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Shoulder Anatomy > Muscles > Flashcards

Muscles Flashcards

1
Q

Briefly describe the position of serratus anterior

A

Covers the upper part of the side of the thorax (anterolateral chest wall). It is sandwiched between the scapula and the ribs, covered by Latissimus Dorsi

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2
Q

State the attachments of serratus anterior

A

(PROXIMAL) interdigitations just anterior to the mid axillary line attaching to lateral surfaces of upper 8/9 ribs and adjacent intercostal fascia.
(DISTAL) attaches to the costal surface of the medial border of scapula, between superior and inferior angles.

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3
Q

Name the nerve that supplies serrratus anterior

A

Long thoracic nerve C5-7

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4
Q

State the actions of serratus anterior

A

Major protractor of the shoulder girdle
Assists in depression of the scapula
Lower fibres laterally rotate scapula.
As a whole muscle will elevate ribs - accessory inspiratory muscle

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5
Q

Give one functional activity in which serratus anterior is important

A

The reaching forwards phase of pushing / punching (boxers)

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6
Q

Give the position of the trapezius

A

Posterior superficial aspect of Neck, Shoulder and Upper back. From skull to thoracic spine and across to the Acromion.

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7
Q

State the attachments of the trapezius

A

(PROXIMAL) 1 – Upper fibres medial third of the superior nuchal line and external occipital protuberance of the occipital bone of the skull.
2 –Middle fibres ligamentum nuchae
3 – Lower fibres spinous processes (C7 -T12) and intervening supraspinous ligaments
(DISTAL) 1 – Upper fibres descend to posterior border of the lateral 1/3 clavicle
2 – Middle fibres pass to medial border of the acromion and superior border of the spine of scapular
3 – Lower fibres attach via an triangular aponeurosis to the medial end of the spine of scapula

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8
Q

State the actions for trapezius

A

Superior fibres – elevate shoulder girdle , (shoulder girdle fixed) lateral neck flexion, (both trapezius) neck extension
Middle fibres – retraction of the scapula
Inferior fibres– depression of the scapula
Superior + inferior fibres lateral rotation of the scapula

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9
Q

Name the nerve that supplies trapezius

A

Motor: accessory nerve (XI)
Sensory: ventral rami of spinal nerves C3-C4 (via cervical plexus)

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10
Q

Briefly describe the deltoid giving its position and arrangement

A

Course thick triangular muscle which caps and surrounds the shoulder joint and gives the shoulder its rounded contour. Functionally it has 3 parts anterior fibres, middle (multipennate) fibres, and posterior fibres.

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11
Q

State the attachments of the deltoid

A

Proximal attachment -
1- anterior fibres the anterior border and upper surface of the lateral third of the clavicle
2- middle fibres lateral margin of the acromion process
3- posterior fibres attach to the lower lip of the crest of the spine of the scapular.
Distal attachment - The Deltoid tuberosity on the lateral surface of the shaft of the humerus

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12
Q

List the actions of the deltoid

A

Middle fibres - abduction of the arm (only after initiation by supraspinatus)

anterior fibres - flex and medially rotate the humerus

posterior fibres - extend and laterally rotate the humerus.

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13
Q

State the attachments of latissmus dorsi

A

proximal attachment - thorocolumbar fascia to spinous processes of T6-T12, all lumbar and sacral vertebrae and intervening supraspinous and interspinous ligaments, iliac crest, lower 3-4 ribs and inferior angle of Scapula.

distal attachment - floor of the inter tubercular sulcus (bicipital groove) on the humerus between pectoralis major and teres major

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14
Q

Give the actions of latissmus dorsi

A

Extension of the flexed arm, adducts and medially rotates the humerus at the shoulder joint

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14
Q

Give innervation of latissmus dorsi

A

Thoracodorsal nerve C6-8

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15
Q

State 2 functional activities in which latissmus dorsi plays an important role

A

1- activities such as swimming and rowing as it pulls the arm down and back from elevation against resistance

2- When using crutches it pulls the trunk forward in relation to the arms lifting the pelvis making this possible.

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16
Q

Briefly describe the position of pectoralis major

A

Pectoralis major is located on the upper part of the anterior surface of the thoracic wall superficial to pectoralis minor and forming the anterior fold of the axilla.

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17
Q

State the attachments of pectoralis major

A

proximal attachments
1- (smaller clavicular fibres)the medial half of the anterior surface of the clavicle,
2-(sternocostal fibres) half of the anterior surface of the manubrium
3-(body of the sternum fibres) the anterior surface of the upper 6 costal cartilages.

distal attachment - lateral lip of the intertubercular sulcus of the humerus.

