What Are the Neck Muscles Called? Anatomy by Group

The neck contains more than twenty pairs of muscles, and anatomists sort them into groups based on their position and function. The broadest division separates them into anterior (front), lateral (side), and posterior (back) groups, but within each of those zones sit distinct layers ranging from the thin sheet of platysma just under the skin to tiny suboccipital muscles buried at the base of the skull. Clinicians further organize the superficial structures into triangles defined by surface landmarks, while radiologists tend to think in terms of deeper fascial compartments.

Superficial Muscles

The muscles you can see or feel most easily on the neck’s surface form the superficial group. Three stand out. The platysma is a broad, paper-thin sheet of muscle that drapes over the front and sides of the neck just beneath the skin. It runs from the chest up to the jaw and pulls the corners of the mouth downward, contributing to facial expressions of surprise or horror. Because it is so thin, the platysma is often the first structure a surgeon cuts through during neck procedures.

The sternocleidomastoid, usually shortened to SCM, is the thick, rope-like muscle that runs diagonally from behind the ear down to the collarbone and breastbone. You can see it pop out when you turn your head sharply to one side. Working alone, one SCM rotates the head to the opposite side and tilts the ear toward the shoulder on the same side. Working together, both SCMs flex the neck forward, like when you tuck your chin to look at your phone.

The trapezius is often thought of as a back muscle, but its upper fibers attach to the skull and the cervical spine, making it a neck muscle as well. The upper trapezius shrugs the shoulders and extends the head backward. Its primary motor supply comes from the spinal accessory nerve, a cranial nerve that takes an unusual path down through the neck.¹ Both the SCM and trapezius share a surprising developmental origin: they arise from cranial pharyngeal mesoderm rather than the somites that give rise to most other body muscles, placing them in the same lineage as certain muscles of the face and even the heart.²

Suprahyoid Muscles

Tucked beneath the chin and jaw are four small muscles that attach above the hyoid bone, the horseshoe-shaped bone in the front of the throat. Together, these suprahyoid muscles lift the hyoid and the larynx during swallowing, which is what closes off the airway so food goes down the right pipe.

The four suprahyoid muscles are the digastric, mylohyoid, geniohyoid, and stylohyoid. Each pulls the hyoid in a slightly different direction. Research on their structural properties shows that the geniohyoid has the greatest potential to pull the hyoid forward, while the mylohyoid is best positioned to pull it upward.³ Architectural analysis further divides them into functional subgroups based on their attachment sites, suggesting that the anteromedial and superoposterior muscles work in concert to elevate the hyoid during a swallow.⁴

The digastric is distinctive because it has two muscle bellies connected by a tendon that loops through a fibrous sling on the hyoid bone. The front belly sits beneath the chin and helps open the mouth against resistance, while the rear belly originates behind the ear. The mylohyoid forms a muscular floor for the mouth, and you can feel it tighten if you press a finger under your chin and push your tongue hard against the roof of your mouth.

Infrahyoid Muscles

Below the hyoid bone, another four strap-like muscles run vertically down the front of the throat. These infrahyoid muscles pull the hyoid and larynx back downward after swallowing raises them. They are the sternohyoid, sternothyroid, thyrohyoid, and omohyoid. All four are thin, flat muscles that lie in layers over the trachea and thyroid gland. A systematic review of their anatomy notes that these muscles are primarily innervated by the ansa cervicalis, a nerve loop formed from upper cervical spinal nerves.⁵

The omohyoid is the oddball of the group. Instead of running straight up and down, it angles from the shoulder blade across the neck to the hyoid, with an intermediate tendon partway along. Anatomical variations of the omohyoid are surprisingly common, and surgeons performing procedures in the neck need to watch for unusual configurations that can complicate access to deeper structures.

Scalene Muscles on the Side

The lateral neck is home to the scalene muscles, typically described as three separate muscles: the anterior, middle, and posterior scalene. They originate from the transverse processes of the cervical vertebrae and insert onto the first and second ribs. When both sides contract together, they help flex the neck forward. When one side contracts alone, it tilts the neck sideways. During heavy breathing, the scalenes also act as accessory respiratory muscles by elevating the upper ribs.

Clinically, the scalenes matter because the brachial plexus, the bundle of nerves supplying the arm, passes between or through them on its way out of the neck. Anatomical variants where nerve trunks pierce through a scalene muscle belly rather than simply passing between muscles are well documented and can contribute to thoracic outlet syndrome, a condition causing pain, tingling, or weakness in the arm.⁶ The scalenes have been identified as the most common site of neurogenic thoracic outlet syndrome, so if you get numbness or weakness running into your arm from the neck, these muscles are often the first place specialists look.

Prevertebral Muscles

Deep behind the throat, pressed against the front surface of the cervical spine, lie the prevertebral muscles. The two main ones are the longus capitis and longus colli. They are sometimes called the deep neck flexors, and they flex the head and neck forward from deep inside the throat, working like an internal counterweight to the powerful extensors on the back of the neck.

