UE Axilla, Arm, Forearm, Hand Muscles

Question 1

Axilla boundaries

Answer 1

Apex: 1st rib, clavicle

Base: skin of armpit

Anterior: pectoralis minor

Posterior: scapula, subscapularis muscle

Medial: thoracic wall, serratus anterior

Lateral: Humerus

Question 2

Axilla contents

Answer 2

Axillary artery, Axillary vein, Axillary lymph nodes, 3 cords of brachial plexus

Question 3

Anterior compartment of the ARM

Answer 3

Actions: Shoulder & elbow flexion

Musculocutaneous Nerve innervation

Brachial Artery

Question 4

Posterior compartment of the ARM

Answer 4

Actions: Shoulder & elbow extension

Radial Nerve innervation

Profunda Brachii Artery

Anconeus also in this compartment

Question 5

Anconeus

Answer 5

Arm muscle

Prox attachment: Lateral epicondyle of humerus

Distal attachment: Lateral surface of the olecranon process

Actions: Elbow extension

Radial Nerve Innervation

Spinal Segments: C7-C8

Question 6

Biceps brachii (2 heads)

Answer 6

Arm muscle

Prox attachment:

• Short head- coracoid process
• Long head- supraglenoid tubercle of scapula

Distal attachment: Radial tuberosity and deep antebrachial fascia (through bicipital aponeurosis)

Actions: Elbow and shoulder flexion, forearm supination

Musculocutaneous Nerve Innervation

Spinal Segments: C5-C6

Question 7

Brachialis

Answer 7

Arm muscle

Prox attachment: Distal anterior shaft of humerus & lateral and medial intermuscular septa

Distal attachment: Coronoid process & ulnar tuberosity

Actions: Elbow flexion

Musculocutaneous Nerve Innervation + Small Branch of Radial Nerve

Spinal Segments: C5-C6

Question 8

Coracobrachialis

Answer 8

Arm muscle

Prox attachment: Coracoid process

Distal attachment: Proximal medial shaft of humerus

Actions: Shoulder flexion and adduction

Musculocutaneous Nerve Innervation

Spinal Segments: C6-C7

Question 9

Triceps brachii (3 heads)

Answer 9

Arm muscle

Prox attachment:

• Long head- Infraglenoid tubercle of scapula
• Lateral head- proximal posterolateral shaft of humerus
• Medial head- distal posteromedial shaft of the humerus

Distal attachment: Olecranon process of the ulna

Actions: Elbow & shoulder extension

Radial Nerve Innervation

Spinal Segments: C6-T1

Question 10

Abductor pollicis longus

Answer 10

Forearm muscle

PA: proximal posterior radius, ulna, & interosseous membrane

DA: base of the 1st metacarpal & trapezium

A: abducts & extends the thumb at carpometacarpal joint & abducts hand at wrist (radial deviation)

Radial Nerve Innervation

Spinal Segments C6-C8

Question 11

Brachioradialis

Answer 11

Forearm muscle

PA: lateral supracondylar ridge of the humerus

DA: distal radius lateral to the styloid process

A: elbow flexion, helps with supination

Radial Nerve Innervation

Spinal Segments C5-C6

Question 12

Extensor carpi radialis brevis

Answer 12

Forearm muscle

PA: lateral epicondyle of the humerus (common extensor origin)

DA: base of 3rd metacarpal

A: extends & abducts hand at wrist (radial deviation)

Radial Nerve Innervation

Spinal Segments C6-C8

Question 13

Extensor carpi radialis longus

Answer 13

Forearm muscle

PA: lateral supracondylar ridge of the humerus

DA: base of the 2nd metacarpal

A: extends & abducts hand at wrist (radial deviation) and assists in elbow flexion

Radial Nerve Innervation

Spinal Segments C6-C8

Question 14

Extensor carpi ulnaris

Answer 14

Forearm muscle

PA: lateral epicondyle of the humerus (common extensor origin)

DA: base of 5th metacarpal

A: extends & adducts hand at wrist (ulnar deviation)

Radial Nerve Innervation

Spinal Segments C6-C8

Question 15

Extensor digitorum

Answer 15

Forearm muscle

PA: lateral epicondyle of the humerus (common extensor origin)

DA: extensor expansions of digits 2-5

A: extends phalanges (primarily at metacarpophalangeal, secondarily at interphalangeal) & hand at wrist

