Trapezius muscle pain is one of the most common musculoskeletal problems.
Patients often complain of acute or chronic neck-shoulder pain. Trapezius
muscle pain is often characterized by pain, stiffness and tightness of upper
fibres of Trapezius muscle, neck and sometimes around the shoulder joint. Tension
headache is another common problem associated with Trapezius pain or
hypertonicity or spasm.
Trapezius is a broad, flat, triangular muscle which extends over the back of neck and upper thorax. Understanding of functional anatomy is crucial to treat Trapezius muscle pain by incorporating proper stretching, and strengthening exercises.
Trapezius is a diamond shaped paired muscles which laterally angles at
the shoulder tips, the superior angle at the occipital protuberance and
superior nuchal line, and the inferior angle at the spine of the twelfth
thoracic vertebrae. Dissection studies have revealed the fascicular anatomy of
Trapezius showing three definite fibres; superior (descending), middle
(transverse), inferior (ascending) part.
Superior (Descending) fibres:
It originates from Occipital bone (superior nuchal line and external
occipital protuberance) and the spinous process of all cervical vertebrae via
the nuchal ligament. Johnson et al performed dissection study and reported that
superior fibres (mainly occipital and nuchal fibres) passed downwardly but
mainly transversely to insert in to the lateral third of the clavicle. Fibres
from C7 and T1 passed transversely to reach the acromion and spine of scapula.
Its thoracic fibres converged to the deltoid tubercle of the scapula.
Volumetric studies have demonstrated that the fibres from C7, T1, and the lower
half of ligamentum nuchae were the largest.
Middle (Transverse) fibres:
Originates from the broad triangular aponeurosis at the level of the
T1-T4 spinous processes. These middle fibres are attached to the medial
acromial margin and superior lip of the crest of the scapular spine.
Inferior (Ascending) fibres:
Originates from the spinous processes of T5-T12. These ascending fibres
pass into an aponeurosis which glides over a smooth triangular surface at the
medial end of the scapular spine and is attached to a tubercle at its lateral
Clinical significance and actions:
- Trapezius works with other muscles in steadying the
scapula on the thorax, controlling it during the arm movement, and maintaining
the level and the poise of the shoulder.
- The occipital attachment is by a fibrous lamina, which
is also adherent to the skin. The spinal attachment is by a broad triangular
aponeurosis from the sixth to the fourth thoracic vertebrae, and by the
tendinous fibres below the fourth thoracic vertebrae.
- The upper fibres of Trapezius acts with levator scapula
to elevate the scapula and with it the point of the shoulder. However, the
study from Johnson et al 1994, have precluded the elevator action of upper and
middle fibres of Trapezius muscle due to its more transverse orientation. The
study has reported, “Rather the action of these fibres is to draw the scapula
and clavicle backwards or to raise scapula by rotating the clavicle about the
- Acting with the serratus anterior, superior fibres of
the Trapezius draws the scapula obliquely upward and rotates the glenoid
cavity, so that the arm can be raised above the head.
- Acting with the Rhomboids , Trapezius retracts the
scapula, bracing back the shoulder.
- Ascending fibres draws the scapula medially downward
and supports the rotating action of the descending fibres.
- Serratus anterior and Trapezius are opposed in
scapular movement round the thorax, but combine as prime movers in lateral
rotation of the scapula.
- With the shoulder girdle fixed, Trapezius tilts the
head to the same side and rotates it to the opposite side.
Trapezius is innervated by the spinal part of the accessory nerve (Cranial nerve XI). Sensory (proprioceptive) branches are derived from th ventral rami of C3 and C4.