Anatomy of thoracic cage

Question 1

The 4 key components of anatomy of thoracic cage

Answer 1

Vertebrae, intervertebral discs, ribs, costal cartilages

Question 2

Function of thoracic cage

Answer 2

Protect viscera, large area for muscle attachment, pectoral girdle for pec major, arm attached via sternoclavicular joint

Question 3

How many pairs of ribs

Answer 3

12

Question 4

True Ribs; number and features

Answer 4

1-7. Rib, CC, Sternum

Question 5

False ribs; number and features

Answer 5

8-10. Rib, CC, CC joined together

Question 6

Floating ribs; number and features

Answer 6

11-12. No CC

Question 7

Typical rib; numbers

Answer 7

3-9

Question 8

Atypical ribs: numbers

Answer 8

1,2,10,11,12

Question 9

Features of a typical rib

Answer 9

Head with 2 facets, neck, tubercle with one facet, shaft, costal cartilage, costal groove for intercostal vein, artery and nerve

Question 10

Features of an atypical rib

Answer 10

Head with one facet, neck, tubercle with one facet, shaft, costal groove for intercostal vein, artery and nerve

Question 11

Features of thoracic vertebrae

Answer 11

Heart shaped body with 2 demifacets, 2 transverse processes with one facet on each, inferior-pointing spinous process, spinal canal

Question 12

Name the joints of the thoracic wall.

Answer 12

Intervertebral, costovertebral, costotransverse, interchondral, costochondral, sternocostal, sternoclavicular

Question 13

Features of Pectoralis Major

Answer 13

Origin/proximal attachment: clavicle, sternum, costal cartilages. Insertion/distal attachment: humerus. Function: adduction and medial rotation of humerus; adduction, flexion and internal rotation of shoulder joint. Innervation: Medial and lateral pectoral nerves.

Question 14

Features of pectoralis minor

Answer 14

Origin/proximal attachment: 3rd-5th rib. Insertion/distal attachment: coracoid process of scapula. Function: Stabilises scapula; draws scapula inferiorly, anteriorly and medially; elevates ribs during exercise and excessive breathing. Innervation: Lateral Pectoral nerve.

Question 15

Name the types of intercostal muscles, and their directions and features

Answer 15

External (anterior inferior), internal (posterior, inferior), innermost intercostal muscles. Supplied by intercostal artery, vein and nerve.

Question 16

How are the intercostal muscles involved in breathing?

Answer 16

External crosses over internal intercostal muscles so can lift ribs during inspiration and crush during expiration

Question 17

Serratus Anterior

Answer 17

Origin/proximal attachment: 1st-8th rib, sometimes 9th. Insertion/proximal attachment: medial border of scapula. Function: protract scapula, holds scapula flat against thoracic cage. Innervation: Long thoracic nerve.

Question 18

Arterial supply of thoracic cage

Answer 18

Segmental arterial blood supply. Aorta heads down in front of vertebrae and at each vertebral level branches into a posterior intercostal artery in costal groove. Subclavian artery branches into anterior intercostal artery in costal grooves at each vertebral level. These arteries are right behind the sternum.