Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

2,515 results found
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Floor of mouth

The floor of mouth is an oral cavity subsite and is a common location of oral cavity squamous cell carcinoma.  Gross anatomy The floor of mouth is a U-shaped space which extends (and includes) from the oral cavity mucosa superiorly, and the mylohyoid muscle sling 2,3.  Boundaries superiorly:...
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Focal fatty deposits in spinal bone marrow

Focal fatty deposits/replacement in spinal bone marrow are well-defined focal fat islands within the bone marrow of spine or other parts of axial skeleton. Epidemiology Common in older individuals, related to age but not to sex. Pathology This process is a normal variant. Histologically, it ...
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Foramen caecum

The foramen caecum represents a primitive tract between the anterior cranial fossa and the nasal space. It is located along the anterior cranial fossa, anterior to the cribriform plate of the ethmoid bone and posterior to the frontal bone, within the frontoethmoidal suture. It lies at a variable...
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Foramen caecum (disambiguation)

Foramen caecum can refer to a number of different anatomical structures: foramen caecum (tongue) foramen caecum (anterior cranial fossa)
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Foramen lacerum

The foramen lacerum is a triangular opening located in the middle cranial fossa anterior to the petrous apex, which forms its posterior border. Its anterior border is formed by the body of the sphenoid bone at the junction of greater wing and pterygoid process and medial border is formed by the ...
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Foramen magnum

The foramen magnum is the largest foramen of the skull and is part of the occipital bone 1. It is oval in shape with a large antero-posterior diameter 2. Gross anatomy The foramen magnum is found in the most inferior part of the posterior cranial fossa 3. It is traversed by vital structures in...
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Foramen of Langer

The foramen of Langer is a defect in the deep pectoralis fascia. It is a defect at the level of the third intercostal space, through which the upper lateral portion of the breast extends into the axilla forming the axillary tail of Spence.
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Foramen of Magendie

The foramen of Magendie (also called median aperture) is one of the foramina in the ventricular system and links the fourth ventricle and the cisterna magna. It is one of the three ways that cerebrospinal fluid (CSF) can leave the fourth ventricle and enter the subarachnoid space. The two other ...
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Foramen of Morgagni

The foramina of Morgagni, also known as the sternocostal triangles, are small defects in the posterior aspect of the anterior thoracic wall between the sternal and costal attachments of the diaphragm. The internal thoracic vessels descend through these foramina to become the superior epigastric ...
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Foramen of Rouviere

The foramen of Rouviere is a rarely seen space in the shoulder joint capsule between middle and inferior glenohumeral ligaments and it may communicate with the subcoracoid recess (inferior subscapularis recess). It should not be confused with an acquired defect.
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Foramen of Weitbrecht

The foramen of Weitbrecht is a small opening in the glenohumeral joint capsule between superior and middle glenohumeral ligaments and is seen communicating with the subtendinous bursa of the subscapularis muscle.
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Foramen ovale (cardiac)

The foramen ovale (or ovalis) is the opening in the interatrial septum in the fetal heart that allows blood to bypass the right ventricle and non-ventilated lungs, shunted from the right atrium to the left atrium. Specifically it represents the opening between the upper and lower portions of the...
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Foramen ovale (disambiguation)

Foramen ovale can refer to a number of different anatomical structures: foramen ovale (head) foramen ovale (cardiac)
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Foramen ovale (skull)

Foramen ovale is an oval shaped opening in the middle cranial fossa located at the posterior base of the greater wing of the sphenoid bone, lateral to the lingula. It transmits the mandibular division of the trigeminal nerve (CN Vc), accessory meningeal artery, emissary veins between the caverno...
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Foramen rotundum

The foramen rotundum is located in the middle cranial fossa, inferomedial to the superior orbital fissure at the base of greater wing of the sphenoid bone. Its medial border is formed by lateral wall of sphenoid sinus. It runs downwards and laterally in an oblique path and joins the middle crani...
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Foramen singulare

The foramen singulare, also known as the singular foramen, is a small opening at the posteroinferior aspect of the fundus of internal auditory canal (IAC) 2,3. It carries the singular or posterior ampullary nerve, a branch of the inferior vestibular nerve which carries afferent information from ...
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Foramen spinosum

