Pectoral Girdle and Shoulder

Question 1

Scapula

Answer 1

Question 2

Scapula Muscles

Answer 2

Question 3

Humerus

Answer 3

Question 4

Clavicle

• What does it do?
• Attachments on inferior surface
• Attachments on superior surface

Answer 4

• Provides a strut for the upper limb and holds it away from the body. Allows a greater range of movement
• Deltoid, subclavius and pec major
• Trapezius, deltoid, pec major and sternocleiomastoid

Question 5

Pectoralis Major

• Attachments
• Function
• Innvervation

Answer 5

• Clavicle, costal cartilage of ribs 1-6, and sternum to biciplital groove of the humerus
• Flexion and adduction of the arm, and medial rotation of the humerus
• Medial (C8-T1), and lateral (C5-7) pectoral nerves from the medial and lateral cords of the brachial plexus

Question 6

Pectoralis Minor

• Attachments
• Function
• Innervation

Answer 6

• 3rd-5th ribs to coracoid process of scapula
• Pulls shoulder anterior and inferiorly. Can elevate ribs if shoulder remains fixed
• Medial pectoral nerve (C8-T1)

Question 7

Serratus Anterior

• Attachments
• Function
• Innervation

Answer 7

• Outer surface of upper 8 ribs to medial border of scapula
• Protraction of scapula
• Long thoracic nerve (C5-7)

Question 8

Trapezius

• Attachments
• Part A function
• Part B function
• Part C function
• Innervation

Answer 8

• Superior nuchal line, nuchal ligament, spinous processes of C7-T12, lateral third of clavicle, acromion and spine of scapula
• Ascending part - depresses scapula
• Transverse part - retracts scapula
• Descending part - elevates scapula and rotates glenoid cavity
• Spinal accessory nerve (CN XI motor), and cervical plexus (C3,4 for pain)

Question 9

Latissimus Dorsi

• Attachments
• Function
• Innervation

Answer 9

• Ilium, thoracolumbar fascia, spinous processes of lower 6 thoracic vertebrae to floor of bicipital groove of humerus
• Extension, medial rotation and adduction of the arm
• Thoracodorsal nerve from the posterior cord of the brachial plexus (C6-8)

Question 10

Levator Scapulae

• Attachments
• Function
• Innervation

Answer 10

• Transverse process of atlas and axis, 3rd and 4th C vertebrae to medial scapular border between superior angle and medial end of scapular spine
• Helps to control scapular position, can elevate shoulder and flex neck on same side
• Direct C3-5 from dorsal scapular nerve

Question 11

Rhomboideous Major and Minor

• Major attachments
• Minor attachments
• Function
• Innervation

Answer 11

• 2-5 thoracic spines to medial border of scapula
• From nuchal ligament and C7 to T1 thoracic spines, to the medial end of the scapular spine
• Retraction of scapula
• Dorsal scapular nerve (C4-5)

Question 12

Deltoid

• Attachments
• Function (middle, anterior and posterior fibres)
• Innervation

Answer 12

• Lateral 1/3rd clavicle, acromion, spine of scapula to deltoid tuberosity of humerus
• Abduction of the arm by middle fibres. Extension and lateral rotation by posterior fibres. Flexion and medial rotation by anterior fibres.
• Axillary nerve (C5-6) from post cord of brachial plexus

Question 13

Teres Major

• Attachments
• Function
• Innervation

Answer 13

• Lateral border of scapula (lower 1/3rd, posterior) to medial lip of bicipital groove of humerus
• Adduction and medial rotation of the arm
• Subscapular branch of the posterior cord of the brachial plexus (lower C5-6)
• Not part of the rotator cuff, but minor is

Question 14

Subclavius

• Attachments
• Function
• Innervation

Answer 14

• Sternal end of 1st rib to middle third of underside of clavicle
• Draws down and slightly forwards during abduction
• Nerve to subclavius (C5-6)

Question 15

Rotator Cuff

• What is it?
• What are the muscles involved?
• What does it do?

Answer 15

• Group of 4 muscles which keep the head of the humerus in the glenoid cavity of the scapula
• Subscapularis, supraspinatus, infraspinatus, and teres minor
• Prevents dislocation from a very shallow joint

Question 16

Subscapularis

• Attachments
• Function
• Innervation

Answer 16

• Subscapular fossa to lesser tubercle of humerus on the anterior side - only muscle in the rotator cuff to do these two things
• Medially rotates the arm on its own
• Upper and lower subscapular nerves (C5-7) from posterior cord of brachial plexus

Question 17

Supraspinatus

• Attachments
• Function
• Innervation

Answer 17

• Supraspinous fossa of the scapula to the greater tubercle of the humerus (upper facet)
• Abducts arm for the first 10-15^o
• Suprascapular nerve (C5,6) from superior trunk of brachial plexus

Question 18

Infraspinatus

• Attachments
• Function
• Innervation

Answer 18

• Infraspinous fossa of the scapula to the greater tubercle of the humerus (middle facet)
• Lateral rotation of the arm
• Suprascapular nerve (C5,6) from the superior trunk of the brachial plexus

Question 19

Teres Minor

• Attachments
• Function
• Innervation

Answer 19

• Upper 2/3 of the lateral border of the scapula to the greater tubercle of the humerus (lower facet)
• Lateral rotation of the arm
• Axillary nerve (C5,6) branch of the posterior cord of the posterior brachial plexus - shared with deltoid

Question 20

Branches of the subclavian

Answer 20

Question 21

Spaces in the Shoulder

• Quadrangular space
• Triangular hiatus

Answer 21

• Axillary nerve and posterior circumflex humeral artery pass through this
• Radial nerve and profunda brachii artery pass through this