Where do the scalene muscles originate and insert?

The scalene muscles are actually a muscle group, which are generally divided into anterior, middle and posterior scalene muscles, but not all people have scalene muscles. The starting point of the scalene muscles is the nodule in front of the transverse process of C3-6, and the insertion point is at the inner edge of the first rib and in front of the subclavian artery, behind the subclavian vein and behind the phrenic nerve. The scalene muscles can help provide a certain stability to the middle and lower cervical spine.

The largest scalene muscle has its origin attached to the posterior tubercle of the transverse process of C2-7, and its insertion point is attached to the upper edge of the first rib and deep in the transverse groove of the subclavian artery, behind the attachment point of the anterior scalene muscle; the posterior scalene muscle has its origin attached to the posterior tubercle of the transverse process of C5-7, and its insertion point is attached to the outer surface of the second rib, which is located behind the middle scalene muscle, deep in the anterior edge of the upper trapezius muscle and the levator scapulae muscle;

Palpation of scalene muscles:

Transverse process of the axis (second cervical vertebra): The landmark points are the mandibular angle and the sternocleidomastoid muscle. The transverse process of the axis is located between them. The anterior tubercle is located in front of the transverse process, and the posterior tubercle is located behind the transverse process. Be careful when palpating.

Transverse processes of the 3rd to 7th cervical vertebrae: The examiner's fingers are placed between the sternocleidomastoid muscle and the upper trapezius muscle, and the transverse processes can be touched by sliding the fingers up and down.

Anterior scalene muscles: Locate the clavicular head of the sternocleidomastoid muscle and reach slightly posteriorly toward the clavicle to palpate the scalene belly with one or two fingers. Move your fingers gradually outward until you can touch the first rib.

Middle and posterior scalene muscles: Locate the levator scapulae, move your hand forward, and you can feel a considerable amount of the middle scalene muscle belly in the clavicular fossa. The posterior scalene muscle is behind the middle scalene muscle.

Scalene muscle function:

Since the scalene muscles are attached to the transverse processes of the cervical vertebrae and the ribs, when the cervical spine is fixed, the contraction of the scalene muscles can lift the ribs to assist in the inhalation movement; when the ribs are fixed, unilateral contraction of the scalene muscles can cause ipsilateral lateral flexion of the cervical spine, and bilateral contraction can assist in flexion of the cervical spine; in addition, the scalene muscles also provide stability to the middle and lower sections of the cervical spine.

Causes of scalene muscle injury:

The common causes of scalene muscle strain are as follows: the head and neck are kept in a fixed position such as lateral flexion or tilt for too long. For example: writing, working at a desk, reading, watching TV, playing mahjong, riding in a car, etc., will keep the anterior scalene muscle in a state of tension and contraction for a long time, causing excessive fatigue and injury. Prolonged lifting and pulling of heavy objects. Because the object is heavy, the head must be in the opposite direction. In this way, under the action of external force for a long time, it is very easy to cause damage to the anterior scalene muscle.