Splenius muscles

File:Splenius muscle.PNG

Diagram of the splenius muscles

The splenius muscles are a group of muscles located in the back of the neck and upper thoracic region. They are part of the superficial layer of the intrinsic back muscles and are primarily responsible for movements of the head and neck.

Anatomy

The splenius muscles consist of two distinct muscles:

• Splenius capitis
• Splenius cervicis

Splenius Capitis

The splenius capitis is a broad, strap-like muscle that originates from the lower half of the ligamentum nuchae and the spinous processes of the C7 to T3 vertebrae. It inserts onto the mastoid process of the temporal bone and the lateral third of the superior nuchal line of the occipital bone.

Splenius Cervicis

The splenius cervicis is located inferior to the splenius capitis. It originates from the spinous processes of the T3 to T6 vertebrae and inserts onto the transverse processes of the C1 to C3 vertebrae.

Function

The primary functions of the splenius muscles include:

• Extension of the head and neck: When both sides of the muscles contract together, they extend the head and neck.
• Lateral flexion and rotation: When one side contracts, it results in lateral flexion and rotation of the head to the same side.

Innervation

The splenius muscles are innervated by the posterior rami of the cervical spinal nerves.

Blood Supply

The blood supply to the splenius muscles is primarily through the branches of the occipital artery and the transverse cervical artery.

Clinical Significance

The splenius muscles can be involved in various clinical conditions, such as:

• Muscle strain: Overuse or sudden movements can lead to strain in these muscles, causing neck pain and stiffness.
• Tension headaches: Tightness in the splenius muscles can contribute to tension-type headaches.

Related Pages

• Muscles of the neck
• Cervical vertebrae
• Occipital bone
• Ligamentum nuchae