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MSK Week 1 > LM 4.2: Upper Extremity Muscles > Flashcards

LM 4.2: Upper Extremity Muscles Flashcards

1
Q

pectoralis major:

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervating nerve
    lateral pectoral
    medial pectoral
  2. nerve root
    clavicular C5, C6, C7
    sternocostal C8 ,T1
  3. action
    humeral adduction
    medial rotation
    scapular protraction
  4. distal attachment along the intertubercular groove of the humerus
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2
Q

pectoralis minor:

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervating nerve
    medial pectoral nerves
  2. nerve root
    C8, T1
  3. action
    scapular stabilization, downward rotation, and depression of the shoulder

axilary breathing muscle during deep/compromised respiration

  1. attaches to the coracoid process of the scapula and to ribs 3-5
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3
Q

sternocleido-mastoid

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervating nerve
    spinal accessory nerve
  2. nerve root
    cranial nerve = C1, C2, C3, C4
  3. action
    - elevated medial clavicle
  • lateral flexion of the head
    4. attaches to the sternum up to behind the ear
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4
Q

serrates anterior

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervating nerve
    long thoracic nerve
  2. nerve root
    C5, C6, C7
  3. action
    protraction of scapula in a punching motion, or in reaching forward
  4. fingerlike projections of the muscle attach proximally to the ribs and to the entire length of the medial border of the anterior scapula, including its inferior angle
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5
Q

subclavius muscle

  1. action
  2. attachment
A
  1. action =
    - acts to depress the clavicle, or elevate the first rib
    - provides structural support for the sternoclavicular joint
  2. attachment = attaches proximally to the costal cartilage of he first rib at the manubrium and distillery to the inferior central clavicle
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6
Q

what happens when the long thoracic nerve is damaged or weak?

A

it innervates the serrates anterior so if the long thoracic nerve has problems, this causes “medial winging” of the scapula on attempted protraction

medial winging is where the medial border of the scapula protrudes from its normal place close to the posterior rib cage

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7
Q

levator scapulae

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by dorsal scapular nerve
  2. C3, C4, C5
  3. elevates the scapula
  4. attaches to the transverse process of the atlas and axis and to the posterior tubercles of the transverse process of the 1st - 4th cervical vertebrae
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8
Q

rhomboid major

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by dorsal scapular nerve
  2. C4, C5
  3. retract the medial border of the scapula superiorly and medially; used in squaring the shoulders = proper posture!!
  4. arises from the spines and supraspinous ligaments of the T2 to T5 thoracic vertebrae, and descends laterally to the medial border of the scapula
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9
Q

rhomboid minor

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by dorsal scapular nerve
  2. C4, C5
  3. retract the medial border of the scapula superiorly and medially; used in squaring the shoulders = proper posture!!
  4. runs from the lower ligamentum nuchae and the spines of the C7 and T1 vertebrae
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10
Q

trapezius

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by spinal accessory nerve
  2. cranial nerve = C1, C2, C3, C4
  3. upward rotation of the glenohumeral fossa

helps steady the scapula and maintaining the poise of the shoulder; acting with levator scapulae muscle, the superior fibers elevate the scapula and with it the point of the shoulder

  1. the lateral angles occur at the shoulder tips, the superior angle at the occipital protuberance and superior nuchal lines, and the inferior angle at the spine of the twelfth thoracic vertebra
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11
Q

latissimus dorsi

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by thoracodorsal nerve
  2. C6, C7, C8
  3. humeral extension, adduction, medial rotation

used for a chin up or pulling the oar toward the chest during the power stroke of rowing

  1. attaches from the axial skeleton to the humerus

proximal attachment arises from the spinous processes of the inferior six thoracic vertebrae, the thoracodorsal fascia, iliac crest, and inferior 3 or 4 ribs

distal attachment is the base of the intertubercular groove of the humerus

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12
Q

supraspinatus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by suprascapular
  2. C5, C6
  3. first 15 degrees of abduction of the shoulder
  4. arises from the medial two-thirds of the supraspinous fossa and attaches to the greater tubercle
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13
Q

infraspinatus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. suprascapular nerve
  2. C5, C6
  3. external (lateral) rotation of the humerus
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14
Q

teres minor

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. axillary nerve
  2. C5, C6
  3. external (lateral) rotation and weak adductor of the humerus
  4. attached to the lowest facet on the greater tubercle of the humerus
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15
Q

subscapularis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. upper subscapular, lower subscapular
  2. C5, C6
  3. adduction internal (medial) rotation of the humerus
  4. attaches distally on the lesser tubercle of the humerus

covers the majority of the anterior/costal surface of the scapula, aptly named the subscapular fossa

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16
Q

which 4 muscles make up the rotator cuff?

