Muscles of the Forearm

Question 1

Anterior forearm muscles

Answer 1

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)

Question 2

Anterior muscles of forearm Nerve Supply

Answer 2

All supplied by the median nerve, except for the FCU and the medial half of the FDP which are supplied by the ulnar nerve

Question 3

Pronator Teres

Answer 3

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

Question 4

Flexor Carpi Radialis

Answer 4

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

Question 5

Palmaris Longus

Answer 5

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

Question 6

Flexor Carpi Ulnaris

Answer 6

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

Question 7

Flexor Digitorum Superficialis

Answer 7

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)

Question 8

Flexor Digitorum Profundus

Answer 8

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)

Question 9

Flexor Pollicis Longus

Answer 9

PA- Distal anterior radius, and interosseous membrane
DA- Distal phalanx of thumb
N/S- Median nerve
A- Flexes phalanges of the first digit (thumb)

Question 10

Pronator Quadratus

Answer 10

PA- Distal ¼ of anterior ulna
DA- Distal ¼ of anterior radius
N/S- Median nerve
A- Pronates the forearm

Question 11

Flexor Retinaculum

Answer 11

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

Question 12

Posterior forearm muscles

Answer 12

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)

Question 13

Posterior Muscles of the formarm Nerve Supply

Answer 13

All muscles are supplied by the radial nerve

Question 14

Extensor retinaculum

Answer 14

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

Question 15

Brachioradialis

Answer 15

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

Question 16

Extensor Carpi Radialis Longus

Answer 16

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

Question 17

Extensor Carpi Radialis Brevis

Answer 17

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

Question 18

Extensor Digitorum

Answer 18

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

Question 19

Extensor Digiti Minimi

Answer 19

PA- Lateral epicondyle of humerus (CEO)
I- Extensor expansion 5th digit
N/S- Radial nerve
A- Extends 5th digit at metacarpophalangeal (MCP) & interphalangeal joints

Question 20

Extensor Carpi Ulnaris

Answer 20

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

Question 21

Supinator

Answer 21

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

Question 22

Abductor Pollicis Longus

Answer 22

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

Question 23

Extensor Pollicis Brevis

Answer 23

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)

Question 24

Extensor Pollicis Longus

Answer 24

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)

Question 25

Extensor Indicis

Answer 25

PA- Posterior of distal ulna and interosseous membrane
DA- Extensor expansion 2nd digit
N/S- Radial nerve
A- Extends 2nd digit