Neck Muscles

Anterior Scalene Origin

The scalenus anteriorThe front of the body or toward the front when standing in the anatomical position. muscle originates from the transverse processes of the third to sixth cervical vertebraeSmallest vertebrae; have transverse foramina for vertebral arteries; often bifid spinous processes.

Anterior Scalene Insertion

The muscle inserts onto the scalene tubercle of the first rib.

Anterior Scalene Actions

Neck Flexion

Lateral Flexion of the Neck

Elevating the First Rib

The anterior scalene is one of the scalene muscles. These muscles are thin and strap-like in your neck. They act like helper ropes, stabilizing and moving the cervical spineProminent ridge on the posterior scapula dividing it into supraspinous and infraspinous fossae. and ribsCurved bones forming the rib cage; articulate with thoracic vertebrae and most with the sternum.. The anterior scalene sits at the very front of the group (hence the name), tucked just behind the sternocleidomastoidFlexor / Rotator From sternum and clavicle to skull behind the ear; turns and bends the head..

It starts at the transverse processes of C3–C6 vertebrae. These are the little bony “wings” on the sides of those neck bones. It then runs downward and slightly outward to insert on the first rib. That diagonal course is important because it links the neck directly to the rib cage.

Functionally, the anterior scalene is a multitasker:

• When it contracts bilaterally (both sides together), it flexes the neck—think of bringing your chin down toward your chest.
• When it contracts unilaterally (one side at a time), it bends the neck laterally (ear toward shoulder). It also helps to rotate the neck a little.
• It attaches to the first rib. Therefore, it acts as an accessory muscle of inspirationThe process of inhaling, driven by diaphragm and external intercostal contraction.. It lifts the first rib upward to help expand the chest when you take a deepAway from the surface of the body. breath.

Origin

The scalenus medius muscle originates from the transverse processes of the cervical vertebrae. Specifically, it arises from the posterior tubercles of the transverse processes of the lower cervical vertebrae (C2 to C7).

Insertion

The muscle inserts onto the superiorAbove or toward the upper part of the body. surface of the first rib, near its posterior aspect.

Actions

Neck Flexion and Lateral Flexion

Assistance in Breathing

Support for Head Movement

The middle scalene is the largest of the three scalene muscles. It sits just behind the anterior scalene on the side of your neck. Imagine the scalenes as a trio of ropes connecting your neck to your ribcage. The middle scalene is the thick, central rope.

It originates higher up. It starts from the transverse processes of C2–C7 vertebrae (nearly the whole cervical spine). Then, it runs downward to insert on the first rib. This insertion is just a little more posterior (toward the back) than the anterior scalene. The middle scalene is bulkier and has a broader origin. It is easy to spot in anatomical dissections compared to its skinnier anterior sibling.

Functionally, the middle scalene is very similar to the anterior scalene:

• When both sides contract together, they flex the neck forward.
• When just one side contracts, it bends the neck laterally (ear to shoulder).
• Like the anterior scalene, it also helps with inspiration by elevating the first rib when you take a deep breath.

Clinically, this one matters because the brachial plexusA network of nerves in the neck and shoulder that control the upper limbs. and subclavian artery actually pass between the anterior and middle scalenes. That little “scalene gap” is like a doorway for nerves and vessels heading into the arm. If the scalenes are tight or enlarged, that doorway can get squeezed. This can lead to thoracic outlet syndrome symptomsSubjective experiences reported by the patient (e.g., nausea, fatigue). like numbnes

Origin

The scalenius posterior muscle originates from the posterior tubercles of the transverse processes of the lower cervical vertebrae. Specifically, it arises from the posterior tubercles of the fourth, fifth, and sixth cervical vertebrae.

Insertion

The muscle inserts onto the second rib, specifically on the external surface of the second rib.

Actions

Postural Support

Assistance in Breathing

Assistance in Neck Movement

The posterior scalene is the smallest and most tucked-away of the scalene trio, but it’s still important. The anterior and middle scalenes are the big ropes tying your neck to your first rib. The posterior scalene is the thinner rope at the back of the bundle.

It originates from the transverse processes of C4–C6 vertebrae. This is a shorter span than the middle scalene. It descends to insert on the second rib, instead of the first. That difference makes it unique—the posterior scalene is the only one of the three that attaches to the second rib.

