|
Stapedial Artery
In human anatomy, the stapedial branch of posterior auricular artery, or stapedial artery for short, is a small artery supplying the stapedius muscle in the inner ear. Structure In humans In humans, the stapedial artery is normally present in the fetus where it connects what is to become the external and internal carotid arteries. Part of the carotid artery system, it originates from the dorsal branch of aortic arch. Its superior supraorbital branch becomes the middle meningeal artery, while its infraorbital and mandibular branches fuses with the external carotid artery and later become the internal maxillary artery. Its trunk atrophies and is replaced by branches from the external carotid artery. In rare cases, the embryonic structure is still present after birth in which case it is referred to as a persistent stapedial artery (PSA). While the prevalence of this anomaly is unknown, it has been estimated to be present in 1 of 5,000 people. In other mammals Structures homologo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Auricular Artery
The posterior auricular artery is a small artery that arises from the external carotid artery, above the digastric muscle and stylohyoid muscle, opposite the apex of the styloid process. It ascends posteriorly beneath the parotid gland, along the styloid process of the temporal bone, between the cartilage of the ear and the mastoid process of the temporal bone along the lateral side of the head. The posterior auricular artery gives off the stylomastoid artery, small branches to the auricle, and supplies blood to the scalp posterior to the auricle. A person may be able to "hear" their own heart rate via this artery, under certain conditions. See also * Anterior auricular branches of superficial temporal artery The anterior auricular branches of the superficial temporal artery are distributed to the anterior portion of the auricula, the lobule, and part of the external meatus, anastomosing with the posterior auricular. They supply the external acousti ... * Posterior auric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortic Arches
The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac. The aortic arches are formed sequentially within the pharyngeal arches and initially appear symmetrical on both sides of the embryo, but then undergo a significant remodelling to form the final asymmetrical structure of the great arteries. Structure Arches 1 and 2 The ''first'' and ''second arches'' disappear early. A remnant of the 1st arch forms part of the maxillary artery, a branch of the external carotid artery. The ventral end of the second develops into the ascending pharyngeal artery, and its dorsal end gives origin to the stapedial artery, a vessel which typically atrophies in humans but persists in some mammals. The stapedial artery passes through the ring of the stapes and di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stapedius Muscle
The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or strirrup bone of the middle ear. Structure The stapedius emerges from a pinpoint foramen or opening in the apex of the pyramidal eminence (a hollow, cone-shaped prominence in the posterior wall of the tympanic cavity), and inserts into the neck of the stapes. Nerve supply The stapedius is supplied by the nerve to stapedius, a branch of the facial nerve. Function The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone. As one of the muscles involved in the acoustic reflex it prevents excess movement of the stapes, helping to control the amplitude of sound waves from the general external environment to the inner ear. Clinical significance Paralysis of the stapedius allows wider oscillation of the stapes, resulting in heightened reaction of the auditory ossicles to sound v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Ear
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts: * The cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. * The vestibular system, dedicated to balance The inner ear is found in all vertebrates, with substantial variations in form and function. The inner ear is innervated by the eighth cranial nerve in all vertebrates. Structure The labyrinth can be divided by layer or by region. Bony and membranous labyrinths The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The three major parts of the bony labyrinth are the vestib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal development begins from the ninth week after fertilization (or eleventh week gestational age) and continues until birth. Prenatal development is a continuum, with no clear defining feature distinguishing an embryo from a fetus. However, a fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional and some not yet situated in their final anatomical location. Etymology The word ''fetus'' (plural ''fetuses'' or '' feti'') is related to the Latin '' fētus'' ("offspring", "bringing forth", "hatching of young") and the Greek "φυτώ" to plant. The word "fetus" was used by Ovid in Metamorphoses, book 1, line 104. The predominant British, Irish, and Commonwealth spelling is '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Carotid Artery
