Source: Angiogenetic cells (mesodermal)

Continuation of the 2 endocardial heart tubes to form right and left primitive aorta

• Which curve dorsally and continue as 2 dorsal aortas (dorsal to gut). Cranially are separate, caudally fuse to form a single dorsal aorta
• And ventral to pharynx fuse – Aortic sac

The 2 dorsal aortas connect with the aortic sac via aortic arch arteries

These are 6 pairs of arteries that run in the 6 pharyngeal arches

Development of arch of aorta:

• Proximal – Aortic sac stem
• Middle – Aortic sac left horn
• Distal – Left 4th aortic arch, lower left dorsal aorta

Recurrent laryngeal nerve:

• Right and left vagi descend lateral to pharynx
• Give recurrent laryngeal nerve
• On right side, 5th and 6th arch disappear (6th arch dorsal branch), therefore hooks around 4th aortic arch ie. subclavian artery
• On left side, hooks around dorsal branch of 6th aortic arch ie. ductus arteriosus

Anomalies of aortic arch:

1. Patent ductus arteriosus – failure to close, hypertrophy of left side of heart
2. Congenital narrowing of aorta – Preductal type (above ductus arteriosus which closes) and Postductal type (below ductus arteriosus which remains open)
3. Right sided aortic arch – Distal part of left dorsal aorta degenerates, distal part of right dorsal aorta persists
4. Double aortic arch – both persist, leads to dysphagia (difficulty in swallowing) and dyspnea (difficulty in breathing)
5. Abnormal right subclavian artery – 4th aortic arch degenerates, therefore arises from right 7th intersegmental artery and descending aorta

Common dorsal aorta branches:

1. Ventral:

• Coelic artery – foregut
• Superior mesenteric artery – midgut
• Inferior mesenteric artery – hindgut

2. Lateral (paired):

• Middle suprarenal artery
• Renal artery
• Gonadal artery

3. Posterolateral (paired):

• Posterior intercostal arteries
• Subcostal arteries
• Lumbar arteries

Umbilical artery:

1. Arises from dorsal aorta
2. Connected to 5th lumbar intersegmental artery
3. Looses connection to dorsal aorta
4. 5th lumbar intersegmental artery gives a branch ie. External iliac artery
5. Continues as internal iliac artery

Development of arteries in lower limb:

Continuation of external iliac artery ⇒ Femoral artery ⇒ descends infront of thigh ⇒ curves to join sciatic artery backwards to form Poplitial artery

Continuation of Internal iliac artery ⇒ Called sciatic artery ⇒ descends in back of lower limb ⇒ to sole of foot ⇒ degenerates to form Inferior gluteal artery, peroneal artery ETC

EIA and IIA anastomose to form anterior and posterior tibial arteries

Development of arteries in upper limb:

7th cervical intersegmental artery ⇒ Subclavian a. ⇒ Axillary a. ⇒ Brachial a. ⇒ Ulnar and Radial a. ⇒ give superficial and deep palmer arches

NB: Brachial a. also gives another branch called anterior interosseous artery. Anterior interosseous artery is replaced by median artery which is replaced by ulnar artery