The foramen spinosum is located in the posteromedial part of greater wing of sphenoid bone posterolateral to foramen ovale which connects the middle cranial fossa with the infratemporal fossa. It transmits the middle meningeal artery, middle meningeal vein, and (usually) the nervus spinosus. Va...
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Foramen tympanicum

The foramen tympanicum (also known as foramen of Huschke) is an anatomical variation in the external acoustic canal (EAC), where a bony defect connects the EAC to the temporomandibular joint (TMJ). Epidemiology Various studies have reported on the occurrence of a foramen tympanicum in the asym...
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Foramen Vesalii

The foramen Vesalii, also know as the foramen of Vesalius, sphenoidal emissary foramen, foramen venosus or canaliculus sphenoidal, is a tiny variably present foramen in the greater wing of the sphenoid bone, located between the foramen ovale and scaphoid fossa. It transmits a sphenoidal emissary...
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Forceps major

The forceps major, also known as the posterior forceps, is a fibre bundle which connects the occipital lobes and crosses the midline via the splenium of the corpus callosum. 
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Forceps minor

The forceps minor, also known as the anterior forceps, is a fibre bundle which connects the lateral and medial surfaces of the frontal lobes and crosses the midline via the genu of the corpus callosum.
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Forearm

The forearm is part of the upper limb below the (upper) arm and above the hand and wrist, comprising the radius and ulna bones. In the supinated anatomical position, the radius is lateral and the ulna is medial. The elbow joint is superior and the wrist joint inferior. Forearm flexion and exten...
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Forefoot

The forefoot is the portion of the foot distal to the midfoot and is composed of the metatarsals and the phalanges. The tarsometatarsal joints (TMTJ) joins the midfoot to the forefoot.
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Fornix (brain)

The fornix is the main efferent system of the hippocampus and an important part of the limbic system. It is one of the commissural fibres connecting the cerebral hemispheres. Gross anatomy Roughly C-shaped, the fornix extends from the hippocampus to the mammillary bodies of the hypothalamus an...
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Fornix (disambiguation)

The term fornix (plural: fornices) is used for anatomical structures in multiple organ systems that all share an arch-like morphology: fornix (brain) fornix (eye) fornix (lacrimal) fornix (pharynx) fornix (renal) fornix (stomach) fornix (vagina) History and etymology Fornix is Latin for...
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Fornix (eye)

The fornix conjunctiva is loose soft tissue lying at the junction between the palpebral conjunctiva (covering the inner surface of the eyelid) and the bulbar conjunctiva (covering the globe). Each eye has two fornices, the superior and inferior fornices. The fornix permits freedom of movement of...
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Fornix (vagina)

The fornices are superior recesses of the vagina formed by the protrusion of the cervix into the vaginal vault. There is a large posterior fornix and a smaller anterior fornix with two small lateral fornices.  History and etymology Fornix is Latin for 'arch'.
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Fossa navicularis

The fossa navicularis refers to a normal mild dilatation of the urethra. It occurs at the most distal/downstream portion of the urethra. It is more evident in males, where it occurs in the penile/pendulous urethra, near the urethral meatus. There is also a fossa navicularis in women: the more f...
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Fossa of Rosenmüller

The fossa of Rosenmüller, also known as the posterolateral or pharyngeal recess, is the most common site of origin for nasopharyngeal carcinoma. Gross anatomy It is located superior and posterior to the torus tubarius (the posterior projection of the cartilaginous portion of the Eustachian tub...
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Fossa ovale

The fossa ovale (or ovalis) is the small oval depression in the interatrial septum at the site of the closed foramen ovale, which closes once fetal circulation ceases in the first few minutes of postnatal life. It represents the overlapping primary and secondary septa of the interatrial septum. ...
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Fourth ventricle

The fourth ventricle is one of the components of the ventricular system in the brain, along with the lateral and third ventricles. It extends from the cerebral aqueduct (of Sylvius) to the obex and is filled with CSF. CSF enters the ventricle via the cerebral aqueduct and leaves via one of four...
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Fovea ethmoidalis

