Lecture 7 - Pectoral Girdle

Question 1

Pectoral Girdle/Pelvic Girdle Stability vs Mobility

Answer 1

• Shoulder (Pectoral) Girdle: Structurally very MOBLIE, Relatively less stable
• Pelvic Girdle: Structurally very STABLE, Relatively less mobile

Question 2

What is the clavicle?

Answer 2

• The only long bone that lies in a horizontal position in the body
• Most common to fracture, because of force exerted when falling on an outstretched arm

Question 3

What are the 3 sections of the clavicle?

Answer 3

• shaft
• sternal end
• acromial end

Question 4

What is the sternal & acromial end of the clavicle?

Answer 4

• Sternal End: Medial end of the clavicle that articulates with the manubrium of the sternum
• Acromial End: Lateral end of the clavicle that articulates with the acromion of the clavicle

Question 5

What is the sternoclavicular (SC) joint?

Answer 5

• The only bony articulation between the pectoral girdle of the upper limb & the axial skeleton
• The SC joint allows considerable mobility, enabling the clavicle & scapula to move in upward/downward & anterior/posterior directions
• supported by the costoclavicular ligament which spans the sternal end of the clavicle & the underlying first rib

Question 6

What are the functions of the clavicle?

Answer 6

• moveable rigid support
• bony passageway
• transmits forces from the upper limb

Question 7

What are the movements of the scapula?

Answer 7

• Upward/downward rotation
• Protraction/retraction
• Elevation/depression

Question 8

What are the 6 general landmarks of the scapula?

Answer 8

• medial border
• lateral border
• superior border
• suprascapular notch
• inferior angle/apex
• superior angle

Question 9

What is the medial/lateral/superior border of the scapula?

Answer 9

• medial Border: Elongated, medial margin of the scapula
• lateral Border: Diagonally oriented lateral margin of the scapula
• Superior Border: Superior margin of the scapula

Question 10

What is the suprascapular notch?

Answer 10

• Small notch located along the superior border of the scapula, medial to the coracoid process

Question 11

What is the inferior (apex)/superior angle of the scapula?

Answer 11

• Inferior Angle/Apex: Inferior corner of the scapula located where the medial & lateral borders meet
• Superior Angle: Corner of the scapula between the superior & medial borders of the scapula

Question 12

What are the 4 landmarks of the posterior surface of the scapula?

Answer 12

• spine of the scapula
• supraspinous fossa
• infraspinous fossa
• acromion process

Question 13

What is the spine of the scapula?

Answer 13

• Prominent ridge passing mediolaterally across the upper portion of the posterior scapula surface

Question 14

What is the supraspinous/infraspinous fossa of the scapula?

Answer 14

• Suprapinous Fossa: Narrow depression located on the posterior scapula, superior to the spine
• Infraspinous Fossa: Broad depression located on the posterior scapula, inferior to the spine

Question 15

What is the acromion process of the scapula?

Answer 15

• The acromion of the scapula?

Question 16

What are the 2 landmarks of the anterior surface of the scapula?

Answer 16

• subscapular fossa
• coracoid process

Question 17

What is the subscapular fossa of the scapula?

Answer 17

• Broad depression located on the anterior (deep) surface of the scapula

Question 18

What is the coracoid process of the scapula?

Answer 18

• Short, hook-like process that projects anteriorly & laterally from the superior margin of the scapula

Question 19

What are the 4 landmarks of the lateral surface of the scapula?

Answer 19

• glenoid fossa
• supraglenoid tubercle
• infraglenoid tubercle
• acromion process

Question 20

What is the glenoid fossa of the scapula?

Answer 20

• Also known as the glenoid cavity
• Shallow depression located on the lateral scapula, between the superior & lateral borders

Question 21

What is the supraglenoid/infraglenoid tubercle of the scapula?

Answer 21

• Supraglenoid Tubercle: Small bump located at the superior margin of the glenoid cavity
• Infraglenoid Tubercle: Small bump located on the lateral border of the scapula, near the inferior margin of the glenoid fossa (cavity)

Question 22

What is the acromioclavicular joint?

Answer 22

• The articulation between the acromion of the scapula & the acromial end of the clavicle
• Provides attachment of the neck & back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm

Question 23

What is the coracoclavicular ligament?

Answer 23

• A strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle
• Provides important indirect support for the acromioclavicular joint

Question 24

What is the coracoacromial ligament?

Answer 24

• A strong triangular ligament of the glenohumeral joint complex
• attaches between the lateral border of the coracoid process 7 the apex of the acromion of the scapula
• Forms the coracoacromial arch; prevents superior displacement of humeral head

Question 25

What is scapulohumeral rhythm?

Answer 25

• movement of the scapula relative to the movement of the humerus
• the scapula can move on the thorax so it can get to the final ranges of motion; scapula compensates the humerus
• normal ROM for shoulder abduction & flexion is 120 degrees
• OVERALL — approximately 2 degrees of shoulder movement for every 1 degree of scapular movement