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Head And Neck Anatomy
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. Structure Bones The head rests on the top part of the vertebral column, with the skull joining at C1 (the first cervical vertebra known as the atlas). The skeletal section of the head and neck forms the top part of the axial skeleton and is made up of the skull, hyoid bone, auditory ossicles, and cervical spine. The skull can be further subdivided into: # the cranium (8 bones: frontal, 2-parietal, occipital, 2-temporal, sphenoid, ethmoid), and # the facial bones (14 bones: 2-zygomatic, 2-maxillary, 2-palatine, 2-nasal, 2-lacrimal, vomer, 2-inferior conchae, mandible). The occipital bone joins with the atlas near the foramen magnum, a large hole () at the base of the skull. The atlas joins with the occipital condyle above and the axis below. The spinal cord passes through the foramen magnum. Musc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MRI Head 5 Slices
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from CT and PET scans. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy. MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft-tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, though "Open" MRI designs mostly relieve this. Additionally, implants and othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occipitalis
The occipitalis muscle (occipital belly) is a muscle which covers parts of the skull. Some sources consider the occipital muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscle along with the frontalis muscle. The occipitalis muscle is thin and quadrilateral in form. It arises from tendinous fibers from the lateral two-thirds of the superior nuchal line of the occipital bone and from the mastoid process of the temporal and ends in the epicranial aponeurosis. The occipitalis muscle is innervated by the facial nerve and its function is to move the scalp back. The muscles receives blood from the occipital artery. Additional image File:Occipitalis muscle animation small.gif, Position of occipitalis muscle (shown in red). See also * Occipitofrontalis muscle The occipitofrontalis muscle (epicranius muscle) is a muscle which covers parts of the skull. It consists of two parts or bellies: the occipital belly, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbicularis Oculi
The orbicularis oculi is a muscle in the face that closes the eyelids. It arises from the nasal part of the frontal bone, from the frontal process of the maxilla in front of the lacrimal groove, and from the anterior surface and borders of a short fibrous band, the medial palpebral ligament. From this origin, the fibers are directed laterally, forming a broad and thin layer, which occupies the eyelids or palpebræ, surrounds the circumference of the orbit, and spreads over the temple, and downward on the cheek. Structure There are at least 3 clearly defined sections of the orbicularis muscle. However, it is not clear whether the lacrimal section is a separate section, or whether it is just an extension of the preseptal and pretarsal sections. Orbital orbicularis The orbital portion is thicker and of a reddish color; its fibers form a complete ellipse without interruption at the lateral palpebral commissure; the upper fibers of this portion blend with the frontalis and corrugator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Risorius
The risorius muscle is a muscle of facial expression. It arises from the fascia over the parotid gland, and inserts into the angle of the mouth. It is supplied by the facial nerve (CN VII). It may be absent or asymmetrical in some people. It retracts the angle of the mouth during smiling. Structure The risorius muscle arises in the fascia over the parotid gland. Passing horizontally forward, superficial to the platysma muscle, it inserts onto the skin at the angle of the mouth. It is a narrow bundle of fibers, broadest at its origin, but varies much in its size and form. It is superficial to the masseter muscle, partially covering it. Nerve supply Like all muscles of facial expression, the risorius is supplied by the facial nerve (CN VII). The specific branch is debated, with some sources giving marginal mandibular branch of the facial nerve and others giving buccal branch of the facial nerve. Development It has been suggested that the risorius muscle is only found in Homininae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mentalis
The mentalis muscle is a paired central muscle of the lower lip, situated at the tip of the chin. It originates from the mentum of the mandible, and inserts into the soft tissue of the chin. It is sometimes referred to as the "pouting muscle" due to it raising the lower lip and causing chin wrinkles. Structure The mentalis muscle originates from the mental protuberance of the mandible near the midline. It inserts into the soft tissue and skin of the chin. Function The mentalis muscle causes a weak upward-inward movement of the soft tissue complex of the chin. This raises the central portion of the lower lip. In the setting of lip incompetence (the upper and lower lips do not touch each other at rest), the mentalis muscle contraction can bring temporary but strained oral competence. In conjunction with the orbicularis oris muscle (for the upper lip), the mentalis muscle allows the lips to "pout". Externally, the mentalis muscle contraction causes wrinkling and dimpling of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buccinator
The buccinator () is a thin quadrilateral muscle occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 91 Structure It arises from the outer surfaces of the alveolar processes of the maxilla and mandible, corresponding to the three pairs of molar teeth and in the mandible, it is attached upon the buccinator crest posterior to the third molar; and behind, from the anterior border of the pterygomandibular raphe which separates it from the constrictor pharyngis superior. The fibers converge toward the angle of the mouth, where the central fibers intersect each other, those from below being continuous with the upper segment of the orbicularis oris, and those from above with the lower segment; the upper and lower fibers are continued forward into the corresponding lip without decussation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platysma
