---
title: "Posterior Scalene | Anatomy and Physiology I"
description: "Posterior scalene is a neck muscle that elevates the second rib and helps with lateral bending, a common landmark in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/posterior-scalene"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 11"
---

# Posterior Scalene | Anatomy and Physiology I

## Definition

The posterior scalene is a deep neck muscle that runs from the cervical vertebrae to the second rib. In Anatomy and Physiology I, you study it as a muscle that helps elevate the rib during breathing and assists with neck lateral bending.

## What It Is

The posterior scalene is one of the deep muscles on the side of the neck in Anatomy and Physiology I. It attaches from the cervical vertebrae to the second rib, so it crosses from the neck into the upper thorax instead of staying only in the neck region.

Because of that attachment pattern, its main action is to elevate the second rib during respiration. That matters most during forceful inhalation, when accessory muscles help lift the rib cage and increase the space inside the thorax. The posterior scalene does not do the whole job of breathing by itself, but it contributes to the extra lift your body uses when demand for oxygen increases.

You also need to know its movement at the neck. When the muscle contracts on one side, it helps with lateral bending, which means tipping the head toward that same side. That makes it part of the group of cervical muscles that can stabilize and move the neck, especially during small postural adjustments.

In lab or diagram study, the posterior scalene is usually identified by where it sits relative to the other scalene muscles. It is the most posterior of the scalene group, lying behind the anterior scalene. Since these muscles are deep and narrow, they are often easier to learn by their attachments and actions than by trying to picture them as a surface shape.

A useful way to think about it is this: if a muscle attaches to a rib, it often influences breathing as well as posture. The posterior scalene is a good example because it links neck anatomy to thoracic mechanics. That connection is a big theme in Anatomy and Physiology I, where structure and function are always tied together.

## Why It Matters

The posterior scalene shows how one small muscle can connect two systems you study all the time in Anatomy and Physiology I: the muscular system and the respiratory system. Instead of thinking of breathing as only a lung process, this muscle reminds you that the rib cage and neck muscles help change thoracic volume during inhalation.

It also helps you build a clearer map of the neck. The scalene muscles are often learned as a group, and the posterior scalene gives you a reference point for identifying nearby muscles and their actions. If you know where it attaches, you can reason through what it moves and why it matters for posture or breathing.

This term also shows up in questions that ask you to match muscle names with actions. If you can connect posterior scalene to the second rib and lateral bending, you can handle diagram labels, muscle action tables, and short-answer prompts more confidently. It is a small term, but it fits into a bigger pattern of how muscles create movement through their attachments.

## Connections

### [Cervical Vertebrae](/anatomy-physiology/key-terms/cervical-vertebrae)

The posterior scalene begins on the cervical vertebrae, so you need the neck bones to locate it correctly. Knowing the vertebral region helps you understand why the muscle sits deep in the side of the neck and why it can affect head and neck movement. It is also a good reminder that muscle action depends on where the origin and insertion are placed.

### Respiration

The posterior scalene assists respiration by elevating the second rib. That makes it part of the accessory muscle set that becomes more noticeable during deeper or more forceful breathing. In A&P, this connects skeletal muscle anatomy to the mechanics of thoracic expansion and shows that breathing is not only a diaphragm story.

### Lateral Bending

One action of the posterior scalene is lateral bending of the neck, which means the head tilts toward the same side. This is the movement to picture when you compare neck muscles that stabilize or flex the cervical region. It is a useful action term because many neck muscles are tested by motion rather than by appearance alone.

### [anterior scalene](/anatomy-physiology/key-terms/anterior-scalene)

The posterior scalene is easier to remember when you compare it with the anterior scalene. Both are deep neck muscles and both help with rib elevation and neck movement, but they sit in different positions in the scalene group. If you mix them up, check the anatomy by location first, then by attachment and action.

## On the AP Exam

A labeled anatomy quiz may ask you to identify the posterior scalene on a neck diagram, name its attachment to the second rib, or match it with its role in inhalation. In muscle action questions, you may need to say that it helps elevate the second rib and assist lateral bending of the neck. If the item compares neck muscles, look for how it differs from the anterior scalene by position. In lab practicals, the quickest move is to trace the muscle from cervical vertebrae to rib and then state what that attachment means for movement.

