LEVATOR SCAPULAE MUSCLE: CHARACTERISTICS, FUNCTIONS, SYNDROMES - ANATOMY AND PHYSIOLOGY - 2025

The levator scapulae muscle, sometimes called the angular muscle of the scapula, is located on the left and right posterolateral part of the neck (the par muscle). Its name comes from the Latin musculus levator scapulae.

Its morphology is very simple, as it resembles a ribbon, it is elongated, flat and thin. It can have between 1 to 5 muscle fascicles or fibers. These are arranged in a staggered manner.

Graphic representation of the levator scapulae muscle Source: modified by Uwe Gille / Anatomography. Edited image.

The function of the muscle lives up to its name, as it is responsible for raising the scapula. It also participates in the adduction and inferior rotation of the lateral edge of the scapula or shoulder blade. Finally, it controls and provides stability to neck movements.

Stretching the muscle can lead to trigger points. This muscle is generally overstretched, due to contraction of the antagonist muscle (pectoralis minor).

People with an levator scapula stretch, in addition to pain from the shoulder blade area to the neck, often have a lowered shoulder and a forward-thrust scapula.

characteristics

It is an even, thin, long and flat muscle that resembles a belt. It is located at the lateral and posterior level of the neck.

Its muscle fibers are oriented towards its vertebral origin and upon reaching it, the fibers become more fleshy (tendinous), while, at the end of insertion (in the scapula), its fibers do not undergo changes.

The muscle fibers as a whole measure between 14.9 to 18.3 cm in length (it varies from one individual to another) and can present between 1 to 5 fascicles. In general, they are divided into upper, middle and lower fascicles.

In 2006 Mardones et al studied 11 corpses and found that one of them presented only 2 fascicles, two cases had 3 fascicles, fourteen cases had 4 fascicles and only three of them had 5 fascicles.

Tiznado mentions that this muscle tends to have many variations in terms of its origin, trajectory, insertion and number of fascicles and considers them important to take it into consideration in reconstructive surgeries (muscle flap), as well as in some pathologies that present with chronic pain shoulder. The abnormal variations were classified into 6 varieties.

On the other hand, this muscle has been used since 1956 to reconstruct muscle defects, such as: in reconstructive head and neck surgeries, replacement of the trapezius muscle due to paralysis or as a protector of the carotid artery, among others.

Origin

It descends from the transverse processes of the upper cervical vertebrae (I-IV).

The origin of the muscle fibers is divided as follows: the transverse processes of the first cervical vertebrae I (atlas) and II (axis) and the posterior tubercles of the cervical vertebrae III and IV.

If the muscle has several fascicles, these are arranged in a staggered manner. The superior originates at the level of the first cervical vertebrae, the intermediate arises at the level of the first segment (superior fascicle) and the inferior originates from the intermediate fascicle.

Some individuals may have an accessory fascicle, originating at the level of the posterior tubercle of the cervical vertebra V.

Insertion

It is inserted directly on the medial border and superior angle of the scapula. If studied by fascicles, they are inserted as follows:

The superior fascicle inserts at the level of the sternocleidomastoid muscle, the intermediate fascicle at the anterolateral border of the trapezius muscle, and the inferior fascicle at the scapula.

Some individuals may have an accessory bundle that is inserted at the fascia of the serratus anterior muscle, using an aponeurotic strap.

Mardones et al. Achieved variation in the insertion sites. They explain that 2 to 4 insertion points can be achieved in the same individual. In their study, 35% of the corpses had 2 points of insertion, 55% 3 points and with 4 points only 10%.

Of these, 100% were inserted at the medial edge of the scapula, 80% at the upper angle of the scapula, 35% at the upper edge, and 85% at the fascia of the serratus anterior muscle.

Innervation

The superior branches of the spinal or cervical nerve (C3 and C4) innervate the superficial part of the muscle, while the dorsal scapular nerve innervates it deeply.

Irrigation

This muscle is supplied by the transverse and ascending cervical arteries.

Features

Its function is very easy to remember, since it lives up to its name, that is, it elevates the scapula. This action is carried out in conjunction with other muscles. Mainly, the levator scapulae muscle is activated when this movement is performed slowly and without opposition to it.

