Head AnatomyThe human head is more than just a nuisance responsible for your headaches. It is a complex anatomical structure weighing up to five kilograms that rests on the bony skull and in turn, the neck. In addition to the evident ears, eyes, nose, and mouth, the head supports a variety of other important structures:
- Muscles of mastication
- Facial muscles
- Salivary glands
In this page, we are going to focus on those five less evident features and learn more about them.
Muscles of mastication
The muscles of mastication are involved in the mechanical digestion, otherwise known as chewing, of food. There are four muscles in total:
Origin - maxillary process of zygomatic bone, Inferior border of zygomatic arch (superficial part), deep/inferior surface of zygomatic arch (deep part)
Insertion - lateral surface of the ramus of the mandible
Innervation - masseteric nerve (branch of the mandibular nerve (CN V3))
Action - elevates and retracts mandible
Origin - temporal fossa, temporal facia
Insertion - apex and medial surface of coronoid process of mandible
Innervation - deep temporal nerves (branches of the mandibular nerve)
Action - elevation and retraction of the mandible
Origin - tuberosity of maxilla, pyramidal process of palatine bone (superficial part); medial surface of lateral pterygoid plate of sphenoid bone (deep part)
Insertion - medial surface of ramus and angle of mandible
Innervation - nerve to medial pterygoid (branch of the mandibular nerve (CN V3))
Action - elevates and protrudes mandible (bilateral contraction); medial movement (rotation) of mandible (unilateral contraction)
Origin - infratemporal crest of greater wing of sphenoid bone (superior head); lateral surface of lateral pterygoid plate of sphenoid bone (inferior head)
Insertion - joint capsule of temporomandibular joint (superior head); pterygoid fovea on neck of condyloid process of mandible (inferior head)
Innervation - nerve to lateral pterygoid (branch of the mandibular nerve (CN V3))
Action - protrudes and depresses mandible, stabilizes condylar head during closure (bilateral contraction); medial movement (rotation) of mandible (unilateral contraction)
All the masticatory muscles move the mandible by acting on the temporomandibular joint. Watch the following videos and read the article to learn more about them.
The facial muscles are the main constituents of your face, playing a significant role in facial expression. Also known as the mimetic muscles, these skeletal muscles allow you to smile, wink, frown, express fear, and so on. There are five main groups of facial muscles, each one consisting of several smaller muscles that are responsible for the movement of a particular region of the face:
- Orbital group
- Nasal group
- Oral group
- Auricular group
- Scalp and neck group
There are quite a lot of them, right? Luckily, they become easier with repetition. In order for you to face anatomy head-on and make your life a little easier with learning the above muscles, tackle the following facial muscles quiz.
Salivary glands are anatomical structures located in close vicinity to the oral cavity. They secrete saliva into the mouth to help with protection, lubrication, and digestion. There are three major salivary glands:
In addition to the major ones, there are also some minor salivary glands. Watch the following video and read the article to learn about all of them.
Major arteries of the head
There are several arteries supplying the head with oxygenated blood. The most important ones for head anatomy branch from the external carotid arteries. These include the: superior thyroid (mostly supplies the neck), ascending pharyngeal, lingual, facial, occipital, posterior auricular, and maxillary arteries.
|Source||Common carotid artery (at the level of the thyroid cartilage in the larynx )|
Superior thyroid artery (S)
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(S): Thyroid gland, infrahyoid muscles, sternocleidomastoid muscle
(A): Pharynx, prevertebral muscles, middle ear, cranial meninges
(L): Intrinsic muscles of the tongue, floor of the mouth
(F): Tonsils, palate, submandibular glands
(O): Posterior region of the scalp
(P): Parotid gland, facial nerve, ear, scalp
(M): External acoustic meatus, tympanic membrane, dura mater, calvaria, mandible, gingivae, teeth; temporal, pterygoid, masseter, buccinator muscles
(S): Temporal region of the scalp
Watch the following videos to learn all about the major arteries of the head.
The most important one in this list is the maxillary artery, the largest terminal branch of the external carotid supplying the deep structures of the face. An equally important artery is the facial artery, which supplies the muscles of facial expression.
Nerves in the head
Since the head is such a ‘vast’ anatomical region, it’s innervation is quite extensive. For the purposes of this page, we’ll only talk about the relevant nerves for the previously mentioned anatomical structures.
The nerves in the head originate from three main sources:
The trigeminal nerve supplies sensory innervation to the forehead and cheek regions of the face via its ophthalmic and maxillary branches. The mandibular division supplies both sensory and motor innervation to the jaw and masticatory muscles. The facial nerve provides motor innervation to the muscles of facial expression. Salivary glands are controlled by autonomic nerves stemming mainly from the same facial nerve. The cervical plexus is formed by the C1 to C5 spinal nerves, giving off two branches innervating the head: lesser occipital and greater auricular nerves.
Solidify your knowledge about the head anatomy with this specially designed quiz that covers the bones, muscles, organs and vessels of the head!