Identify the muscles of the head and neck.
The Correct Answer and Explanation is :
The occipitalis muscle, also known as the occipital belly of the occipitofrontalis muscle, is a thin, quadrilateral muscle located at the back of the head. It plays a crucial role in moving the scalp backward.
Anatomy of the Occipitalis Muscle:
- Origin: The occipitalis originates from the lateral two-thirds of the superior nuchal line of the occipital bone and the mastoid process of the temporal bone.
- Insertion: It inserts into the epicranial aponeurosis, a tendinous sheet that connects the occipitalis to the frontalis muscle at the forehead.
- Innervation: The muscle is innervated by the posterior auricular nerve, a branch of the facial nerve (cranial nerve VII).
- Function: The primary function of the occipitalis is to retract the scalp. When it contracts, it pulls the scalp backward, which can assist in raising the eyebrows and wrinkling the forehead. This action is coordinated with the frontalis muscle, allowing for the movement of the entire scalp.
Clinical Relevance:
Understanding the anatomy and function of the occipitalis muscle is important in various medical fields, including neurology and plastic surgery. Dysfunction or injury to this muscle or its innervation can affect facial expressions and scalp movement. For instance, damage to the facial nerve can impair the function of both the occipitalis and frontalis muscles, leading to difficulties in moving the scalp and forehead.
In summary, the occipitalis muscle is a vital component of the scalp’s muscular system, contributing to facial expressions and the movement of the scalp.