Elbow and forearm muscles

Question 1

Answer 1

Biceps Brachii

• O: Long head = supraglenoid tubercle & glenohumeral labrum
  
  • Short Head = coracoid process of scapula
• I: radial tuberosity & bicipital aponeurosis
• A: Flexion & supination of elbow; flexion of shoulder; stabilization of anterior aspect of shoulder; abduction of shoulder (long head); adduction of shoulder (short head)
• N: musculocutaneus nerve C5, C6

Question 2

Answer 2

Coracobrachilais

• O: apex of coracoid process of scapula
• I: medial shaft of humerus (middle 1/3)
• A: flexion and adduction of shoulder; horizotal adduction of shoulder
• N: musculocutaneus nerve C5, C6, C7

Question 3

Answer 3

Brachialis

• O: anterior distal 1/2 of humerus
• I: ulnar tuberosity & coronoid process of ulna
• A: flexion of elbow (initiation)
• N: musculocutaneus nerve & small branch from radial nerve C5, C6, C7

Question 4

Answer 4

Triceps Brachii

• O: Long head: infraglenoid tubercle & neck of scapula
  
  • ​Lateral head: upper half of posterior surface of shaft of humerus (above radial groove)
  • medial head: posterior shaft of humerus (below radial groove)
• I: olecranon process of ulna
• A: extension of elbow (prime mover); adduction & exension of shoulder (long head only)
• N: radial nerve C6, C7, C8; axillary nerve (long head)

Question 5

Answer 5

Anconeus

• O: lateral epicondyle of humerus ( posterior surface)
• I: lateral side of olecranon process & upper 1/4 of the posterior surface of the body of ulna
• A: extension of elbow; stabilizes the ulna during pronation and supination
• N: radial nerve C6 C7 C8

Question 6

Answer 6

Pronator Teres

• O: Humeral (superficial) head: immediatly proximal to the medial epicondyle of the humerus via common flexor tendon & deep antibrachial fascia
  
  • Ulnar (deep) head: medial side of the coronoid process of the ulna
• I: middle of the lateral surface of radius ( pronator tuberosity)
• A: pronation of forearm & weak flexion of elbow
• N: median nerve C6, C7

Question 7

Answer 7

Pronator Quadratus

• O: medial side, anterior distal 1/4 of ulna
• I: lateral anteroir distal 1/4 of radius
• A: pronation of forearm
• N: median nerve C7, C8

Question 8

Answer 8

Brachioradialis

• O: lateral supracondylar ridge of the humerus
• I: lateral side of the base of the styloid process of radius
• A: flexion of elbow; pronation of forearm when supinated; supination of forearm when pronated
• N: radial nerve C5, C6

Question 9

Answer 9

Supinator

• O: lateral epicondyle of humerus and supinator crest of ulna
• I: lateral surface of the proximal 1/3 of the body of radius, covering part of the anterior & posterior surfaces
• A: supination of forearm (proximal radioulnar joint)
• N: radial nerve C6, C7

Question 10

Answer 10

Flexor carpi Radialis

• O: Common flexor tendon from the medial epicondyal of the humerus & deep antebrachial fascia
• I: Base of 2nd and slip to the base of 3rd metacarpal bone (anterior side)
• A: flexion of wrist; radial deviation; may assist in flexion and pronation of forearm
• N: median nerve C6, C7

Question 11

Answer 11

Palmaris Longus

• O: common flexor tendon from the medial epicondyle of the humerus & deep antebrachial fascia
• I: flexor retinaculum & palmar aponeurosis
• A: tense the palmar fascia, flexes wrist & may assist elbow flexion
• N: median nerve C7, C8

Question 12

Answer 12

Flexor Carpi Ulnaris

• O: Humeral head: medial epicondyle (common flexor tendon)
  
  • Ulnar head: by aponeurosis medial margin of olecranon, proximal 2/3 of the medial ulna & from the deep antebrachial fascia
• I: pisiform & hamate bones (via pisohamate ligament) & base of 5th metacarpal bone (via pisometacarpal ligament)
• A: Flexion of wrist, ulnar deviation, stabilizies wrist to permit powerful thumb motions, elbow flexion (weak action)
• N: ulnar nerve C7, C8

