Section 01 of 20
Introduction
Posterior scalene is the smallest and most posterior of the three scalene muscles. It runs down the side of the neck from the lower cervical vertebrae to the outer surface of the second rib, behind the middle scalene and deep to the trapezius and levator scapulae.
Sometimes it is partly fused with the middle scalene. The brachial plexus and the subclavian artery pass between the anterior and middle scalenes, in front of the posterior scalene, which is why the scalene group is discussed in relation to arm symptoms.
Section 02 of 20
Origin
| Origin | The posterior tubercles of the transverse processes of the lower cervical vertebrae, typically C4–C6 (some sources list C5–C7). |
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An anatomical image for this section will be added when verified source media becomes available.
Section 03 of 20
Insertion
| Insertion | The outer surface of the second rib, behind the attachment of serratus anterior (sometimes reaching the third rib). |
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An anatomical image for this section will be added when verified source media becomes available.
Section 04 of 20
Actions
No dedicated action video is currently available. This movement is explained below and video will be added when verified source media becomes available.
| Primary action | Elevation of the second rib during inspiration. |
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| Secondary actions | Lateral flexion of the neck to the same side and neck stabilization. |
| Movement at the joint | Cervical spine and the second costovertebral joints. |
| Heads / fiber groups | Single small muscle, sometimes fused with the middle scalene. |
| Functional examples | Deep breathing; tilting the head toward the shoulder; carrying a load; reaching. |
Elevation of the second rib
Raises the second rib during inspiration (accessory breathing muscle).
Lateral flexion of the neck
One side bends the neck to that side.
Neck stabilization
Helps steady the cervical spine during head and arm movement.
Section 05 of 20
Nerve Innervation
| Nerve | Anterior (ventral) rami of the lower cervical nerves, roughly C6–C8 (sources vary slightly). |
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The lower trunks of the brachial plexus lie close to the front of this muscle, and the long thoracic and dorsal scapular nerves pass through the scalene group. Numbness, tingling, or weakness in the arm or hand may reflect nerve or vascular involvement, not only muscle tightness.
Section 06 of 20
Blood Supply
| Blood | The ascending cervical artery, the transverse cervical artery, and the deep cervical artery. |
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Section 07 of 20
Pictures and Visual Anatomy
An anatomical image for this section will be added when verified source media becomes available.
Section 08 of 20
Functional Movement
Posterior scalene works with every deep breath, particularly during exercise or labored breathing, and when tilting the head toward the shoulder. It also stabilizes the neck when carrying a load or reaching.
Section 09 of 20
Synergists and Antagonists
Synergists: the anterior and middle scalenes, sternocleidomastoid, and levator scapulae (lateral flexion and rib elevation), and the diaphragm and intercostals in breathing. Antagonists: the opposite-side scalenes and lateral neck muscles (lateral flexion), and the muscles that lower the ribs (such as the internal intercostals and abdominal muscles).
Section 10 of 20
Palpation and Location
Client position and technique
Position the client supine with the head neutral and supported. Locate the posterior border of the sternocleidomastoid and the anterior border of the upper trapezius, and slide the fingers into the soft tissue between them in the lower neck, above the clavicle and behind the middle scalene. Ask for a slow deep breath in to feel the muscle tighten and rise slightly.
Protect nearby structures
The brachial plexus, the subclavian artery, and the lung apex are nearby. Use light, slow, flat-finger pressure, avoid pinching or pressing deeply, and never press against a pulse. Stop if the client reports tingling, numbness, arm pain, dizziness, or cough.
Section 11 of 20
Massage Therapy Relevance
Tension in the posterior scalene may be associated with neck and shoulder tightness, breathing pattern problems, and pain that spreads toward the shoulder blade and the back of the arm. Many other conditions can produce the same symptoms, so careful screening matters.
Section 12 of 20
Dysfunction: What Happens When Movement Goes Wrong
Changes in how a muscle works can change how a joint moves. The points below describe possibilities that may be associated with altered muscle function; they are not diagnoses, and one muscle is never assumed to be the sole cause of a problem.
When the muscle is weak
Weakness may reduce lateral neck stability and may be associated with more work by sternocleidomastoid and the upper trapezius.
When it is tight or shortened
Tightness may be associated with limited neck side-bending, an elevated upper rib, and neck and shoulder tension.
When it is overused
Upper-chest breathing, sustained forward head posture, and carrying loads may overload the muscle and may contribute to neck and shoulder ache.
