Thorax Flashcards
Clinical significance of superficial fascia of abdomen and thorax?
- continuity of fascia
- superficial veins anastomose with larger vessels
- if blockage of vena cava, veins will hypertrophy and serve as alternate path back to heart
Thorax functions?
- Protection of important cardiac and respiratory structures
- Respiration framework offers stabilization during inhalation and exhalation
- Attachment and support for muscles of upper limbs, neck, abdomen
3 major spaces of thorax?
- Central compartment (mediastinum)
- thoracic organs except lungs - Right and left pulmonary cavities
- lungs
Specific features of thoracic vertebrae?
- long spinous processes
- facets on body for head of ribs
- facets on transverse processes for tubercle of rib
Which thoracic vertebrae are closely related to the Aorta?
T5-T8
Lower rib fracture clinical significance?
- could puncture liver or spleen
- huge cardiac output going here
Location of bone marrow biopsies?
- Ilium used most often
- Sternum can also be used, but risk of puncturing heart
Manubrium?
- widest
- thickest
- Jugular notch: level of T3 posterior
- clavicular notches
- Sternal angle: level of T4 posterior (junction of 2nd rib)
Body of sternum? clinical significance?
- joined to manubrium by Fibrocartilage
- transverse lines
- bone marrow found here
Xiphoid process? clinical significance?
- smallest
- variable in size and shape
- hyaline cartilage surrounding bone, ossified
- Epigastric mass from xiphoid
True ribs?
- 1st 7 ribs
- articulate with sternum through their own costal cartilage
- vertebrosternal
False ribs?
- ribs 8, 9, 10
- articulate to sternum via costal cartilage #7
- vertebrochondral
Floating ribs?
- ribs 11 and 12
- do not articulate with sternum
- muscles of posterior abdomen attach here
Supernumerary ribs?
- common
- more common in cervical than lumbar
- extra ribs
Typical ribs?
- Ribs 3-9
- head, neck, and shaft
Angle of rib? Clinical significance?
- where ribs extends anterolaterally at same level of spinous process
- shaft turns medially and down
- most common fracture is anterior to angle
Costal groove? clinical significance?
- inferior groove of rib
- protects intercostal artery, vein, and nerve
- Pleural effusion: fluid accumulation in chest (CHF, pneumonia, cancer), compresses lungs
- require pleurocentesis (stick needle to remove fluid), needle must be stuck superior to rib to not puncture neurovascular bundle
First rib? Clinical significance?
- highest, broadest, strongest, flattest, most curved, shortest
- closely associated with brachial plexus, Axillary artery and vein (subclavian vessels pass over 1st rib)
- Anterior scalene muscles attach to scalene tubercle
- Phrenic nerve lies on anterior surface of scalene
- axillary artery/vein is anterior
- brachial plexus is posterior
- closely related to apex of lung, if broken may cause pneumothorax
- tumor on lung could grow and disrupt neurovascular structures
- Horner’s syndrome: tumor grows posterior into sympathetic trunk to affect autonomic NS
Importance of 2nd rib?
- twice as long as first
- tuberosity for Serratus Anterior muscle
Costal cartilages? Clinical significance?
- bars of hyaline cartilage
- progressively ossify
- costal margin: costal cartilage of ribs 8, 9, 10
- Clinical: ossification and osteoporosis with age, ribs fracture easier, hurts to cough, greater risk of pneumonia, can be fatal
- Clinical: joints are synovial, can become fibrous over time becoming irritated or inflamed (costochondritis), pain can be mistaken for heart issue
External intercostal muscles attachments?
- lower margin of 1st 11 ribs
- from tubercles of ribs behind to cartilages of ribs in front
- give way to external intercostal membrane
External intercostal muscles function?
elevate ribs and muscle of inspiration
Anterior vs posterior arteries and veins in intercostal grooves?
- anterior: from internal thoracic vessels
- posterior: from Aorta
Levator Costarum attachments?
- transverse process of 7th cervical to 11th thoracic vertebrae
- insert into lower adjacent rib between tubercle and angel
Levator costarum function and innervation?
- function: elevate ribs for inspiration
- innervation: dorsal rami
Internal intercostal attachments?
- lower margin of rib and costal cartilage
- fibers pass down and back to upper margin of lower ribs and cartilage
- from medial ends of intercostal spaces to angle of ribs
- give way to intercostal membrane
Internal intercostal function?
expiration
Innermost intercostals?
- part of internal intercostals separated by intercostal vessels and nerves
- not well developed
- subcostal: variable in number, arise form ribs near angles and insert 2-3 ribs below
- sternocostalis: sternum to costal cartilage
Transversus thoracis?
- attaches on posterior side of sternum and goes up and lateral to ribs
- innervated by anterior rami
- function in expiration
Diaphragm attachments?
- most important muscle of respiration (increases volume of thorax)
- no bony attachments
- inserts on central tendon (attaches to pericardium)
- divided into halves and has three parts (sternal, costal, lumbar)
Sternal part of diaphragm?
- fibers arise from back of diploid and descend to central tendon
- sternocostal triangle: transmits the superior epigastric vessels (branch of internal thoracic artery)
Costal part of diaphragm?
arise from inner surfaces of lower 6 costal cartilages and lower 4 ribs
Lumbar part of diaphragm?
- arise from two fibrous arches and bodies of L1 and L2
- medial and lateral arcuate ligament
- part of diaphragm arises from lumbar vertebrae
- forms two muscular crura that ascend to central tendon
- forms aortic opening
Medial arcuate ligament location?
over Psoas major muscle
Lateral arcuate ligament location?
over Quadratus lumborum
Action of diaphragm?
- central tendon descends when it contracts, increase volume of thorax and air rushes in
- facilitates return of blood to heart through vena cava
- each half separates nerve supply
- hiccups are spasmodic contraction of diaphragm
- no one can voluntarily hold breath to point of asphyxiation
Innervation and blood supply of diaphragm?
- Phrenic nerve (C3, 4, 5)
- supplies from underneath blood vessels
- rich sensory response (peritoneum, pericardium, pleura)
- each half has separate nerve supply
Shoulder pain related to diaphragm?
- shoulder pain over trapezius
- epigastric pain, xray shows free air under diaphragm
- perforated abdominal organ, ruptured posterior gastric ulcer
- continuous with inferior aspect of diaphragm
- referred pain to neck
Internal thoracic artery and branches?
- first branch of Subclavian Artery
- passes down through thorax behind costal cartilages
- ends at 6th intercostal space by dividing into terminal branches:
- Superior Epigastric (pierces diaphragm)
- Musculophrenic
Sternocostal triangle?
space for passage of Superior epigastric vessels (branch of internal thoracic artery)
Thoracic nerves?
- meningeal branches
- dorsal rami
- ventral rami
- first, second, third intercostal nerves supply the arm and thorax
Joints of thorax?
- Costovertebral
- Costotransverse (synovial- motion)
- Costochondral (hyaline-no motion)
- Sternocostal (starts as synovial but fibrous over time, 2-7)
Movements of thoracic cage?
- movements change volume of rib cage, creates vacuum for air to rush in
- inhalation (ribs rise and move laterally)
- intercostal muscles especially external
