Muscles of the Forearm

Question 1

Muscles of the anterior compartment: PRONATOR TERES (superficial)

Answer 1

Origin: two heads
Ulnar head - coronoid process of ulna
Humeral head - medial epicondyle & supracondylar ridge of humerus
Insertion: lateral surface of radius (mid shaft)
Innervation: median nerve
Action: pronation of forearm, flexion of elbow

Question 2

Muscles of the anterior compartment: FLEXOR CARPI RADIALIS (superficial)

Answer 2

Origin: medial epicondyle
Insertion: base of 2nd metacarpal
Innervation: median nerve
Action: flexion and abduction of hand @ wrist

Question 3

Muscles of the anterior compartment: PALMARIS LONGUS (superficial)

Answer 3

Origin: medial epicondyle
Insertion: flexor retinaculum and palmar aponeurosis
Innervation: median nerve
Action: flexion of hand @ wrist, tension of palmar aponeurosis

Question 4

Muscles of the anterior compartment: FLEXOR CARPI ULNARIS (superficial)

Answer 4

Origin: two heads
Ulnar head - olecranon and posterior border of ulna
Humeral head - medial epicondyle
Insertion: pisiform, hamate, 5th metacarpal
Innervation: ulnar nerve
Action: flexion and adduction of hand @ wrist

Question 5

Muscles of the anterior compartment: FLEXOR DIGITORUM SUPERFICIALIS (intermediate)

Answer 5

Origin: two heads
Humero-ulnar head - medial epicondyle & margin of coronoid process
Radial head - oblique line (anterior) border of radius
Insertion: middle phalanges of digits 2-5
Innervation: median nerve
Action: flexion of proximal IP and MCP joints

Question 6

Muscles of the anterior compartment: FLEXOR DIGITORUM PROFUNDUS (deep)

Answer 6

Origin: anterior and medial surfaces of ulna and interosseous membrane
Insertion: bases of distal phalanges of digits 2-5
Innervation: lateral half by median nerve, medial half by ulnar nerve
Action: flexion of MCP and distal IP joints

Question 7

Muscles of the anterior compartment: FLEXOR POLLICIS LONGUS (deep)

Answer 7

Origin: anterior surface of radius and interosseous membrane
Insertion: base of distal phalanx of thumb
Innervation: median nerve
Action: flexion of MCP and IP joint of thumb

Question 8

Muscles of the anterior compartment: PRONATOR QUADRADUS (deep)

Answer 8

Origin: distal anterior surface of ulna
Insertion: distal anterior surface of radius
Innervation: median nerve
Action: pronation of forearm

Question 9

Muscles of the posterior compartment: BRACHIORADIALIS (superficial)

Answer 9

Origin: lateral supracondylar ridge of humerus & intermuscular septum
Insertion: lateral distal end of radius
Innervation: radial nerve
Action: flexion of elbow (when forearm mid-pronation)

Question 10

Muscles of the posterior compartment: EXTENSOR CARPI RADIALIS LONGUS (superficial)

Answer 10

Origin: lateral supracondylar ridge of humerus & intermuscular septum
Insertion: base of 2nd metacarpal
Innervation: radial nerve
Action: extension and abduction of wrist

Question 11

Muscles of the posterior compartment: EXTENSOR CARPI RADIALIS BREVIS (superficial)

Answer 11

Origin: lateral epicondyle & intermuscular septum
Insertion: base of 2nd & 3rd metacarpals
Innervation: radial nerve
Action: extension and abduction of wrist

Question 12

Muscles of the posterior compartment: EXTENSOR CARPI ULNARIS (superficial)

Answer 12

Origin: lateral epicondyle & posterior surface of ulna
Insertion: base of 5th metacarpal
Innervation: posterior interosseous nerve
Action: extension and adduction of wrist

Question 13

Muscles of the posterior compartment: EXTENSOR DIGITORUM (superficial)

Answer 13

Origin: lateral epicondyle & intermuscular septum
Insertion: base of middle & distal phalanges of digits 2-5
Innervation: posterior interosseous nerve
Action: extension of wrist & digits 2-5

Question 14

Muscles of the posterior compartment: EXTENSOR DIGITI MINIMI (superficial)

Answer 14

Origin: lateral epicondyle & intermuscular septum
Insertion: dorsal surface of end of 5th distal phalanx
Innervation: posterior interosseous nerve
Action: extension of 5th digit

Question 15

Muscles of the posterior compartment: SUPINATOR (deep)

Answer 15

Origin: two heads
Superficial head- lateral epicondyle & radial collateral & anular ligaments
Deep head - supinator crest of ulna
Insertion: lateral surface of radius superior to oblique line
Innervation: posterior interosseous nerve
Action: supination of forearm at RUJ

Question 16

Muscles of the posterior compartment: ABDUCTOR POLLICIS LONGUS (deep)

Answer 16

Origin: posterior surface of ulna, radius & interosseous membrane
Insertion: base of 1st metacarpal
Innervation: posterior interosseous nerve
Action: abduction and extension of CMC joint of thumb

Question 17

Muscles of the posterior compartment: EXTENSOR POLLICIS BREVIS (deep)

Answer 17

Origin: posterior surface of radius and interosseous membrane
Insertion: base of proximal phalanx of thumb
Innervation: posterior interosseous nerve
Action: extension of MCP and CMC joints of thumb

Question 18

Muscles of the posterior compartment: EXTENSOR POLLICIS LONGUS (deep)

Answer 18

Origin: posterior surface of ulna & interosseous membrane
Insertion: base of distal phalanx of thumb
Innervation: posterior interosseous nerve
Action: extension of all thumb joints

Question 19

Muscles of the posterior compartment: EXTENSOR INDICIS (deep)

Answer 19

Origin: posterior surface of ulna & interosseous membrane
Insertion: base of proximal phalanx of 2nd digit
Innervation: posterior interosseous nerve
Action: extension of 2nd digit