Despite their reputation in rehabilitation circles as cervical “stabilizers,” these muscles are actually quite small and produce limited compressive force. Detailed fascicular analysis has shown that longus capitis and longus colli have a limited capacity to stabilize the cervical spine through raw force alone, which suggests their stabilizing role may rely more on fine-tuning joint position and providing proprioceptive feedback than on brute-strength compression.⁷ This is an area where clinical rehab programs sometimes overstate the evidence, prescribing deep neck flexor exercises as the key to cervical stability when the reality is more nuanced.

Posterior Neck Muscles

The back of the neck has the densest layering of muscle in the whole region, stacked from superficial to deep. The splenius capitis and splenius cervicis form the most superficial of the true posterior neck muscles beneath the trapezius. They extend and rotate the head, and you can feel the splenius capitis working if you press against the back of your head and try to look up.

Deeper still, the semispinalis capitis and semispinalis cervicis are the workhorses of neck extension. Studies of neck muscle function have confirmed that the semispinalis capitis and cervicis, along with the splenius capitis, are the muscles most extensively used during head extension.⁸ Underneath those run the multifidus and rotatores, short muscles that span just one or two vertebrae and contribute to fine rotational control and segmental stiffness. Interestingly, in people with neck pain, applying localized resistance at the level of the second cervical vertebra can selectively activate the semispinalis cervicis over the more superficial splenius capitis, a finding that has practical implications for rehabilitation targeting specific deep muscles.⁹

Imaging studies of the cervical extensors show that men have larger cross-sectional areas than women across all posterior neck muscles. The relative proportions differ too: men tend to have a greater percentage of upper trapezius and semispinalis within their total extensor volume, while women show a greater relative proportion of levator scapulae.¹⁰ No side-to-side differences were found in either sex, which means asymmetry on imaging is a useful red flag for pathology rather than a normal variant.

Suboccipital Muscles and the Myodural Bridge

At the very top of the posterior neck, tucked beneath the semispinalis capitis, sit four small suboccipital muscles: the rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis superior, and obliquus capitis inferior. These muscles control the fine movements between the skull and the top two vertebrae, the atlas (C1) and axis (C2). When you nod “yes” or shake your head “no,” these are the muscles managing the precise adjustments.

One of the more interesting discoveries about the suboccipital muscles is the myodural bridge, a connective tissue connection that links certain suboccipital muscles directly to the dura mater, the tough membrane surrounding the spinal cord. This bridge is now recognized as normal human anatomy, not a pathological finding.¹¹ Anatomical studies have identified that the myodural bridge in the space between the skull and atlas originates from the rectus capitis posterior minor, while the bridge spanning the atlas-axis gap draws from the rectus capitis posterior minor, rectus capitis posterior major, and obliquus capitis inferior. These connections are composed mainly of type I collagen fibers running in parallel, which means they can transmit pulling forces efficiently from muscle to dura during head movement.¹²

Why does this matter? The prevailing theory is that the myodural bridge helps prevent the dura from folding or buckling inward during neck extension, which could otherwise compress the spinal cord. The rectus capitis posterior major appears to exert greater mechanical traction on the dura than the rectus capitis posterior minor due to its larger cross-sectional area.¹³ Some clinicians have also explored whether tension in this bridge contributes to cervicogenic headaches, though the evidence on that connection remains limited.

Nerve Supply Across the Groups

The muscles of the neck draw their nerve supply from several sources, and the pattern roughly matches the groupings above. The cervical plexus, formed from the ventral rami of the first four cervical spinal nerves, provides motor and sensory branches to many of the anterior and lateral muscles.¹⁴ The infrahyoid strap muscles, as noted earlier, receive their motor input primarily from the ansa cervicalis, a loop arising from C1 through C3.

The SCM and trapezius are exceptions. Both are supplied primarily by the spinal accessory nerve (cranial nerve XI), which exits the skull and descends through the neck. But the relationship is not exclusive: cervical plexus branches merge with the spinal accessory nerve on the undersurface of the trapezius in all specimens studied, suggesting the cervical plexus contributes at least proprioceptive input and possibly some motor fibers.¹⁵ This dual supply is clinically important: during neck dissection surgery for cancer, surgeons try to preserve the spinal accessory nerve to maintain shoulder function, but damage to cervical plexus branches can still cause subtle deficits.

The posterior neck muscles are innervated by the dorsal rami of the cervical spinal nerves, while the suboccipital muscles receive their supply from the suboccipital nerve, which is the dorsal ramus of C1. This segregation of anterior muscles from ventral rami and posterior muscles from dorsal rami is a pattern that repeats throughout the spine.