A
  1. supraspinatus
  2. infraspinatus
  3. teres minor
  4. subscapularis

they all have roots of C5 and C6

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17
Q

how does teres major play an indirect part in the rotator cuff?

A

does not participate in the shoulder capsule/rotator cuff, BUT it does performs upward rotation of the glenoid fossa and humeral adduction. It contributes to the posterior axial fold

medial rotator and adductor of the humerus; also helps stabilize the humeral head in the gloenoid cavity

innervated by lower subscupular nerve

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18
Q

what makes the muscles of the rotator cuff susceptible to wear and tear?

A

the coracobrachialis and short head of the biceps brachii attachments to the coracoid process

the subscapularis and supraspinatus muscles pass deep to these attachments to the coracoid process

this makes these muscles of the rotator cuff susceptible to wear and tear during shoulder flexion, abduction, and rotation

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19
Q

teres major

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by lower sub scapular nerve
  2. C5, C6, C7
  3. internal rotation; forms posterior fold of axilla and upward rotation

4.

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20
Q

coracobrachialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A

the deepest of the brachial anterior compartment muscles

  1. innervated by musculocutaneous nerve
  2. C5, C6
  3. flexion; resists shoulder dislocation
  4. proximal insertion is the tip of the coracoid process, deep to the short head of the biceps brachii, and posterior to the long head of biceps brachii

distal insertion is the medial, middle third of the humerus. It assists in humeral flexion and adduction

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21
Q

deltoid

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A

the most superficial of the brachial anterior compartment muscles; it overlies the point of the shoulder, and gives it a rounded appearance

  1. innervated axillary nerve
  2. C5, C6
  3. abduction, flexion, extension at the glenohumeral joint
  4. anterior segment proximal attachment to the lateral third of the clavicle

middle segment proximal attachment to the acromion process of the scapula

posterior segment proximal attachment to the spine of the scapula

distal attachment of the deltoid is the deltoid tuberosity of the humerus

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22
Q

what are the 3 segments of the deltoid?

A

the deltoid has 3 functional segments

when working independently, each segment act on the humerus individually

the anterior segment flexes the humerus after initiation of the motion by the supraspinatus muscle for the first 15°

the posterior segment extends the humerus

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23
Q

what are bursae?

A

synovial membranes filled with fluid that prevent tissue damage from sliding/friction

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24
Q

what are the two important bursa in the body?

A
  1. subscapularis bursa

communicates normally with the joint space of the glenohumeral joint

  1. subacromial bursa

does not normally communicate with the joint space

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25
Q

biceps brachii

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by musculocutaneous nerve
  2. C5, C6
  3. flexion/supination of the forearm
  4. the long head occupies the inter tubercular groove of the humerus and travels through the glenohumeral joint space to attach to the supraglenoid tubercle

the short head is anterior to the long head and its proximal attachment is on the coracoid process

the distal attachment is to the biceps aponeurosis and radial tuberosity

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26
Q

why is the biceps brachia susceptible to injury?

A

As a two joint muscle, the biceps brachii is susceptible to injury and repetitive stress. One common diagnosis is rupture of the tendon of the long head. This is often a result of repetitive stress. The rupture typically occurs at the attachment to the supraglenoid tubercle. As the long head resides in the intertubercular groove (sulcus), irritation to the tendon may result in tenosynovitis as the tendon rides back and forth. A rupture is often the result of chronic inflammation in patients over the age of 35 years.

27
Q

long head of the triceps brachii

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  2. C7, C8 roots
  3. extension of the forearm
  4. proximal attachment of the long head of triceps brachii is the infraglenoid tubercle

distal attachment is the olecranon process

28
Q

triceps brachii medial and lateral heads

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  2. C7, C8
  3. ulna extension at elbow joint
  4. the medial head is the deepest portion of triceps brachii; the proximal attachment is along the posterior humerus, distal to the radial groove

proximal attachment of the lateral head is also the posterior humerus distal to the radial groove

29
Q

brachioradialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  2. C5, C6
  3. radius flexion
30
Q

brachialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by musculocutaneous nerve
  2. C5, C6
  3. ulna flexion; it’s the primary flexor of the forearm
  4. proximal attachment is on mid-shaft of the anterior humerus and distal to the coronoid process and tuberosity of the ulna
31
Q

pronator teres

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve
  2. C6, C7
  3. pronation = rotates radius on the ulna
  4. ulnar head attaches to the coronoid process of the ulna; the humeral head attaches to the medial epicondyle

distal attachment is to the radius

32
Q

flexor carpi radialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve
  2. C7, C8
  3. wrist flexion
  4. distal attachment is the base of the 2nd metacarpal
33
Q

palmaris longus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve
  2. C6, C7
  3. wrist flexion

