The Thoracic Wall & Scapula Wk5

Question 1

What is the importance of the thorax?

Answer 1

– Housesthelungs
– Housestheheartandgreatvessels
– Its musculature acts as the bellows that inflate and deflate the lungs
– It is a site for passage of major viscera between the pharynx and abdomen
– It is the site for attachments of upper limbs to the axial skeleton
– It is an important site for clinical procedures
• Chest compressions
• Auscultation of heart sounds
• Percussion of the lungs
• Imaging of the heart and lungs
• Harvesting of bone marrow

Question 2

What are prominent features of the anterior thoracic wall?

Answer 2

– The Clavicle
– Roundedness of Shoulders (Left & Right Comparison) – Pectoralis Muscles
– Manubro-sternal Joint
– Sternoclavicular Joint
– Nipples - use for determining where things are
– Sternum or Breast Bone
– Suprasternal Notch
– Decreasing width of the chest with fall in height

Question 3

What are prominent features of the posterior view of the thoracic wall?

Answer 3

– The Scapulae
• Blades of scapulae
• InferiorAnglesofscapulae
– Undulations of the vertebral column
• Trajectory of central gutter is important
• Central gutter is indicative of locations of spinous processes of vertebrae
– Back Muscles
– Vertebra Prominens
– Roundedness of the Shoulders (Left & Right Comparisons)
– Decreasing width of the chest with fall in height

Question 4

What are the boundaries of the thorax?

Answer 4

• Superior
– Superior Thoracic Aperture 
• Inferior
– Thoracic Diaphragm
• Antero-Latero-Posterior
– Ribs
• Anterior
– Manubrium, Sternum & Xiphoid Process
• Posterior
– Thoracic vertebrae
• Scapulae (shoulder blades)

Question 5

What is the superior aperture of the thorax?

Answer 5

• Also known as the thoracic inlet
• It is the obliquely truncated apex of thorax
• The suprasternal notch is located here
• It is also known as the 
– Jugular Notch
– or
– Fossa jugularis sternalis
• Itis:
– A large, visible dip in between the neck and the
two collarbones in human anatomy
– Occurs at the superior border of the manubrium of the sternum, between the clavicular notches
– A site of clinical importance

Question 6

What are the margins of the aperture?

Answer 6

– Body of first thoracic vertebra (T1)
– 1st ribs and their cartilages
– Manubrium of the sternum
– Suprasternal Notch

Question 7

Tissue layers of the thorax overview

Answer 7

• They are a continuous series of layers of tissues
• They span from the skin to the parenchyma of the lung
• They can be artificially divided into 2 categories
– Tissues that constitute the thoracic wall
– Tissue that fill the cavity of the thorax

Question 8

What are the 10 layers of tissues (superficial to deep)?

Answer 8

– Skin
– Superficial Fascia
– Pectoral Fascia
– Pectoralis Major
– Clavipectoral Fascia
– Pectoralis Minor
– External Intercostal Muscle
– Internal Intercostal Muscle & Ribs
– Innermost Muscle
– Endothoracic Fascia
The muscular layers vary according to the region of the chest wall - some muscles cover only limited territories e.g. may include pectoralis major or not etc.

Question 9

What are the fascial layers of the thoracic wall?

Answer 9

• There are 3 layers of Thoracic fascia to note
– They are all part of the deep fascia of the thorax
• The most superficial 2 layers are collectively known as
– Fascia Pectoralis
• The deepest layer of fascia is known as
– Endothoracic Fascia

Question 10

What is the fascia pectoralis?

Answer 10

• It is separable into 2 layers
– Superficial Layer of Fascia Pectoralis
– Deep Layer of Fascia Pectoralis
• Superficial Layer of Fascia Pectoralis
– It is known as Pectoral Fascia
– Surface sheet covers the outer surface of the pectoralis major muscle
– It separates the thoracic piece of the pectoralis major muscle from breast tissue

Question 11

What is the deep layer of fascia pectoralis?

