NECK MUSCLES

GENERAL INFORMATION

The neck muscles play a crucial role in stabilising and moving the head and neck, facilitating posture, breathing, and a range of head movements. They are essential for everyday activities like turning the head, nodding, and maintaining an upright posture. The major neck muscles also support the shoulders and help with respiration by elevating the ribs during breathing.

ORIGIN

• Sternocleidomastoid: Manubrium of the sternum and medial clavicle.
• Trapezius (upper fibres): External occipital protuberance and nuchal ligament.
• Scalenes: Transverse processes of C2-C7 vertebrae.
• Levator Scapulae: Transverse processes of C1-C4 vertebrae.
• Splenius Capitis: Spinous processes of C7-T3 vertebrae and ligamentum nuchae.

INSERTION POINT

• Sternocleidomastoid: Mastoid process of the temporal bone and superior nuchal line.
• Trapezius (upper fibres): Lateral third of the clavicle and acromion of the scapula.
• Scalenes: First and second ribs.
• Levator Scapulae: Superior part of the medial border of the scapula.
• Splenius Capitis: Mastoid process and lateral third of the superior nuchal line.

MAJOR ARTERIES

• External Carotid Artery: Supplies the sternocleidomastoid and other superficial neck muscles.
• Subclavian Artery: Supplies the scalene muscles and deeper neck structures.
• Transverse Cervical Artery: Supplies the trapezius and surrounding neck muscles.

NEURAL INNERVATION

• Sternocleidomastoid: Spinal accessory nerve (CN XI) and cervical plexus (C2-C3).
• Trapezius (upper fibres): Spinal accessory nerve (CN XI) and cervical plexus (C3-C4).
• Scalenes: Anterior rami of C3-C8 spinal nerves.
• Levator Scapulae: Dorsal scapular nerve (C5) and cervical nerves (C3-C4).
• Splenius Capitis: Posterior rami of cervical nerves (C3-C4).

TRIGGER POINT

Trigger points in the neck muscles, particularly in the sternocleidomastoid and upper trapezius, can cause referred pain to the head, jaw, and shoulders. These trigger points often result from poor posture, stress, or repetitive strain, leading to tension headaches and neck stiffness.

CONCENTRIC FUNCTION

• Sternocleidomastoid: Rotates the head to the opposite side and flexes the neck.
• Trapezius (upper fibres): Elevates the scapula and helps extend the neck.
• Scalenes: Elevates the first and second ribs during deep inhalation and flexes the neck laterally.
• Levator Scapulae: Elevates the scapula and assists in neck extension.
• Splenius Capitis: Extends and laterally flexes the neck, also aiding in head rotation.

ECCENTRIC FUNCTION

• Sternocleidomastoid: Controls head extension and lateral flexion, preventing excessive movement.
• Trapezius (upper fibres): Controls the lowering of the scapula during movements like lowering the shoulders.
• Scalenes: Controls rib depression and stabilises the neck during exhalation and side movements.
• Levator Scapulae: Controls downward movement of the scapula and helps stabilise the neck during flexion.
• Splenius Capitis: Regulates neck flexion, preventing sudden forward motion of the head.

ISOMETRIC FUNCTION

The neck muscles stabilise the head and neck during static positions, such as holding the head upright during prolonged sitting or standing. The sternocleidomastoid and trapezius work together to maintain neck and shoulder alignment during isometric contractions, such as when resisting external forces or carrying weight on the shoulders.

RELATED MUSCLE – SCIENTIFIC NAMES

• Longus Colli: Assists in neck flexion and stabilisation.
• Rhomboids: Assists in scapular movement and stabilisation.
• Suboccipital Muscles: Help in fine head movements and stabilisation.
• Platysma: Involved in facial expressions and neck tension.
• Omohyoid: Stabilises the hyoid bone and aids in neck movement.

ANTAGONIST

• Sternocleidomastoid: Opposes the trapezius by flexing the neck instead of extending it.
• Levator Scapulae: Works against the trapezius during scapular elevation and stabilisation.
• Scalenes: Opposes neck extensors like the splenius capitis by flexing the neck.
• Splenius Capitis: Opposes the sternocleidomastoid in head rotation and neck flexion.
• Trapezius (upper fibres): Opposes the levator scapulae by controlling scapular depression.

COMMON INJURIES:

• Neck Strain: Overstretching or tearing of neck muscles from sudden movements, causing pain, stiffness, and reduced range of motion.
• Tension Headaches: Often caused by trigger points in the sternocleidomastoid and upper trapezius, leading to pain radiating to the head.
• Whiplash: Neck sprain or strain caused by sudden acceleration-deceleration, leading to muscle damage, pain, and limited mobility.
• Cervical Radiculopathy: Compression of cervical nerves, often caused by tight scalenes or poor posture, leading to pain and tingling down the arm.
• Trapezius Myalgia: Chronic tension in the trapezius muscle, leading to pain and discomfort, particularly around the neck and shoulders.

EXERCISES

• Chin Tucks: Gently pull the chin towards the neck, strengthening the deep neck flexors and improving posture and neck alignment.
• Neck Extensions: While seated or standing, slowly extend the head backwards to engage the trapezius and splenius capitis, strengthening the neck extensors.
• Lateral Neck Flexion: Tilt the head sideways, bringing the ear towards the shoulder to strengthen the sternocleidomastoid and scalenes.
• Scapular Shrugs: Lift the shoulders upwards to engage the upper trapezius, enhancing neck and shoulder strength and stability.
• Isometric Neck Hold: Press the forehead into the hand while resisting movement, engaging the neck muscles to improve overall neck stability.

STRETCHES

• Levator Scapulae Stretch: Gently rotate and tilt the head towards the opposite side while pulling the shoulder down to stretch the levator scapulae.
• Upper Trapezius Stretch: Tilt the head to one side, using the hand to apply gentle pressure for a deeper stretch in the upper trapezius.
• Sternocleidomastoid Stretch: Rotate the head and gently tilt it backwards to stretch the SCM, reducing tightness and improving neck mobility.
• Scalene Stretch: Sit or stand, tilt the head to one side while pulling the opposite shoulder down, stretching the scalenes.
• Neck Rotation Stretch: Rotate the head gently from side to side, stretching the sternocleidomastoid and splenius capitis to improve neck flexibility.