too small to be primary flexor so it’s often used as a donor tendon in surgery

  1. distal attachment on the palmar fascia
34
Q

flexor carpi ulnaris

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. wrist flexion
  4. distal attachment to the pisiform bone, the hook of the hamate and the 5th metacarpal
35
Q

flexor digitorum superficialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve
  2. C7, C8
  3. PIP flexion
36
Q

flexor digitorum profundus 2n-3rd

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median (anterior interosseous branch) nerve
  2. C7, C8
  3. DIP flexion
37
Q

flexor digitorum profundus 4th-5th

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. CIP flexion
38
Q

flexor pollicis longus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median (anterior interosseous branch) nerve
  2. C7, C8
  3. thumb IP flexion
  4. proximal attachment is along the radius and interosseous membrane
39
Q

pronator quadratus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by mediate (anterior interosseous branch) nerve
  2. C7, C8
  3. pronation of forearm
40
Q

brachioradialis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  2. C5, C6
  3. forearm flexion
  4. found in the posterior compartment; most superficial muscle along the radial side of the forearm

arises from the proximal two-thirds of the lateral supracondylar ridge of the humerus and attaches to the distal end of the radius, just proximal to the styloid process

41
Q

extensor carpi radialis longus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  2. C6, C7
  3. wrist extension and abduction
  4. arises mainly from lateral supracondylar ridge of the humerus

inserts on base of the 2nd metacarpal

42
Q

extensor carpi radialis brevis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial) nerve
  2. C6, C7
  3. wrist extension
43
Q

extensor digitorum

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial) nerve
  2. C7, C8
  3. PIP extension
  4. arises from the lateral epicondyle of the humerus.

divides distally into 4 tendons and attachments enter a fibrous expansion of the medial 4 fingers

44
Q

extensor digiti minimi

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial) nerve
  2. C7, C8
  3. small finger PIP extension
  4. attachments are the lateral epicondyle and the extensor expansion of the 5th finger
45
Q

extensor carpi ulnaris

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial) nerve
  2. C7, C8
  3. wrist extension
  4. attachments are the lateral epicondyle and the base of the 5th metacarpal
46
Q

anconeus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by radial nerve
  3. assists triceps in extending the elbow joint
  4. arises from the posterior surface of the lateral epicondyle of the humerus
47
Q

supinator

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN ( radial)
  2. C5, C6
  3. supination
48
Q

abductor pollicis longus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN ( radial)
  2. C7, C8
  3. thumb abduction
49
Q

extensor pollicis brevis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial)
  2. C7, C8
  3. thumb extension at MCP joint
50
Q

extensor pollicis longus

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial)
  2. C7, C8
  3. thumb extension IP
51
Q

extensor indices proprius

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by PIN (radial)
  2. C8, T1
  3. second finger MCP extension
52
Q

abductor pollicis brevis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve, recurrent branch
  2. C8, T1
  3. thumb abduction
53
Q

flexor pollicis brevis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve, recurrent brach
    * the deep head is innervated by the deep branch of the ulna nerve
  2. C8, T1
  3. thumb flexion at the metacarpophalangeal joint (MCP)
54
Q

opponens pollicis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by median nerve, recurrent branch
  2. C8, T1
  3. opposition of the thumb, by medially rotating and flexing the metacarpal on the trapezium
55
Q

what are the 3 thenar muscles?

A
  1. opponens pollicis
  2. abductor pollicis bravis
  3. flexor pollicis brevis

three short muscles located at the base of the thumb responsible for the fine movements of the thumb and are innervated by the median nerve

56
Q

abductor digiti minimi

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. small finger abduction
57
Q

flexor digiti minimi

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. small finger flexion at the MCP joint
58
Q

opponens digiti minimi

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. small finger opposition; rotates the metacarpal of the little finger towards the palm
59
Q

which muscles are in the hypothenar group?

A
  1. abductor digiti minimi,
  2. flexor digiti minimi
  3. opponens digiti minimi
60
Q

lumbricals

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. first and second lumbricals (the most radial two) are innervated by the MEDIAN nerve

third and fourth lumbricals (most ulnar two) are innervated by the DEEP branch of the ULNAR nerve

  1. C8, T1
  2. MP flexion, IP extension
  3. there are four bellies and they DO NOT attach to bone! Instead- they attach proximally to the tendons of FDP and distally to the extensor expansions
61
Q

palmar interosseous

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. finger adduction
62
Q

dorsal interosseous

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. innervated by ulnar nerve
  2. C8, T1
  3. finger abduction
63
Q

adductor pollicis

  1. innervating nerve
  2. nerve root
  3. action
  4. attachment
A
  1. ulnar nerve
  2. C8, T1
  3. thumb adduction

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