"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. 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 occipital bone joins with"
"the Latin equivalent to ""forehead"". (Etymology of ""sinciput"": from ""semi-"" ""half"" + ""caput"" ""head"".) The bone of the forehead is the squamous part of the frontal bone. The overlying muscles are the occipitofrontalis, procerus, and corrugator supercilii muscles, all of which are controlled by the temporal branch of the facial nerve. The sensory nerves of the forehead connect to the ophthalmic branch of the trigeminal nerve and to the cervical plexus, and lie within the subcutaneous fat. The motor nerves of the forehead connect to the facial nerve. The ophthalmic branch of the trigeminal nerve, the supraorbital nerve, divides at"
"the dens, used in the diagnosis of dissociation injuries. Genetic disorders can cause a prominent occiput as found in Edwards syndrome, and Beckwith–Wiedemann syndrome. The identification of the location of the fetal occiput is important in delivery. Occipital : from Latin occiput ""back of the skull,"" from ob ""against, behind"" + caput ""head"" . distinguished from sinciput (anterior part of the skull). In many animals these parts stay separate throughout life; for example, in the dog as four parts: squamous part (supraoccipita); lateral parts–left and right parts (exoccipital); basilar part (basioccipital). The occipital bone is part of the endocranium, the"
"Forehead In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the forehead is marked by the supraorbital ridge, the bone feature of the skull above the eyes. The two sides of the forehead are marked by the temporal ridge, a bone feature that links the supraorbital ridge to the coronal suture line and beyond. In ""Terminologia Anatomica"", ""sinciput"" is given as"
"body section posterior to that bearing the legs and head (the prosoma or cephalothorax). Abdomen The abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The region occupied by the abdomen is termed the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax. The abdomen stretches from the thorax at the thoracic diaphragm to the pelvis at the pelvic brim. The pelvic brim stretches from the lumbosacral joint (the intervertebral disc between"
"Subcapitulum The subcapitulum (from Latin ""sub"", under and ""capitulum"", small head), also known as infracapitulum, hypognathum or hipognatum, refers to the ventral part of the gnathosoma (the part of the body comprising the mouth and feeding parts) or the fusion of the palpal coxae and the labrum (the upper or anterior mouthpart) complex present in the mites on which the mouth, pedipalps (the second pair of appendages), lips and pharynx are located. In its central part, the gutter hypostome (the anterior part of the subcapitulum) is formed, which in the forceps is transformed into a serrated pricking system. The anterolateral"
"Cingulate cortex The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe. It receives inputs from the thalamus and the neocortex, and projects to the entorhinal cortex via the cingulum. It is an integral part of the limbic system, which is involved with emotion formation and processing, learning, and memory. The combination of these three functions makes"
"Midgut The midgut is the portion of the embryo from which most of the intestines develop. After it bends around the superior mesenteric artery, it is called the ""midgut loop"". It comprises the portion of the alimentary canal from the end of the foregut at the opening of the bile duct to the hindgut, about two-thirds of the way through the transverse colon. During development, the human midgut undergoes a rapid phase of growth in which the loop of midgut herniates outside of the abdominal cavity of the fetus and protrudes into the umbilical cord. This herniation is physiological (occurs"
"Midgut The midgut is the portion of the embryo from which most of the intestines develop. After it bends around the superior mesenteric artery, it is called the ""midgut loop"". It comprises the portion of the alimentary canal from the end of the foregut at the opening of the bile duct to the hindgut, about two-thirds of the way through the transverse colon. During development, the human midgut undergoes a rapid phase of growth in which the loop of midgut herniates outside of the abdominal cavity of the fetus and protrudes into the umbilical cord. This herniation is physiological (occurs"
"Anterior cingulate cortex The anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex that resembles a ""collar"" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, and 33. It appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate. It is also involved in certain higher-level functions, such as attention allocation, reward anticipation, decision-making, ethics and morality, impulse control (e.g. performance monitoring and error detection), and emotion. The anterior cingulate cortex can be divided anatomically based on cognitive (dorsal), and emotional"
"Occipital bone The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord. Like the other cranial bones, it is classed as a flat bone. Due to its many attachments and features, the occipital bone is described in"