The fovea ethmoidalis is a portion of the ethmoid bone and represents its superior portion (part of the ethmoid roof) which is seen as a continuation of the superior orbital roof to the cribriform plate.  
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Foveola pharyngica recess

A foveola pharyngica recess is one of the variants of the inferior median clival canal, thought to represent a remnant of the notocord. It represents a blind ending recess in the anteroinferior surface (nasopharyngeal) surface of the clivus 1,2. 
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Frenulum (disambiguation)

Frenulum (plural: frenula) is an anatomical term and refers to a small fold of soft tissue that checks the movement of an anatomical part. frenulum (clitoris) frenulum (ileocaecal valve) frenulum (labia minora) frenulum (penis) frenulum (tongue) History and etymology Frenulum derives from...
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Frontal bone

The frontal bone is a skull bone that contributes to the cranial vault. It contributes to form part of the anterior cranial fossa. Gross anatomy The frontal bone has two portions: vertical portion (squama): has external/internal surfaces horizontal portion (orbital): has superior/inferior su...
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Frontal bullar cells

The frontal bullar cells are a subset of variably present frontal recess cells located above the ethmoid bulla. Terminology They are nearly identical to suprabullar cells. The distinguishing features with the latter are that the frontal bullar cells are located above the frontal ostium and ext...
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Frontal cells

Frontal cells are anterior ethmoid air cells located along the anterior aspect of the frontal recess. They are a subset of frontal recess cells and are classified into four types according to Kuhn's classification. They are seen on CT in 20-33% of patients 1. See also functional endoscopic si...
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Frontal infundibulum

The frontal infundibulum is a term that refers to the funnel-shaped inferior narrowing of the frontal sinus. Together with the frontal ostium and frontal recess, it forms the frontal sinus outflow tract.
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Frontal intersinus septal cells

Frontal intersinus septal cells, also known as interfrontal sinus septal cells, are a subtype of medial frontal recess cells. Gross anatomy The frnotal intersinus septal cells lie within the intersinus septum between the frontal sinuses. They usually drain in the medial aspect of the frontal r...
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Frontal lobe

The frontal lobe is by far the largest of the four lobes of the cerebrum (along with the parietal lobe, temporal lobe, and occipital lobe), and is responsible for many of the functions which produce voluntary and purposeful action.  Gross anatomy The frontal lobe is the largest lobe accounting...
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Frontal nerve

The frontal nerve is the largest and main branch of the ophthalmic division of the trigeminal nerve. It divides off the ophthalmic division just before entering the orbit through the superior orbital fissure outside and superolateral to the tendinous ring, where it lies between the lacrimal nerv...
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Frontal ostium

The frontal ostium is an opening of the frontal sinus below the frontal infundibulum that drains into the frontal recess. Together with the frontal infundibulum and recess, it forms the frontal sinus outflow tract.
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Frontal pole

The frontal pole is one of the three poles of the brain (along with the occipital pole and temporal pole), and corresponds to the anterior most rounded point of the frontal lobe. It does not have easily defined boundaries, but is roughly equivalent to the frontopolar cortex, which in turn is co...
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Frontal recess

The frontal recess is an opening in the inferior aspect of the frontal sinuses that allows drainage of the sinus. Terminology The frontal recess is also known as the nasofrontal duct. However, since it doesn't have bony walls of its own, it is more appropriately referred to as a recess rather ...
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Frontal recess cells

Frontal recess cells are anterior ethmoid air cells that pneumatise the frontal recess. Their clinical relevance lies in their potential to obstruct the frontal recess outflow. As such, they should be reported by the radiologist preoperatively, especially in cases of frontal sinusitis. Named fr...
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Frontal sinus

The frontal sinuses are the paranasal sinuses within the frontal bone. They are lined with mucosa and are most often two in number. Summary location: anterior frontal bones on either side of the midline behind the brow ridges blood supply: supratrochlear, supraorbital and anterior ethmoidal a...
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Frontal sinus outflow tract

