Embryology and Anatomy Flashcards
Gestational week when primitive embryonic heart tube forms
3rd week
Gestational week and day when heart starts beating and looping occurs
4th week - Day 22
Gestational week when AV canal divides into tricuspid and mitral valves
4-6 weeks
Gestational week when outflow tract septates into PA and aorta
6-8 weeks
What does the primary heart field become
Embryonic ventricle (precursor to LV) and embryonic atria (becomes atrial appendages)
What does the secondary heart field become
Proximal bulbus cordis (precursor to RV), distal bulbus cordis (infundibulum), truncoaortic sac (outflow tracts)
Neural crest cell abnormalities can lead to what type of defects
Conotruncal defects (ToF, truncus, IAA) - affect the great arteries
What highlights a right atrium
- Septum secundum covers over septum primum on RA side
- Broad based appendage
- Pectinate muscles extend onto lateral RA wall
Borders of triangle of Koch and what does it contain
- Septal leaflet of TV
- Coronary sinus os
- Tendon of Todaro
- Contains the AV node
What highlights a left atrium
- Two attachments of septum primum onto back/left of septum secundum on LA side
- Narrow, finger like appendage
- Pectinate muscles only in LA appendage
Where is the hole in a secundum ASD
Septum primum
Where is the hole in a primum ASD
Canal septum
Defining a right ventricle
- Coarse trabeculations
- Tricuspid valve - chordal attachments to the free wall and septum (SEPTOPHILIC) and tricuspid valve is more apically displaced
- Moderator band
Defining a left ventricle
- Fine trabeculations
- Mitral valve - chordal attachments to the free wall only (SEPTOPHOBIC)
- Smooth septal surface at the base
What does the 3rd embryonic arch become
Common carotid artery
What does the 4th embryonic arch become
The aortic arch on one side and the innominate artery on the other side
What does the 6th embryonic arch become
Ductus arteriosus
Embryonic arch process to form normal left aortic arch
- Regression of the right dorsal aorta and right 6th arch
- 4th arch persists and forms the arch, left 6th arch is the ductus
Embryonic arch process to form left aortic arch with aberrant right subclavian artery
Regression of the right 4th arch and right 6th arch
Embryonic arch process to form right aortic arch with mirror image branching
Regression of the left dorsal aorta but both 6th arches remain
Embryonic arch process to form right aortic arch with aberrant left subclavian artery
- Regression of left 4th arch (but both 6th arches remain)
- If right ductus persists then not a vascular ring
- If left ductus persists then it IS a vascular ring
Most common symptomatic vascular ring
Double aortic arch
IAA Type A embryologic development
- Regression of both dorsal aortas
- A = AFTER all arch vessels arise (distal to L subclavian)
IAA Type B embryologic development
- Regression of left 4th arch and right dorsal aorta
- B = BETWEEN (interruption between L carotid and L subclavian)
- Commonly associated with 22q11 deletion
IAA Type C embryologic development
- Break in the trunco-aortic sac and regression of right dorsal aorta
- C = CAROTIDS (interruption between R carotid and L carotid)
Asplenia (right sidedness) segmental anatomy abnormalities
- Almost 100% complete AV canal
- Commonly have PS/PA
- TAPVR
- Bilateral SVC with LSVC directly to LA, can have absent coronary sinus
- Bilateral sinus nodes
- Descending aorta and IVC on the same side of the vertebral column
- High incidence of bowel malrotation
- Liver midline with two mirror image right lobes
Polysplenia (left sidedness) segmental anatomy abnormalities
- 2/3 patients with AV canal
- Most have normal VA connections but can have sub-aortic or aortic stenosis
- Ipsilateral PV drainage
- Bilateral SVCs with LSVC to CS
- Interrupted IVC
- Complete heart block
Most reliable way to distinguish mitral vs tricuspid valve
Level of attachment at the cardiac crux
Associations with left juxtaposition of the atrial appendage
Abnormal ventriculoarterial connections
Associations with right juxtaposition of the atrial appendage
Simpler lesions like ASD, single SA node
Valve located at the entrance of the IVC
Eustachian valve
Valve remnant at the os of the coronary sinus
Thebesian valve
Fine filamentous network that represents persistent of the valves of the sinus venosus
Chiari network
– Directs blood from IVC and SVC across the PFO
– In normal patients, this regresses to form the crista terminalis
Embryologic structure that gives rise to R SVC
R anterior cardinal vein and R common cardinal vein
Embryologic structure that gives rise to L SVC
L anterior cardinal vein
Ductus venosus remnant
Ligamentum venosum
Umbilical vein remnant
Round ligament of the liver
Position of the AV node in tricuspid atresia
- Floor of the blind right atrium
- Bundle of His then courses onto the crest of the intraventricular septum and runs posterior to the VSD rim
Most common asymptomatic aortic arch anomaly
Left arch with aberrant right subclavian (0.5% of the general population)
What is Uhl anomaly
Partial of complete absence of the RV myocardium leading to thinned out myocardium
Definition of overriding AV valve
Empties into 2 ventricles and is always associated with a malalignment VSD
What is a straddling valve
Involves anomalous insertion of the chordae tendinae - has to have a VSD but may not be malalignment type
What structures pass under the transverse arch
RPA and left bronchus
Most common great artery relationship in DORV
Side by side (aorta to the right of the
Most common associated lesion with DORV
- Pulmonary stenosis (seen in 50% of patients)
- Next is ASD (25%)
What is a parachute mitral valve
All chordal attachments to a single papillary muscle
What is a mitral arcade
Valve leaflets attach directly to the papillary muscle (absent or short chordae)
What type of cells are in the last 1-3 cm of pulmonary veins
Contractile cardiac myocytes which helps to inhibit retrograde flow in atrial systole but can be a source of Afib
Coronary artery supply of the posterior medial papillary muscle
Right coronary artery (also supplies the inferior wall of the LV)
Name of the valve that drains the great cardiac vein
Vieussens valve
- Bicuspid valve located at the site of the cardiac vein that drains with the coronary sinus
Most common coronary anomaly in otherwise normal hearts
Anomalous left circumflex from the right main coronary artery
AV nodal artery arises from which coronary
90% of the time from the RCA
10% from the left circumflex
Normal branching pattern of PAs relative to the bronchus
- RPA travels anterior to the right upper lobe bronchus
- LPA travels posterior to the left upper lobe bronchus
Characteristics of fibromas
- Single, firm intramural tumors involving the ventricular free wall or septum
- Frequently present with ventricular arrhythmias
Characteristics of rhabdomyomas
- Well-circumscribed, non-capsulated intramural or intracavitary lesion
- Most commonly in the ventricles but can be anywhere and also usually have multiple
Characteristics of myxoma
- Pedunculated and friable
- Occur most commonly in the LA
- Associated with cardiac obstruction (80%), embolism (70%) and systemic illness (60%)
Hi Kamel
<3
What is the ligament of Marshall
Small fibrous ridge traveling anterior to the pulmonary veins and left pulmonary artery
Represents residual of the left sided superior vena cava
What does septum primum and septum secundum become
- Primum: valve of the fossa ovalis
- Secundum: limbus of the fossa ovalis
What is the transverse sinus
Tunnel shaped structure that runs between the anterior/superior walls of the atria and posterior/inferior to the great vessels
Can be used to help find remnant of pulmonary artery in pulmonary atresia
