---
title: "Scalene Muscles | Anatomy and Physiology I"
description: "Scalene muscles are three neck muscles that run from the cervical vertebrae to the ribs, helping move the neck and assist breathing in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/scalene-muscles"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 11"
---

# Scalene Muscles | Anatomy and Physiology I

## Definition

Scalene muscles are three pairs of muscles on each side of the neck that run from the cervical vertebrae to the first two ribs. In Anatomy and Physiology I, they are studied as neck movers and accessory muscles of respiration.

## What It Is

Scalene muscles are a trio of paired neck muscles in Anatomy and Physiology I: the anterior, middle, and posterior scalenes. They sit deep in the side of the neck and connect the cervical vertebrae to the first rib and, in some cases, the second rib.

Their job is split between movement and support. When both sides contract together, they help flex the neck forward. When one side contracts, they can bend the neck to the same side and contribute to a little rotation. Because they are deep and anchored to the ribs, they also help steady the neck during head and upper-body movement.

The scalenes matter for breathing too. They are not the main muscles of respiration, but they can lift the first two ribs during forced inhalation. That extra rib lift gives the lungs a bit more room, which is useful when you are exercising, struggling to breathe, or taking a deep breath.

A common way A&P classes cover the scalenes is by pairing anatomy with function. You may be asked to identify where they attach, name the three scalene muscles, or explain why they count as accessory muscles of respiration. That means you need both the location and the action, not just a memorized label.

They also show how body systems overlap. The cervical vertebrae provide the bony origin, the neck muscles create movement, and the ribs become part of the breathing mechanism. That connection makes the scalenes a good example of how skeletal landmarks and muscle actions work together in the neck and thorax.

## Why It Matters

Scalene muscles matter because they connect neck anatomy to both movement and breathing, which is exactly the kind of structure-function link Anatomy and Physiology I asks you to make. If you can trace where the scalenes attach and what they pull on, you can explain why a muscle in the neck can affect the ribs and chest.

They also show up in the axial muscle unit as part of the deeper muscles of the head, neck, and back. That helps you place them correctly on diagrams instead of confusing them with surface neck muscles. On labeling activities, you often need to identify the muscle group by location, especially because the scalenes sit close to other neck structures.

The scalenes are useful for understanding accessory respiration. When the body needs extra airflow, muscles that usually stabilize or move other parts can help lift the rib cage. That idea shows up in questions about forced inhalation, exercise, or respiratory effort.

They are also a good reminder that one muscle can have more than one action. In A&P, that kind of multi-tasking is common, so learning the scalenes helps you read muscle names as systems of attachment and motion, not just vocabulary words.

## Connections

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

The scalenes attach to the cervical vertebrae, so these bones are the fixed starting points for their contractions. If you know the cervical vertebrae, you can make sense of why the scalenes sit in the side of the neck and how they can bend or stabilize that region.

### Respiration

Scalene muscles are accessory muscles of respiration, which means they help during deeper or more forceful inhalation. They lift the first and second ribs, increasing thoracic volume a little. That makes them different from the diaphragm, which does the main work of quiet breathing.

### Axial Muscles

The scalenes are part of the axial muscle system because they act on the head, neck, and trunk rather than the limbs. In this unit, they help show how axial muscles support posture, movement, and breathing all at once.

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

The anterior scalene is one of the three scalenes, so it is the most specific name inside the broader muscle group. It is often mentioned separately because it has its own attachments and can be easier to identify on diagrams than the whole scalene set.

## On the AP Exam

A labeling question may ask you to find the scalenes on a neck or thorax diagram and connect them to the cervical vertebrae and first ribs. A short-answer item might give you a movement or breathing scenario and ask which muscles assist with it, especially during forced inhalation. In muscle charts, you may need to match the scalenes with the actions of neck flexion, lateral flexion, or rib elevation. If a lab practical uses models or cadaver images, look for the deep, side-of-neck position rather than the larger superficial neck muscles. The usual trap is remembering only that they are in the neck and missing their role in respiration, or vice versa.

## Key Takeaways

- Scalene muscles are a group of three paired muscles on each side of the neck: anterior, middle, and posterior.
- They run from the cervical vertebrae to the first two ribs, which is why they can affect both neck motion and rib movement.
- Their main roles are neck stabilization, neck flexion or side-bending, and assistance with forced inhalation.
- In Anatomy and Physiology I, they are a good example of an axial muscle that links skeletal landmarks to movement.
- If you can identify their attachments, you can usually explain their actions without memorizing extra facts.

## FAQs

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

Scalene muscles are three paired neck muscles that attach the cervical vertebrae to the first two ribs. In A&P, you learn them as deep axial muscles that move and stabilize the neck and help lift the ribs during forced breathing.

### Where are the scalene muscles located?

They are located deep on the side of the neck, between the cervical vertebrae and the upper ribs. Because of that position, they sit under or near other neck muscles and are often easier to identify on diagrams than in a surface view.

### Do the scalene muscles help with breathing?

Yes. They are accessory muscles of respiration, so they help mainly during deep or forceful inhalation. By lifting the first and second ribs, they create a little more space in the chest for air to enter.

### Are the scalenes part of the axial muscles?

Yes, they are part of the axial muscle group because they act on the head, neck, and trunk. This is a common place students connect muscle location with function, since axial muscles are tied to posture, breathing, and movement of the central body.

## 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

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- [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`)
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