The frontal sinus outflow tract is the drainage pathway of the frontal sinus. It is an hourglass-shaped structure with its waist at the frontal ostium. Terminology Depending on the references, the term frontal sinus outflow tract is either used synonymously with frontal recess or it can ref...
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Frontoethmoidal suture

The frontoethmoidal suture is a short cranial suture located in the anterior cranial fossa, between the orbital process of frontal and orbital plate of ethmoid bones. It forms part of the medial wall of the orbit. The anterior and posterior ethmoidal foramina are seen just superior to it, throu...
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Frontolacrimal suture

The frontolacimal suture is the cranial suture between the frontal and lacrimal bones.
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Frontomaxillary-suture

The frontomaxillary suture is the site where the nasal process of frontal bone meets the frontal process of the maxilla.
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Frontonasal suture

The frontonasal suture is the cranial suture between the frontal bone and the two nasal bones. This suture meets the internasal suture at the nasion.
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Frontopolar artery

The frontopolar artery is a branch of the A2 segment of the anterior cerebral artery (ACA), commonly arising after the medial frontobasal artery and coursing obliquely across the medial surface of the cerebral hemisphere towards the frontal pole.
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Frontopolar cortex

The frontopolar cortex is located at the frontal pole of each frontal lobe, and is comprised of three roughly horizontal gyri: superior, middle and inferior frontopolar gyri.  It contains Brodmann area 10, which is thought to contribute to many aspects of cognition 1,2. Despite many studies re...
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Frontozygomatic suture

The frontozygomatic suture (or zygomaticofrontal suture) is between the frontal process of the zygomatic bone and the zygomatic process of the frontal bone.
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Fundus (disambiguation)

Fundus (plural: fundi) is used as an anatomical term for many organs and is generally used in the sense of a part that is the lower part or is distant from the main aperture: fundus (stomach) fundus (gallbladder) fundus (uterus) fundus (eye) fundus (urinary bladder) fundus (internal acoust...
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Fusiform gyrus

The fusiform gyrus, also known as the temporo-occipital gyrus is a structure that lies on the basal surface of the temporal and occipital lobes. It forms part of Brodmann area 37, along with the inferior and middle temporal gyri. As its name suggests, it is composed of a temporal or anterior por...
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Galea aponeurotica

The galea aponeurotica (also called the Galeal or epicranial aponeurosis or the aponeurosis epicranialis) is a tough fibrous sheet of connective tissue that extends over the cranium, forming the middle (third) layer of the scalp. Gross anatomy Attachments anteriorly: frontalis posteriorly o...
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Gallbladder

The gallbladder is a pear-shaped musculomembranous sac, lodged in a fossa on the undersurface of the right lobe of the liver, and extending from near the right extremity of the porta hepatis to the anterior border of the liver.  Gross anatomy It typically measures from 7 to 10 cm in length and...
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Gallbladder agenesis

Agenesis of the gallbladder is a rare congenital anomaly. Epidemiology The incidence is <0.1% (range 0.04-0.1%). There is strong female predominance present among the symptomatic cases. Clinical presentation Most patients with agenesis of the gallbladder are asymptomatic. Although some patie...
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Gallbladder duplication

Gallbladder duplication is a rare anatomic anomaly characterised by the presence of an accessory gallbladder. There is no increased risk for malignancy or calculi compared to a single gallbladder. Epidemiology Prevalence is estimated at 1 in 3000.  Classification Boyden's classification divi...
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Gallbladder triplication

Gallbladder triplication is an extremely rare anomaly. There are three types of gallbladder triplication are described according to the number of cystic duct and their insertion: Three gallbladders and three cystic ducts which unite to form a common cystic duct before joining the common bile du...
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Gastric bubble

The gastric bubble is a radiolucent rounded area generally nestled under the left hemidiaphragm representing gas in the fundus of the stomach. On a lateral radiograph, the gastric bubble is usually located between the abdominal wall and spine. It can be seen on chest or abdominal plain films. I...
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Gastric lymph node stations

Gastric lymph node stations were originally divided into 16 groups proposed by the Japanese Research Society for Gastric Cancer in 1963. Gross anatomy The areas of stomach which drain into regional lymph nodes: cardia and proximal lesser curvature drain into left gastric lymph nodes, then int...
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Gastrocnemius muscle

