5. TRAPEZIUS

The trapezius muscles are the most superficial muscle layer of the upper back and back of the neck.

The trapezii (plural) form a kite-shaped sheet of muscle that extends from mid-back to the base of the skull, and across the upper back towards each shoulder.

The left and right trapezius muscles meet on the body's midline.

The trapezius muscles seen from behind. A kite-shape lying over the ribs, upper back, shoulders and neck. Starting as a point, midline at the level of the bottom ribs, each trapezius extends up and outwards, towards the shoulders forming a triangle. This is the lower trapezius muscles. The widest part of the trapezii is across the bottom of the neck, level with the shoulders. This is the middle trapezius, where the muscle fibres lie horizontal. The trapezii become narrower towards the head, curved as the upper trapezius forms the back and sides of the neck. The trapezius muscles should be free to move without pain or tension, supporting the head and arms through a full range of natural movement.

trapezius keeping it simple

Wikipedia: Trapezius: from Late Latin trapezium, from Greek τραπέζιον (trapézion), literally "a little table", a diminutive of τράπεζα (trápeza), "a table", itself from τετράς (tetrás), "four" + πέζα (péza), "a foot; end, border, edge"

The trapezii are large, thin muscles. They are sculpted down the sides of the neck and as they extend out to each shoulder, attaching to both the scapula (shoulder blade) and clavicle (collar bone) of each arm.

The trapezius muscles shown in the outline of a human figure seen from the side-back view. A large blanket of muscle over the back of the upper body, a kite/diamond shaped sheet that curves on the contours of the upper body. From the back of the head, curving down the back and sides of the neck, spreading out towards each shoulder. Then the left and right trapezii extend down the upper back to meet as a point mid back, level with the last ribs.

The whole of each trapezius muscle should be free to fully extend, without pain or tension, supporting the head and arms through a full range of natural movement.

Midline Attachments Of The Trapezius Muscles.

The left and right trapezius muscles attach to the cervical and thoracic vertebrae (bones of the spine) via the nuchal & supraspinous ligaments.

nuchal & supraspinous ligaments

Front, off-center view of the upper body. Showing the base of the skull, thoracic vertebrae and trapezius muscles. The cervical vertebrae are not shown so that the nuchal ligament, between and attaching to the trapezius muscles, can be seen. Also showing the scapula and clavicle of each arm, and how the trapezius muscles curve down the neck and extend over the top of the shoulder region.

Sections Of The Trapezius.

Current descriptions split each trapezius into 3 functional sections - the upper, middle and lower trapezius, based on the direction of the muscle fibres.

Upper trapezius

Middle trapezius

Lower trapezius

Upper Trapezius.

{A.k.a. the superior (i.e. higher than the other sections) trapezius or the descending (i.e. the muscle fibres descend) trapezius.}

The upper trapezius attaches to:

Base of the skull. External occipital protuberance and medial third of the superior nuchal line of the occipital bone, via a thin fibrous lamina.
Nuchal ligament (ligamentum nuchae).
Lateral third of the clavicle (collar bone).
Spinal process of the 7^th (last) cervical vertebra and its supraspinous ligament.

Off-center front view of the trapezius muscles showing the attachments of the upper trapezius portion of the muscle. The uppermost attachment is to the base of the skull, a linear attachment with the external occipital protuberance on the midline. The trapezius muscles drop down from the skull and extend out towards the shoulders, curving and extending forward. The cervical vertebrae (neck bones) have been removed to reveal the nuchal ligament which is like an odd-shaped triangle of connective tissue, a blade of connective tissue, that forms a septum in the back of the neck, extending between the trapezii and attaching to the cervical vertebrae. Showing the clavicle/collar bone where the front-most piece of the upper trapezius attaches. The scapula bones and thoracic vertebrae are also shown.

Middle Trapezius.

{A.k.a. transverse (i.e. the muscle fibres run horizontally) trapezius.}

The middle trapezius attaches to:

Spinal processes of the 1^st to 4^th thoracic vertebrae and the supraspinous ligament.
Medial side of the acromion of the scapula (shoulder blade).

