Bifurcation of pulmonary trunk
Bifurcatio trunci pulmonalis
The point beneath the aortic arch where the pulmonary trunk splits into the right and left pulmonary arteries.
At a glance
- English
- Bifurcation of pulmonary trunk
- Latin (TA2)
- Bifurcatio trunci pulmonalis
- System
- Artery
- Region
- Trunk
- Side
- Single, on the midline
About the bifurcation of pulmonary trunk
The pulmonary trunk carries deoxygenated blood from the right ventricle towards the lungs. It is short, only around five centimetres, and runs upwards and backwards from the pulmonary valve, first in front of and then to the left of the ascending aorta. Its end is the bifurcation, where it divides into two pulmonary arteries, one for each lung.
The division lies in the concavity of the aortic arch, roughly at the level of the sternal angle, and in front of the tracheal bifurcation and the left main bronchus. The trunk is enclosed in the pericardium together with the ascending aorta, and it divides close to the point where it leaves the pericardial sac. The two branches are unequal. The right pulmonary artery is the longer: it passes horizontally to the right behind the ascending aorta and the superior vena cava and in front of the right main bronchus. The left is shorter and continues the line of the trunk, crossing in front of the descending aorta and the left bronchus.
Near the bifurcation, at the start of the left pulmonary artery, the ligamentum arteriosum attaches. This fibrous cord is the remnant of the fetal ductus arteriosus and joins the pulmonary artery to the underside of the aortic arch. The left recurrent laryngeal nerve hooks around the arch just lateral to it, and the superficial and deep cardiac plexuses lie close by.
The bifurcation is a common place for a large embolus to lodge; a clot straddling both branches is called a saddle embolus and may obstruct blood flow to both lungs. On chest CT the diameter of the trunk is measured at this level, and a widened trunk suggests pulmonary hypertension. A ductus that stays open after birth connects the aorta to the region of the bifurcation.
Course and supply
- Arises from
- The terminal end of the pulmonary trunk, which arises from the right ventricle at the pulmonary valve.
- Ends in
- Divides into the right and left pulmonary arteries.
- Supplies
- Distributes deoxygenated blood from the right ventricle to the two lungs.
Anthromica
See the bifurcation of pulmonary trunk where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