The gastrocnemius muscle is one of the calf muscles (triceps sure) in the superficial posterior compartment of the leg which sits superificial to the much larger soleus muscle. It gives the calf its distinctive two-headed appearance and is a primary plantarflexor. Summary origin: superior to a...
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Gastroduodenal artery

The gastroduodenal artery (GDA) is a terminal branch of the common hepatic artery which mainly supplies the pylorus of the stomach, proximal duodenum, and the head of the pancreas. Due to its proximity to the anterior wall of the first part of the duodenum, the gastroduodenal artery is one of th...
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Gastrointestinal tract

The gastrointestinal tract includes any part of the oral cavity, oropharynx, hypopharynx, oesophagus, stomach, small bowel, colon, rectum and anal canal. 
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Gastro-oesophageal junction

The gastro-oesophageal junction (GOJ) (also known as the oesophagogastric junction) is the part of the gastrointestinal tract where the oesophagus and stomach are joined. Gross anatomy The GOJ is normally mostly intra-abdominal and is 3-4 cm in length. To some extent, the oesophagus slides in ...
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Gastrosplenic ligament

The gastrosplenic ligament is a peritoneal ligament which is formed by ventral part of dorsal mesentery. Gross anatomy The gastrosplenic ligament extends from the greater curvature of the stomach to the hilum of the spleen. It contains the short gastric arteries. Related anatomy During porta...
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General anatomy

General anatomy is best described as the study of general anatomic concepts and structures removed from the specific regional anatomy focus.
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General topography of the abdomen

To facilitate clinical description, the general topography of the abdomen is divided into four quadrants or nine regions by lines on the surface of the anterior abdominal wall. The four quadrants are created by vertical and horizontal lines passing through the umbilicus, whereas the nine regions...
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Geniculate ganglion

The geniculate ganglion contains fibres for taste and somatic sensation and is located in the petrous temporal bone.  Gross anatomy It is located at the first genu of the facial nerve at the anterior most part of the Fallopian canal at the junction between the labyrinthine and tympanic segment...
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Genioglossus muscle

The genioglossus muscle is a fan-shaped extrinsic muscles of the tongue which makes up the bulk of the tongue. Summary origin: superior mental spine of the symphysis menti (posterior surface of midline mandible) insertion: entire tongue mass and body of the hyoid bone nerve supply: hypogloss...
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Geniohyoid muscle

The geniohyoid muscle is one of the suprahyoid muscles of the neck that is innervated by the ventral ramus of C1. Geniohyoid draws the hyoid bone up and forward during mastication and assists the opening of the mandible. Summary origin: inferior mental spine of the mandible also known as the g...
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Genitofemoral nerve

The genitofemoral nerve is a branch of the lumbar plexus arising within the substance of the psoas major muscle from the union of anterior rami of L1 and L2 spinal nerves. The nerve descends in the retroperitoneum to give off genital and femoral terminal branches supplying the skin over the ante...
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Gerdy's tubercle

Gerdy's tubercle is the eponymous name for the lateral condyle of the proximal tibia (where it is located anterolaterally). It is where the iliotibial band and anterior tibialis muscle inserts. 
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Giacomini vein

The Giacomini vein or thigh extension of the small saphenous vein refers to a variation in lower limb venous anatomy where the small saphenous vein (SSV) continues through to the thigh as a distinct branch. The persistence of this vein may play a contributory role in the development of chronic ...
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Gilula three carpal arcs

Gilula three carpal arcs refer to the alignment described on posteroanterior or anteroposterior wrist radiographs and are used to assess normal alignment of the carpus: first arc: is a smooth curve outlining the proximal convexities of the scaphoid, lunate and triquetrum second arc: traces the...
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Glabella

The glabella is the smooth midline bony prominence between the supraciliary arches of the frontal bone, representing the most anterior part of the forehead when standing erect and look straight ahead. The metopic suture traverses the glabella, between the two frontal bones. Just below it is the ...
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Glenohumeral joint

