In human anatomy, the sternocleidomastoid muscle inserts on which structure?

• A. Mastoid process of the temporal bone and lateral part of the superior nuchal line of the occipital bone
• B. Spinous processes of the cervical vertebrae
• C. Coracoid process of the scapula
• D. Medial third of the clavicle and manubrium of the sternum

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the anatomy of the sternocleidomastoid muscle. It is a paired muscle in the neck that plays a key role in head movement and rotation.
2. Step 2: Identify the origin points of the sternocleidomastoid muscle, which are the medial third of the clavicle and the manubrium of the sternum. These are the starting points where the muscle attaches.
3. Step 3: Determine the insertion points, which are the locations where the muscle attaches after crossing the neck. The insertion points are important because they indicate where the muscle exerts its action.
4. Step 4: Recall that the sternocleidomastoid inserts on the mastoid process of the temporal bone and the lateral part of the superior nuchal line of the occipital bone. These bony landmarks are located on the skull behind the ear and at the back of the head.
5. Step 5: Compare the given options with the known insertion points. The correct insertion is the mastoid process of the temporal bone and the lateral part of the superior nuchal line of the occipital bone, not the spinous processes of cervical vertebrae, coracoid process of the scapula, or the origin points.