Radial Nerve Innervation

Spinal Segments C6-C8

Question 16

Extensor digiti minimi

Answer 16

Forearm muscle

PA: lateral epicondyle of the humerus (common extensor origin)

DA: digital expansion of the 5th digit

A: extends 5th digit (metacarpophalangeal & interphalangeal)

Radial Nerve Innervation

Spinal Segments C7-C8

Question 17

Extensor indicis

Answer 17

Forearm muscle

PA: posterior surface of the ulna & interosseous membrane

DA: digital expansion of the 2nd digit

A: extends 2nd digit (metacarpophalangeal & interphalangeal)

Radial Nerve Innervation

Spinal Segments C7-C8

Question 18

Extensor pollicis longus

Answer 18

Forearm muscle

PA: middle 1/3 of the posterior surface of the ulna & interosseous membrane

DA: base of the 1st distal phalanx

A: extends thumb (CMC & metacarpophalangeal & interphalangeal)

Radial Nerve Innervation

Spinal Segments C6-C8

Question 19

Flexor carpi radialis

Answer 19

Forearm muscle

PA: medial epicondyle (common flexor origin)

DA:palmar aspect of the base of the 2nd metacarpal

A: flexes & abducts hand at wrist (radial deviation) & may assist in pronation of the forearm & flexion of the elbow

Median Nerve Innervation

Spinal Segments C6-C8

Question 20

Flexor carpi ulnaris

Answer 20

Forearm muscle

PA: medial epicondyle (common flexor origin) of humerus & proximal ulnar shaft

DA: pisiform

A: flexes & adducts hand at wrist (ulnar deviation)

Ulnar Nerve Innervation

Spinal Segments C7-T1

Question 21

Flexor digitorum profundus

Answer 21

Forearm muscle

PA: anterior proximal 2/3 of the ulna & interosseous membrane

DA: base of the distal phalanges of digits 2-5

A: flexion of digits 2-5 (metacarpophalangeal & distal interphalangeal & proximal interphalangeal), & flexion of hand at wrist

Median (2nd & 3rd digits) & Ulnar (4th & 5th digits) Nerve Innervation

Spinal Segments C7-T1

Question 22

Flexor digitorum superficialis

Answer 22

Forearm muscle

PA: medial epicondyle (common flexor origin) of the humerus

DA: sides of the middle phalanges of digits 2-5

A: flexion of digits (metacarpophalangeal & proximal interphalangeal) & hand at wrist

Median Nerve Innervation

Spinal Segments C7-T1

Question 23

Flexor pollicis longus

Answer 23

Forearm muscle

PA: anterior surface of the radius & interosseous membrane

DA: base of the distal phalanx of the thumb

A: flexes thumb (metacarpophalangeal & interphalangeal)

Median Nerve Innervation (anterior interosseous nerve)

Spinal Segments C7-T1

Question 24

Palmaris longus

Answer 24

Forearm muscle

PA: medial epicondyle of the humerus (common flexor origin)

DA: palmar aponeurosis

A: flexes hand at wrist & tenses palmar fascia

Median Nerve Innervation

Spinal Segments C7-C8

Question 25

Pronator quadratus

Answer 25

Forearm muscle PA: anterior surface of the distal ulna DA: anterior surface of the distal radius A: pronates the forearm Median Nerve Innervation (anterior interosseous nerve) Spinal Segments C8-T1

Question 26

Pronator teres

Answer 26

Forearm muscle PA: medial epicondyle & ulnar coronoid process DA: lateral aspect of the radius A: pronates & flexes the forearm Median Nerve Innervation Spinal Segments C7-C7

Question 27

Supinator

Answer 27

Forearm muscle PA: lateral epicondyle of the humerus, radial collateral ligament, & supinator crest of the ulna DA: lateral surface of the proximal radius A:supinates forearm Radial Nerve Innervation Spinal Segments C5-C6

Question 28

Abductor digiti minimi

Answer 28

Hand muscle PA: pisiform DA: ulnar side of the base of the proximal phalanx of the 5th digit A: abducts 5th digit (pinky) Deep branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 29

Abductor pollicis brevis

Answer 29

Hand muscle PA: transverse carpal ligament DA: radial side of the base of the proximal phalanx of the thumb A: abducts thumb Recurrent branch of Median Nerve Innervation Spinal Segments C6-T1

