Basic Anatomy of the Thoracic Wall Flashcards
Prominent features of chest wall (anterior)
- Clavicle
- Pectoralis muscles
- Manubro-sternal joint
- Sternoclavicular joint
- Nipples
- Sternum
- Suprasternal notch
Prominent features of chest wall (posterior)
- Scapulae
- Back muscles
- Vertebra prominens (C7)
Boundaries of thorax
- Superior thoracic aperture (superior)
- Upper part of diaphragm (inferior)
- Ribs (antero-latero-posterior)
- Thoracic vertebrae (posterior)
Margins of superior thoracic aperture
- Body of T1 vertebra
- 1st ribs (+ cartilages)
- Manubrium of sternum
10 tissue layers of chest wall
- Skin
- Superficial fascia
- Pectoral fascia
- Pectoralis major
- Clavipectoral fascia
- Pectoralis minor
- External intercostal muscles
- Internal intercostal muscles
- Innermost muscle
- Endothoracic fascia
3 layers of thoracic fascia
- 2 most superficial = fascia pectoralis (collectively)
- Deepest = endothoracic fascia
2 layers of fascia pectoralis
- Superficial layer (pectoral fascia)
- Deep layer
What does the superficial layer of fascia pectoralis cover?
Outer surface of pectoralis major (separates from breast tissue)
What 2 structures does the deep layer of fascia pectoralis separate?
Pectoralis major and minor
What is the top of the deep layer of fascia pectoralis fused with?
- Clavicle
- Coracoid process
What 2 structures does the endothoracic fascia separate?
Internal thoracic wall and underlying pleura
Components of a typical rib
- Head (2 facets)
- Neck
- Tubercle (1 facet)
- Body/shaft
- Proximal end (costal cartilage)
What facets are found on a typical thoracic vertebra and what is each for?
- 2 demifacets on superior and inferior aspects of vertebral body for articulation with the head of adjacent ribs
- 1 oval facet at the end of the transverse process for articulation with with the tubercle of its own rib
Which thoracic vertebrae are atypical and in what way?
- T1 = superior facet is complete as rib 1 only articulates with T1
- T9 = no inferior facet as rib 10 only articulates with T10
- T10 = superior facet is complete and no inferior facet as T10 and rib 10 only articulate with each other
- T11 + T12 = superior facet is complete and no inferior or transverse facets as the vertebrae and their ribs only articulate with each other, and only by the head of the rib and not the tubercle
Which ribs are the true ribs?
1-7
Which ribs are false ribs and what does that mean?
- 8-12
- Don’t articulate directly with sternum (either costal cartilage of rib 7 or floating)
Which ribs are floating ribs?
11 and 12
What does rib 1 articulate with and by what type of joint?
Articulates with manubrium by fibrous joint (no movement)
What does rib 2 articulate with and by what type of joint?
- Manubrium and body of sternum
- Synovial joint
What do ribs 3-6 articulate with and by what type of joint?
- Body of sternum
- Synovial joint
What does rib 7 articulate with and by what type of joint?
- Body and xiphoid process of sternum
- Synovial joint
What are the 3 parts of the sternum?
- Manubrium
- Body
- Xiphoid process
Actions of pectoralis major
- Flexor of the arm
- Adductor of the arm
Parts of the pectoralis major
- Clavicular part
- Sternocostal part
Actions of the clavicular part of pectoralis major
- Elevates shoulder
- Draws arm forwards and medialward
Actions of sternocostal part of pectoralis major
- Same as clavicular part
- Also draws shoulder downwards
Where does serratus anterior attach?
- Lateral surfaces of upper 8-9 ribs
- Deep fascia overlying related intercostal spaces
- Costal surface of medial border of scapula
What nerve supplies serratus anterior?
Long thoracic nerve (root values C5-C7)
Actions of serratus anterior
- Protraction and rotation of scapula
- Keeps medial border and inferior angle of scapula opposed to thoracic wall
What muscles are associated with the ribs?
- Intercostal muscles
- Transversus thoracis
- Levatores costarum
Types of intercostal muscles
- External
- Internal
- Innermost
Where does the neurovascular bundle of intercostal muscles run and what is it housed by?
- Runs on inferior aspect of ribs
- Housed by sub-costal groove
