GENERAL INFORMATION
The medius scalene, positioned deeply within the lateral neck, is one of the three scalene muscles. It plays a critical role in both cervical spine mobility and respiratory function. This medius scalene from the cervical vertebrae to the first rib facilitates lateral flexion of the neck, rotation, and acting as an accessory muscle of respiration. The medius scalene is pivotal for activities that require turning the head or lifting the chest during deep breaths. Due to its location and functions, it is often implicated in neck discomfort and respiratory complications when strained or overused.
ORIGIN
The medius scalene originates from the posterior tubercles of the transverse processes of the C2 to C7 cervical vertebrae. This broad origin provides a sturdy base for its powerful actions on the neck and thorax.
INSERTION POINT
It inserts onto the first rib, specifically on the scalene tubercle. Which lies posterior to the groove for the subclavian artery. This insertion is critical for its role in elevating the first rib during inhalation.
MAJOR ARTERIES
Blood supply to the Middle Scalene comes predominantly from the ascending cervical artery, which branches off the thyrocervical trunk, ensuring the muscle receives ample oxygenation and nutrients.
NEURAL INNERVATION
This muscle is innervated by the anterior rami of cervical spinal nerves C3 to C8, allowing for coordinated movements of the neck and effective participation in respiratory mechanics.
TRIGGER POINT
Trigger points in the medius scalene can cause symptoms including sharp pain in the neck, referred pain to the chest, and even tingling or numbness in the arms, often mistaken for thoracic outlet syndrome.
CONCENTRIC FUNCTION
When contracting concentrically, the medius scalene elevates the first rib, aiding in forced inhalation, and assists in bending the neck to the same side and rotating it to the opposite side.
ECCENTRIC FUNCTION
Eccentrically, it controls the lowering of the rib during exhalation and moderates neck movement back to a neutral position, contributing to smooth respiratory and cervical motions.
ISOMETRIC FUNCTION
Isometrically, the medius scalene stabilises the first rib and cervical vertebrae during activities that require static postures, supporting the neck and upper chest.
RELATED MUSCLE-SCIENTIFIC NAMES
- Anterior Scalene
- Posterior Scalene
- Sternocleidomastoid
ANTAGONIST
- Opposite Medius Scalene
- Sternocleidomastoid (during specific movements)
- Splenius muscles
COMMON INJURIES
- Muscle Strain: Typically caused by abrupt or excessive movements, leading to acute pain and restricted motion.
- Thoracic Outlet Syndrome: Pressure on the nerves or blood vessels in the neck and arm, causing pain, numbness, or tingling in the upper limb.
EXERCISES
- Neck Side Bends: Tilt the head sideways towards the shoulder to engage and strengthen the medius scalene.
- Scalene Stretch With Arm Elevation: Lift the arm on the side being stretched to increase the effectiveness of the exercise.
- First Rib Mobilisation: Use gentle stretches combined with deep breathing to mobilise the first rib and activate the scalene muscles.
- Cervical Rotation With Resistance: Rotate the head against mild resistance to enhance the strength and flexibility of the neck muscles.
- Breathing Exercises: Practice deep breathing while consciously relaxing the neck to improve respiratory function and muscle activation.
STRETCHES
- Scalene Stretch: Gently pull the head toward the opposite shoulder to effectively stretch the medius scalene.
- Cross-Body Neck Stretch: Extend the neck diagonally across the body to target the muscle from different angles.
- First Rib Release Stretch: Use a foam roller or therapist’s hand to apply gentle pressure on the first rib, easing tension in the scalenes.
- Overhead Arm Reach: While leaning to the side, extend the arm overhead to deepen the stretch in the neck and thoracic area.
- Yoga Neck Stretches: Engage in yoga positions that focus on lateral neck flexibility, such as “Extended Triangle Pose,” to relax and stretch the neck muscles.