Question 30

Adductor pollicis

Answer 30

Hand muscle PA: capitate & 2nd/3rd metacarpals (oblique head) & palmar aspect of the 3rd metacarpal (transverse head) DA: base of the proximal phalanx of the thumb A: adducts thumb Deep branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 31

Dorsal interossei

Answer 31

Hand muscle PA: adjacent sides of the metacarpals DA: proximal phalangeal bases & dorsal digital expansions of digits 2-4 A: abducts (metacarpophalangeal), flexes (metacarpophalangeal) & extends (interphalangeal) digits 2-4 Deep Branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 32

Flexor digiti minimi brevis

Answer 32

Hand muscle PA: hamate DA: ulnar side of the base of the proximal phalanx of the 5th digit A: flexes (metacarpophalangeal) 5th digit Deep branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 33

Flexor pollicis brevis

Answer 33

Hand muscle PA: transverse carpal ligament & trapezium DA: radial side of the base of the proximal phalanx of the thumb; deep head blends with opponens pollicis A: flexes (metacarpophalangeal) thumb Recurrent branch of the Median Nerve (superficial head) & deep branch of Ulnar Nerve (deep head) Innervation Spinal Segments: superficial head C6-T1; deep head C8-T1

Question 34

Lumbricals

Answer 34

Hand muscle PA: tendons of the flexor digitorum profundus DA: radial side of dorsal digital expansions of digits 2-5 A: flexes metacarpophalangeal & extends interphalangeal joints of digits 2-5 Deep branch of Ulnar Nerve (3rd & 4th lumbricals C8-T1) and Median Nerve Innervation (1st & 2nd lumbricals C7-8-T1) Spinal Segments C7-T1

Question 35

Opponens digiti minimi

Answer 35

Hand muscle PA: hook of the hamate DA: ulnar margin of shaft of 5th metacarpal A: opposition of 5th digit to thumb Deep branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 36

Opponens pollicis

Answer 36

Hand muscle PA: transverse carpal ligament & trapezium DA: palmar surface of 1st metacarpal A: opposition of thumb to 5th digit Recurrent Median Nerve Innervation Spinal Segments C6-T1

Question 37

Palmar interossei

Answer 37

Hand muscle PA: palmar aspects of metacarpals 2, 4, & 5 DA: dorsal digital expansions of digits 2, 4, 5 A: adducts& flexes metacarpophalangeals, extends interphalangeal digits 2, 4, 5. Deep branch of Ulnar Nerve Innervation Spinal Segments C8-T1

Question 38

Extensor pollicis brevis

Answer 38

Forearm muscle PA: posterior radial surface & interosseous membrane DA: base of the 1st proximal phalanx A: extends thumb (metacarpophalangeal) & extends and abducts CMC joint Radial Nerve Innervation Spinal Segments C6-C8

Question 39

Forearm Posterior Compartment

Answer 39

Elbow & hand extension, supination Radial Nerve Innervation Radial artery (posterior interosseous)

Question 40

Cubital Fossa boundaries

Answer 40

from lateral to medial epicondyles brachioradialis pronator teres The bicipital aponeurosis covers and protects the brachial artery and median nerve passing through here.

Question 41

Forearm Anterior Compartment

Answer 41

Elbow & hand flexion, pronation Median Nerve Innervation Ulnar artery (anterior interosseous)

Question 42

Anterior compartment of forearm superficial layer muscles

Answer 42

Pronator teres Flexor carpi radialis Palmaris longus (all median nerve) Flexor carpi ulnaris (ulnar nerve)

Question 43

Anterior compartment of forearm intermediate layer muscles

Answer 43

Flexor digitorum superficialis | median nerve

Question 44

Anterior compartment of forearm deep layer muscles

Answer 44

Flexor digitorum profundus (deep) (medial/ulnar split innervation: digits 2-3 radius, digits 4-5 ulna) ``` Flexor pollicis longus Pronator quadratus (anterior interosseous nerve from median nerve) ```

Question 45

Posterior compartment of forearm superficial layer

Answer 45

``` 6 muscles: Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris ``` extension movement

Question 46

Posterior compartment of forearm deep layer

Answer 46

``` supinator extensor indicis (index finger) ``` 3 outcropping thumb muscles abductor pollicis longus extensor pollicis brevis extensor pollicis longus (wraps around dorsal tubercle of radius and changes direction to thumb)