Arterial supply, venous drainage and collateral circulation in the nose of the anaesthetized dog

Abstract

1. In pentobarbitone-anaesthetized dogs, nasal blood flows were measured with electromagnetic flow sensors. 2. The terminal internal maxillary artery was found to supply 22 ± 2.2 ml min-1 (one side) to the nasal mucosa via the sphenopalatine and major palatine branches; the artery was found to receive multiple supply routes from common carotid, vertebral and subclavian arteries. 3. Nasal mucosa was found to receive collateral flow from contralateral terminal internal maxillary artery (about 5 to 10% of normal flow) and branches of subclavian arteries (about 36% of normal flow). 4. Nasal mucosa was found to have two venous systems: the low-flow (12 ± 1.0 ml min-1; both sides) and low-pressure (7 ± 0.6 mm Hg) sphenopalatine veins draining the posterior nasal cavity and the high-flow (30 ± 1.4 ml min-1; both sides) and high-pressure (17 ± 1.0 mmHg) dorsal nasal veins draining the anterior nasal cavity. 5. P(O2) of nasal venous blood was found to range from 62 ± 2.9 mm Hg to 65 ± 3.4 mmHg. During nitrogen challenge to the nose, the sphenopalatine venous P(O2) dropped to 35 ± 3.0 mm Hg while the dorsal nasal venous P(O2) remained unchanged, suggesting that the sphenopalatine veins were responsible for draining capillary flow and dorsal nasal arteriovenous anastomotic flow as well. 6. Microscopic examination of the vascular casts confirmed that arteriovenous anastomoses were located only in the anterior nasal cavity.