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19
Q

Give the actions of pectoralis major

A

A powerful adductor and medial rotator of the humerus at the shoulder joint,

clavicular fibres- can flex the humerus to the horizontal,
sternocostal fibres - can extend the flexed humerus against resistance.

Also with the humerus fixed (for example when gripping the back of a chair) it pulls on the upper ribs to assist in inspiration in respiratory distress.

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19
Q

State innervation of pectoralis major

A

Medial pectoral nerve C8-T1

Lateral pectoral nerve C5-7

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20
Q

Name the rotator cuff muscles

A

Supraspinatus, Infraspinatus, Subscapularis and Teres minor muscles

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21
Q

State the attachments of the Supraspinatus muscle

A

Proximal attachment: medial two-thirds of the supraspinatus fossa.
Distal attachment: the tendon attaches to the superior facet on the greater tubercle of the humerus.

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22
Q

State the attachments of infraspinatus

A

Proximal- Medial 2/3 infraspinous fossa of scapula and covering fascia
Distal- middle facet of greater tubercle of humerus

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23
Q

State attachments of teres minor

A

Proximal - upper 2/3 lateral border of scapula

Distal - inferior facet of greater tubercle of humerus

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24
Q

State attachments of subscapularis

A

Proximal- medial 2/3 subscapular fossa and covering fascia

Distal - lesser tubercle of humerus

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25
Q

List the actions of each of the rotator cuff muscles

A

Supraspinatus: initiates the initial abduction of the shoulder
Infraspinatus and Teres Minor: Lateral rotation of the humerus
Subscapularis: Medial rotation of the Humerus

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26
Q

State innervation of rotator cuff muscles

A

Supraspinatus & infraspinatus - suprascapular nerve C5-6
Teres minor - axillary nerve C5-6
Subscapularis- subscapular nerve C5-7

27
Q

Briefly describe the importance of the rotator cuff muscles as a group

A

The rotator cuff muscles stabilise the head of the humerus in the small and shallow glenoid fossa of the scapula to prevent unwanted shearing movement caused by the more powerful muscles acting over the shoulder joint

28
Q

Briefly describe the position of subclavius

A

short, triangular muscle of the thoracic wall that Lies inferior to clavicle

29
Q

State the attachments of the subclavius

A

Origiin: Costal cartilage, sternal end of rib 1
Insertion: Anteroinferior surface of middle third of clavicle

30
Q

Give the actions of subclavius

A

Steadies/fixates the clavicle

Depresses the lateral end of clavicle to draw the shoulder inferiorly and anteriorly

31
Q

State the innervation of subclavius

A

Subclavian Nerve C5,6

32
Q

Briefly describe the position of pectoralis minor

A

superficial muscle on the anterior aspect of the chest or thoracic wall, located deep only to the pectoralis major muscle

33
Q

State attachments for pectoralis minor

A

Origin: Anterior surface, costal cartilages of ribs 3-5
Insertion: Supramedial surface of coracoid process of scapula

34
Q

Give actions of pectoralis minor

A

Assists protraction & depression of scapula
MR the scapula (against resistance)

Forced inspiration (Accessory muscle of respiration) - recruited to lift ribs to increase anteroposterior diameter of thorax to increase O2 in lungs

36
Q

State nerve supply of pectoralis minor

A

Medial & lateral pectoral nerves C5-T1

37
Q

Briefly describe the position of levator scapulae

A

long and slender muscle that anatomically belongs to the superficial layer of extrinsic muscles of the back.

upper part of the muscle lies underneath the splenius capitis and sternocleidomastoideus muscles

lower part is covered by trapezius.

Only the middle part of the levator scapulae remains uncovered (most easily palpated in this area). In addition, the middle part helps to form the floor of the posterior triangle of the neck

38
Q

State attachments for levator scapulae

A

Origin: Transverse processes of vertebrae C1-C4
Insertion: Medial border of scapula (from superior angle to root of spine of scapula)

39
Q

Give actions of levator scapulae

A

Elevation and medial rotation of scapula

40
Q

State nerve supply of levator scapulae

A

Dorsal Scapula nerve C4-5

41
Q

Briefly describe the position of the rhomboids

A

two bilateral, superficial muscles located in the upper back called rhomboid minor and rhomboid major.

overlie the deep (intrinsic) muscles of the back and are covered by the trapezius muscle.