Answer 11

• It separates
– Pectoralis Major muscle
• from
– Pectoralis Minor muscle
• At the top, it is fused with the clavicle and coracoid process
• In the subclavian area from two sides surrounds a small chest muscle and subclavian muscle, forming a dense plot, called fascia clavipectoralis
• It also goes on to form fascia of the axilla (fascia axillaris).

Question 12

Summary of fascia pectoralis?

Answer 12

The most superficial 2 layers of thoracic fascia are collectively known as
– Fascia Pectoralis
• It is separable into
– Pectoral Fascia
• Superficial layer of Fascia Pectoralis
– Clavipectoral Fascia
• Deeper layer of Fascia Pectoralis

Question 13

What is endothoracic fascia?

Answer 13

• It is the 3rd and deepest layer of fascia of the thoracic region
• It is in itself, a layer of loose connective tissue deep to the intercostal spaces and ribs
• It separates the internal thoracic wall from the underlying pleura
• It forms the outermost membrane of the thoracic cavity

Question 14

What is the bony thorax?

Answer 14

• Manubrium
• Sternum
• Xiphoid Process
• Coastal cartilages
• Clavicles
• Ribs
• Thoracic Vertebrae
• It is the bony skeleton of the body giving rise to what we commonly refer to as the chest
• It is formed by 12 pairs of ribs
• Thoracic vertebrae (n=12)
• Sternum (n=1)
• Manubrium of the sternum (n=1)
• Manubrosternal joint

Question 15

What does a rib have?

Answer 15

• Head (two facets)
• Neck
• Tubercle(facet)
• Angle
• Proximal end–costal cartilage

Question 16

What are the anterior articulations of ribs?

Answer 16

• Rib 1 to sternum (manubrium) 
– Fibrous joint
– No movement
• Ribs 2 – 7 true ribs
– Synovial (gliding) joints
– Radiate sternocostal ligaments
• Ribs 8-10 = false, articulate with costal cartilage of rib 7
• 11-12 = false & floating ribs

Question 17

Anatomy summary of sternum

Answer 17

Top to bottom

• jugular notch
• manubrium of sternum
• sternal angle (manubriosternal joint)
• transverse ridges
• body of sternum
• xiphoid process

Question 18

What are the muscles of the thoracic region?

Answer 18

• Muscles of the thoracic region are divisible into 2 categories
– Muscles that attach the upper limb to the axial skeleton
– Muscles of Respiration

Question 19

What muscles are associated with movements of the upper limb?

Answer 19

– Pectoralis Major 
– Pectoralis Minor 
– Subclavius
– Serratus Anterior 
– Latissimus Dorsi 
– Rhomboid Major 
– Rhomboid Minor 
– Trapezius
– Muscles of The Scapula 
– Terres Minor
– Terres Major

Question 20

What are the actions of pectoralis major muscle?

Answer 20

• Itisa:
– Flexorofthearm
– Adductorofthearm
• Clavicular Part of Pectoralis Major
• It elevates the shoulder
• Draws the arm forward and medial-ward
• Sternocostal Part of Pectoralis Muscle
• Has same actions as the clavicular portion but also draws the shoulder downwards

Question 21

What is the serratus anterior?

Answer 21

• It has a serrated presentation
• It attaches on
– Lateral surfaces of upper 8–9 ribs and deep fascia overlying the related intercostal spaces
– Costal surface of medial border of scapula
• It is supplied by the Long Thoracic Nerve (Root Values C5 to C7)
• Its actions are:
– Protraction and rotation of the scapula
– Keeps medial border and inferior angle of scapula opposed to thoracic wall
• Winging of the scapula

Question 22

What is the neurovascular bundle of intercostal muscles?

Answer 22

• The neurovascular bundle of the intercostal muscles runs on the inferior aspect of the ribs
• It is housed under the cover of the sub-costal groove
• Any procedures on the thoracic wall must be carried out on the upper surface of the ribs
• This avoids damage to the neurovascular bundle