What Happens in Whiplash

The neck’s muscular anatomy becomes clinically relevant during whiplash injuries, which are overwhelmingly associated with rear-end vehicle collisions. During impact, the cervical spine is thrown into an abnormal S-shaped curve, with the lower vertebrae extending while the upper vertebrae flex, before the whole neck whips into extension. This produces pronounced strain especially at the C2-C3 and C4-C5 levels, with increased tensile strain in the facet joint capsules.¹⁶

Both the anterior and posterior neck muscles experience strains that exceed the injury threshold for active muscle, but the extensors on the back of the neck bear the worst of it. This is consistent with clinical reports that pain after rear-end collisions concentrates in the posterior cervical region.¹⁷ In people who develop chronic symptoms after whiplash, the deep dorsal muscles, particularly the semispinalis cervicis and multifidus, show altered mechanical properties. Compared to healthy controls, people with whiplash-associated disorders showed higher deformation in these muscles, and the degree of multifidus deformation correlated with self-reported pain, disability, and fatigue.¹⁸

Cervical Dystonia and Abnormal Muscle Drive

Cervical dystonia, sometimes called spasmodic torticollis, is a neurological condition in which neck muscles contract involuntarily, pulling the head into abnormal postures. The muscles most commonly affected include the SCM, splenius capitis, levator scapulae, and trapezius, though the specific combination varies from person to person and determines which direction the head is pulled.

What makes cervical dystonia distinctive is not just which muscles are active but how they are being driven. Frequency analysis of muscle activity in patients reveals an abnormal low-frequency drive to neck muscles at roughly 5 to 7 Hz, along with an absence of the normal 10 to 12 Hz peak seen in healthy controls. The pattern of this abnormal drive correlates with the clinical posture the patient adopts.¹⁹ EMG studies have also documented that in some cases, multiple posterolateral neck muscles show abnormally high activity even when the patient is fully relaxed, indicating that the problem is not simply one of voluntary over-contraction but of disordered signaling from the brain.²⁰

Posture and Upper Crossed Syndrome

If you spend hours at a desk or staring at a screen, your neck muscles develop predictable imbalances often described as upper crossed syndrome. In this pattern, certain muscles become shortened and tight while their functional opposites become weak and overstretched. The muscles that tend to tighten include the SCM, upper trapezius, levator scapulae, scalenes, suboccipitals, and pectoralis major and minor. The muscles that weaken include the deep neck flexors, serratus anterior, rhomboids, and the middle and lower portions of the trapezius.²¹

The result is the classic forward-head, rounded-shoulder posture familiar to anyone who has spent too long hunched over a laptop. Rehabilitating this pattern typically involves stretching and releasing the overactive muscles while strengthening the inhibited ones. Knowing which muscles belong to which group helps you understand why a therapist might simultaneously prescribe chin tucks to activate the deep neck flexors and stretches targeting the upper trapezius and SCM.

How Neck Muscles Shape Your Voice

An often-overlooked function of the neck muscles is their influence on phonation. The larynx, which houses the vocal folds, is suspended in the neck by the hyoid muscles, and any tug on the laryngeal framework from surrounding muscles changes vocal fold tension and therefore pitch. Computational modeling predicts that when neck muscles pull the thyroid cartilage in a superior-anterior direction with a sufficient forward component, or in an inferior or inferior-anterior direction, tension in the vocal folds increases and fundamental frequency rises. Pulling in a superior, superior-posterior, or inferior-posterior direction tends to decrease tension and lower pitch.²²

This has real implications for singers and people with voice disorders. Excessive tension in the strap muscles or suprahyoid group, sometimes called vocal hyperfunction, can push the fundamental frequency of the voice in unwanted directions and contribute to vocal fatigue. Voice therapists who work with these patients spend significant time addressing the balance of extrinsic laryngeal muscles, which is really just another way of saying they are working on neck muscle coordination.

Reflexive Head Stabilization

Beyond voluntary movement, the neck muscles participate in reflexes that keep your head stable as your body moves. The vestibulocollic reflex uses signals from the inner ear’s balance organs to drive compensatory neck muscle contractions that hold the head steady. Research in animal models has shown that proprioceptive input from neck muscle stretch receptors potentiates the gain of this reflex, meaning the reflex works more effectively when the neck muscles are actively reporting their own stretch state back to the nervous system.²³ Since almost all voluntary head movements involve the head rotating relative to the neck, this feedback loop between vestibular signals and neck muscle proprioception is constantly at work during daily life.

Evolutionary Roots of the Neck Muscle Groups

The neck is, in evolutionary terms, a relatively new structure. Fish do not have necks; the skull is fused to the pectoral girdle. When vertebrates moved onto land, a mobile head-trunk junction became essential for looking around, breathing air, and eventually feeding without moving the whole body. Comparative anatomy and embryonic lineage tracing show that the four major neck muscle groups found in land vertebrates were already present in some form in fish ancestors. Two groups derive from somitic mesoderm: the dorsal epaxial and hypaxial muscles, and the hypobranchial muscles that expanded anteriorly to form the tongue in land animals. Two more groups, the cucullaris-derived muscles (which became the trapezius and SCM in mammals) and the laryngeal musculature, trace to cardiopharyngeal mesoderm.² The key developmental changes during the water-to-land transition were an anterior expansion of the hypobranchial muscles into the oral cavity and a posterior expansion of cardiopharyngeal mesoderm-derived progenitors to form the trapezius and SCM.²⁴ The neck, in other words, was not built from scratch. It was assembled by repurposing and rearranging muscle groups that already existed in a fish body plan, a vivid example of evolutionary tinkering rather than invention.