42
Q

State attachments for the rhomboids

A

Origin
Rhomboid minor: ligamentum nuchae, Spinous processes of vertebrae C7-T1
Rhomboid major: Spinous process of vertebrae T2-T5 and supraspinous ligaments

Insertion
Rhomboid minor: Root (medial end) of spine of scapula
Rhomboid major: distal 3/5 Medial border of scapula (from inferior angle to root of spine of scapula)

43
Q

Give actions of the rhomboids

A

Powerful Retraction

Medial rotation of scapula (from a overreaching position and against resistance)

44
Q

State nerve supply of the rhomboids

A

Dorsal Scapula nerve C4-5

45
Q

Give one functional activity in which trapezius is important

A

• Steadies scapula and clavicle (upper fibres)
○ Against gravity or when weights are carried in the hand.
○ Vacuuming, dusting, writing

• Provides fixation(both sides)
	○ Controls head position, leaning forward as in writing or reading.

• Produces lateral rotation of scapula (upper & lower fibres)
	○ Brushing/combing hair
	○ Placing objects on/off shelf

• Produces retraction of scapula (middle fibres)
	○ Putting on coat/ opening doors 
	○ Produces good shoulder girdle posture

• Produces depression of scapula against resistance (lower fibres)
	○ Pushing up with hands on chair to stand from sitting
46
Q

Give position and arrangement of coracobrachialis

A

long and slender muscle of the anterior compartment of the arm

47
Q

Give attachments of coracobrachialis

A

Origin: Apex of coracoid process
Insertion: Anteromedial surface of shaft of humerus

48
Q

Give actions of coracobrachialis

A

Weak assister of ADD, flexion of humerus

49
Q

Give nerve supply of coracobrachialis

A

Musculocutaneous nerve C5-7

50
Q

Give position and arrangement of biceps brachii

A

biceps brachii muscle (biceps) is a large, thick muscle of the arm consisting of a long head and a short head

biceps brachii lies superficial to the brachialis and coracobrachialis muscles, and essentially forms the anterior side of the arm.

51
Q

Give attachments of biceps brachii

A

Origin:
Short head – apex of coracoid process
Long – supraglenoid tubercle of scapula, glenoid labrum (passing through bicipital groove)

Insertion: Converge as single tendon to posterior radial tuberosity, deep fascia of forearm (via bicipital aponeurosis)

52
Q

Give actions of biceps brachii

A

Flexion of shoulder (weak)/elbow (powerful)

Powerful Supination of superior & inferior Radio-ulnar joints (forearm)

53
Q

Give the nerve supply of biceps brachii

A

Musculo-cutaneous nerve, C5,6

54
Q

Give position and arrangement of triceps brachii

A

triceps brachii muscle consists of a long, medial and lateral head and is the only constituent of the posterior muscle group of the arm, spanning almost the entire length of the humerus.

55
Q

Give attachments of triceps brachii

A

Origin:
Long head –infra-glenoid tubercle of scapula, adjacent lateral border of scapula
Lateral head – posterior surface of the humerus (supralateral to radial groove)
Medial head – posterior surface of the humerus (inferomedial to radial groove)

Insertion: Converge as single tendon to upper surface of olecranon of ulna & deep fascia of forearm

56
Q

Give actions of triceps brachii

A

Whole muscle - Powerful extension at elbow

Long head also adducts & extends shoulder

57
Q

Give the nerve supply of triceps brachii

A

Radial nerve, C6-8

58
Q

Name the muscles that produce flexion of the shoulder joint

A

Anterior fibres deltoid, clavicular head of pectoralis major, coracobrachialis, long head of biceps brachii

59
Q

Name the muscles that produce extension of the shoulder joint

A

Posterior fibres of deltoid, Teres Major, Latissimus Dorsi, Pectoralis Major (sternocostal head) from flexion to neutral (against resistance), long head triceps brachii

60
Q

Name the muscles that produce abduction of the shoulder joint

A

Supraspinatus (initial 15 degrees), middle fibres deltoid

61
Q

Name the muscles that produce adduction of the shoulder joint

A

• Against resistance by:

Pectoralis Major, Latissimus Dorsi, Teres Major, Coracobrachialis, long head triceps brachii

62
Q

Name the muscles that produce MR of the shoulder joint

A
  • Subscapularis
  • Pectoralis Major
  • Latissimus Dorsi
  • Deltoid (ant fibres)
  • Teres major
63
Q

Name the muscles that produce LR of the shoulder joint

A

Infraspinatus, Teres Minor, Deltoid (post fibres)

65
Q

Give position and arrangement of teres major

A

thick muscle of the shoulder joint. It spans from the inferior aspect of the scapula to the proximal part of the humeral shaft

66
Q

Give attachments of teres major

A

Proximal- lower 1/3 lateral border and inferior angle of scapula
Distal - medial lip of intertubercular sulcus of humerus

67
Q

Give innervation of teres major

A

Lower subscapular nerve C6-7

68
Q

Give functional activity of teres major, latissmus dorsi & pectoralis major

A

Climbing - All work strongly from a flexed position to extend humerus against resistance

Shoulder Anatomy (5 decks)

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