Section 01 of 20
Introduction
Middle scalene is the largest and longest of the three scalene muscles. It runs from the cervical vertebrae down to the first rib, behind the anterior scalene, and lies deep to sternocleidomastoid and the lower part of the neck.
The gap between the anterior and middle scalenes, the interscalene triangle, is a narrow passage for the brachial plexus and the subclavian artery, which is why scalene tension is discussed in relation to arm symptoms.
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Origin
| Origin | Posterior tubercles of the transverse processes of the cervical vertebrae C2–C7. |
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Section 03 of 20
Insertion
| Insertion | Upper surface of the first rib, behind the groove for the subclavian artery. |
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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 first rib during inspiration. |
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| Secondary actions | Lateral flexion of the neck to the same side, and neck flexion with both sides. |
| Movement at the joint | Cervical spine and the first costovertebral joints. |
| Heads / fiber groups | Single muscle with slips from C2–C7. |
| Functional examples | Deep breathing; looking to the side; carrying a heavy bag; laboured breathing during exercise. |
Elevation of the first rib
Raises the first rib during inspiration (accessory breathing muscle).
Lateral flexion of the neck
Bends the neck to the same side when one side works.
Neck flexion and stabilization
Both sides together help flex the neck and stabilize the cervical spine.
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Nerve Innervation
| Nerve | Anterior (ventral) rami of the cervical spinal nerves, roughly C3–C8 (sources vary slightly). |
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The long thoracic nerve passes through the muscle, and the brachial plexus emerges beside it. Numbness, tingling, or weakness in the arm or hand may reflect nerve or vascular involvement, not only muscle tightness.
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Blood Supply
| Blood | Ascending cervical artery (from the inferior thyroid artery), with branches from the deep cervical and transverse cervical arteries. |
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Pictures and Visual Anatomy
Section 08 of 20
Functional Movement
Middle scalene works with every breath, especially deep or labored breathing, and with side-bending the head. It is active when looking to the side, carrying a heavy bag, and in heavy breathing during exercise.
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Synergists and Antagonists
Synergists: anterior and posterior scalenes (rib elevation and side-bending), sternocleidomastoid, and levator scapulae (lateral flexion). Antagonists: the opposite-side scalenes and lateral neck muscles (lateral flexion), and the neck extensors (flexion).
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Palpation and Location
Client position and technique
Position the client supine with the head neutral and supported. Find the posterior border of sternocleidomastoid and slide just behind it, above the clavicle, to reach the scalenes. Ask the client to take a slow, deep breath in to feel the muscle tighten, and follow it upward toward the transverse processes.
Protect nearby structures
The brachial plexus, subclavian artery, carotid artery, phrenic nerve, and lung apex are close. Use light, slow, flat-finger pressure, avoid pinching or pressing deeply, and stop if the client reports tingling, numbness, arm pain, dizziness, or cough.
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Massage Therapy Relevance
Because the scalenes lift the first rib and border the brachial plexus, they are commonly considered in neck pain, breathing pattern problems, and thoracic outlet complaints. Many other conditions can cause the same symptoms, so careful screening matters.
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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 strength 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 first 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 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.
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Conditions, Pathologies, and Pain Relationships
Scalene tightness and neck pain
Sustained forward head posture and upper-chest breathing may keep the scalenes under load and may be associated with neck and shoulder pain.
Thoracic outlet syndrome
Crowding at the interscalene triangle or first rib may be associated with arm pain, tingling, or heaviness; this needs assessment and referral.
Trigger point referral
Trigger points may refer pain to the chest, upper back, shoulder blade, and arm, and sometimes the thumb side of the hand.
Differential considerations
Cervical radiculopathy, carpal tunnel syndrome, heart and lung problems, and shoulder disorders can all cause neck, chest, and arm pain.
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Example Clinical Relationship
A client who breathes mainly into the upper chest reports neck tightness and an ache down the outside of the arm after long computer sessions. The scalenes may be involved, and the pattern may be associated with scalene tension, but cervical nerve root problems and thoracic outlet syndrome can look similar. Light, gentle work may support comfort, while a cold or discolored arm, worsening weakness, or chest pain needs referral.
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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 lateral 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 in comfortable range; do not force stretch. |
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| Regional work | Consider sternocleidomastoid, the anterior and posterior scalenes, levator scapulae, upper trapezius, and pectoralis minor when assessment supports it. |
| Avoid | Deep pressure on the front and side of the neck, the interscalene groove, or any point that reproduces arm tingling. |
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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 vertebral artery disease, or anticoagulant use.
- Avoid sustained or deep pressure on the anterior and lateral neck.
- Stop if pressure causes dizziness, arm numbness, tingling, or shortness of breath.
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Red Flags and When to Refer
Red flags and referral
- Sudden severe headache or neck pain, 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.
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Study Summary
Attachments
Origin: posterior tubercles of the C2–C7 transverse processes. Insertion: upper surface of the first rib.
Actions
Elevates the first rib; side-bends and stabilizes the neck.
Supply
Anterior rami of C3–C8; ascending cervical artery.
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Instructor Narration
Open narration transcript
Middle scalene is the largest and longest of the scalene muscles. It runs from the cervical vertebrae to the first rib.
It arises from the posterior tubercles of the transverse processes of C2 to C7 and inserts on the upper surface of the first rib.
It raises the first rib during breathing, bends the neck to the same side, and stabilizes the neck. The other scalenes and sternocleidomastoid help it, and the opposite-side neck muscles oppose it.
The anterior rami of the cervical nerves supply it, roughly C3 to C8, and the ascending cervical artery provides its blood.
Palpate just behind sternocleidomastoid above the clavicle, 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: C2 to C7 posterior tubercles to the first rib; first rib elevation and side-bending; cervical anterior rami.
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