When it is strained
A strain may cause sharp pain at the side of the neck with side-bending or deep breathing; cervical spine problems can look similar.
When it is inhibited or others compensate
Reduced activation may be associated with poor neck stability and more work by superficial neck muscles.
When it does not coordinate well with synergists and antagonists
Poor coordination with the other scalenes and the diaphragm may alter breathing mechanics and may be associated with neck and chest symptoms.
Section 13 of 20
Conditions, Pathologies, and Pain Relationships
Scalene tightness and neck pain
Sustained head-forward posture and upper-chest breathing may keep the scalenes under load and may be associated with neck and shoulder pain.
Thoracic outlet syndrome
Crowding of the space around the scalenes and the first rib may be associated with arm pain, tingling, or heaviness; this needs assessment and referral.
Trigger point referral
Tender points in the scalene group may refer pain to the chest, upper back, shoulder blade, and back of the arm, and sometimes to the hand.
Differential considerations
Cervical radiculopathy, carpal or cubital tunnel syndrome, heart and lung problems, and shoulder disorders can all cause neck, chest, and arm pain.
Section 14 of 20
Example Clinical Relationship
A client who breathes mainly into the upper chest reports neck tension and an ache along the back of the shoulder blade and upper arm after long computer sessions. The scalenes, including posterior scalene, may be involved, and the pattern may be associated with scalene tension, but nerve root and thoracic outlet problems can look similar. Light, gentle work may support comfort, while a cold or discolored arm, worsening weakness, or chest pain needs referral.
Section 15 of 20
Massage and Treatment Approaches
For healthy, non-acute tissue, position the client supine with the head supported and the neck relaxed. Use very light effleurage over the side of the neck, then gentle, slow kneading and light static pressure, working with the client's breathing and within comfort.
| Movement | Use gentle neck side-bending and breathing work within comfort; do not force stretch. |
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| Regional work | Consider the middle and anterior scalenes, sternocleidomastoid, levator scapulae, upper trapezius, and pectoralis minor when assessment supports it. |
| Avoid | Deep or sustained pressure on the lower side of the neck, the area above the clavicle, or any point that reproduces arm tingling. |
Section 16 of 20
Precautions and Contraindications
Precautions and contraindications
- Recent neck injury or whiplash, suspected fracture, or instability.
- Use caution with known thoracic outlet syndrome, cervical rib, carotid or subclavian artery disease, or anticoagulant use.
- Avoid deep pressure on the lower lateral neck and above the clavicle.
- Stop if pressure causes dizziness, arm numbness, tingling, or shortness of breath.
Section 17 of 20
Red Flags and When to Refer
Red flags and referral
- Sudden severe neck pain or headache, dizziness, vision changes, slurred speech, or facial numbness.
- Chest pain, shortness of breath, or pain that spreads to the jaw or left arm.
- A pale, cold, swollen, or discolored arm or hand, or arm weakness that is getting worse.
- Neck pain with fever, stiffness, or unexplained weight loss.
Section 18 of 20
Study Summary
Attachments
Origin: posterior tubercles of C4–C6 transverse processes. Insertion: outer surface of the second rib.
Actions
Elevates the second rib; side-bends and stabilizes the neck.
Supply
Anterior rami of C6–C8; ascending cervical, transverse cervical, and deep cervical arteries.
Section 19 of 20
Instructor Narration
Open narration transcript
Posterior scalene is the smallest and most posterior of the scalene muscles, running from the lower neck to the second rib.
It arises from the posterior tubercles of the lower cervical transverse processes and inserts on the outer surface of the second rib.
It raises the second rib during breathing and bends the neck to the same side. The other scalenes and sternocleidomastoid help it, and the opposite-side neck muscles oppose it.
The anterior rami of the lower cervical nerves supply it, and the ascending cervical, transverse cervical, and deep cervical arteries provide its blood.
Palpate in the lower side of the neck between sternocleidomastoid and upper trapezius, with a slow inhalation. Use light pressure only, because the brachial plexus and subclavian artery are close.
Neck pain, thoracic outlet symptoms, and trigger point referral can overlap with radiculopathy and heart or lung problems. Refer sudden severe neck pain, dizziness, chest pain, a cold or discolored arm, or worsening weakness.
Remember: C4 to C6 posterior tubercles to the second rib; second rib elevation and side-bending; anterior rami C6 to C8.
Section 20 of 20