Skeleton and trapezius muscles off-center view from behind. The middle trapezius consists of horizontal running fibres extending from midline attachments to the upper thoracic vertebrae via the supraspinous ligament to the acromion of the scapula (the part of the shoulder blade nearest the shoulder).

Lower Trapezius.

{A.k.a. inferior (i.e. lower than the other sections) trapezius or the ascending (i.e. the muscle fibres ascend) trapezius.}

The lower trapezius attaches to:

Spinal processes and the supraspinous ligament of the 5^th to 12^th (last) thoracic vertebrae.
Posterior crest of spine of the scapula (shoulder blade).
Deltoid tubercle of spine of the scapula.

Side view of the upper body and trapezius muscles showing the sculpted shape of the upper trapezius and its attachments to the clavicle/collar bone. The supraspinous ligament and the thoracic vertebrae can be seen and are where the left and right lower trapezius meet midline. The trapezius muscles come to a point at the 12th (last) thoracic vertebrae where the bottom ribs emerge. The fibres of the lower trapezius muscles extend upwards and outwards, like a fan, from the lowest point of the muscles. Movement of the upper body should originate from the lower trapezius, following the orientation of these muscle fibres.

Movement of the upper body should begin from the lower trapezii.

With Base-Line support in place, think of activating both your lower trapezii starting from midback, extending upwards and outwards towards your shoulder blades.

Skeleton seen from behind showing the trapezius muscles covering the upper back and neck. Movement of the upper body should start from the lower trapezii illustrated by arrows starting from midline level with the last ribs, extending up and outwards towards the shoulders.

Attachments Of The Trapezius - Summary.

2 images showing the bones and ligaments where the trapezius muscles attach. Back view and off-center front view. It looks complicated because the trapezius muscles attach to many structures. The left and right trapezius muscles have a horizontal linear attachment to the base of the skull, at the superior nuchal line of the occipital bone, meeting midline at the external occipital protuberance - the bump at the back of the skull. They also have a midline linear attachment to the skull known as the medial nuchal line which extends from the external occipital protuberance. Midline, the trapezii attach to the cervical and thoracic vertebrae via the nuchal and supraspinous ligaments. There are attachments to the lateral third of the clavicle/collar bone. The trapezius muscles attach to the scapula/shoulder blade in multiple sites: the deltoid tubercle, the spine of the scapula, the acromion of the scapula. Feel your anatomy to familiarise yourself with where the bones associated with the trapezii are located.

Between the 6^th cervical and 3^rd thoracic vertebrae (the base of the nuchal ligament and start of the supraspinous ligament) the trapezius muscles are connected to the midline by a broad semi-elliptical aponeurosis (thin sheet of strong connective tissue), forming a tendinous ellipse between the shoulder blades.

The trapezius muscles seen from behind. There is an ellipse (oval-like) sheet of connective tissue between the shoulder blades where the left and right trapezius muscles attach to the base of the nuchal ligament, at the 6th (last) cervical vertebrae, and to the top of the supraspinous ligament between the first and third thoracic vertebrae.

photo human cadaver tendinous ellipse

Posture, Alignment And The Trapezius Muscles.

The trapezii are the primary muscles responsible for the posture (positioning) and state of alignment of the upper body. Sensory information provided by the trapezii allows us to feel the relative alignment of the upper body, whilst voluntary control of these muscles means we can adjust our positioning in order to improve alignment.

body alignment and balance

The trapezii should be free of restrictions, guiding the head and arms through a full range of natural movement when connected to Base-Line (pelvic floor and rectus abdominis) support.

Base-Line muscles Base-Line to upper body

View from front, looking down. Showing the bones of the upper body, the ribs and the bones of the pelvis. The left and right trapezius muscles can be seen attaching to the clavicle, scapula and spine. The nuchal ligament lies midline between the trapezii in the neck region. The Base-Line muscles are also shown, the rectus abdominis up the front of the abdomen, either side of the midline linea alba, and the pelvic floor at the base of the torso. With Base-Line support in place i.e. the rectus abdominis muscles fully active and extended which aligns the lower body, the trapezius muscles are responsible for alignment of the upper body.