The anatomy of the head, neck and brain is complex and extensive. To better understand headaches, it is important to be aware of some specific anatomical structures within this region.
Although the bones of the skull themselves are not responsible for the pain associated with a headache, it is worthy to know the names and location of the main skull bones when discussing headaches.
For instance the frontal bone is the skull bone that lies under the forehead. Health care professionals may refer to headaches as being a "frontal headache". Similarly, most people know where their temples are, which are the soft indentations at the side of the forehead. The temples overlie the temporal and sphenoid skull bones. The occipital bone is at the back of the head. Headaches in this region are often termed occipital headaches. The maxillary bone is the bone that houses the top row of teeth. The mandible, houses the bottom row and is more commonly known as your jaw bone. Lastly, the two parietal bones are the large skull bones at the top of your head above your ears.
The temporomandibular joint, or TMJ, is in layman"s terms, the jaw joint. The TMJ connects the mandible bone or jaw bone to the skull itself. The TMJ is a complicated joint that contains a moveable disc. The joint works to open and close your jaw for activities such as speaking, chewing and singing.
The anatomy of the upper neck is also very important in regards to headaches, as irritation of the structures in this area can be the cause of certain types of headaches. The upper three neck (cervical) vertebrae and their related anatomical structures in particular often contribute to pain in the head. The upper most cervical vertebrae (C1) is called the atlas, and the skull sits directly on this vertebrae. The next vertebrae (C2), is called the axis. The axis has a protruding piece of bone called the odontoid process that fits into the atlas above; C1 and C2 work together to create rotational movement of the head on the neck, and this joint alone allows 45 degree of left and right rotation of the head. The third cervical vertebrae (C3) is similar to the rest of the lower cervical vertebrae, but due to its close proximity to the upper neck, it acts more closely in conjunction with the atlas and axis during neck movements.
The main nerves in the body provide sensation (sensory supply), movement (motor supply), or both. The sensory and motor nerve supply to the upper neck, head and skull come from the nerves that are associated with the upper three cervical vertebrae (C1, C2 and C3) as well as from one of the cranial nerves that originates from inside the brain (the trigeminal nerve). The nerves associated with the upper three cervical vertebrae originate from the spinal cord deep within in the neck. The C1-3 nerves supply the local neck structures of the upper three vertebrae such as the ligaments, joints, muscles and tendons. The C1-3 nerves also combine together to create larger nerves, which supply the skin sensation to the occipital and parietal regions of the skull.
The sensory and motor nerve supply to each side of the face and jaw comes from the trigeminal nerve on that same side, which is one of the twelve cranial nerves that originate from deep inside the brain. The trigeminal nerve (also termed the 5th cranial nerve or CN V) has three branches, the ophthalmic branch, the maxillary branch, and the mandibular branch. These branches together supply the sensation from high above the forehead and temple area all the way down to the jaw including the nose, lips, teeth, gums and sinuses. The motor supply of the trigeminal nerve includes some of the muscles of mastication (chewing) including the large temporalis muscle and the strong masseter muscle. The trigeminal nerve also supplies nerve input to a number of the blood vessels of the brain as well as the lining of the brain (the meninges). Another important cranial nerve in regards to headaches is the facial nerve (also termed the 7th cranial nerve or CN VII). This nerve supplies motor function to the muscles used to create facial expressions as well as the occipitalis muscle as the back of the head. It also supplies sensation to part of the tongue including the sensation of taste in this area.
In regards to the headache-related muscles of the head, neck and shoulder, there are many muscles that can be associated with headache pain, however a few are more worthy of noting than others. Though there are certain types of headaches that are caused by muscle tightness itself, there are other cases where muscle tightness is a result of the headaches pain itself.
As mentioned above, two of the main muscles of mastication, namely the temporalis and the masseter muscles can be related to headache pain. These muscles are in close anatomical proximity to common headache locations and their nerve supply, the trigeminal nerve, also supplies the sensation to the front of the head and temple area. The temporalis muscle is located on each side of your head under the temples; if you clench your teeth while touching this area you will feel the temporalis muscle bulge under your fingers. The masseter muscle is located over each jaw. Similarly if you touch this area and again clench your teeth you will feel the masseter muscle bulge.
The occipitalis muscle is located on either side of your head at the back of the skull, behind your ears and towards your neck. The function of this muscle is to move the scalp backwards.
There are several small muscles at the extreme upper part of the neck, which attach from one vertebrae to the next as well as attach from the top two vertebrae (C1 & C2) up onto the skull. Collectively these muscles are called the suboccipital muscles. They are responsible for some of the movement of the upper two cervical vertebrae as well as some of the movement of the head itself on the neck.
The trapezius muscle is the large muscle at the top of your shoulder, which creates the angle of the neck. Beneath this muscle are several long muscles of the neck, which attach from the cervical vertebrae down to both other cervical vertebrae and extend even farther down into the thoracic region.
In addition to the nerves, and muscles of the head, neck and jaw there is a network of blood vessels that carry blood to all the structures of this area including the brain. This network of vessels is extremely complex and too extensive to describe but they should be noted as important anatomy that can be related to headache pain.
Lastly, the brain itself is an important structure to discuss in regards to headaches. The main brain structure that most people think of when the brain is mentioned is termed the cerebral cortex. The cortex assimilates a great deal of the information that is sent to the brain. It plays a major part in memory, attention, perceptual awareness, thought, language, and consciousness. The cortex is divided into specific lobes, which are named similarly to the skull bones of the same area. These are the frontal, parietal, temporal and occipital lobes. Each area is specifically responsible for a function of the brain. Although the brain in its entirety is obviously important, the occipital lobe, which is the primary vision center of the brain, is particularly important to note when discussing headaches. Concurrent visual disturbances occur for many people during headaches and this is thought to have something do with brain input to and from the occipital lobe.
It should be mentioned that the location of your headache pain is not often in the same location as the structures that are causing your pain and this is termed referred pain. Referred pain occurs when an irritated structure causes pain in another location away from the original irritated site.