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Digastric Muscle
The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly is attached to the digastric fossa of mandible; the two bellies are united by an intermediate tendon which is held in a loop that attaches to the hyoid bone. The anterior belly is innervated via the mandibular nerve (cranial nerve V), and the posterior belly is innervated via the facial nerve (cranial nerve VII). It may act to depress the mandible or elevate the hyoid bone. The term "digastric muscle" refers to this specific muscle even though there are other muscles in the body to feature two bellies. Anatomy The digastric muscle consists of two muscular bellies united by an intermediate tendon with the posterior belly longer than the anterior belly. The two bellies of the digastric muscle have different embryological origins - the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Mandible
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing joints with the cranium's temporal bones. The mandible hosts the lower teeth (their depth delineated by the alveolar process). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels. Amongst other functions, the jawbone is essential for chewing food. Owing to the Neolithic advent of agriculture (), human jaws evolved to be smaller. Although it is the strongest bone of the facial skeleton, the mandible tends to deform in old age; it is also subject to fracturing. Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally, the bone is of great forensic significance. Struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mastoid Process
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, the mastoid part articulates with two other bones. Etymology The word "mastoid" is derived from the Greek word for "breast", a reference to the shape of this bone. Surfaces Outer surface Its outer surface is rough and gives attachment to the occipitalis and posterior auricular muscles. It is perforated by numerous foramina (holes); for example, the mastoid foramen is situated near the posterior border and transmits a vein to the transverse sinus and a small branch of the occipital artery to the dura mater. The position and size of this foramen are very variable; it is not always present; sometimes it is situated in the occipital bone, or in the suture between the temporal and the occipital. Mastoid process The mastoid process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submental Triangle
The submental triangle (or suprahyoid triangle) is a division of the anterior triangle of the neck. Boundaries It is limited to: * Lateral (away from the midline), formed by the anterior belly of the digastricus * Medial (towards the midline), formed by the midline of the neck between the mandible and the hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ... * Inferior (below), formed by the body of the hyoid bone *Floor is formed by the mylohyoideus *Roof is formed by investing layer of deep cervical fascia Contents It contains one or two lymph glands, the submental lymph nodes (three or four in number) and Submental veins and commencement of anterior jugular veins. (The contents of the triangle actually lie in the superficial fascia over the roof of submental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Triangle
The carotid triangle (or superior carotid triangle) is a portion of the anterior triangle of the neck. Anatomy Boundaries It is bounded: * Posteriorly by (the anterior border of) the sternocleidomastoid muscle, * Anteroinferiorly by (the superior belly of) the omohyoid muscle. * Superiorly by (the posterior belly of) the digastric muscle. Roof The roof is formed by: * Integument, * Superficial fascia, * Platysma, * Deep fascia. Floor The floor is formed by (parts of) the: * Thyrohyoid membrane, *Hyoglossus, * Constrictor pharyngis medius and constrictor pharyngis inferior muscles. Contents Arteries * Internal carotid artery * External carotid artery and some of its branches: ** Superior thyroid artery, ** Ascending pharyngeal artery, ** Lingual artery, ** Facial artery, ** Occipital artery. Veins * internal jugular vein and its tributaries (correspondng to the branches of the corresponding artery): ** Superior thyroid vein, ** Lingual veins, ** Comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submandibular Triangle
The submandibular triangle (or submaxillary or digastric triangle) corresponds to the region of the neck immediately beneath the body of the mandible. Boundaries and coverings It is bounded: * ''above'', by the lower border of the body of the mandible, and a line drawn from its angle to the mastoid process; * ''below'', by the posterior belly of the Digastricus; in front, by the anterior belly of the Digastricus. It is covered by the integument, superficial fascia, Platysma, and deep fascia, ramifying in which are branches of the facial nerve and ascending filaments of the cutaneous cervical nerve. Its floor is formed by the Mylohyoideus anteriorly, and by the hyoglossus posteriorly. Triangles * Beclard Triangle * Lesser Triangle * Pirogoff Triangle Divisions It is divided into an anterior and a posterior part by the stylomandibular ligament. Anterior part The anterior part contains the submandibular gland, superficial to which is the anterior facial vein, while imbedded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Triangle Of The Neck