"is divided into three major sections: a cephalon (head section) with eyes, mouthparts and sensory organs such as antennae; a thorax of multiple segments which are similar to each other; and a pygidium, or tail section. In many species the cephalon had sutures running from back to front round the outside edges of the eyes. These sutures divided the cephalon into 3 pieces. The sutures in trilobites' cephalons were unusual because it seems their main function was to create ""weaknesses"" which made it easy for this part of the carapace (""armor"") to split when the animal needed to molt. Suture"
"a foregut, a midgut and a hindgut, and is situated dorsally. The foregut begins at the mouth, passes through the oesophagus, and opens into a sac which contains the grinding apparatus of the gastric mill. The hepatopancreas feeds into the midgut, where digestive enzymes are released, and nutrients taken up. The hindgut forms faecal pellets, which are then passed out through the muscular anus. The circulatory system is based around a compact, triangular heart, which pumps blood into three main arteries. Excretion is carried out through the gills, and by specialised glands located at the base of the antennae, and"
"a central structure in learning to correct mistakes, indicates that the cingulum is involved in appraisal of pain and reinforcement of behavior that reduces it. Cingulotomy, the surgical severing of the anterior cingulum, is a form of psychosurgery used to treat depression and OCD. The cingulum was one of the earliest identified brain structures. The cingulum is described from various brain images as a C shaped structure within the brain that wraps around the frontal lobe to the temporal lobe right above the corpus callosum. It is located beneath the cingulate gyrus within the medial surface of the brain therefore"
"from four components: the septum transversum (central tendon), the pleuroperitoneal membranes, the dorsal mesentery of the esophagus, and muscular components from somites at cervical levels three to five (C3–5) of the body wall. Since the septum transversum is located initially opposite cervical segments of three to five, and since muscle cells for the diaphragm originate from somites at these segments, the phrenic nerve, which innervates the diaphragm, also arises from these segments of the spinal cord (C3, 4, and 5). The thoracic cavity is divided into the pericardial cavity and two pleural cavities for the lungs by the pleuropericardial membranes."
"Limbic lobe The limbic lobe is an arc-shaped region of cortex on the medial surface of each cerebral hemisphere of the mammalian brain, consisting of parts of the frontal, parietal and temporal lobes. The term is ambiguous, with some authors including the paraterminal gyrus, the subcallosal area, the cingulate gyrus, the parahippocampal gyrus, the dentate gyrus, the hippocampus and the subiculum; while the Terminologia Anatomica includes the cingulate sulcus, the cingulate gyrus, the isthmus of cingulate gyrus, the fasciolar gyrus, the parahippocampal gyrus, the parahippocampal sulcus, the dentate gyrus, the fimbrodentate sulcus, the fimbria of hippocampus, the collateral sulcus, and"
"penis consists of three cylindrical bodies of spongy tissue filled with blood vessels along its length. Two of these bodies lie side-by-side in the upper portion of the penis called corpora cavernosa. The third, called the corpus spongiosum, is a tube that lies centrally beneath the others and expands at the end to form the tip of the penis (glans). The raised rim at the border of the shaft and glans is called the corona. The urethra runs through the shaft, providing an exit for sperm and urine. The root consists of the expanded ends of the cavernous bodies, which"
"opisthosoma or abdomen. Segmentation has almost entirely been lost and the prosoma and opisthosoma are fused, only the positioning of the limbs indicating the location of the segments. At the front of the body is the gnathosoma or capitulum. This is not a head and does not contain the eyes or the brain, but is a retractable feeding apparatus consisting of the chelicerae, the pedipalps and the oral cavity. It is covered above by an extension of the body carapace and is connected to the body by a flexible section of cuticle. The mouthparts differ between taxa depending on diet;"
"Orbit (anatomy) In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. “Orbit” can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of which the eye occupies . The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and nasolacrimal duct, the eyelids, medial and lateral palpebral ligaments, check ligaments, the"
"is ambiguous, with some authors including the paraterminal gyrus, the subcallosal area, the cingulate gyrus, the parahippocampal gyrus, the dentate gyrus, the hippocampus and the subiculum; while the Terminologia Anatomica includes the cingulate sulcus, the cingulate gyrus, the isthmus of cingulate gyrus, the fasciolar gyrus, the parahippocampal gyrus, the parahippocampal sulcus, the dentate gyrus, the fimbrodentate sulcus, the fimbria of hippocampus, the collateral sulcus, and the rhinal sulcus, and omits the hippocampus. The insular cortex is a portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes)."