Question 13

Answer 13

Flexor Digitorum Superficialis

• O: Humeral-ulnar head: CFT of MEoH, coronoid process of ulna, medial(ulnar) collateral ligament
  
  • Radial Head: oblique line of radius along upper anterior border
• I: 4 tendons into sides of middle phalanges 2nd-5th digits (tendons spit at insertion)
• A: flexion of fingers 2-5 (PIP, MCP), wrist and hand, flexion of elbow(weak action)
• N: Median nerve C7,C8,T1

Question 14

Answer 14

Flexor digitorum profundus

• O: anterior & medial surfaces of ulna (proximal 1/2) interosseous membrane & deep antebrachial fascia
• I: 4 tendons into bases of distal phalanges 2-5
• A: finger flexion (DIP, PIP, MCP) may assist w/flexion of wrist
• N: Medial nerve C8, T1 (radial 1/2 of mus)
  
  • Ulnar nerve C8, T1 (ulnar 1/2 of mus)

Question 15

Answer 15

Flexor Pollicis Longus

• O: middle anterior surface of radius & interosseous membrane
• I: anterior aspect of base of distal phalanx of thumb
• A: flexes IP joint of thumb, assist in flexion of MCP, CMC joints, may assist in wrist flexion
• N: median nerve C7, C8

Question 16

Answer 16

extensor carpi radialis longus

• O: distal 1/3 of the lateral supracondylar ridge of the humerus (below brachioradialis)
• I: dorsal surface of base of the 2nd metacarpal bone, radial side
• A: extension of wrist, radial deviation, flexion & supination of elbow(weak action)
• N: radial nerve C5, C6

Question 17

Answer 17

extensor carpi radialis brevis

• O: common extensor tendon from LEoH
• I: dorsal surface of the base of 3rd metacarpal bone
• A: extension of wrist, radial deviation, flexion of elbow joint(weak action)
• N: radial nerve C7, C8

Question 18

Answer 18

Extensor digitorum

• O: CET from the LEoH & deep antebrachial fascia
• I:dorsal expansion hood of phalanges 2-5
• A: extension of fingers 2-5 (MCP, PIP, & DIP joints), extension of wrist, extention of elbow( W/A)
• N:radial nerve C7, C8

Question 19

Answer 19

Extensor digiti minimi

• O: CET from LEoH & deep antebrachial fascia
• I: middle and distal phalanges of 5th digit (extensor expansion)
• A: extension of pinky (5th dig) extension of wrist, extension of elbow(W/A)
• N: radial nerve C6, C7, C8

Question 20

Answer 20

extensor carpi ulnaris

• O: Humeral head: LEoH via CET
  
  • Ulnar head: posterior shaft of ulna
• I: base of ulnar side 5th metacarpal
• A: ulnar deviation, extension of wrist, extension of elbow(W/A)
• N: radial nerve C6, C7, C8

Question 21

Answer 21

extensor indicis

• O:posterisl distsl 1/3 of ulna (distal to O of EPL), and interosseous membrane
• I: base of middle & distal phalanx of index finger (via extensor expansion & extensor digitorum muscle tendon)
• A: extension of index finger (MCP, PIP, & DIP) extension of hand at wrist, adduction of index finger (W/A)
• N: radial nerve C7, C8

Question 22

Answer 22

Abductor pollicis longus

• O: posterior surface body of ulna, (distal to O of supinator), radias & interosseous membrane (middle 1/3 of forearm)
• I: base of 1st metacarpal (radial side)
• A: abduction of thumb (CMC joint) radial deviation, assists w/ extension & rotation of thumb, assists w/ flexion & supination of hand @ wrist
• N: radial nerve C7, C8

Question 23

Answer 23

Extensor Pollicis Brevis

• O: posterior surface body of radius (distal to O of APL, & interosseous membrane)
• I: base of proximal phalanx of thumb, dorsal surface
• A: extension of proximal phalanx of thumb, metcarpal thumb, & radial deviation
• N: radial nerve C7, C8

Question 24

Answer 24

extensor pollicis longus

• O: middle 1/3 posterior surface of ulna (distal to O of APL, and interosseous membrane)
• I: base of the distal phalanx of thumb dorsal surface
• A: extension of thumb (CMC, MCP, IP) assists in extension and radial deviation of wrist
• N: radial nerve C7, C8