The anterior triangle is a region of the neck. Structure The triangle is inverted with its apex inferior to its base which is under the chin. Investing fascia covers the roof of the triangle while visceral fascia covers the floor. Anatomy Muscles: * Suprahyoid muscles - Digastric (Ant and post belly), mylohyoid, geniohyoid and stylohyoid. * Infrahyoid muscles - Omohyoid, sternohyoid, sternothyroid, and thyrohyoid. Nerve supply 2 Bellies of digastric * Anterior: Mylohyoid nerve * Posterior: Facial nerve Stylohyoid: by the facial nerve, by a branch from that to the posterior belly of digastric. Mylohyoid: by its own nerve, a branch of the inferior alveolar (from the mandibular division of trigeminal nerve), which arises just before the parent nerve enters the mandibular foramen, pierces the sphenomandibular ligament, and runs forward on the inferior surface of the mylohyoid, supplying it and the anterior belly of the digastric. Geniohyoid: by a branch from the hypoglossa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submandibular Gland
The paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the floor of the mouth. In adult humans, they each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as parotid gland secretion rises to 50%. The average length of the normal adult human submandibular salivary gland is approximately 27 mm, while the average width is approximately 14.3 mm. Structure Each submandibular gland is divided into a superficial lobe and a deep lobe, the two being separated by the mylohyoid muscle: * The superficial lobe comprises most of the gland, with the mylohyoid muscle runs under it * The deep lobe is the smaller part Submandibular duct Secretions are delivered into the submandibular duct on the deep portion after which they hook around the posterior edge of the mylohyoid muscle and proceed on the superior surface laterally. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digastric Muscle
The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly is attached to the digastric fossa of mandible; the two bellies are united by an intermediate tendon which is held in a loop that attaches to the hyoid bone. The anterior belly is innervated via the mandibular nerve (cranial nerve V), and the posterior belly is innervated via the facial nerve (cranial nerve VII). It may act to depress the mandible or elevate the hyoid bone. The term "digastric muscle" refers to this specific muscle even though there are other muscles in the body to feature two bellies. Anatomy The digastric muscle consists of two muscular bellies united by an intermediate tendon with the posterior belly longer than the anterior belly. The two bellies of the digastric muscle have different embryological origins - the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digastric Branch Of Facial Nerve
The digastric branch of facial nerve provides motor innervation to the posterior belly of the digastric muscle. It branches from the facial nerve (CN VII) near to the stylomastoid foramen as the CN VII exits the facial canal The facial canal (also known as the Fallopian canal) is a Z-shaped canal in the temporal bone of the skull. It extends between the internal acoustic meatus and stylomastoid foramen. It transmits the facial nerve (CN VII) (after which it is nam ... (it thus branches proximal to the parotid plexus of facial nerve). It commonly arises in common with the stylohyoid branch of facial nerve. References External links * () * () * http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-5.HTM Facial nerve {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Alveolar Nerve
The inferior alveolar nerve (IAN) (also the inferior dental nerve) is a sensory branch of the mandibular nerve (CN V3) (which is itself the third branch of the trigeminal nerve (CN V)). The nerve provides sensory innervation to the lower/mandibular teeth and their corresponding gingiva as well as a small area of the face (via its mental nerve). Structure Origin The inferior alveolar nerve arises from the mandibular nerve. Course After branching from the mandibular nerve, the inferior alveolar nerve passes posterior to the lateral pterygoid muscle. It issues a branch (the mylohyoid nerve) before entering the mandibular foramen to come to pass in the mandibular canal within the mandible. Passing through the canal, it issues sensory branches for the molar and second premolar teeth; the branches first form the inferior dental plexus which then gives off small gingival and dental nerves to these teeth themselves. The nerve terminates distally/anteriorly (near the second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synovial Sheath
A synovial sheath is one of the two membranes of a tendon sheath which covers a tendon. The other membrane is the outer fibrous tendon sheath. The tendon invaginates the synovial sheath from one side so that the tendon is suspended from the membrane by the mesotendon, through which the blood vessels reach the tendon, in places where the range of movement is extensive. The mesotendon disappears or remains in the form of narrow tendinous bands as threads known as vincula tendina. The synovial sheath is found where the tendon passes under ligaments and through osseofibrous tunnels; their function is to reduce friction between the tendon and their surrounding structure. An example is the common synovial sheath for the flexor tendons of the hand. See also * Synovial membrane Synovial () may refer to: * Synovial fluid * Synovial joint A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greater Cornu
The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. Unlike other bones, the hyoid is only distantly articulated to other bones by muscles or ligaments. It is the only bone in the human body that is not connected to any other bones. The hyoid is anchored by muscles from the anterior, posterior and inferior directions, and aids in tongue movement and swallowing. The hyoid bone provides attachment to the muscles of the floor of the mouth and the tongue above, the larynx below, and the epiglottis and pharynx behind. Its name is derived . Structure The hyoid bone is classed as an irregular bone and consists of a central part called the body, and two pairs of horns, the greater and lesser horns. Body The body of the hyoid bone is the central part of the hyoid bone. *At the front, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
