The neck contains more than 20 paired muscles organized into three main groups: anterior (front), lateral (side), and posterior (back). These muscles work together to move your head in every direction, stabilize your spine, assist with breathing, and control swallowing and speech. Here’s a breakdown of each group and what the individual muscles do.
The Two Muscles You Can See and Feel
The sternocleidomastoid (SCM) and the trapezius are the most prominent neck muscles and the ones most people can identify by touch. The SCM runs from your breastbone and collarbone up to the bony bump behind your ear. When both sides contract together, they flex your neck forward. When only one side fires, it tilts your head toward that shoulder while rotating your face to the opposite side. The SCM also helps with forced breathing by lifting the chest.
The trapezius is the large, kite-shaped muscle spanning the back of your neck, shoulders, and upper back. Its upper fibers work with the SCM to stabilize your head during everyday activities like talking and chewing, and to bend the neck sideways. Together, these two muscles also divide the neck into its two major anatomical landmarks: the anterior triangle (in front of the SCM) and the posterior triangle (bordered by the SCM in front, the trapezius in back, and the collarbone below).
The platysma sits just beneath the skin on the front of the neck. It’s a thin, sheet-like muscle that extends from the chest up to the jawline. You can see it tense when someone grimaces or pulls the corners of their mouth downward.
Hyoid Muscles: The Swallowing Group
A small U-shaped bone called the hyoid sits in the front of your neck, roughly at the level of your chin. Eight muscles attach to it, split into two sets based on whether they sit above or below the bone. Together, these muscles control swallowing, speech, and the movement of your voice box.
The four suprahyoid muscles (above the hyoid) are the digastric, mylohyoid, geniohyoid, and stylohyoid. They pull the hyoid bone upward and forward, which is the motion that opens your throat when you swallow. They also help open the jaw.
The four infrahyoid muscles (below the hyoid) are the sternohyoid, sternothyroid, thyrohyoid, and omohyoid. These connect the hyoid bone to the sternum, voice box, and shoulder blade, and they pull the hyoid downward after swallowing to reset its position. The sternothyroid is unique in this group because it attaches to the thyroid cartilage rather than directly to the hyoid bone, but it still helps control the hyoid’s movement indirectly through the thyrohyoid.
Scalene Muscles: The Lateral Group
Three muscles run along each side of the neck between the spine and the first two ribs. The anterior scalene and middle scalene both attach to the first rib, while the posterior scalene attaches to the second rib. All three bend the neck toward the same side when they contract. They also serve as accessory breathing muscles: the anterior and middle scalenes elevate the first rib, and the posterior scalene elevates the second rib, expanding the upper chest during a deep breath.
Deep Cervical Flexors
Pressed directly against the front of the cervical spine are the longus capitis and longus colli, often called the deep cervical flexors. The longus capitis runs from the base of the skull down to the middle cervical vertebrae and flexes the head. The longus colli is more complex, with three separate portions spanning from the upper cervical spine down to the upper thoracic spine, and it flexes the neck itself.
Despite being commonly described as spinal stabilizers, research from a fascicular anatomy study found that these muscles actually produce relatively small compression forces, suggesting their ability to stabilize the cervical spine through brute force is limited. They likely contribute more to fine positional control than to heavy structural support.
Posterior Neck Muscles
The back of the neck has three layers of muscle stacked from surface to spine.
Superficial Layer
Below the trapezius sit the splenius capitis and splenius cervicis. The splenius capitis originates from the lower half of a tough ligament running down the back of the neck and from the spinous processes of vertebrae C7 through T3. When both sides contract, they extend your head backward. When one side contracts alone, it works with the opposite SCM to rotate and tilt the head to the same side. The splenius cervicis performs a similar role but acts more on the neck than the skull.
Deep and Deepest Layers
The deep layer includes the semispinalis capitis, semispinalis cervicis, and multifidus cervicis. These muscles run between vertebrae and help with extension and rotation of the head and neck, providing more segmental control than the larger superficial muscles.
The deepest layer contains the four suboccipital muscles, tucked right beneath the base of the skull: the rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis inferior, and obliquus capitis superior. These small muscles specialize in fine head movements. The rectus capitis posterior major and obliquus capitis inferior handle both extension and rotation, while the rectus capitis posterior minor and obliquus capitis superior primarily extend the head. Think of them as the precision controls for nodding and small rotational adjustments.
Also in this deepest layer are the interspinales cervicis and intertransversarii colli, small muscles connecting adjacent vertebrae that assist with subtle spinal adjustments.
Levator Scapulae: A Common Source of Neck Pain
The levator scapulae technically connects the neck to the shoulder blade, originating from the transverse processes of the top four cervical vertebrae and inserting along the inner border of the scapula. It elevates the shoulder blade and helps tilt the neck. This muscle is one of the most frequent culprits behind a stiff, achy neck. When it’s irritated or tight, it produces deep pain along the top of the shoulder blade and up into the side of the neck, with restricted ability to look down or tilt your head away from the affected side.
Quick Reference by Group
- Superficial front and side: platysma, sternocleidomastoid
- Suprahyoid: digastric, mylohyoid, geniohyoid, stylohyoid
- Infrahyoid: sternohyoid, sternothyroid, thyrohyoid, omohyoid
- Deep cervical flexors: longus capitis, longus colli, rectus capitis anterior, rectus capitis lateralis
- Lateral (scalenes): anterior scalene, middle scalene, posterior scalene
- Posterior superficial: trapezius, splenius capitis, splenius cervicis
- Posterior deep: semispinalis capitis, semispinalis cervicis, multifidus cervicis
- Suboccipital: rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, obliquus capitis inferior