12.2: Muscles of the Head and Neck
- Page ID
- 53685
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Head
The epicranius muscle is also very broad and covers most of the top of the head. The epicranius muscle includes a middle section which is all aponeurosis (white, fibrous, flat, tendon-like tissue). The actual muscle tissue is only found over the forehead (the portion of the muscle called the epicranius frontalis, or frontal belly of epicranius) and the back of the head (the portion of the muscle called the epicranius occipitalis, or occipital belly of the epicranius).
The buccinator muscles, one on each side of the face, compress the cheeks when contracted. The name is from the Latin for trumpet, which requires blowing air out of the cheeks to play, and also reflects the anatomical adjective for the cheek, buccal.
The two masseter muscles are also on each side of the face. They close the jaw when contracted. Its name is derived from the same Greek root as mastication, which means to chew.
The zygomaticus major muscles and the zygomaticus minor muscles are found on each side of the face both have their origins on the zygomatic bone. They both can change the shape of the mouth by elevating it.
Above: Muscles of the head.
Above: Deeper muscles of the head. This diagram shows the masseter removed (superficial and deep), temporalis removed, risorius removed, and zygmaticus major removed. Buccinator is shown in red, lateral pterygoid in green, and medial pterygoid in black.
Above: Cadaver images of the muscles of the head.
Clinical Application: The Buccinator Muscle
The buccinator muscle is a deep muscle of the cheek. Its primary role is to assist in mastication (chewing) by keeping food between upper and lower teeth. If you’ve ever bitten your cheek bad enough, you may have bitten down on your buccinator (although under most instances, you only bite down on the epithelium and superficial fascia that lines the innermost surfaces of your cheeks). The buccinator muscle also assists infants with suckling and adults with whistling.
Eye
The movements of the eyeball are controlled by six muscles. The muscles "rectus" are straight muscles and the "oblique" muscles are positioned at an angle in relationship to the straight muscles. Each of the ocular muscles are named for their positions (superior, inferior, lateral and medial): superior rectus, superior oblique, inferior rectus, inferior oblique, lateral rectus, and medial rectus. Additionally, levator palpebrae superioris, located superiorly to the eye, raises the eyelid.
Above: Diagram of the ocular muscles of the right eye. The lateral rectus is shown as broken only to allow view of medial rectus.