Anatomy - The Pectoral region

Question 1

What is the origin of pectoralis major?

Answer 1

• Medial third of clavicle
• the anterior surface of the sternum.
• superior surfaces of the first 6 costal cartilages.

Question 2

What are the 4 vertical lines of the chest wall called?

Answer 2

1. Mid-clavicular. 2. Anterior axillary line. 3. Mid axillary line. 4. Posterior axillary line.

Question 3

What is the insertion of pecotralis major?

Answer 3

Humerus.

Question 4

What is the origin and insertion of a muscle?

Answer 4

The origin is the fixed attachment of the muscle, where the muscle starts. The insertion will move with contraction and is where the muscle ends.

Question 5

What is the innervation of pectoralis major?

Answer 5

Medial and lateral pectoral nerves.

Question 6

What is the action of pectoralis major?

Answer 6

• Adduction and medial rotation of the humerus at the shoulder.
• draws the scapula anteroinferior
• flexure of the upper limb

Question 7

What is the origin of pectoralis minor?

Answer 7

Ribs 3-5.

Question 8

What is the insertion of pectoralis minor?

Answer 8

The coracoid process of the scapula.

Question 9

What is the innervation of pectoralis minor?

Answer 9

Medial pectoral nerve.

Question 10

What is the action of pectoralis minor?

Answer 10

Protraction of the shoulder.

Question 11

What is the origin of serratus anterior?

Answer 11

lateral aspects of ribs 1 to 8

Question 12

What is the insertion of serratus anterior?

Answer 12

Costal surface of the medial border of the scapula.

Question 13

What is the innervation of serratus anterior?

Answer 13

Long thoracic nerve.

Question 14

What is the action of serratus anterior?

Answer 14

• Protraction of the scapula.
• Holds the scapula against the ribcage

Question 15

1) What is the first co-ordinate for an anatomical position?

Answer 15

Counting the ribs

Question 16

Describe the five vertical lines which are commonly used to provide a 2nd co-ordinate?

Answer 16

• The midline - down the centre of the sternum
• Mid clavicle line- taken from the middle of the clavicle
• anterior axillary line - from the fold of muscle the anterior of the axilla (front of the arm pit)
• mid axillary line - from the middle of the axilla and usually the widest part of the thorax
• posterior axillary line - from the fold muscle at the posterior of the axilla

Question 17

Which layers do the mammary glands lie within?

Answer 17

subcutaneous layer

Question 18

What is the large muscle covering the shoulder region?

Answer 18

• deltoid muscle
• lateral to pectoralis major’s attachment to the clavicle

Question 19

What is found in the groove between the deltoid and pectoralis major? What is its clinical importance?

Answer 19

• cephalic vein
• a superficial vein of the arm
• inserting wires and catheters to heart

Question 20

What does the lower border of the pectoralis major and minor form?

Answer 20

anterior axillary fold

Question 21

Describe lymph drainage of the breast and its clinical relevance?

Answer 21

• drains medial to the nipple, passing through intercostal spaces to lymph nodes in thorax
• called internal mammary thoracic lymph nodes
• lateral breast draining into lymph nodes in the axilla

Question 22

Describe a pacemaker and its clinical relevance?

Answer 22

• inserted under local anesthetics under skins next to left cephalic vein
• wire passes through left cephalic vein, through venous system to the tip of the right ventricle or sinoatrial node

Question 23

Describe how you would identify the intercostal spaces?

Answer 23

• Find the sternal notch at the top of the sternum and run down the midline until you find the sternal angle, a ridge
• this is where the 2nd costal cartilage is attached, from here count spaces lateral to the sternum

Question 24

How does the contraction of the pectoralis major assist in breathing?

Answer 24

pull the ribs outwards to increase volume, and decrease pressure in thorax

Question 25

Which bony structures lie subcutaneously in the anterior chest wall?

Answer 25

• sternum
• clavicle

Question 26

Which coastal cartilage forms the sternum angle?

Answer 26

2nd rib

Question 27

What are the 2 articulations of the clavicle?

Answer 27

• sternoclavicular joint
• acromioclavicular joint