However, it is not its only function. It collaborates with other muscles in the movement of scapular adduction and inferior rotation of the lateral border of the scapula.

Also, it is a stabilizer of the flexion and movements of the neck, specifically rotation and lateral inclination. It also tilts the spine.

Syndromes

Trigger points

Exposure to extreme cold, acute infections of the upper respiratory system and keeping the shoulder elevated for a long time are causes that can cause the formation of trigger points (painful knots) in this muscle.

An example could be the inappropriate use of a cane (cane or crutch too high).

The mistake is often made of wanting to solve the problem by stretching the muscle, but in this particular case it is not useful, since the levator scapulae muscle is usually overstretched.

By observing a lowered shoulder and the scapula tilted anteriorly, it can be ensured that the levator scapulae muscle is stretched.

The ideal treatment does not only involve working the muscle that has the trigger points, but it is also advisable to stretch the antagonist muscle that must be contracted, in this case the pectoralis minor.

To treat trigger points, in addition to massage being useful, other techniques such as dry needling can be used at the points in question. This treatment will produce a local spasm response (REL), where the muscle contracts suddenly.

This lowers the concentration of neurotransmitters. Neurotransmitters are responsible for triggering a series of reactions that produce pain.

Related disorders

Stiff neck

Taira et al 2003 cited in Tiznado 2015, assure that an abnormal contracture in the levator scapulae may be the cause of torticollis, due to cervical dystonia.

Sprengel deformity

It is a congenital pathology that presents with an abnormal permanent elevation of the scapula. Eulenberg in 1863 describes the first case, but it was not until 1891 that Sprengel gave the name to this anomaly. For his part, Cavendish classified the pathology according to the degree of involvement (very mild, mild, moderate and severe).

This pathology can involve dysplasia or abnormal development of the scapula, as well as muscle atrophy or hypoplasia.

In addition to malformations in morphology and position of the scapular bone, other abnormalities may appear, including: absence, hypoplasia or fibrosis of certain muscles such as the trapezius, rhomboids and levator scapulae.

These abnormalities can produce a series of clinical signs, the most common being restriction in the movement of the shoulder joint, imbalance of the shoulder girdle, disorders of the cervical spine, among others.

Head forward

This is a disorder that occurs with the retraction of the levator scapula muscle, along with other muscles such as: pectorals (major and minor) and upper trapezius. And with weakness in the deep flexor muscles of the neck, rhomboids and serratus anterior.

This disorder is characterized by presenting a forward position of the head (postural disorder).

The patient who suffers from it also presents hyperextension of the head, thoracic kyphosis and drooping shoulders.

References

1. Mardones F, Rodríguez A. Levator Scapulae Muscle: Macroscopic Characterization. Int. J. Morphol, 2006; 24 (2): 251-258. Available at: scielo.conicyt.cl.
2. Pinzón Ríos ID. Head forward: a look from biomechanics and its implications on human body movement. Rev. Univ. Ind. Santander. Health 2015; 47 (1): 75-83.
3. Mardones F, Rodríguez A. Levator Scapula Muscle: Irrigation and Innervation. Int. J. Morphol. 2006; 24 (3): 363-368. Available in: scielo. conicyt.cl.
4. "Levator scapulae muscle" Wikipedia, The Free Encyclopedia. 28 Apr 2019, 11:19 UTC. 19 Sep 2019, 12:23
5. Arias J. 2016. Effectiveness of the inclusion of dry needling of myofascial trigger points in pain after shoulder surgery. Degree work to qualify for the degree of Doctor. Complutense University of Madrid Faculty of Nursing, Physiotherapy and Podiatry. Available at: eprints.ucm.es.
6. Tiznado G, Bucarey S, Hipp J, Olave E. Neck Muscle Variations: Accessory Fasciculus of the Levator Scapulae Muscle. 2015; Int. J. Morphol, 33 (2): 436-439. Available at: scielo.conicyt.cl
7. Álvarez S, Enguídanos M. Sprengel's deformity. Rev Pediatr Aten Primaria 2009; 11 (44): 631-638. Available at: scielo.isciii.es