---
title: "Posterior Spinal Arteries | Anatomy and Physiology I"
description: "Posterior spinal arteries are paired vessels that supply the dorsal spinal cord, especially sensory pathways for touch and proprioception, in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 13"
---

# Posterior Spinal Arteries | Anatomy and Physiology I

## Definition

Posterior spinal arteries are paired arteries that run along the back of the spinal cord and supply the dorsal columns and dorsal horn. In Anatomy and Physiology I, they show how the spinal cord gets the blood flow needed for sensory function.

## What It Is

Posterior spinal arteries are the paired vessels that carry oxygenated blood to the back side of the spinal cord in Anatomy and Physiology I. They travel along the dorsal surface, one on each side, and help feed the dorsal columns and the dorsal horn of the gray matter.

Their job is not to supply the whole spinal cord. Instead, they cover a narrower region than the anterior spinal artery, which is why a blood flow problem in this area tends to affect sensory pathways more than motor pathways. That dorsal region contains tracts that carry fine touch, vibration, and proprioception, the sense that tells you where your body is in space.

These arteries usually arise from the vertebral arteries, but they can also branch from the posterior inferior cerebellar arteries. That variation matters because the spinal cord relies on connected arterial sources, and the exact origin can differ from person to person. In lab diagrams or vessel tracing questions, the key idea is the route: vertebral artery or PICA to posterior spinal arteries to the posterior spinal cord.

The posterior spinal arteries do not work alone. They are part of a larger spinal vascular network that includes the anterior spinal artery and segmental feeders. Because the spinal cord is long and narrow, it needs blood delivered through several vessels, not one single pipe. If one route is reduced, symptoms depend on which cord region loses blood supply.

When these arteries are blocked or damaged, the result is usually a sensory problem pattern. A person may keep much of their strength but lose vibration sense, fine touch, or position sense below the affected level. That difference between sensation and movement is what makes posterior spinal artery problems a useful example in A&P when you are comparing spinal cord anatomy with neurologic function.

## Why It Matters

Posterior spinal arteries matter because they connect vascular anatomy to nervous system function. In Anatomy and Physiology I, you are not just memorizing vessel names, you are linking blood supply to the exact areas of the spinal cord that process sensory information.

This term helps you explain why a spinal cord injury or vascular event can produce a specific pattern of symptoms. If the dorsal columns are underperfused, the problem is not random. You would expect impaired proprioception, reduced fine touch, or trouble sensing vibration, while some motor function may remain more intact if other pathways are spared.

It also fits into the larger CNS circulation unit, where blood vessels are studied as support systems for nervous tissue. Neurons are highly dependent on oxygen and glucose, so even a short disruption can affect conduction and tissue survival. That is why spinal cord ischemia is such a serious concept, and why vascular anatomy shows up in case questions, diagram labeling, and symptom matching.

This term is also useful for comparing the back and front of the spinal cord. Once you know what the posterior spinal arteries supply, the anterior spinal artery becomes easier to remember because each vessel feeds different functional territory. That comparison is a common way instructors check whether you understand structure plus function, not just a list of vessels.

## Connections

### Anterior spinal artery

This is the main vessel students compare with the posterior spinal arteries. The anterior spinal artery supplies the front of the spinal cord, including regions tied more closely to motor function and pain and temperature pathways. Looking at both arteries together helps you see how the cord has different vascular territories, which is why different blood flow problems create different symptom patterns.

### [Vertebral arteries](/anatomy-physiology/key-terms/vertebral-arteries)

The posterior spinal arteries often branch from the vertebral arteries, so this is the upstream vessel to recognize. In diagrams, the vertebral arteries are part of the larger route bringing blood to the brainstem and spinal cord. If you trace origin and branching, you can follow how oxygenated blood reaches the posterior spinal cord.

### Spinal cord ischemia

This term describes reduced blood flow to spinal cord tissue, which is the clinical consequence you think about when spinal arteries are compromised. Posterior spinal artery problems can contribute to ischemia in the dorsal cord regions. The symptom pattern depends on which tracts lose oxygen first, so ischemia questions often turn into anatomy-to-symptom matching.

### [Atherosclerosis](/anatomy-physiology/key-terms/atherosclerosis)

Atherosclerosis can reduce arterial blood flow by narrowing vessels or promoting clot formation, so it is one possible background cause of ischemic problems. In a vascular or case-based question, you may need to connect plaque buildup with reduced perfusion to nervous tissue. It is not specific to the spinal cord, but it can set up a circulation problem that affects it.

## On the AP Exam

A quiz or lab practical may ask you to label the posterior spinal arteries on a spinal cord diagram, trace where they come from, or match them with the sensory deficits they produce. If you get a case question, look for loss of proprioception, vibration, or fine touch with a pattern that points to the dorsal spinal cord. The move is to connect vessel location with function, not just name the artery. In short-answer prompts, you may need to explain why a blood supply problem here affects sensory pathways more than motor output.

