GENERAL INFORMATION
The lateral neck muscles, primarily comprising the sternocleidomastoid and the scalene group (anterior, middle, and posterior scalenes), play pivotal roles in the movement and stabilisation of the cervical spine. Lateral neck muscles facilitate various head movements, including rotation, flexion, and lateral bending, contributing significantly to neck mobility and posture. Vital for both dynamic actions and static postures. Lateral neck muscles are engaged during everyday activities such as turning the head, looking up, and even breathing, as they assist in rib elevation during respiratory efforts.
ORIGIN
The origin of Lateral neck muscles is as follows:
- Sternocleidomastoid: Originates from the manubrium of the sternum and the medial portion of the clavicle.
- Scalenes: The anterior scalene originates from the transverse processes of the third to sixth cervical vertebrae. Meanwhile, the middle scalene arises from the second to seventh cervical vertebrae and the posterior scalene. On the other hand, originates from the sixth and seventh cervical vertebrae.
INSERTION POINT
- Sternocleidomastoid: Inserts at the mastoid process of the temporal bone and the lateral portion of the superior nuchal line.
- Scalenes: The anterior scalene inserts on the scalene tubercle of the first rib, while the middle scalene also attaches to the first rib. In contrast, the posterior scalene inserts on the second rib.
MAJOR ARTERIES
- Sternocleidomastoid: Supplied primarily by the occipital artery and branches of the external carotid artery.
- Scalenes: Receive blood supply from branches of the thyrocervical trunk.
NEURAL INNERVATION
- Sternocleidomastoid: Innervated by the accessory nerve (cranial nerve XI) and cervical spinal nerves (C2, C3).
- Scalenes: Innervated by the cervical spinal nerves (C3 to C8).
TRIGGER POINT
Trigger points in lateral neck muscles can cause referred pain, often leading to headaches, neck stiffness, and even symptoms that mimic conditions like carpal tunnel syndrome due to nerve entrapment.
CONCENTRIC FUNCTION
- Sternocleidomastoid: Facilitates rotation of the head to the opposite side and flexes the neck or elevates the chin.
- Scalenes: Elevate the ribs during forced inhalation and assist in lateral flexion of the neck.
ECCENTRIC FUNCTION
Lateral neck muscles control the slow lowering of the head back to the neutral position and stabilise the neck during movement, preventing jerky or uncontrolled motions.
ISOMETRIC FUNCTION
They maintain head and neck posture, particularly in static positions, supporting the cervical spine against gravitational forces and other loads.
RELATED MUSCLE-SCIENTIFIC NAMES
- Levator Scapulae
- Trapezius
- Platysma
ANTAGONIST
- Trapezius (lower fibers)
- Splenius Capitis
- Splenius Cervicis
COMMON INJURIES
- Muscle Strain: Common in lateral neck muscles due to their constant use in neck movements and posture maintenance, leading to pain and reduced mobility.
- Whiplash: Resulting from sudden movements, typically in accidents, causing severe muscle stretching or tears.
EXERCISES
- Neck Rotation Exercise: Turn the head slowly from side to side to engage and strengthen the sternocleidomastoid and scalenes.
- Shoulder Shrugs: Elevate the shoulders towards the ears to activate the upper trapezius and levator scapulae synergistically with the neck muscles.
- Upright Rows: Perform with dumbbells or a barbell to enhance scapular retraction and neck muscle engagement.
- Resistance Band Pull-Aparts: Use a band held in front of you at neck height, and pull the band outward to strengthen the shoulder and neck area.
- Platysma Stretch Exercise: Frequently contract the platysma muscle by pulling the lips back against the teeth and opening the mouth slightly.
STRETCHES
- Lateral Neck Stretch: Tilt the head to the side to stretch the sternocleidomastoid and relieve tension.
- Neck Flexion Stretch: Gently pull the head forward, lowering the chin to the chest to stretch the back of the neck.
- Diagonal Neck Stretch: Combine lateral and forward bending to stretch different fibres of the neck muscles.
- Overhead Arm Stretch: Raise one arm overhead and lean to the opposite side to stretch the lateral neck and upper shoulder area.
- Yoga Poses For Neck Relief: Engage in yoga poses such as “Cow Face” that stretch and relieve tension in the neck and upper shoulders.
