Shoulder girdle

Question 1

List the retractors of the scapula

Answer 1

Rhomboid minor, rhomboid major, trapezius, levator scapulae

Question 2

List the protractors of the scapula

Answer 2

Serratus anterior, pectoralis minor

Question 3

List the elevators of the scapula

Answer 3

Trapezius, levator scapulae

Question 4

List of the lateral rotators of the scapula

Answer 4

Trapezius, serratus anterior

Question 5

List the medial rotators of the scapula

Answer 5

Rhomboid major, rhomboid minor, pectoralis minor, levator sacpulae

Question 6

List the flexors of the shoulder

Answer 6

Pectoralis major, deltoid (anterior fibres), biceps brachii (long head), coracobrachialis

Question 7

List the extensors of the shoulder

Answer 7

Latissimus dorsi, teres major, pectoralis major, deltoid (posterior fibres), triceps (long head)

Question 8

List the abductors of the shoulder

Answer 8

Supraspinatus, deltoid (middle fibres)

Question 9

List the medial rotators of the shoulder

Answer 9

Subscapularis, teres major, latissimus dorsi, pectoralis major, deltoid (anterior fibres)

Question 10

List the lateral rotators of the shoulder

Answer 10

Teres minor, infraspinatus, deltoid (posterior fibres)

Question 11

What is the origin, insertion, action and innervation of rhomboid minor

Answer 11

Origin: spines and supraspinatus ligaments of C7-T1, lower part of ligamentum nuchae
Insertion: medial end of spine of scapular
Action: rectracts and medially rotates scapular
Innervation: dorsal scapular nerve (C4, C5)

Question 12

What is the origin, insertion, action and innervation of rhomboid major

Answer 12

Origin: spines and supraspinatus ligaments of T2-T5
Insertion: medial border or scapula between root of spine and inferior angle
Action: retracts and medially rotates scapula
Innervation: dorsal scapular nerve (C4, C5)

Question 13

What is the origin, insertion, action and innervation of serratus anterior

Answer 13

Origin: outer surfaces and superior borders of upper eight, nine or ten ribs and intervening intercostal fascia
Insertion: costal surface of medial border of scapula
Action: protracts and laterally rotates scapula
Innervation: long thoracic nerve (C5-C7

Question 14

What is the origin, insertion, action and innervation of pectoralis minor

Answer 14

Origin: outer surface of third to fifth ribs and adjoining intercostal fascia
Insertion: upper surface and medial border of coracoid process
Action: protracts and medially rotates scapula
Innervation: medial and lateral pectoral nerves (C5-T1)

Question 15

What is the origin, insertion, action and innervation of pectoralis major

Answer 15

Origin: clavicular attachment- sternal half of anterior surface of clavicle; sternocostal attachment- anterior surface of manubrium, body of sternum, upper six costal cartilages, sixth rib, aponeurosis of external oblique muscle
Insertion: lateral lip of interubercular sulcus of humerus
Action: protracts and medially rotates scapula
Innervation: medial and lateral pectoral nerves (C5-T1)

Question 16

What is the origin, insertion, action and innervation of deltoid

Answer 16

Origin: anterior fibres-anterior border of lateral third of clavicle; middle fibres- lateral margin of acromion process; posterior fibres- lower edge of crest of spine of scapular
Insertion: deltoid tuberosity of humerus
Action: anterior fibres- flex and medially rotates shoulder; middle fibres- abduct shoulder; posterior fibres- extend and laterally rotate shoulder
Innervation: axillary nerve (C5,C6)

Question 17

What is the origin, insertion, action and innervation of biceps brachii

Answer 17

Origin: long head- supraglenoid tubercle of scapular and glenoid labrum; short head- apex of coracoid processinsertion: posterior part of radial tuberosity, bicipital aponeurosis into deep fascia over common flexor origin
Action: flexes shoulder and elbow, supinates forearm
Innervation: musculocutaneous nerve (C5,C6)

Question 18

Explain the structure and function of the posterior sternoclavicular ligament

Answer 18

Although not as strong as the anterior ligament, the posterior ligament is also a broad band running obliquely downwards and medially. Laterally it attaches to the superior and posterior parts of the medial end of the clavicle, while medially it is attached to the back of the upper part of the manubrium sterni. The sternal attachment of sternohyoid extends across, and reinforces part of, the posterior ligament

Question 19

Explain the structure and function of the interclavicular ligament

Answer 19

It strengthens the capsule superiorly and is formed by fibres attaching to the upper aspect of the sternal end of one clavicle passing across the jugular notch to join similar fibres from the opposite side. Some of these fibres attach to the floor of the jugular notch

Question 20

What is the origin, insertion, action and innervation of coracobrachialis

Answer 20

Origin: apex of coracoid process
Insertion: midway along medial border of humerus
Action: adducts shoulder and acts as a weak flexor
Innervation: musculocutaneous nerve (C5-C7)

Question 21

Explain the structure and function of the acromioclavicular joint

Answer 21

The synovial acromioclavicular joint connects the clavicle with the shoulder blade. The role that this joint plays in the movement of the pectoral girdle is considered by some to be greater than that of the sternoclavicular joint, particularly for movements in or close to the sagittal plane.