The glenohumeral joint is a synovial joint between the head of the humerus and the glenoid. Summary articulation: ball and socket joint between the head of the humerus and the glenoid joint: shoulder ligaments: glenohumeral, coracohumeral and transverse humeral ligaments movements: arm flex...
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Glenohumeral ligaments

There are three glenohumeral ligaments (GHL), which are thickenings of the glenohumeral joint capsule and are important passive stabilisers of the joint.  Gross anatomy Superior glenohumeral ligament runs from the superior aspect of the glenoid and coracoid process to the fovea capitis just s...
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Glenoid

The glenoid or glenoid cavity or fossa is the shallow depression of the scapula found on the lateral angle. Gross anatomy Attachments  glenoid labrum: the cavity has a fibrocartilaginous structure on its margin called the glenoid labrum which is continuous superiorly with the tendon of the lo...
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Glenoid labrum

The glenoid labrum is a fibrocartilaginous structure that attaches as a rim to the articular cartilage of the glenoid fossa and serves to deepen and increase the surface area. In this capacity, it acts as a static stabiliser of the glenohumeral joint, preventing dislocation and subluxation at th...
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Glenoid labrum variants

There are a number of glenoid labral variants, whose importance is mainly due to the fact that the unwary may misinterpret them as pathology (e.g. Bankart lesion or labral tear). These include: Buford complex sublabral foramen superior sublabral sulcus pseudo-SLAP lesion
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Glial cells

Glial cells, or neuroglia, are cells that surround the neurones of the central nervous system embedded between them, providing both structural and physiological support 1-3.  Together they account for almost half of the total mass 1 and 90% of all cells of the central nervous system 3. These num...
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Glisson's capsule

Glisson's capsule is the external fibrous layer that envelops liver lobules.​ Related pathology Right upper quadrant pain can be caused by distension of Glisson's capsule 3. This can be caused by several processes, including a haematoma or a mass. History and etymology It is named after Fran...
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Globe

The globes or simply, the eyes are paired spherical sensory organs, located anteriorly on the face within the orbits, which house the visual apparatus. Gross anatomy Location The globe is suspended by the bulbar sheath in the anterior third of the bony orbit.  Size Each globe is an approxim...
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Globus pallidus

The globus pallidus (plural: globus pallidi) is a paired structure and one of the nuclei that make up the basal ganglia. It is a subcortical structure at the base of the forebrain and in anatomical relation to the caudate nucleus and putamen. It forms the lentiform nucleus with the putamen. Eac...
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Glomus body

The glomus body is a component of the dermis that is involved in thermoregulation.  Gross anatomy It consists of a specialised arteriovenous anastomosis surrounded by a connective tissue capsule. They are most numerous in the fingers and toes and exist to shunt blood from the skin surface when...
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Glossopharyngeal nerve

The glossopharyngeal nerve is the ninth (IX) of the twelve pairs of cranial nerves. It exits the brainstem out from the sides of the upper medulla, just rostral to the vagus nerve and has sensory, motor, and autonomic components. Gross anatomy Origin The sensory ganglion cells lie in the supe...
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Gluteal muscles

The superficial gluteal muscles lie within the gluteal region posterolateral to the bony pelvis and proximal femur. From superficial to deep lie the gluteus maximus, medius and minimus. The gluteus maximus is an important muscle for hip extension and lateral rotation. Gluteus medius and minimus ...
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Gluteus maximus muscle

The gluteus maximus is the largest muscle in the gluteal region and overlies most of the other gluteal muscles. Summary origin gluteal surface of the ilium behind the posterior gluteal line the lumbar fascia lateral mass of sacrum sacrotuberous ligament insertion: gluteal tuberosity of th...
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Gluteus medius muscle

The gluteus medius and gluteus minimus muscles are two muscles of the more superficial group in the gluteal region. Summary origin: gluteal surface of the ilium between the posterior and anterior gluteal line insertion: posterolateral surface of the greater trochanter of femur arterial suppl...
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Gluteus minimus muscle

The gluteus minimus and gluteus medius muscles are two muscles of the more superficial group in the gluteal region. Summary origin: gluteal surface of the ilium between the anterior and inferior gluteal lines insertion: anterior surface of the greater trochanter of femur arterial supply: sup...

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