Levator scapulae muscle: the strap muscle that lifts the shoulder blade

What it is

A muscle of the posterolateral neck that raises the scapula.

Location

Origin: transverse processes of C1–C4. Insertion: superior angle and upper medial border of the scapula.

Function

Elevates the scapula and rotates the glenoid cavity downward.

Body system

Muscular · paired (left and right)

FMA ID

FMA32540 (Foundational Model of Anatomy)

Key facts

• Innervation: dorsal scapular nerve (C5) and cervical nerves C3–C4
• Blood supply: dorsal scapular and transverse cervical arteries

The levator scapulae is a small strap-like muscle that begins in the neck and descends to attach to the scapula. It belongs to the deep layer of the extrinsic shoulder muscles, together with rhomboid major and rhomboid minor; trapezius and latissimus dorsi form the superficial layer. (TeachMeAnatomy: The Extrinsic Muscles of the Shoulder.)

Its upper part lies under the splenius capitis and sternocleidomastoid muscles, and its lower part is covered by the trapezius. Its middle part is exposed in the neck, where it helps to form the floor of the posterior triangle. (Kenhub: Levator scapulae muscle.)

The posterior triangle of the neck lies between the posterior border of sternocleidomastoid, the anterior border of trapezius and the middle third of the clavicle. Its floor is made of splenius capitis, levator scapulae and the anterior, middle and posterior scalenes, all covered by prevertebral fascia. The accessory nerve (cranial nerve XI) crosses the triangle superficially, on top of this floor. Deeper, the cervical plexus forms within the floor muscles and the trunks of the brachial plexus cross the floor. (TeachMeAnatomy: Posterior Triangle of the Neck.)

Origin: the posterior tubercles of the transverse processes of the C1 to C4 vertebrae. Insertion: the superior part of the medial border of the scapula. (University of Washington Musculoskeletal Atlas: Levator scapulae.)

Kenhub describes the fibres as descending laterally from the first four cervical vertebrae to insert at the superior angle and medial border of the scapula. (Kenhub: Levator scapulae muscle.)

Below levator scapulae, rhomboid minor attaches to the medial border at the level of the scapular spine, and rhomboid major attaches between the spine and the inferior angle. The three muscles together cover the whole medial border. (TeachMeAnatomy: The Extrinsic Muscles of the Shoulder.)

Levator scapulae elevates the scapula and tilts its glenoid cavity inferiorly by rotating the scapula. This downward rotation turns the shoulder socket to face more downward, the opposite of the rotation that trapezius produces when the arm is raised. (University of Washington Musculoskeletal Atlas: Levator scapulae.)

Kenhub describes its main function as elevating and retracting the shoulder girdle. When the scapula is fixed, the muscle acts on the neck: contraction on one side bends the neck towards the same side (ipsilateral lateral flexion), and contraction on both sides helps to extend the neck. (Kenhub: Levator scapulae muscle.)

Levator scapulae is not the only muscle that lifts the scapula. The upper fibres of trapezius also elevate the scapula, but they rotate it upward during abduction of the arm, whereas levator scapulae rotates it downward. The middle fibres of trapezius retract the scapula and the lower fibres pull it down. Trapezius is supplied by the accessory nerve. (TeachMeAnatomy: The Extrinsic Muscles of the Shoulder.)

The rhomboids lie in the same deep layer as levator scapulae and share its nerve, the dorsal scapular nerve. Rhomboid major arises from the spinous processes of T2 to T5 and rhomboid minor from C7 to T1; both retract and rotate the scapula. (TeachMeAnatomy: The Extrinsic Muscles of the Shoulder.)

Levator scapulae has a double nerve supply: direct branches of the cervical nerves C3 and C4, and the dorsal scapular nerve (C5). Its arterial supply in the University of Washington atlas is the dorsal scapular artery. (University of Washington Musculoskeletal Atlas: Levator scapulae.)

Kenhub describes the cervical supply as coming from the anterior rami of C3 and C4, and the blood supply as two branches of the thyrocervical trunk. Sources therefore differ in how they name its arteries. (Kenhub: Levator scapulae muscle.)

The dorsal scapular nerve is a branch of the brachial plexus that arises directly from the C5 root, before the trunks form. (TeachMeAnatomy: The Brachial Plexus.)

The dorsal scapular nerve arises just above the clavicle, pierces scalenus medius, and descends between levator scapulae and serratus posterior superior or scalenus posterior. It runs along the rhomboids, usually with the dorsal scapular artery or the deep branch of the transverse cervical artery, and supplies levator scapulae, rhomboid major and rhomboid minor. (Kenhub: Dorsal scapular nerve.)

An isolated lesion of the dorsal scapular nerve that paralyses levator scapulae is very rare. The muscle also receives branches from C3 and C4. (Kenhub: Levator scapulae muscle.)

Dorsal scapular nerve syndrome is usually caused by entrapment of the nerve, often in scalenus medius. Since the nerve is the only motor supply to the rhomboids, injury lets the scapula drift laterally, limits shoulder movement and causes pain along the medial border of the scapula. (Kenhub: Dorsal scapular nerve.)

The shoulder shrug is used to test trapezius and the accessory nerve. The commonest cause of accessory nerve damage is iatrogenic, for example during procedures such as cervical lymph node biopsy. Other signs of accessory nerve damage include muscle wasting, partial paralysis of sternocleidomastoid and an asymmetrical neckline. (TeachMeAnatomy: The Extrinsic Muscles of the Shoulder.)

The nearest named structures in the 3D model, measured from the centre of each part:

• Splenius capitis · muscular
• Deep cervical artery · cardiovascular
• Scalenus posterior · muscular
• Longissimus capitis · muscular
• Omohyoid · muscular
• Scalenus medius · muscular
• Descending part of trapezius · muscular
• Scalenus anterior · muscular
• Longissimus cervicis · muscular
• Cervical rotator · muscular