Question 22

What is the origin, insertion, action and innervation of infraspinatus

Answer 22

Origin: medial two-thirds of infraspinous fossa and infraspinous fascia
Insertion: middle facet of greater tubercle of humerus, posterior aspect of capsule of shoulder joint
Action: laterally rotates shoulder
Innervation: suprascapular nerve (C5,C6)

Question 23

Explain the structure and function of the sternoclavicular joint

Answer 23

The synovial sternoclavicular joint provides the only point of bony connection between the pectoral girdle and upper limb, and the trunk. Although the joint is functionally a ball and socket joint, it does not have the form of such a joint. A fibrous capsule surrounds the whole joint like a sleeve attaching to the articular margins of both the clavicle and the sternum, with its inferior part passing between the clavicle and the upper surface of the first costal cartilage.

Question 24

Explain the structure and function of the anterior sternoclavicular ligament

Answer 24

A strong, broad band of fibres attaching above to the superior and anterior parts of the medial end of the clavicle, passing obliquely downwards and medially to the front of the upper part of the manubrium sterni. It is reinforced by the tendinous origin of sternomastoid

Question 25

Explain the structure and function of the coracoclavicular ligament

Answer 25

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Question 26

Explain the structure and function of the gleno-humeral joint

Answer 26

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Question 27

Explain the structure and function of the glenoid fossa

Answer 27

It is situated at the superolateral angle of the scapula and faces laterally, anteriorly and slightly superiorly. It is pear-shaoed in outline, with a narrower region superiorly, and concave both vertically and transversely. However, the concavity of the joint is irregular and less deep that the convexity of the head of the humerus. The articular surface of the fossa is little more than one-third of that of the humeral head. It is deepened to some extent bu the presence of the glenoid labrum

Question 28

Explain the structure and function of the superior glenohumeral ligament

Answer 28

This slender ligament arises from the upper part of the glenoid margin and adjacent labrum immediately anterior to the attachment of the tendon of the long head of biceps. It runs laterally parallel to the biceps tendon to the upper surface of the lesser tubercle

Question 29

Explain the structure and function of the inferior glenohumeral ligament

Answer 29

Usually the best developed of the three ligaments but is occasionally absent. It arises from the glenoid margin below the notch in its anterior border and the adjacent anterior border of the glenoid labrum. It descends slightly obliquely to the humerus to attach to the anteroinferior part of the anatomical neck. As it passes from scapula to humerus, the upper part of the inferior ligament may merge with the lower part of the middle

Question 30

Explain the structure and function of the transverse humeral ligament

Answer 30

At the upper end of the intertubercular groove, the transverse humeral ligament bridges the gap between the greater and lesser tubercles. It is formed by some of the transverse fibres of the capsule and serves to hold the biceps tendon in the intertubercular groove as it leaves the joint

Question 31

Explain the structure and function of the glenoid labrum

Answer 31

As in the hip joint, the glenoid fossa is deepened by the presence of a fibrocartilaginous rim, the glenoid labrum. It is triangular in cross-section, with a thin free edge and is about 4mm deep. The base of the labrum attaches to the margin of the glenoid fossa; the outer surface gives attachment to the joint capsule posteriorly and superiorly, while the inner (joint) surface is in contact with the head of the humerus and is lined by cartilage continuous with that of the glenoid fossa. The upper part of the labrum may not be completely fixed to the bone so that its inner edge may project into the joint like a meniscus. The superior outer margin of the labrum gives attach,ent to the tendon of the long head of biceps, while inferiorly the tendon of the long head of triceps partly arises from it.

Question 32

Explain the structure and function of the coracohumeral ligament

Answer 32

Fairly broad, strong band arising from the lateral border of the coracoid process near its root. It becomes flattened as it passes laterally with its two margins diverging above the intertubercular groove to attach to the upper part of the anatomical neck in the region of the greater and lesser tubercles and to the intervening transverse humeral ligament. The anterior border of the medial part of the ligament is free, but as it passes laterally it fuses with the tendon of subscapularis as it blends with the capsule prior to its insertion on the lesser tubercle, the posterior part of the ligament blends with the tendon of supraspinatus as it attaches to the superior facet on the greater tubercle

Question 33

Explain the structure and function of the coracoacromial ligament

Answer 33

Not directly associated with the joint but forms, with the coracoid and acromion processes, a fibro-osseous arch above the head of the humerus. It is a strong, triangular ligament, whose anterior and posterior borders tend to be thicker than the intermediate part. Occasionally the pectoralis minor tendon is prolonged and pierces the base of the ligament to become continuous with the coracohumeral ligament. The coracoacromial ligament is attached by a broad base to the lateral border of the horizontal part of the coracoid process, with the blunt apex fixed to the apex of the acromion in front of the acromioclavicular joint. Superiorly are the clavicle and deltoid, while inferiorly it is separated from the tendon of the supraspinatus and the shoulder joint by the subacromial bursa. The arch so formed by the ligament and bony processes serves to increase the surface upon which the head of the humerus is supported when force is transmitted upwards along the humerus

Question 34

What muscles make up the rotator cuff? Explain its function

Answer 34

Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and the subscapularis muscle.

Question 35

Describe the structure of the scaupula

Answer 35

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Question 36

Describe the structure of the humerus

Answer 36

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Question 37

Describe the structure of the clavicle

Answer 37

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