## posterior scalene vs anterior scalene

These are commonly confused because both are deep cervical muscles in the scalene group and both help with neck movement and rib elevation. The posterior scalene sits behind the anterior scalene and attaches to the second rib, while the anterior scalene is more anterior in the neck and is usually emphasized for its attachment to the first rib. When you are labeling diagrams, position is the fastest way to separate them.

## Key Takeaways

- The posterior scalene is a deep neck muscle that runs from the cervical vertebrae to the second rib.
- Its main respiratory action is elevating the second rib, especially during deeper inhalation.
- It also assists with lateral bending of the neck on the same side where it contracts.
- In Anatomy and Physiology I, it is best learned as part of the scalene group and as a bridge between neck motion and breathing mechanics.
- If you can locate its attachments, you can usually reason out its action on both the neck and rib cage.

## FAQs

### What is posterior scalene in Anatomy and Physiology I?

The posterior scalene is a deep muscle on the side of the neck. It runs from the cervical vertebrae to the second rib and helps with neck lateral bending and rib elevation during breathing.

### What does the posterior scalene do?

It elevates the second rib, which helps during inhalation, especially when breathing becomes deeper or more forceful. It also assists with lateral bending of the neck to the same side.

### How is the posterior scalene different from the anterior scalene?

Both are neck muscles in the scalene group, but the posterior scalene sits farther back and is associated with the second rib. The anterior scalene is more anterior, so diagram questions often use position as the quickest clue.

### How do I remember the posterior scalene for lab practicals?

Start with its attachments: cervical vertebrae to second rib. Then connect that to its two big actions, neck lateral bending and assistance in respiration. If you remember that it is the back member of the scalene group, you can usually place it correctly on a model or chart.

## Related Study Guides

- [11.3 Axial Muscles of the Head, Neck, and Back ](/anatomy-physiology/unit-11/3-axial-muscles-head-neck/study-guide/T18iHjO6luAZ0pd7)

## 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-scalene#resource","name":"Posterior Scalene | Anatomy and Physiology I","url":"https://fiveable.me/anatomy-physiology/key-terms/posterior-scalene","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/anatomy-physiology/key-terms/posterior-scalene#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-scalene#term","name":"posterior scalene","description":"The posterior scalene is a deep neck muscle that runs from the cervical vertebrae to the second rib. In Anatomy and Physiology I, you study it as a muscle that helps elevate the rib during breathing and assists with neck lateral bending.","url":"https://fiveable.me/anatomy-physiology/key-terms/posterior-scalene","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 is posterior scalene in Anatomy and Physiology I?","acceptedAnswer":{"@type":"Answer","text":"The posterior scalene is a deep muscle on the side of the neck. It runs from the cervical vertebrae to the second rib and helps with neck lateral bending and rib elevation during breathing."}},{"@type":"Question","name":"What does the posterior scalene do?","acceptedAnswer":{"@type":"Answer","text":"It elevates the second rib, which helps during inhalation, especially when breathing becomes deeper or more forceful. It also assists with lateral bending of the neck to the same side."}},{"@type":"Question","name":"How is the posterior scalene different from the anterior scalene?","acceptedAnswer":{"@type":"Answer","text":"Both are neck muscles in the scalene group, but the posterior scalene sits farther back and is associated with the second rib. The anterior scalene is more anterior, so diagram questions often use position as the quickest clue."}},{"@type":"Question","name":"How do I remember the posterior scalene for lab practicals?","acceptedAnswer":{"@type":"Answer","text":"Start with its attachments: cervical vertebrae to second rib. Then connect that to its two big actions, neck lateral bending and assistance in respiration. If you remember that it is the back member of the scalene group, you can usually place it correctly on a model or chart."}}]},{"@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 11","item":"https://fiveable.me/anatomy-physiology/unit-11"},{"@type":"ListItem","position":4,"name":"posterior scalene"}]}]}
```