Overview Anatomy of the Thorax Flashcards
Structure of sternum
Manubrium
Body of sternum
Xiphisternum
What separates the manubrium and body of sternum
sternal angle
What level is the sternal angle
rib 2
What would you feel superior of the manubrium?
jugular/suprasternal notch
Costal margin
ribs 7-10, bottom edge of ribcage
Subcostal angle
cartilage of ribs 7-10
Planes of chest wall
suprasternal plane
plane of sternal angle
xiphisternal plane
Level of suprasternal plane
suprasternal notch anteriorly
T2 posteriorly
Level of plane of sternal angle
sternal angle anteriorly
T4,5 posteriorly
Level of xiphisternal plane
xiphisternum anteriorly
T9 posteriorly
Lines of the chest wall
midaxillary line: armpit
midsternal line: sternum
midclavicular line: clavicle
Types of intercostal muscles
external, internal, innermost
Importance of intercostal muscles
respiration, keeping intercostal space rigid
Direction of internal and external icms
external - hands in pockets
internal - hands on bbobs
Location of icms in relation to each other
external, internal, intercostal nerves arteries and veins adn collateral bundle, innermost
What surrounds each lung?
serous pleural sac
Structure of serous pleural sac
visceral pleura
parietal pleura
Visceral pleura
lines the lungs, shiny, very thin, can’t remove when dissecting
continuous with each other
Parietal pleura
lines pulmonary cavity (ribcage), on outside, continuous with each other
What is in pleural cavity?
fluid - against friction, so no pain
Aperatures of thorax
superior thoracic aperature
inferior thoracic aperature
Superior thoracic aperature
opening for structures to enter/leave the neck/thorax
T1, rib 1, suprasternal notch
narrower than inferior
Inferior thoracic aperature
opening at lower part of thoracic cavity (closed by diaphragm)
T12, costal cartilage of ribs 7-10. xiphisternum
Thoracic outlet syndrome
compression of arteries and nerves against clavicle and 1st rib
most common: brachial plexus
True ribs
1-7 attach directly to sternum
False ribs
8-10 attach to sternum via 7th costal cartilage
Typical ribs
3-9
head, neck, body, superior and inferior facet, tubercle, angle, costal groove
Atypical ribs
1, 2, 10, 11, 12
Superior facet
articulates with vertebrae above
Inferior facet
articulates with numerically corresponding vertebrae
Costal groove
for intercostal vein, artery and nerve
1st rib structure
one facet on head, tubercle, scalene tubercle, 2 grooves
Scalene tubercle
on 1st rib
scalanus anterior attaches
Grooves of 1st rib
- subclavian artery groove
2. subclavian vein groove
Types of vertebrae
cervical
thoracic
lunbar
sacral
Thoracic vertebrae structure
vertebral body, lamina, pedicle, spinal, transverse and articulatory process, articular facet
Lamina
flat roof of vertebral arch
connect with the pedicles to surround and protect the spinal cord
Pedicle
connects lamina to vertebral body
Spinous process
bony projection off posterior vertebrae, where lamina joins
provides the point of attachment for muscles and ligaments of the spine
Transverse process
right and left attachments for muscles and ligaments
articulation for ribs
Articulatory process
superior and inferior projections of vertebra, fit with adjacent vertebrae
Facet
point of contact
eg. on transverse process for tubercle of rib
Pectoral muscles
pectoralis major and minor
Parts of pectoralis major
clavicular and sternocostal head
Attachments of pec major
clavicular head: medial half of clavicle
sternocostal head: sternum + upper 6 costal cartilages
intertubercular groove of humerus
Actions of pec major
adductor (bring arm down)
medial rotator (arm towards midline)
flexor (if arm extended) vice versa
accesory muscle of respiration if pectoral girdle is fixed
Nerve supply of pec major
clavicular head : lateral pec nerves (C4-7)
sternocostal head: medial pec nerves (C8, T1)
Attachments of pec minor
coracoid process of scapula
ribs 3-5 near the cartilages
Actions of pec minor
depressor of scapula (+ therefore shoulder)
protractor of scapula (shoulder forward)
accesory muscle of respiration if pectoral girdle is fixed
Nerve supply of pec minor
medial pectoral nerve (C8, T1)
Articulation of breast
base extends from rib 2-6
from lateral margin of sternum to midaxillary line
axillary tail runs superiorly and laterally towards axilla
What is the breast?
modified sebaceous gland
Structure of breast
15-20 lobes sending lactiferous ducts to the nipple
lobes: glands and adipose tissue separated by fibrous septa
Location of breast
sits on retromammary space which separates breast from deeper pec muscles
Clinical importance of lymphatic drainage of the breast
frequency of breast cancer and its spread into other parts of the body by lymph and blood vessels
need to examine many regions eg. arm
What is the mediastinum?
central part of thoracic cavity that lies between the pleural cavities
Boundaries of mediastinum
anterior: sternum
posterior: thoracic vertebrae column
superior: thoracic inlet and root of neck
inferior: diaphragm
Sections of mediastinum
superior
inferior
separated by plane of sternal angle (manubriosternal joint to T4/5)
Superior mediastinum contents
thymus (lymphoid organ, lump of fat) SVC + brachiocephalic vein phrenic nerves arch of aorta and branches origins of internal thoracic arteries pulmonary a and v vagus n recurrent laryngeal branches trachea oesophagus thoracic duct
Inferior mediastinum regions
anterior, middle, posterior
Contents of anterior inferior mediastinum
internal thoracic a and v
anterior intercostal branches
thymus poss
sternopericardial ligaments
Contents of middle inferior mediastinum
heart and pericardium
phrenic nerve
pericardiophrenic a and v
IVC
Contents of posterior inferior mediastinum
descending aorta azygous v oesophagus thoracic duct sympathetic trunks
Phrenic nerve
C3-5, passes through superior thoracic aperature, superior and middle inferior mediastinum
innervates diaphragm
Floating ribs
11-12 do not attach to sternum