## posterior spinal arteries vs Anterior spinal artery

These two are easy to mix up because both supply the spinal cord, but they feed different sides and different functional areas. The posterior spinal arteries supply the dorsal columns and dorsal horn, which are mainly sensory. The anterior spinal artery supplies the anterior two-thirds of the cord, where major motor and pain-temperature pathways run. If a question mentions proprioception or fine touch, think posterior spinal arteries.

## Key Takeaways

- Posterior spinal arteries are paired vessels that supply the back portion of the spinal cord.
- They mainly nourish the dorsal columns and dorsal horn, so they are tied to sensory processing.
- These arteries usually branch from the vertebral arteries, though they can also come from the posterior inferior cerebellar arteries.
- Damage or blockage can cause sensory loss, especially problems with proprioception, vibration, and fine touch.
- In Anatomy and Physiology I, this term shows how blood flow patterns line up with spinal cord function.

## FAQs

### What are posterior spinal arteries in Anatomy and Physiology I?

They are paired arteries that run along the posterior side of the spinal cord and supply blood to the dorsal columns and dorsal horn. In A&P, they show how vascular anatomy supports sensory pathways like fine touch and proprioception.

### Where do the posterior spinal arteries come from?

They usually branch from the vertebral arteries, but they can also arise from the posterior inferior cerebellar arteries. That variation matters when you trace blood flow in a diagram or compare vessel routes in a lab exercise.

### What happens if the posterior spinal arteries are blocked?

A blockage can reduce blood flow to the posterior spinal cord and cause sensory deficits. The classic pattern is loss of proprioception, vibration, or fine touch below the affected level, because those pathways run through the dorsal columns.

### How are posterior spinal arteries different from the anterior spinal artery?

The posterior spinal arteries supply the back part of the cord, while the anterior spinal artery supplies the front and most of the cord. That difference matters because the posterior vessels are more associated with sensory pathways, while the anterior vessel is tied more closely to motor and pain-temperature pathways.

## Related Study Guides

- [13.3 Circulation and the Central Nervous System ](/anatomy-physiology/unit-13/3-circulation-central-nervous-system/study-guide/CvPockAsqI7E7aok)

## About This Document

Canonical Fiveable pages are available as Markdown at the same path plus `.md`.

- [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns
- [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing
- [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`)
- [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`)

## Structured Data

```json
{"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries#resource","name":"Posterior Spinal Arteries | Anatomy and Physiology I","url":"https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:20:41.765Z","isPartOf":{"@type":"Collection","name":"Anatomy and Physiology I Key Terms","url":"https://fiveable.me/anatomy-physiology/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries#term","name":"posterior spinal arteries","description":"Posterior spinal arteries are paired arteries that run along the back of the spinal cord and supply the dorsal columns and dorsal horn. In Anatomy and Physiology I, they show how the spinal cord gets the blood flow needed for sensory function.","url":"https://fiveable.me/anatomy-physiology/key-terms/posterior-spinal-arteries","inDefinedTermSet":{"@type":"DefinedTermSet","name":"Anatomy and Physiology I Key Terms","url":"https://fiveable.me/anatomy-physiology/key-terms"}},{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What are posterior spinal arteries in Anatomy and Physiology I?","acceptedAnswer":{"@type":"Answer","text":"They are paired arteries that run along the posterior side of the spinal cord and supply blood to the dorsal columns and dorsal horn. In A&P, they show how vascular anatomy supports sensory pathways like fine touch and proprioception."}},{"@type":"Question","name":"Where do the posterior spinal arteries come from?","acceptedAnswer":{"@type":"Answer","text":"They usually branch from the vertebral arteries, but they can also arise from the posterior inferior cerebellar arteries. That variation matters when you trace blood flow in a diagram or compare vessel routes in a lab exercise."}},{"@type":"Question","name":"What happens if the posterior spinal arteries are blocked?","acceptedAnswer":{"@type":"Answer","text":"A blockage can reduce blood flow to the posterior spinal cord and cause sensory deficits. The classic pattern is loss of proprioception, vibration, or fine touch below the affected level, because those pathways run through the dorsal columns."}},{"@type":"Question","name":"How are posterior spinal arteries different from the anterior spinal artery?","acceptedAnswer":{"@type":"Answer","text":"The posterior spinal arteries supply the back part of the cord, while the anterior spinal artery supplies the front and most of the cord. That difference matters because the posterior vessels are more associated with sensory pathways, while the anterior vessel is tied more closely to motor and pain-temperature pathways."}}]},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Anatomy and Physiology I","item":"https://fiveable.me/anatomy-physiology"},{"@type":"ListItem","position":2,"name":"Key Terms","item":"https://fiveable.me/anatomy-physiology/key-terms"},{"@type":"ListItem","position":3,"name":"Unit 13","item":"https://fiveable.me/anatomy-physiology/unit-13"},{"@type":"ListItem","position":4,"name":"posterior spinal arteries"}]}]}
```