Muscles of the Forearm Flashcards
Anterior forearm muscles
Superficial Muscle Group: pronator teres (PT) flexor carpi radialis (FCR) palmaris longus (PL) flexor carpi ulnaris (FCU)
Intermediate Muscle Group:
flexor digitorum superficialis (FDS)
Deep Muscle Group (do not cross the elbow joint): flexor digitorum profundus (FDP) flexor pollicis longus (FPL) pronator quadratus (PQ)
Anterior muscles of forearm Nerve Supply
All supplied by the median nerve, except for the FCU and the medial half of the FDP which are supplied by the ulnar nerve
Pronator Teres
PA- Humeral head: Medial epicondyle of humerus (CFO) Ulnar head: Coronoid process
DA- Lateral surface of the radius, middle section
N/S- Median nerve
A- Pronates and flexes forearm
Flexor Carpi Radialis
PA- Medial epicondyle of humerus (CFO)
DA- Base of 2nd metacarpal (anteriorly)
N/S- Median nerve
A- Flexes and radially deviates (abducts) hand at wrist joint
Palmaris Longus
PA- Medial epicondyle of humerus (CFO)
DA- Flexor retinaculum and palmer aponeurosis
N/S- Median nerve
A- Flexes hand at wrist joint and tenses palmer aponeurosis
Flexor Carpi Ulnaris
PA- Humeral head: Medial epicondyle of humerus (CFO)
Ulnar head: Olecranon process of ulna
DA- Pisiform, hook of the hamate & 5th metacarpal (anteriorly)
N/S- Ulnar nerve
A- Flexes and ulnar deviates (adducts) hand at wrist joint
Flexor Digitorum Superficialis
PA- Medial epicondyle of humerus (CFO) & anterior surface radius
DA- Middle phalanges of medial 4 digits (2-5)
N/S- Median nerve
A- Flexes middle phalanges, producing flexion at the proximal interphalangeal joints (PIPs) and metacarpophalangeal joints (MCPs)
Flexor Digitorum Profundus
Divides into 4 tendons for insertion
Tendons pass under the split tendons of FDS
PA- Medial and anterior surfaces of proximal ulna and interosseous membrane
DA- Distal phalanges of medial 4 digits (2-5)
N/S- Lateral half (digits 2&3): Median nerve. Medial half (digits 4&5): Ulnar nerve
A- Flexes distal phalanges at the distal interphalangeal joints (DIPs)
Flexor Pollicis Longus
PA- Distal anterior radius, and interosseous membrane
DA- Distal phalanx of thumb
N/S- Median nerve
A- Flexes phalanges of the first digit (thumb)
Pronator Quadratus
PA- Distal ¼ of anterior ulna
DA- Distal ¼ of anterior radius
N/S- Median nerve
A- Pronates the forearm
Flexor Retinaculum
Transverse fibrous tissue band between the outer carpal bones
Prevents bow stringing of tendons
Forms the carpal tunnel (covered in later workshop) through which the flexor tendons and median nerve pass
Clinical relevance: carpal tunnel syndrome
Posterior forearm muscles
Superficial Muscle Group: Brachioradialis Extensor carpi radialis longus (ECRL) Extensor carpi radialis brevis (ECRB) Extensor digitorum (ED) Extensor digiti minimi (EDM) Extensor carpi ulnaris (ECU)
Deep Muscle Group: Supinator Abductor pollicis longus (APL) Extensor pollicis brevis (EPB) Extensor pollicis longus (EPL) Extensor indicis (EI)
Posterior Muscles of the formarm Nerve Supply
All muscles are supplied by the radial nerve
Extensor retinaculum
Attaches to the distal ulnar and radius
Creates 6 osseofibrous tunnels which the extensor tendons pass through
Holds the extensor tendons in position and prevents bow stringing
Brachioradialis
PA- Lateral supracondylar ridge of humerus
DA- Lateral surface of distal radius
N/S- Radial nerve
A- Flexes forearm when it is in the mid-prone position
Extensor Carpi Radialis Longus
PA- Lateral supracondylar ridge of humerus
DA- Base of 2nd metacarpal bone (posteriorly)
N/S- Radial nerve
A- Extends and radially deviates (abducts) hand at wrist joint
Extensor Carpi Radialis Brevis
PA- Lateral epicondyle of humerus (CEO)
DA- Base of 3rd metacarpal bone (posteriorly)
N/S- Radial nerve
A- Extends and radially deviates (abducts) hand at wrist joint
Extensor Digitorum
PA- Lateral epicondyle of humerus (CEO)
DA- Extensor expansions of medial 4 digits
N/S- Radial nerve
A- Extends medial 4 digits (2-5) at metacarpophalangeal (MCP) & interphalangeal joints
Extensor Digiti Minimi
PA- Lateral epicondyle of humerus (CEO)
I- Extensor expansion 5th digit
N/S- Radial nerve
A- Extends 5th digit at metacarpophalangeal (MCP) & interphalangeal joints
Extensor Carpi Ulnaris
PA- Lateral epicondyle of humerus (CEO) and posterior border of ulna
DA- Base of 5th metacarpal bone (posteriorly)
N/S- Radial nerve
A- Extends & ulnar deviates (adducts) hand at wrist joint
Supinator
PA- Lateral epicondyle of humerus (CEO) & supinator crest of ulnar
DA- lateral, posterior & anterior surfaces of the proximal radius
N/S- Radial nerve
A- Supinates forearm
Abductor Pollicis Longus
PA- Posterior surface of radius, interosseous membrane and ulna
DA- Base of 1st metacarpal
N/S- Radial nerve
A- Abducts thumb and extends it at the carpometacarpal joint
Extensor Pollicis Brevis
PA- Posterior of distal radius and interosseous membrane
DA- Base of proximal phalanx of thumb
N/S- Radial nerve
A- Extends proximal phalanx of thumb at metacarpophalangeal joint (MCP) (as well as carpometacarpal joint of thumb)
Extensor Pollicis Longus
PA- Posterior surface of ulna (middle 1/3) and interosseous membrane
DA- Base of distal phalanx of thumb
N/S- Radial nerve
A- Extends distal phalanx of thumb at interphalangeal joint (as well as metacarpophalangeal & carpometacarpal joint)
Extensor Indicis
PA- Posterior of distal ulna and interosseous membrane
DA- Extensor expansion 2nd digit
N/S- Radial nerve
A- Extends 2nd digit
