GENERAL INFORMATION
The splenius capitis is a broad, strap-like muscle located in the back of the neck. Specifically, it is one of the deeper muscles of the neck, situated underneath the sternocleidomastoid. Consequently, it functions to extend, laterally flex, and rotate the head. Therefore, understanding its structure and function is essential for comprehending neck mechanics.
ORIGIN OF SPLENIUS CAPITIS
The splenius capitis originates from the lower half of the ligamentum nuchae (a ligament of the back of the neck) and the spinous processes of the seventh cervical and first three thoracic vertebrae. Therefore, it has a solid foundational attachment, ensuring its stability and effectiveness in movement.
INSERTION POINT
This muscle inserts into the mastoid process of the temporal bone and the lateral third of the superior nuchal line of the occipital bone, both in the skull. Thus, it connects crucial points in the head and neck region. As a result, it plays a significant role in head and neck movement.
MAJOR ARTERIES OF SPLENIUS CAPITIS
The splenius capitis is supplied by branches of the transverse cervical artery and occipital artery, which provide it with a rich blood supply for its functions. Consequently, these arteries ensure the muscle receives the necessary nutrients and oxygen.
NEURAL INNERVATION
The splenius capitis is innervated by the posterior rami of the middle and lower cervical spinal nerves, which play a crucial role in its activation and control. Therefore, proper nerve function is vital for the muscle’s performance.
TRIGGER POINT FOR SPLENIUS CAPITIS
Trigger points in the splenius capitis are typically found in the muscle belly, which is located in the back and side of the neck. These points can be stimulated through manual pressure or massage for relief. Hence, targeted therapy can alleviate discomfort and improve muscle function.
CONCENTRIC FUNCTION OF SPLENIUS CAPITIS
The splenius capitis is responsible for extending and rotating the head and neck. When both sides of the muscle act together, they extend the neck. Conversely, when only one side contracts, it bends the neck to the same side (lateral flexion) and rotates the head to the same side. Thus, it is integral to various head and neck movements.
ECCENTRIC FUNCTION
The splenius capitis controls the speed and direction of the head and neck during flexion and rotation to the opposite side. Consequently, it plays a critical role in maintaining head and neck stability during these movements and is essential for coordinated and controlled actions.
ISOMETRIC FUNCTION OF SPLENIUS CAPITIS
In an isometric contraction, the splenius capitis stabilises the head and neck during movements that involve the upper body. Therefore, it provides essential support during various activities and helps maintain proper posture and alignment.
RELATED MUSCLES (SCIENTIFIC NAMES)
- Splenius Cervicis: Works in conjunction with splenius capitis for neck rotation and extension.
- Semispinalis Capitis: Extends and rotates the head, synergistic to splenius capitis.
- Sternocleidomastoid: Contrasts by flexing the neck, providing dynamic neck movement.
- Upper Trapezius: Assists in neck extension and lateral neck movements.
- Levator Scapulae: Elevates and stabilises the scapula, indirectly supporting neck movements.
- Scalene Muscles (Anterior, Middle, Posterior): Aid in neck flexion and assist in respiratory function.
ANTAGONIST
- Sternocleidomastoid: Acts to flex the neck, opposing the extension caused by the splenius capitis.
- Scalene Muscles: These muscles facilitate neck flexion and lateral bending, opposing extension and rotation.
- Longus Colli: Primarily responsible for neck flexion, acting as a direct antagonist to neck extension.
COMMON INJURIES
- Whiplash: Sudden movement causing neck injury, often during vehicle accidents.
- Muscle strain: Due to poor posture or overuse, leading to pain and limited movement.
- Cervical radiculopathy: Nerve pain caused by pressure or nerve root irritation in the neck.
EXERCISES
- Neck Extension Exercises: Strengthen the splenius capitis by extending the head against resistance.
- Gentle Rotation Exercises: Enhance flexibility and reduce stiffness by rotating the neck gently.
- Shoulder Shrugs: Improve strength in neck and shoulder muscles, supporting the upper trapezius and neck.
- Chin Tucks: Promote better posture and alignment, strengthening the neck flexors.
- Isometric Neck Holds: Maintain a static position to strengthen muscles without moving the head.
STRETCHES
- Lateral Neck Stretch: Eases the splenius and trapezius muscles, improving lateral flexibility.
- Neck Rotation Stretch: Increases mobility and relieves tension in the neck muscles.
- Levator Scapulae Stretch: Specifically targets the levator scapulae, reducing upper neck and shoulder tension.
- Upper Trapezius Stretch: Stretches the trapezius, alleviating stress and aiding in neck and shoulder relaxation.
- Chin to Chest Stretch: Gently stretch the posterior neck muscles, promoting relaxation and flexibility.
Regular incorporation of these exercises and stretches can significantly improve neck strength, flexibility, and overall health, reducing the risk of injury and enhancing daily functionality.