Anatomy Flashcards
Anterior relations of thymus
Pretracheal fascia
Sternohyoid
Sternothyroid
Manubrium
Upper part of sternum
Blood supply to intercostals
1-2 = superior intercostal A
2-6 = internal thoracic A
7-10 = musculophrenic A
Divisions of subclavian A
1st part = origin to medial border of anterior scalene
2nd part = posterior to anterior scalene
3rd part = lateral border of anterior scalene to lateral border of 1st rib
Br of subclavian A
1st part:
- Vertebral A
- Internal thoracic A
- Thyrocervical trunk
2nd part:
- Costocervical A
- Dorsal scapular A
3rd part:
None
Br of thyrocervical trunk
Inferior thyroid A
Superficial cervical A
Suprascapular A
Br of costocervical trunk
Superior intercostal A
Deep cervical A
Posterior relations of thymus
- Pericardium
- Arch of aorta + x3 br
- L brachiocephalic
- Trachea
Bifurcation / termination of internal thoracic A
6th IC space into:
- Superior epigastric A
- Musculophrenic A
Embryological origin of the diaphragm
4 components:
- Septum transversum - central tendon
- Pleuroperitoneal membranes - closes the
pericardioperitoneal canal - Dorsal mesentery of the oesophagus - crus’ grow
within it - Muscular components from somites @ levels (C3-C5)
Cause for congenital diaphragmatic hernia
Incomplete fusion of the pleuroperitoneal membrane w/ the septum transversum + dorsal mesentery of the oesophagus
Fusion closes the pericardioperitoneal canal
L pericardioperitoneal canal + therefore, is more likely to remain patent -> congenital diaphragmatic hernia
Derivatives of the septum transversum
- Central tendon of the diaphgram
- Falciform lig
- Coronary lig of the liver
- Lesser omentum
- CT of liver / GB
- Kuppfer cells
Level of the nipple
= 4th intercostal space
Levels of the domes of the diaphragm
R dome sits higher than the L dome
R = 4th IC space (nipples) in expiration
L = 5th IC space in expiration
Origins of the x3 arcuate lig
Median = crura
Medial = psoas fascia
Lateral = quadrates lumborum fascia
Prevertebral fascia
Sup attach - cranial base
Inf attach - body of T4 (fuses w/ the ant longitudinal attach)
Ext laterally below the clavicle forming the axillary sheath
Pretracheal fascia
Sup attach - hyoid bone / oblique line of thyroid cartilage
Inf attach - adventitia of arch / fibrous pericardium
Aortic arches
Arch 1 = part of maxillary + external carotid A
Arch 2 = part of stapedial + hyoid A
Arch 3 = common carotid / 1st part of internal carotid A
Arch 4 = part of aortic arch + proximal R subclavian A
Arch 5 = disappears
Arch 6 = pulm A + ductus arteriosus
Course of R vagus N
Runs in the carotid sheath initially posterior -> lateral
Passes through the thoracic inlet posterior to the subclavian V + anterior to the subclavian A
Gives off the recurrent laryngeal N, which hooks around the subclavian A + ascends to the thyroid
Passes medial to the azygos arch
Runs posterior to the hilum
Pierces the diaphragm w/ the oesophagus @ T10
Course of L vagus N
Runs in the carotid sheath initially posterior -> lateral
Passes through the thoracic inlet posterior to the subclavian V + anterior to the subclavian A
Passes anterior to the aortic arch where it gives off the recurrent laryngeal N, which hooks around the ligament arteriosum
Runs posterior to the hilum
Pierces the diaphragm w/ the oesophagus @ T10
Oesophageal constrictions
- Cricoid cartilage = 15cm (known as the cervical constriction)
- Crossing of aortic arch = 22.5cm
- L bronchus = 27cm
- Diaphragmatic hiatus = 40cm
* distance in cm from the incisor teeth*
Tetralogy of Fallot
- Overriding aorta
- High VSD
- Pulmonary stenosis
- RV hypertrophy
Embryological divisions of the heart
- Truncus arteriosus - pulmonary trunk + asc aorta
- Bulbus cordis - smooth outflow tracts of ventricles
- Ventricle
- Atria
- Sinus venosus
- R sinus horn = SVC (common cardinal vein)
IVC (vitelline vein) - L sinus horn = coronary sinus
- R sinus horn = SVC (common cardinal vein)
Epithelium of respiratory tract
Pseudo-stratified epithelium
Trachea
Origin = inf border of the cricothyroid cartilage
End = bifurcation @ T4/T5
Length = 10cm, 5cm cervical + 5cm thoracic
~16-20 C-shaped hyaline cartilage incomplete rings
Emergency cricothyroidotomy
= incision through the cricothyroid membrane
Tracheostomy
Incision 2cm below cricoid cartilage
Interval between x2 sternohyoid muscles
Retract laterally L + R sternothyroids
Divide thyroid isthmus
Circular incision through 2nd + 3rd tracheal rings
Blood supply of trachea
- Inferior thyroid A
2. Bronchial A
N supply of trachea
Vagus directly + recurrent laryngeal br
Sympathetic from upper thoracic ganglia of the sympathetic trunk
Relation of transverse sinus to inflow/outflow tracts of the heart
Anterior to transverse sinus = aorta + pulm trunk
Posterior to transverse sinus = SVC + pulm Vs
Embryonic vein origins
Anterior cardinal vein = brachiocephalic Vs
Supracardinal vein = azygos / hemiazygos / accessory
R Subcardinal vein = IVC
Subcardinal anastomosis = L renal vein
Sacrocardinal anastomosis = lower IVC, common iliac V
Embryonic vein origins of the IVC
R vitelline V
R subcardinal V
R sacrocardinal V
Sacrocardinal anastomosis
Veins that drain into R brachiocephalic
- R Internal jugular V
- R subclavian V
- R supreme IC V
- R internal thoracic V
- R vertebral V