Functionally, it works in the same family of motions:

• Unilateral contraction bends the neck laterally (bringing your ear toward your shoulder).
• Bilateral contraction can help flex the neck forward a little.
• Most importantly, when you take a deep breath, it lifts the second rib. This action helps with inspiration. It expands the upper chest.

Clinically, the posterior scalene isn’t as directly involved in the “scalene gap” for the brachial plexus and subclavian artery. That area is more between the anterior and middle scalenes. However, it can still tighten and contribute to neck stiffness or postural problems.

Origin

The levator scapulae muscle originates from the transverse processes of the first four cervical vertebrae, namely C1 to C4

Insertion

The muscle inserts into the superior part of the medial borderLong edge parallel to the vertebral column (closer to spine). of the scapulaTriangular “shoulder blade” on posterior thorax; connects clavicle and humerus., particularly at the scapular spine.

Actions

Elevation of the Scapula

Assisting Neck Movement

Support for Shoulder Movement

Origin

The sternocleidomastoid muscle originates from two distinct sites:

The manubriumSuperior, triangular portion of the sternum; articulates with clavicles and first ribs. of the sternum, which is the upper part of the breastbone.

The medialToward the midline of the body third of the clavicle, one of the long bones in the shoulder girdle.

Insertion

The sternocleidomastoid muscle inserts on the mastoid process of the temporal boneBones on the sides of the skull near the ears; house structures of hearing and balance.. This is a prominent bony projection on the skull, located behind the ear.

Actions

Head Rotation

Neck Flexion

Lateral Flexion of the Neck

The name sternocleidomastoid literally tells you where it goes:

• Sterno– → from the manubrium of the sternum
• Cleido– → from the medial third of the clavicle
• –mastoid → to the mastoid process of the temporal bone (that big bump just behind your ear) and part of the superior nuchal line of the occipitalPosterior and base of the skull; curves under to form the back of the head. bone

So you’ve got two heads (sternal and clavicular) fanning upward and converging on the mastoid. Because it’s so large and superficialNear the surface of the body., you can easily see or feel it when you turn your head.

Turgery. Clinicians often palpate just in front of the SCM to feel the carotid pulse.

Torticollis (“wry neck”) is a condition where the SCM is shortened or spasms, twisting the head to one side. In newborns, this can result from birth trauma or positioning.

Why It’s Famous:
It’s one of the most visible muscles in the human body. You can see it stand out when someone turns their head. It is also noticeable when they strain their neck. Artists love drawing it. Doctors use it as a landmark. Anyone who’s ever sung, shouted, or gasped has relied on it to assist in lifting

Origin

The splenius capitis muscle originates from the spinous processes of the seventh cervical (C7) vertebra. It also originates from the upper thoracic vertebraeHeart-shaped body, long downward spinous process, and facets for rib attachment. (T1-T3).

Insertion

This muscle inserts into the mastoid process of the temporal bone and the occipital bone.

Actions

Neck Extension

Lateral Flexion of the Neck

Rotation of the Head

The splenius capitis is a “hidden gem” neck muscle. It doesn’t get the attention of the sternocleidomastoid (SCM). However, it’s crucial for head and neck movementA fundamental property of life involving motion of the body or its parts.. Think of it as a strong strap running from the upper spine to the skull. This strap helps you tilt and turn your head with control.

Location & Attachments:
The splenius capitis originates from the lower half of the nuchal ligament. This is a strong band along the back of the neck. It also originates from the spinous processes of C7–T3 or T4 vertebrae. From there, its fibers run upward and outward like a fan. They insert on the mastoid process of the temporal bone (that bump you can feel just behind your ear). Additionally, they insert on the lateralAway from the midline of the body. part of the superior nuchal line of the occipital bone. That means it ties your upper thoracic and lower cervical spine directly to the back of your head.

Functions:

• Unilateral contraction (one side at a time) makes the head rotate and bend laterally toward that side. Imagine trying to glance over your shoulder—that’s the splenius capitis at work.
• Bilateral contraction (both sides together) extends the head and neck, like when you look upward toward the ceiling.
  In short: it’s part of your “look up, look around” toolkit.

Clinical Note:
Tightness in the splenius capitis often contributes to tension headaches. It can also lead to neck stiffness. This is because it atta