04/26/2026
Neck/Shoulder Muscle Anatomy 🙌🏻
Trapezius-
Origin: Superior nuchal line and external occipital protuberance (for upper fibers), nuchal ligament along C1-6 and the spinous processes of C7-T3 (for middle fibers), and spinous processes of T4-12 (for lower fibers).
Insertion: Postero-lateral third of the clavicle (for upper fibers), medial acromial margin and the superior crest of the scapular spine (for middle fibers), and the lateral aspect of the medial scapular spine (for lower fibers).
Function: Head and cervical spine extension, rotation of the head and neck (the right upper traps turns the head to the left when it contracts, and the left rotates the head to the right), elevation of the shoulder girdle, and upward rotation of the scapulae
Levator scapulae-
Origin: Transverse processes of C1-4.
Insertion: Superior angle to the root of the scapular spine.
Function: Cervical spine extension, rotation of the neck (the right levator scapulae muscle rotates the neck to the right, the left rotates it to the left), elevation and downward rotation of the scapula.
Splenius Capitis-
Origin: Spinous processes of C7-T3 and the nuchal ligament.
Insertion: Lateral superior nuchal line and the mastoid process.
Function: Extension of the head and neck, as well as lateral flexion and rotation of the head and neck when contracted unilaterally (the right splenius capitis rotates the head and neck to the right while the left muscle rotates the head and neck to the left.