"Calvaria (skull) The calvaria or skullcap (feminine Latin noun with plural ""calvariae""; however, many medical texts list the word as ""calvarium"", neuter Latin noun with plural ""calvaria"") is the upper part of the neurocranium and covers the cranial cavity containing the brain. It forms the main component of the skull roof. The calvaria (skullcap) is made up of the superior portions of the frontal bone, occipital bone, and parietal bones. In the human skull, the sutures between the bones normally remain flexible during the first few years of postnatal development, and fontanelles are palpable. Premature complete ossification of these sutures"
"Neurocranium In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skullcap. The remainder of the skull is the facial skeleton. In comparative anatomy, neurocranium is sometimes used synonymously with endocranium or chondrocranium. The neurocranium is divided into two portions: In humans, the neurocranium is usually considered to include the following eight bones: The ossicles (three on each side) are usually not included as bones of the neurocranium. There may"
"Mesosoma The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings. In hymenopterans of the suborder Apocrita (wasps, bees and ants), it consists of the three thoracic segments and the first abdominal segment (the propodeum). For historical reasons, in ants it is commonly referred to by the alternative name alitrunk. In scorpions, it is composed of six segments and forms the first part of the abdomen, containing all"
"is observed in non-primate species, the limbic lobe was thus declared to be ""bestial"". As with other parts of the cortex, there have been and continue to be discrepancies concerning boundaries and naming. Brodmann (1909) further distinguished Areas 24 (anterior cingulate) and 23 (posterior) based on granularity. Most recently, it was included as a part of the limbic lobe in the Terminologia Anatomica (1998) following von Economo's (1925) system. Cingulate cortex The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately"
"Abdomen The abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The region occupied by the abdomen is termed the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax. The abdomen stretches from the thorax at the thoracic diaphragm to the pelvis at the pelvic brim. The pelvic brim stretches from the lumbosacral joint (the intervertebral disc between L5 and S1) to the pubic symphysis and is the edge of the pelvic"
"Berengario da Carpi in his ""Commentaria super anatomia Mundini"" (1521). Andreas Vesalius, in his ""De humani corporis fabrica"", was the first to compare the second element of the ossicles to an anvil, thereby giving it the name ""incus"". The final part of the long limb was once described as a ""fourth ossicle"" by Pieter Paaw in 1615. Incus The incus or anvil is a bone in the middle ear. The anvil-shaped small bone is one of three ossicles in the middle ear. The ""incus"" receives vibrations from the malleus, to which it is connected laterally, and transmits these to the"
"also play a role in anxiety disorders during adolescence. For details regarding MRI definitions of the cingulate cortex based on the Desikan-Killiany Brain atlas, see: Posterior cingulate cortex The posterior cingulate cortex (PCC) is the caudal part of the cingulate cortex, located posterior to the anterior cingulate cortex. This is the upper part of the ""limbic lobe"". The cingulate cortex is made up of an area around the midline of the brain. Surrounding areas include the retrosplenial cortex and the precuneus. Cytoarchitectonically the posterior cingulate cortex is associated with Brodmann areas 23 and 31. The posterior cingulate cortex forms a"
"The remaining parts of the cephalon, called fixed and free cheeks (or fixigenae and librigenae) are flat. The fracture lines (or sutures) that in moulting separate the librigenae from the fixigenae are divergent just in front of the eyes, becoming parallel near the border furrow and slightly convergent at margin. From the back of the eyes the sutures bends outward and slightly backward, curving backward at the lateral border furrow and cutting the posterior margin in the inner bend of the spine (or opisthoparian sutures). The articulating middle part of the body (or thorax) has 7 segments, the outer tips"
"Neck The neck is the part of the body, on many vertebrates, that separates the head from the torso. It contains blood vessels and nerves that supply structures in the head to the body. These in humans include part of the esophagus, the larynx, trachea, and thyroid gland, major blood vessels including the carotid arteries and jugular veins, and the top part of the spinal cord. In anatomy, the neck is also called by its Latin names, cervix or collum, although when used alone, in context, the word ""cervix"" more often refers to the uterine cervix, the neck of the"
"cases the sclerites are fused to various degrees. Thorax The thorax or chest (from the Greek θώραξ ""thorax"" ""breastplate, cuirass, corslet"" via ) is a part of the anatomy of humans and various other animals located between the neck and the abdomen. The thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. In humans and other hominids, the thorax is the chest region of the"
"Endocranium The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy. Structurally, the endocranium consists of a boxlike shape, open at the top. The posterior margin exhibit the ""foramen magnum"", an opening for the spinal cord. The floor of the endocranium has several paired openings for the cranial nerves, and the anterior margin holds a spongy construction, allowing for the external nasal nerves to pass through. All bones of the"
"Incisive bone In human anatomy, the incisive bone or (Latin) os incisivum is the portion of the maxilla adjacent to the incisors. It is formed from the fusion of a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals. While Johann Wolfgang von Goethe was not the first one to discover incisive bone in the humans, he was the first to prove its presence across mammals. Hence, incisive bone is also known as Goethe's bone In other animals the"
"Ciliary body The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The vitreous humor is produced in the non-pigmented portion of the ciliary body. The ciliary body is part of the uvea, the layer of tissue that delivers oxygen and nutrients to the eye tissues. The ciliary body joins the ora serrata of the choroid to the root of the iris. The ciliary body is a ring-shaped thickening of tissue inside the eye that divides the posterior chamber from"