phalanx of the thumb at the 1st IP joint. It also extends the wrist, CMC, and MCP joints
Which nerve innervates the extensor pollicis longus?
Radial nerve
What muscles form the thenar group in the hand?
Abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
What muscles are part of the hypothenar group in the hand?
Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi
Which muscle is responsible for adducting the thumb in the hand?
Adductor pollicis
What structures are found in the central compartment of the hand?
A: Long flexor tendons, lumbrical muscles
What muscles belong to the interosseous group in the hand?
Dorsal and palmar interossei
What are the muscles in the thenar group of the hand?
Abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
What is the insertion point of the abductor pollicis brevis?
Base of proximal phalanx of the thumb
What action is performed by the abductor pollicis brevis?
Abduction of the thumb
Where does the flexor pollicis brevis insert?
Base of proximal phalanx of the thumb
What action does the flexor pollicis brevis perform?
Flexion of the Thumb
What is the insertion point of the opponens pollicis?
1st metacarpal
What action is performed by the opponens pollicis?
Opposition of the thumb
What nerve innervates the thenar group muscles?
Recurrent branch of the median nerve
What are the muscles in the hypothenar group of the hand?
Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi
Where does the abductor digiti minimi insert?
Base of proximal phalanx of the 5th digit
What is the primary action of the abductor digiti minimi?
Abduction of the 5th digit
What is the insertion point of the flexor digiti minimi?
Base of proximal phalanx of the 5th digit
What action does the flexor digiti minimi perform?
Flexion of the 5th digit
Where does the opponens digiti minimi insert?
5th metacarpal
What action is performed by the opponens digiti minimi?
Opposition of the 5th digit
What nerve innervates the hypothenar group muscles?
Deep branch of the ulnar nerve
What muscle makes up the adductor group in the hand?
Adductor pollicis
What are the two heads of the adductor pollicis?
Transverse head and oblique head
Where does the adductor pollicis insert?
Base of proximal phalanx of the thumb
What is the primary action of the adductor pollicis?
Adduction of the thumb
What nerve innervates the adductor pollicis?
Deep branch of the ulnar nerve
What muscles make up the central group of the hand?
Lumbricals
Where do the lumbricals originate?
Flexor digitorum profundus tendons
Where do the lumbricals insert?
Extensor expansion
What is the action of the lumbricals?
Flexion of MCP joints and extension of IP joints
What muscles make up the interossei group?
Palmar interossei and dorsal interossei
What is the origin of the interossei muscles?
In-between metacarpals
Where do the interossei muscles insert?
Base of proximal phalanx and extensor expansion
What is the action of the palmar interossei?
Palmar interossei adduct the fingers (PAD)
What is the action of the dorsal interossei?
Dorsal interossei abduct the fingers (DAB)
What nerve innervates the interossei muscles?
Deep palmar branch of the ulnar nerve
What additional action do the interossei muscles assist with?
Assist lumbricals in flexion of MCP joints and extension of IP joints