The platysma muscle is a superficial muscle of the human neck that overlaps the sternocleidomastoid. It covers the anterior surface of the neck superficially. When it contracts, it produces a slight wrinkling of the neck, and a "bowstring" effect on either side of the neck. Structure The platysma muscle is a broad sheet of muscle arising from the fascia covering the upper parts of the pectoralis major muscle and deltoid muscle. Its fibers cross the clavicle, and proceed obliquely upward and medially along the side of the neck. This leaves the inferior part of the neck in the midline deficient of significant muscle cover. Fibres at the front of the muscle from the left and right sides intermingle together below and behind the mandibular symphysis, the junction where the two lateral halves of the mandible are fused at an early period of life (although not a true symphysis). Fibres at the back of the muscle cross the mandible, some being inserted into the bone below the oblique li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depressor Anguli Oris
The depressor anguli oris muscle (triangularis muscle) is a facial muscle. It originates from the mandible and inserts into the angle of the mouth. It is associated with frowning, as it depresses the corner of the mouth. Structure The depressor anguli oris arises from the lateral surface of the mandible. Its fibres then converge. It is inserted by a narrow fasciculus into the angle of the mouth. At its origin, it is continuous with the platysma muscle, and at its insertion with the orbicularis oris muscle and risorius muscle. Some of its fibers are directly continuous with those of the levator anguli oris muscle, and others are occasionally found crossing from the muscle of one side to that of the other; these latter fibers constitute the transverse muscle of the chin. The depressor anguli oris muscle receives its blood supply from a branch of the facial artery. Nerve supply The depressor anguli oris muscle is supplied by the marginal mandibular branch of the facial nerve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depressor Labii Inferioris
The depressor labii inferioris (or quadratus labii inferioris) is a facial muscle. It helps to lower the bottom lip. Structure The depressor labii inferioris muscle arises from the lateral surface of the mandible. This is below the mental foramen, and the origin may be around 3 cm wide. It inserts on the skin of the lower lip, blending in with the orbicularis oris muscle around 2 cm wide. At its origin, depressor labii is continuous with the fibers of the platysma muscle. Some yellow fat is intermingled with the fibers. Nerve supply The depressor labii inferioris muscle is supplied by the marginal mandibular branch of the facial nerve. Function The depressor labii inferioris muscle helps to depress and everts the lower lip. It is the most important of the muscles of the lower lip for this function. It is an antagonist of the orbicularis oris muscle. It is needed to expose the mandibular (lower) teeth during smiling. Clinical significance Resection The depressor labii ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levator Labii Superioris Alaeque Nasi
The levator labii superioris alaeque nasi muscle is, translated from Latin, the "lifter of both the upper lip and of the wing of the nose". It has the longest name of any muscle in an animal. The muscle is attached to the upper frontal process of the maxilla and inserts into the skin of the lateral part of the nostril and upper lip. Overview Historically known as Otto's muscle, it dilates the nostril and elevates the upper lip, enabling one to snarl. Elvis Presley is famous for his use of this expression, earning the muscle's nickname "The Elvis muscle". A mnemonic to remember its name is, "Little Ladies Snore All Night." Snore- because it is the labial elevator closest to the nose. The levator labii superioris alaeque nasi is sometimes referred to as the "angular head" of the levator labii superioris muscle. See also * Levator labii superioris * Frontalis muscle The frontalis muscle () is a muscle which covers parts of the forehead of the skull. Some sources consider the fron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levator Labii Superioris
The levator labii superioris (pl. ''levatores labii superioris'', also called quadratus labii superioris, pl. ''quadrati labii superioris'') is a muscle of the human body used in facial expression. It is a broad sheet, the origin of which extends from the side of the nose to the zygomatic bone. Structure Its medial fibers form the ''angular head'' (also known as the levator labii superioris alaeque nasi muscle,) which arises by a pointed extremity from the upper part of the frontal process of the maxilla and passing obliquely downward and lateralward divides into two slips. One of these is inserted into the greater alar cartilage and skin of the nose; the other is prolonged into the lateral part of the upper lip, blending with the infraorbital head and with the orbicularis oris. The intermediate portion or ''infraorbital head'' arises from the lower margin of the orbit immediately above the infraorbital foramen, some of its fibers being attached to the maxilla, others to the zy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygomaticus Minor
The zygomaticus minor muscle is a muscle of facial expression. It originates from the zygomatic bone, lateral to the rest of the levator labii superioris muscle, and inserts into the outer part of the upper lip. It draws the upper lip backward, upward, and outward and is used in smiling. It is innervated by the facial nerve (VII). Structure The zygomaticus minor muscle originates from the zygomatic bone. It inserts into the tissue around the upper lip, particularly blending its fibres with orbicularis oris muscle. It lies lateral to the rest of levator labii superioris muscle, and medial to its stronger synergist zygomaticus major muscle. It travels at an angle of approximately 30°. It has a mean width of around 0.5 cm. Nerve supply The zygomaticus minor muscle is supplied by the buccal branch of the facial nerve (VII). Variation The zygomaticus minor muscle may have either a straight or a curved course along its length. It may attach to both the upper lip and the latera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
