Below the main part of the head are muscles of the neck. These muscles extend both deep and superficially from the base of the skull to the back. They work together to flex (bend) the head when nodding, take part in breathing, and act in unison with the eye muscles, causing the head to turn from side to side with the eyes.
The deltoid is a large, thick powerful muscle. It is triangular in form with a coarse texture. On its broad side, it originates from the clavicle (collar bone) and from the spine of the scapula (shoulder blade). The muscle covers the outer side of the shoulder joint, giving the shoulder its rounded appearance, and inserts in the humerus (upper arm bone). The deltoid muscle moves the humerus bone and is used to raise the arm outward from the side. It works with the pectoralis major to move the arm forward and works with the teres major and latissimus dorsi to move the arm back.
The digastric muscle is a small muscle located on the under side of the jaw. It assists the mylohyoid and geniohyoid muscles in moving the hyoid bone and the tongue upward and forward and then upward and backward during the process of swallowing.
The hyoglossus is a thin, flat strap of muscle located on each side of the tongue. It originates from the side of the wishbone-shaped hyoid bone in the throat and passes vertically to be inserted inside of the tongue. When the two muscles contract, they depress the tongue and turn the sides down. The genioglossus, the styloglossus, the palatoglossus and the hyoglossus work together to move the tongue.
The mylohyoid muscle is flat and triangular in form and lies just beneath the digastric muscle spanning the bottom of the jaw. It assists the geniohyoid, which lies just beneath the mylohyoid muscle, and the digastric muscles in moving the hyoid bone and the tongue upward and forward and then upward and backward during the process of swallowing.
The omohyoid muscle consists of two large triangles at each side of the neck united by a central tendon. It originates from the upper part of the scapula and runs upward along the neck behind the sternomastoid muscle and is inserted in the lower portion of the hyoid bone. This muscle moves the hyoid bone backward and from side to side, assisting swallowing, speech, and chewing.
The sternohyoid is a narrow, ribbon-thin muscle located on the front of the neck. It originates on each side of the neck from the clavicle (collar bone) and the upper part of the first piece of the sternum (breast bone). The muscles run upward and come together in the middle of their course (both pieces of the muscle lie side by side), but do not actually touch and are inserted in the front of the hyoid bone. The muscle pulls the hyoid bone down, as in swallowing, and assists in flexion of the head and neck.
The sternothyroid is a short wide muscle that lies just beneath the sternohyoid muscle. It originates from the first bone of the sternum (breast bone) and from the edge of the cartilage of the first rib and is inserted into the thyroid cartilage. It acts as a depressor of the thyroid cartilage.
The stylohyoid muscle lies just above and in front of the digastric muscle and is perforated by the digastric tendon. It is a thin and slender muscle that originates at the base of the styloid process and inserts into the hyoid bone. It raises the hyoid bone and the base of the tongue and is used when swallowing.
The thyrohyoid is a small muscle that is quadrilateral in form and forms a continuation of the sternothyroid muscle. It originates from the thyroid cartilage and inserts into the lower region of the hyoid bone. It acts as an elevator of the thyroid cartilage, the opposite of the sternothyroid.
The inferior pharyngeal constrictor muscle originates from the thyroid cartilage and inserts into the pharynx (throat). The three constrictor muscles (the inferior pharyngeal, the superior pharyngeal, and the middle constrictor) help move food and drink down through the esophagus when swallowing. The inferior pharyngeal constrictor muscle is the thickest and most superficial of the three. The superior constrictor muscle is thin and lies near the upper part of the pharynx.
The middle pharyngeal constrictor is a flat, fan-shaped muscle that originates along the upper border of the hyoid bone. The muscle fibers diverge, some run below the inferior constrictor muscle and some overlap the superior constrictor muscle. The three constrictor muscles contract to help move food and drink down through the esophagus when swallowing.
The masseter muscle is located on the side of the jaw. It extends from the zygomatic bone to the ramus, and angle and body of the mandible (jaw). It is one of the chewing muscles that lifts the mandible which pulls the mouth shut. It is also used when we talk.
The platysma muscle is a broad, thin sheet of muscle that originates in the pectoral and deltoid (chest and shoulder) muscles and runs upward over the collar bone and inward along each side of the neck. This muscle works to draw the lower lips and corner of the mouth sideways and down partially opening the mouth. It is used when expressing surprise. It also increases the diameter of the neck as seen during intense breathing from fast running.
The levator scapula lies along the back and side part of the neck. It originates deep in the side of the neck near the base of the skull, passes down and back and inserts in the scapula (shoulder blade). As the name implies, this muscle is the "shoulder blade lifter". This muscle tenses up, becoming hard and stiff, when you carry a weight on your shoulder.
The longus capitis muscle originates in various places from the skull and neck vertebrae and descends vertically down to the lower back. It is a part of the erector spinae muscle group that help keep the spine erect, link the vertebrae, and help bend and twist the back.
The rectus capitis muscles are small triangular muscles that extend from the cervical vertebrae and insert in the occipital bone at the base of the skull. They tilt head back and rotate it from side to side.
The three scalene muscles (the scalenus posticus, the scalenus medius, and the scalenus anticus) work together to aid in breathing. As we inhale, they lift the first and second rib. They also bend the spinal column to one side or the other. The scalenus posticus is the smallest of the three muscles, originating from the lower two or three cervical (neck) vertebrae and descends to insert into the second rib. The scalenus medius is the largest and longest of the three muscles. It originates from the lower six cervical vertebrae and is inserted into the first rib. The scalenus anticus lies deep at the side of the neck, behind the sternomastoid. It originates from the third, fourth, fifth, and sixth cervical vertebrae and descends to the first rib. It also separates the subclavien artery and vein.
The semispinalis capitis is a deep muscle on the back of the neck. It originates from the spine (7th cervical down to the 6th or 7th thoracic vertebrae) and inserts into the elongated area at the base of the skull. It is a deep muscle that lies under the trapezius. Both the trapezius and the semispinalis capitis create the muscular column on the back of the neck. The semispinalis capitis muscle extends the head and rotates it so the face is directed to the opposite side.
The splenius capitis muscle runs along the back of the neck and joins the skull and spine. It is narrow and pointed at its origin and becomes broader, dividing into two portions with separate insertions. The splenius capitis is inserted into the mastoid process of the temporal bone and the splenius colli is inserted in two or three upper cervical (neck) vertebrae. It is used to rotate and tilt the head from side to side.
The sternocleidomastoid muscle is located in the neck. It is a thin, broad muscle that narrows at the center. It originates from two heads, one from the sternum (breastbone) and one from the clavicle (collar bone), and runs upward, inserting into the mastoid (the temporal bone behind the ear). This muscle is used to tilt the head from side to side.
The trapezius is one of the biggest shoulder muscles and the most superficial
muscle on the back of the neck and upper trunk. It is a broad, flat
triangular muscle that lies just below the skin, covering the upper back
part of the neck and shoulders. It links the neck with the spine
(dorsal vertebrae), ribs, and shoulder bones (scapula). This muscle
is used to turn and tilt the head, raise and twist the arms, and to shrug
or steady the shoulders. The trapezius is a postural muscle as well
as an active mover.
Posterior neck muscles
Pain referral:
posterior neck muscles
Pain referral: trapezius
for injury info Bone Doctor