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This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat. == Musculoskeletal system == The head is positioned upon the superior portion of the vertebral column, attaching the skull upon C-1 (the first cervical vertebra known as the atlas). The skeletal section of the head and neck forms the superior segment of the axial skeleton and comprises skull, hyoid bone, auditory ossicles, and cervical spine. The skull can be further subdivided into: (a) cranium (8 bones: frontal, 2-parietal, occipital, 2-temporal, sphenoid, ethmoid), and (b) facial bones (14 bones: 2-zygomatic, 2-maxillary, 2-palatine, 2-nasal, 2-lacrimal, vomer, 2-inferior conchae, mandible). As the fetus develops, the facial bones usually form into pairs, and then fuse together. As the cranium fuses, sutures are formed that resemble stitching between bone plates. In a newborn, the junction of the parietal bones with the frontal and occipital bones, form the anterior (front) and posterior (back) fontanelle, or soft spots. The separation of the cranial bone plates at time of birth facilitate passage of the head of the fetus through the mother's birth canal, or pelvic girdle. The parietal bones, and occipital bone can overlap each other in the birth canal, and form the unusual looking "cone head" appearance in a newborn when delivered in a natural, or vaginal, delivery. The occipital bone articulates with the atlas near the foramen magnum. The atlas articulates with the occipital condyle superiorly and the axis inferiorly. The spinal cord passes through the foramen magnum providing continuity for the central nervous system (CNS). Articulation of the neck includes: flexion, extension, (nodding yes), and rotation (shaking head no). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Head and neck anatomy」の詳細全文を読む スポンサード リンク
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