Learning Objectives
Master the vascular anatomy of Epistaxis. Distinguish between common anterior bleeds and life-threatening posterior hemorrhages, and identify the specific arterial contributions to the Kiesselbach plexus for the USMLE Step 1.
1. Anterior vs. Posterior Epistaxis
The clinical significance of a nosebleed is largely determined by its anatomical location and the caliber of the vessel involved.
| Location | Vessel / Source | Clinical Features |
|---|---|---|
| Anterior (Most Common) | Kiesselbach Plexus (at the caudal septum). | Usually minor; caused by trauma (nose picking), dry air, or allergic rhinitis. |
| Posterior (Severe) | Sphenopalatine Artery (branch of maxillary artery). | Can be life-threatening; often requires packing or surgical ligation. Often associated with hypertension. |
2. The Kiesselbach Plexus (Little’s Area)
This area is a highly vascularized region of the anteroinferior nasal septum where several arterial branches anastomose.
Mnemonic: Kiesselbach drives his Lexus with his LEGS
- L — Superior Labial artery (from Facial a.)
- E — Ethmoidal arteries (Anterior and Posterior)
- G — Greater palatine artery
- S — Sphenopalatine artery
3. Common Etiologies
Nosebleeds are often multifactorial, ranging from simple irritation to benign vascular tumors.
| Cause | Key Details |
|---|---|
| Trauma | Digital trauma (nose picking) is the #1 cause in children. |
| Environmental | Low humidity/dry air causes mucosal friability. |
| Juvenile Angiofibroma | Benign but highly vascular tumor; classically seen in adolescent males. |
| Systemic | Hypertension, anticoagulation, or Osler-Weber-Rendu syndrome. |
Activity:
High-Yield Clinical Pearls:
- Maxillary Artery: The Sphenopalatine artery is the terminal branch of the maxillary artery. If posterior bleeding cannot be controlled, the maxillary artery may be ligated in the pterygopalatine fossa.
- Nasal Packing: Anterior packing is common, but posterior packing carries a risk of triggering the nasopulmonary reflex, potentially causing bradycardia or apnea.
- Septal Perforation: Chronic epistaxis management or cocaine use (vasoconstriction) can lead to septal ischemia and eventual perforation.