OSCE - Anatomy Flashcards
Name the aspect of the heart supplied by the following blood vessels:
- RCA
- Right marginal artery
- Left circumflex artery
- LAD
- Left marginal artery
What are the descending pathways and ascending pathways in the spinal cord?
What is contained within the grey matter of the spinal cord?
Cell bodies
Unmyelinated neurones
What is the blood supply to the spinal cord?
- ONE anterior spinal artery - originate from vertebral arteries, supplies anterior 2/3 of the spinal cord
- TWO posterior spinal arteries - originates from posterior cerebellar arteries
- RADICULAR arteries - from vertebral, ascending cervical, intercostal and lumbar arteries.
What happens if there is cessation of blood flow in the anterior spinal artery?
Paralysis below the level of the lesion
Loss of pain temperature sesation at and below the level of the lesion.
Light touch and proprioception remain in tact
What clinical signs follow hemisection of the spinal cord?
Ipsilateral loss of light touch, proprioception and motor function below lesion.
Contralateral loss of pain and temperature sensation usually 2-3 levels below the lesion.
At what vertebral level does the trachea commence?
C6
What structures lie anterior and posterior to the trachea where it starts?
Anterior - skin, subcutaneous tissue, strap muscles, isthmus of the thyroid, thyroid artery
Posterior - oesophagus, recurrent laryngeal nerve (groove between oesophagus and trachea.
Where is surgical tracheostomy inserted?
2nd and 4th tracheal rings
At what level does the trachea bifurcate?
T4-5
What is the nerve to the trachea?
Anterior and posterior pulmonary plexuses
Branch of the vagus and sympathetic nerves
What are the differences between right and left main bronchi?
RIGHT:
WIDER, MORE VERTICAL
SHORTER (2.5cm vs 5cm)
How many segmental bronchi are there?
10
3 upper lobe
2 middle lobe
5 lower lobe
How many lobes and fissures present in each lung?
Each lung has an oblique fissure, but the right lung has a transverse fissure also.
Therefore three lobes right lung, two lobes left lung.
Describe the basic histology of the trachea to the terminal bronchioles.
Trachea –> 10 generations of bronchi have descending cartilaginous support, and surrounded by smooth muscle and elastic fibres. They have GOBLET CELLS which produce mucus - lined with ciliated columnar epithelial cells.
Next FIVE generations - no cartilage or goblet cells, but still have elastic tissue and smooth muscle fibres. They lined with ciliated cuboidal epithelium
The alveolar walls consist of simple squamous epithelium. Also the tissues surrounding the alveoli contain elastic fibres which allow the alveoli to expand during inspiration and recoil during expiration.
Describe the alveoli in the lung.
Approximately 300 million alveoli are in the lungs.
The average diameter of the alveoli is approximately 250um and their walls are extremely thin.
There are two types of cells in the alveoli: type I pneumocytes which are thin squamous epithelial cells that forms 90% of the alveoli surface. Most of the gas exchange take place between these cells.
Type II pneumocytes are round secretory that produce surfactant, which makes it easier for the alveoli to expand during inspiration
What is the blood supply and venous drainage of the lungs?
The bronchial arteries arising from the aorta provide blood supply to the non-respiratory airways, pleura, and connective tissue while
the pulmonary arteries supply the respiratory units (acini) and participate in gas exchange.
Venous drainage is mainly by the pulmonary veins (right and left superior and inferior pulmonary veins),
though the venous of drainage from the walls of the larger bronchi is carried out by the bronchial veins.
All four veins (pulmonary veins) drain into the left atrium.
THE FIRST RIB, name three unique features
It is the shortest rib, most curved, no angle
Has a SINGLE articular facet for articulation with the body of T1
TWO grooves superior surface
No costal groove on the inferior surface
What structures pass on the grooves?
Subclavian vein medially
Subclavian artery and lower trunk of brachial plexus
Separating the two scalene tubercle which attaches to scalenus anterior
Ribs 2-7:
- which part of the rib houses the neurovascular bundle?
- between which layer does the intercostal muscles lie?
- Neurovascular bundle lies within the COSTAL GROOVE
2. INTERNAL and INNERMOST Intercostal muscles
Name three indications for an intercostal nerve block.
Rib fractures
Thoracic surgery
Chest drain insertion
Breast surgery
What are the unique features of the 11th and 12th rib?
They are floating, and attach only to the vertebrae and not the sternum
What are the three layers of the heart?
Endocardium, Myocardium, Epicardium
Which arteries supply the SA and AV node?
Right coronary artery supplies SA node in 60%
Right coronary artery supplies AV node in 80%
Describe venous drainage of the heart
VIA CORONARY SINUS - blood from small, middle, oblique and great coronary veins into right atrium
Directly into right atrium via anterior cardiac vein and cordae minimae
What is the nerve supply to the heart?
Cardiac plexus that contains sympathetic and parasympathetic branches.
Sympathetic: T1-T4, via cervical and upper thoracic ganglian
Parasympathetic: via vagus nerve
In the foetal circulation describe the route of blood flow.
UMBILICAL VEIN
PORTAL SINUS - LIVER and DUCTUS VENOSUS - IVC
IVC - RA - FORAMEN OVALE - LA - PULMONARY ARTERY - DUCTUS ARTERIOSUS and AORTA
What changes lead to closure of the foramen ovale?
- Lung expansion - decreased PVR and PA pressure
- SVR increases due to loss of low resistance placenta
- Systemic pressure exceed aortic pressure
- Foramen ovale flaps functionally close.
What structure does ductus arteriosus connect?
What is it called after birth?
Pulmonary artery and the descending aorta
Ligamentum arteriosum
What does the umbilical cord contain?
1 umbilical vein
2 arteries
At what level does the oesophagus pierce the diaphragm?
T10
What level does the aorta pierce the diaphragm?
T 12
What level does the IVC pierce the diaphragm?
T8
What are the attachments of the diaphragm? (6)
ANTERIOR: lower 6 ribs
MEDIALLY: xiphisternum
LEFT and RIGHT crux to lumbar vertebrae
POSTERIOR: medial arcuate ligament to psoas, lateral arcuate ligament to the quadratus lumborum
CENTRAL: Pericardium
Motor innervation to the diaphragm?
PHRENIC NERVE
C3 - 5
SENSORY INNERVATION OF THE DIAPHRAGM?
Central tendon - phrenic nerve
Peripheries - intercostal nerve
At what level does the phrenic nerve pierce the diaphragm?
T8
What is the course of the IJV from base of skull to its termination?
- JUGULAR FORAMEN
- Descends in CAROTID SHEATH
- Initially runs lateral to internal carotid - then anterior and lateral to COMMON CAROTID.
- Joins BRACHIAL VEIN to from BRACHIOCEPHALIC VEIN.
What is contained in the carotid sheath?
IJV
Common carotid
Vagus nerve
What is the motor innervation to the larynx?
- RECURRENT LARYNGEAL NERVE intrinsic muscles of larynx except cricothyroid.
- External branch of SUPERIOR LARYNGEAL NERVE to cricothyroid.
