What is the sternocleidomastoid muscle?
The sternocleidomastoid (SCM) is a large, superficial muscle located in the neck. The muscle is shaped like a broad, thin band and functions as a prime mover of head rotation, head tilt, and head flexion, and also plays a secondary role in breathing. (1)
The right and left sternocleidomastoid muscles work together and are capable of producing both unilateral and bilateral contractions, depending on the specific movement required. In addition, it often becomes strained or tight in people with poor posture, which can cause neck pain and headaches.
Origin, insertion and function
Origin
Sternal head: superior part of anterior surface of manubrium sterni
Clavicular head: superior surface of medial third of the clavicle
Insertion
Lateral surface of mastoid process and lateral half of superior nuchal line.
Function
Flexes and laterally rotates cervical spine. Protracts head when acting together . Extends neck when neck already partially extended.
Common signs of a weak sternocleidomastoid
Common signs that your sternocleidomastoid muscles may be weak include:
- Poor posture, including forward head posture and rounded shoulders
- Limited range of motion in the neck
- Neck pain or headaches
- Tension or discomfort in the neck and shoulder region
- Reduced ability to turn or tilt the head
- Difficulty maintaining balance and stability, especially during physical activity or movement.
Exercises to strengthen the sternocleidomastoid
Exercises to strengthen the sternocleidomastoid muscle include:
Isometric Neck Tilt:
- Stand or sit with good posture.
- Tilt your head to one side and hold the position for 5-10 seconds.
- Repeat on the other side.
- Perform 2-3 sets of 10 repetitions on each side.
Neck Rotation:
- Stand or sit with good posture.
- Slowly rotate your head to one side, hold for a count of 2-3, then return to center.
- Repeat on the other side.
- Perform 2-3 sets of 10 repetitions on each side.
Resistance Band Pull:
- Attach a resistance band to a sturdy object at head height.
- Stand facing the band with feet shoulder-width apart.
- Grasp the band with both hands and pull it towards your chest, keeping your elbows close to your sides.
- Hold for a count of 2-3, then slowly release.
- Perform 2-3 sets of 10 repetitions.
Wall Slide:
- Stand facing a wall with feet shoulder-width apart and arms extended.
- Slowly slide your hands down the wall, keeping your arms straight, until your arms are parallel to the floor.
- Hold for a count of 2-3, then slowly slide back up to starting position.
- Perform 2-3 sets of 10 repetitions.
It is important to perform these exercises under the guidance of a physical therapist or a healthcare professional to ensure proper form and to avoid injury. Additionally, it is recommended to perform them consistently and progressively increase resistance to maximize results.
References:
- Bordoni B, Varacallo M. Anatomy, Head and Neck, Sternocleidomastoid Muscle. [Updated 2022 Apr 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532881/