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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 The maxillary artery (eg, internal 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 branche .... Its trunk atrophies and is replaced by branches from the external carotid artery. In rare cases, the embryo ... [...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. It ascends along the side of the head. It supplies several muscles of the neck and several structures of the head. Structure Origin The artery arises from (the posterior aspect of) the external carotid artery. Its origin occurs immediately superior to the digastric muscle and stylohyoid muscle, and opposite the apex of the styloid process. Course The artery passes superior-ward in beneath the parotid gland and styloid process of temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone .... Next, it courses along a groove between the cartilage of the auricle and the mastoid process. It then divides into its terminal auricular and occipital branches. Branches and distribu ... [...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 an ... [...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. It ascends along the side of the head. It supplies several muscles of the neck and several structures of the head. Structure Origin The artery arises from (the posterior aspect of) the external carotid artery. Its origin occurs immediately superior to the digastric muscle and stylohyoid muscle, and opposite the apex of the styloid process. Course The artery passes superior-ward in beneath the parotid gland and styloid process of temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone .... Next, it courses along a groove between the cartilage of the auricle and the mastoid process. It then divides into its terminal auricular and occipital branches. Branches and distribu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stapedius Muscle
The stapedius is the smallest skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ... 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 stirrup 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 ... [...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 (ability), 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 labyrin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fetus
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Prenatal development is a continuum, with no clear defining feature distinguishing an embryo from a fetus. However, in general 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 may not yet be situated in their final Anatomy, anatomical location. In human prenatal development, fetal development begins from the ninth week after Human fertilization, fertilization (which is the eleventh week of Gestational age (obstetrics), gestational age) and continues until the childbirth, birth of a newborn. Etymology The word ''wikt:fetus#English, fetus'' (plural ''wikt:fetuses#English, fetuses'' or rarely, the solecism ''wikt:feti#English, feti''''Oxford English Dict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Carotid Artery
The external carotid artery is the major artery of the head and upper neck. It arises from the common carotid artery. It terminates by splitting into the superficial temporal and maxillary artery within the parotid gland. Structure Origin The external carotid artery arises from the common carotid artery just inferior to the upper border of the thyroid cartilage. At its origin, this artery is closer to the skin and more medial than the internal carotid, and is situated within the carotid triangle. Course and fate It curves to pass anterosuperiorly before inclining posterior-ward to reach the space posterior 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. Relations At the origin, external carotid artery is more medial than internal carotid artery. When external carotid artery ascends the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Carotid Artery
The internal carotid artery is an artery in the neck which supplies the anterior cerebral artery, anterior and middle cerebral artery, middle cerebral circulation. In human anatomy, the internal and external carotid artery, external carotid arise from the common carotid artery, where it bifurcates 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". In clinical settings, however, usually the classification system of the internal carotid artery 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; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Meningeal Artery
The middle meningeal artery (') is typically the third branch of the maxillary artery#First portion, 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 (skull), 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 easi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Maxillary Artery
The maxillary artery (eg, internal 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persistent Stapedial Artery
A persistent stapedial artery (PSA) is a rare anomaly in human anatomy where the stapedial branch of posterior auricular artery, or simply stapedial artery, remains within the ear of a fetus after the first ten weeks of pregnancy. Whilst not problematic for the majority of people with the anomaly, it can cause difficulties with hearing. Signs and symptoms Most cases of PSA cases remain asymptomatic for a person's life; however, symptoms can include vertigo, pulsatile tinnitus, conductive hearing loss or sensorineural hearing loss via bone erosion of the otic capsule in rare cases. Hearing loss in children can also cause developmental delays. Cause During pregnancy, the stapedial artery originates as a branch of the hyoid artery in the dorsal branch of the second aortic arch, which is in turn connected to the internal carotid artery. The stapedial artery after passing through the stapes splits into two vessels, the supraorbital branch and the maxillomandibular branch, the lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primates
Primates is an order of mammals, which is further divided into the strepsirrhines, which include lemurs, galagos, and lorisids; and the haplorhines, which include tarsiers and simians ( monkeys and apes). Primates arose 74–63 million years ago first from small terrestrial mammals, which adapted for life in tropical forests: many primate characteristics represent adaptations to the challenging environment among tree tops, including large brain sizes, binocular vision, color vision, vocalizations, shoulder girdles allowing a large degree of movement in the upper limbs, and opposable thumbs (in most but not all) that enable better grasping and dexterity. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
