The Auricular region, or the muscles of the ear, consists of three small, fan-shaped muscles: attrahens auriculam, retrahens auriculam, and attolens ariculam. The Attrahens auriculam, also referred to as the auricularis anterior, is the smallest of the three muscles and is located just in front of the ear. It originates from the galia aponeurotica and inserts in the cartilage of the ear. Some anatomists consider this muscle to be a part of the temporoparietalis. The Attollens auriculam, also referred to as the auricularis superior, is the largest of the three muscles and is located just above the ear. It originates from the galia aponeurotica and inserts in the cartilage of the ear. This muscle is also considered to be a part of the temporoparietalis. The Retrahens auriculam is also referred to as the auricularis posterior and is located just behind the ear. It originates from the mastoid process and inserts into the root of the ear. All three muscles are innervated by the facial nerve (VII cranial nerve) and supplied by branches of the facial artery. These muscles have very little action, the Attrahens auriculam draws the ear upward and forward. The Attollens auriculam slightly raises it and the retrahens auriculam draws it back. As a general rule, they cannot be contracted by an individual voluntarily. Research Auricular Region
The concha is the deep, bowl-shaped part of the earcartilage that attaches directly to the side of the head at the front of the mastoid process of the skull. The opening to the auditory canal is located in the lower front corner of the concha. The concha helps funnel sound into the auditory canal. Research Concha
The rearmost part of the temporal bone is referred to as the mastoid process. Sometimes also called the mastoid bone (because it is demarcated from the rest of the temporal bone by a suture line), this process joins the occipital bone at the lower ends of the lambdoid suture. Research Mastoid Process
The skull is one of the principle groups of bones in the human anatomy. The skull consists of twenty-six bones: eight bones form the skull, which houses the brain and ear ossicles, plus fourteen facial bones, which form the front of the face, jaw, nose, orbits, and the roof of the mouth, three more bones make up the inner ear ossicles, and one more, the hyoid bone, is in the neck and is attached to the temporal bone by ligaments and anchors the tongue. The skull also contains a dental arcade of teeth, which are technically not bones, though they do share some of the compositional characteristics of bonetissue. Children may grow twenty deciduousteeth, which will eventually fall out and be replaced by the permanent teeth.
The bones of the skull include the frontal bone, the occipital bone, two parietal bones, and two temporal bones. The lower rearmost part of each temporal bone is called the mastoid process, but because it is separated from the temporal bone, proper, by a suture, it is often considered a separate bone. The sphenoid bone forms the central base of the skull and spans the skull from side to side, the greater wings forming side plates of the skull. The sections of the ethmoid bone are positioned between the orbits, forming the walls and roof of the nasal cavity, while the three middle ear ossicles (stapes, malleus, and incus) are located within the temporal bones on each side of the skull. The U-shaped hyoid bone is found in the neck, and is attached by ligaments to the temporal bones. In the face, the two maxillary bones form much of the orbits, nose, upper jaw and roof of the mouth, while the zygomatic bones form the cheeks. The lachrymal bones are located on the inner sides of the orbits and are attached to the ethmoid bone and maxillary bones. Within the nasal cavity, the vomer is located in the low center and forms the thin flat bone of the nasalseptum, while two inferior urbinates form the lower sides of the cavity and two palate bones form the floor of the nasal cavity as well as the roof of the mouth.
The mandible is the only movable part of the skull, forming the lower jaw and mounting the teeth. The bones of the skull, with the exception of the mandible, are held together by very thin sutures, or seams, in which the periosteum of the individual bones interweave with each other, and are cemented by a fibrous, connective tissue. In the newborn, these sutures are not yet developed, with the bones being attached by cartilage which ossifies over time as the bones of the skull fuse together. The most evident external sutures of the skull include the coronal suture, joining the frontal bone and parietal bone, the sagittal suture, joining the parietal bones to each other, the lambdoid suture, joining the occipital and parietal bones, the squamous suture, joining the temporal and sphenoid bones to the parietal bone on each side of the skull.
The pterion is the short segment of the suture joining the squamous and parietal bones. The bones of the skull also feature a number of sinuses and foramina. Four pairs of sinuses flank the nasal cavity. Two are found in the maxillary bone, and are called maxillary sinuses. The sphenoid bone forms two paranasal sinuses called the sphenoids, and the ethmoid bone forms the two paranasal sinuses called ethmoids. Additionally, the frontal sinuses are located in the frontal bone just behind the roof of each orbit. The foramen magnum is a large, round opening in the base of the skull which admits the spinal cord, while at the base of each temporal bone is the external auditory meatus, which serve as the auditory canals. Just above each orbit in the frontal bone is a small notch or hole, called a supraorbital foramen, and just below each orbit, in the maxillary bone, is an infraorbital foramen. Two more openings, one on each side of the skull, can be found in the frontal processes of the zygomatic bones, and are called zygomatofacial foramina.
On each side of the mandible, just below the lower canines, are the mental foramina. These facial foramina serve to admit blood vessels and nerves through and into the bone. The teeth are mounted in the maxillary bone and the mandible, and are brought together for chewing by the hinge-like motion of the mandible. An average adult will have thirty-two teeth, evenly arrayed on the maxilla and mandible. Research Skull
The splenius capitis muscle runs along the back of the neck and joins the skull and spine. It is narrow and pointed at its origin from the last four cervical vertebrae and the supraspinous ligament of the first and second thoracic vertebrae. It becomes broader, dividing into two portions with separate insertions. The splenius capitis is inserted into the mastoid process of the temporal bone and the splenius colli (splenius cervicis) is inserted in two or three upper cervical vertebrae. The splenius capitis is innervated by dorsal branches of the second to sixth cervical nerves and is supplied by muscular branches of the aorta. It is used to rotate and tilt the head from side to side. Research Splenius Capitis
The sternocleidomastoid (sternocleidomastoideus; sternomastoid) muscle is located in the neck. It is a thin, broad muscle that narrows at the center. It originates from two heads, one from the sternum and and one from the clavicle , and runs upward, inserting into the mastoid process. The sternocleidomastoid muscle is innervated by the accessory nerve and the cervical plexus. It is supplied by the occipital arteryans the superior thyroidartery. This muscle is used to tilt the head from side to side. Research Sternocleidomastoid
The two temporal bones form the lower sides of the skull and part of the cranial floor. They also protect the organs responsible for hearing and equilibrium. A canal (called the external auditory meatus) passes through the lower part of the temporal bone and admits the earcanal. The temporal bone features the zygomatic process, which is a protrusion from the back part of the temporal bone which loops forward to meet the zygomatic bone to form the zygomatic arch. At the middle of this zygomatic arch is a small protrusion downward, called the articular tubercle. The front part of the temporal bone, forming the side of the skull slightly above and to the front of the ear, joins the greater wing of the sphenoid bone to compose the temple region of the skull. This frontal section of the temporal bone is called the squamous part, as it is also joined to the parietal bone at the squamous suture. The rearmost part of the temporal bone is referred to as the mastoid process. Research Temporal Bones
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Auricular Region
