Anatomy of Scalene Muscles ; Posterior scalene, Anterior Scalene, Middle Scalene ; Origin, Insertion

Anatomy of the Scalene Muscles
The scalene muscles are a group of three paired muscles located in the lateral neck. They are important for various neck movements and respiration. The three muscles are named based on their positions: anterior scalene, middle scalene, and posterior scalene.

Anterior Scalene Muscle
Origin:

Transverse Processes: From the anterior tubercles of the transverse processes of the C3-C6 cervical vertebrae.

Insertion:

First Rib: Scalene tubercle on the inner border of the first rib.

Function:

Flexion of the Neck: Bends the neck forward.

Lateral Flexion: Bends the neck sideways.

Elevation of the First Rib: Assists in lifting the first rib during inspiration.

Innervation:

Cervical Spinal Nerves: C4-C6.

Middle Scalene Muscle
Origin:

Transverse Processes: From the posterior tubercles of the transverse processes of the C2-C7 cervical vertebrae.

Insertion:

First Rib: Upper surface of the first rib, posterior to the subclavian groove.

Function:

Lateral Flexion of the Neck: Bends the neck sideways.

Elevation of the First Rib: Assists in lifting the first rib during inspiration.

Innervation:

Cervical Spinal Nerves: C3-C8.

Posterior Scalene Muscle
Origin:

Transverse Processes: From the posterior tubercles of the transverse processes of the C5-C7 cervical vertebrae.

Insertion:

Second Rib: Outer surface of the second rib.

Function:

Lateral Flexion of the Neck: Bends the neck sideways.

Elevation of the Second Rib: Assists in lifting the second rib during inspiration.

Innervation:

Cervical Spinal Nerves: C6-C8.

Functional Significance
The scalene muscles are essential for neck movement and stabilization, as well as assisting in respiration by elevating the first and second ribs during deep breathing. They also play a role in maintaining proper posture of the cervical spine.

Clinical Relevance
Thoracic Outlet Syndrome: Compression of the brachial plexus and subclavian vessels between the scalene muscles and surrounding structures can lead to symptoms like pain, numbness, and weakness in the upper limb.

Muscle Spasms or Strain: Can result in neck pain and restricted movement.

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