The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. External carotid artery supplies blood to the face and neck. Structure The external carotid artery begins at the upper border of thyroid cartilage, and curves, passing forward and upward, and then inclining backward to the space behind the neck of the mandible, where it divides into the superficial temporal and maxillary artery within the parotid gland. It rapidly diminishes in size as it travels up the neck, owing to the number and large size of its branches. At its origin, this artery is closer to the skin and more medial than the internal carotid, and is situated within the carotid triangle. Development In children, the external carotid artery is somewhat smaller than the internal carotid; but in the adult, the two vessels are of nearly equal size. Relations At the origin, external carotid artery is mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Carotid Artery
The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these bifurcate at cervical vertebrae C3 or C4. The internal carotid artery supplies the brain, including the eyes, while the external carotid nourishes other portions of the head, such as the face, scalp, skull, and meninges. Classification Terminologia Anatomica in 1998 subdivided the artery into four parts: "cervical", "petrous", "cavernous", and "cerebral". However, in clinical settings, the classification system of the internal carotid artery usually follows the 1996 recommendations by Bouthillier, describing seven anatomical segments of the internal carotid artery, each with a corresponding alphanumeric identifier—C1 cervical, C2 petrous, C3 lacerum, C4 cavernous, C5 clinoid, C6 ophthalmic, and C7 communicating. The Bouthillier nomenclat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Meningeal Artery
The middle meningeal artery ('' la, arteria meningea media'') is typically the third branch of the first portion of the maxillary artery. After branching off the maxillary artery in the infratemporal fossa, it runs through the foramen spinosum to supply the dura mater (the outer meningeal layer) and the calvaria. The middle meningeal artery is the largest of the three (paired) arteries that supply the meninges, the others being the anterior meningeal artery and the posterior meningeal artery. The anterior branch of the middle meningeal artery runs beneath the pterion. It is vulnerable to injury at this point, where the skull is thin. Rupture of the artery may give rise to an epidural hematoma. In the dry cranium, the middle meningeal, which runs within the dura mater surrounding the brain, makes a deep groove in the calvarium. The middle meningeal artery is intimately associated with the auriculotemporal nerve, which wraps around the artery making the two easily identifiable i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Maxillary Artery
The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches of the external carotid artery, arises behind the neck of the mandible, and is at first imbedded in the substance of the parotid gland; it passes forward between the ramus of the mandible and the sphenomandibular ligament, and then runs, either superficial or deep to the lateral pterygoid muscle, to the pterygopalatine fossa. It supplies the deep structures of the face, and may be divided into mandibular, pterygoid, and pterygopalatine portions. First portion The ''first'' or ''mandibular '' or ''bony'' portion passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs along the lower border of the lateral ptery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primates
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including humans). Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dextrous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs , to the eastern gorilla, weighing over . There are 376–524 species of living primates, depending on which classification is used. New primate species continue to be discovered: over 25 species were described in the 2000s, 36 in the 2010s, and three in the 2020s. Primates have large bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cranial Fossa
The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest. It is bounded in front by the posterior margins of the lesser wings of the sphenoid bone, the anterior clinoid processes, and the ridge forming the anterior margin of the chiasmatic groove; behind, by the superior angles of the petrous portions of the temporal bones and the dorsum sellæ; laterally by the temporal squamæ, sphenoidal angles of the parietals, and greater wings of the sphenoid. It is traversed by the squamosal, sphenoparietal, sphenosquamosal, and sphenopetrosal sutures. It houses the temporal lobes of the brain and the pituitary gland. A middle fossa craniotomy is one means to surgically remove acoustic neuromas (vestibular schwannoma) growing within the internal auditory canal of the temporal bone. Middle part The middle part of the fossa presents, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strepsirrhini
Strepsirrhini or Strepsirhini (; ) is a Order (biology), suborder of primates that includes the Lemuriformes, lemuriform primates, which consist of the lemurs of Fauna of Madagascar, Madagascar, galagos ("bushbabies") and pottos from Fauna of Africa, Africa, and the lorises from Fauna of India, India and southeast Asia. Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct Adapiformes, adapiform primates which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison. Strepsirrhines are defined by their "wet" (moist) rhinarium (the tip of the snout) – hence the colloquial but inaccurate term "wet-nosed" – similar to the rhinaria of canines and felines. They also have a smaller brain than comparably sized sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Primates")
