CVS_9 Development Of Arterial Aortic Arches (PDF)

# Cardiovascular System ## Development of Arterial Aortic Arches ### Arterial Aortic Arches - Formation - Fate - Congenital anomalies - Short questions ### Formation of Arterial Aortic Arches - Formation of two primitive aorta. - Folding of embryo and formation of ventral and dorsal aorta from...

# Cardiovascular System ## Development of Arterial Aortic Arches ### Arterial Aortic Arches - Formation - Fate - Congenital anomalies - Short questions ### Formation of Arterial Aortic Arches - Formation of two primitive aorta. - Folding of embryo and formation of ventral and dorsal aorta from each tube. - Fusion of both ventral aorta leads to the formation of the aortic sac. - Fusion of lower part of both dorsal aorta → formation of single dorsal aorta. - Development of six arterial aortic arches - The 5th aortic arch degenerates very early in fetal life. ### Fate of Arterial Aortic Arches | Aortic arch | Right Side | Left Side | |---|---|---| | 1st aortic arch | It degenerates on both sides leaving a small portion called the maxillary artery. | It degenerates on both sides leaving a small portion called the stapedial artery (second-stapedial). | | 2nd aortic arch | It degenerates on both sides leaving a small portion called the stapedial artery (second-stapedial). | It degenerates on both sides leaving a small portion called the stapedial artery (second-stapedial). | | 3rd aortic arch | It gives the following: - Common carotid artery. - Proximal portion of the internal carotid artery (it distal part is formed by the rest of the cranial segment of the dorsal aorta. - The external carotid artery appears as a newly developing vessel from common carotid artery. | It gives the following: - Common carotid artery. - Proximal portion of the internal carotid artery (it distal part is formed by the rest of the cranial segment of the dorsal aorta. - The external carotid artery appears as a newly developing vessel from common carotid artery. | | 4th aortic arch | Right subclavian artery. - It degenerates on both sides. - Ventral part: Right pulmonary a. - Dorsal part: Degenerates - Its cranial half degenerates on both sides. - Its Rt. caudal half gives innominate a. - Disappears. - It forms part of the right subclavian a. | Main part of the arch of the aorta. - Ventral part: Left pulmonary a. - Dorsal part: Ductus arteriosus. - Its Lt. caudal1/2 gives proximal part of aortic arch. - Distal part of the aortic arch. - Caudal to 6th aoetic arch it forms descending aorta. - It forms left subclavian artery. | | Dorsal aorta (between 3rd and 4th arches) | It degenerates on both sides. | It degenerates on both sides. | | 6th aortic arch | Its cranial half degenerates on both sides. | Its Lt. caudal1/2 gives proximal part of aortic arch. | | Aortic sac | Its Rt. caudal half gives innominate a. | Distal part of the aortic arch. | | Dorsal aorta (between 4th and 6th arches) | Disappears. | Caudal to 6th aoetic arch it forms descending aorta. | | Seventh intersegmental a. | It forms part of the right subclavian a. | It forms left subclavian artery. | ### Rt. subclavian artery: - It is formed from: - Rt. 4th aortic arch. - Rt. 7th intersegmental a. - Part of dorsal aorta that lies between Rt. 4th aortic arch and Rt. 7th intersegmental a. ### Lt. subclavian artery: - It is formed only from the Lt. 7th intersegmental a. ### Aortic sac: - It is crinal half degenerates. - It is caudal half divides into two parts: - Lt. horn forms arch of aorta caudal to the 4th arch. - Rt. horn forms innominate a. ### Arch of the aorta: - It is formed from: - Left horn of aortic sac. - Left forth arch. - Dorsal aorta distal to the 4th arch. ### Relation of the recurrent laryngeal nerve: - On the left side: It hooks around ductus arteriosus (future ligamentum arteriosus). So Lt. recurrent laryngeal n. hooks around lig. arteriosus. - On the right side: The distal segment of the right sixth arch degenerates, and the fifth arch degenerates too. Hence the right recurrent laryngeal nerve hooks around the distal segment of the right forth arch (future right subclavian artery). ## Anomalies of Arterial Aortic Arches ### 1. Double aortic arch: - Cause: Persistent Rt. dorsal aorta distal to Rt. 4th arch ### 2. Right sided aortic arch. - Cause: Reversal of normal development between both sides ### 3. Retropharyngeal subclavian. - Cause: Abnormal origin of right subclavian artery ### 4. Patent ductus arteriosus - Cause: None closure of ductus arteriosus ### 5. Transposition of the great vessels - Cause: Reversed pattern of spiral aortico-pulmonary septum. ### 6. Coarctation of the aorta - Cause: It means narrowing of the arch of aorta after the arch gives off left subclavian artery. ### Patent ductus arteriosus is abnormal communication between which of the following? - a. Superior vena cava & pulmonary trunk - b. Right & left atria - c. Ascending aorta & pulmonary trunk - d. Arch of aorta & pulmonary trunk ### The ductus arteriosus develops from which of the following aortic arches? - a. Fourth. - b. Third. - c. Fifth. - d. Sixth.