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.

31 results found
Article

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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Garrington sign (teeth)

Garrington sign is thickening of the periodontal ligament/membrane space of involved teeth in the setting of gnathic osteosarcoma. Symmetrical widening of the space can be seen early in the disease process due to infiltration of tumour cells. 
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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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Genioplasty

Genioplasty or in more simple terms chin augmentation refers to a surgical procedure performed to improve facial balance and/or rejuvenate the lower facial third - mandible. An osseous genioplasty refers to surgery which is performed by creating an osteotomy and then mobilising an inferior segme...
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Geographic skull

A geographic skull is a radiographic appearance which is seen in eosinophilic granuloma (EG) and characterised by destructive lytic bone lesions, the edges of which may be bevelled, scalloped or confluent.
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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 ...
Article

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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Globe rupture

Globe rupture is an ophthalmologic emergency. A ruptured globe or an open-globe injury must be assessed in any patient who has suffered orbital trauma because open-globe injuries are a major cause of blindness. In a blunt trauma, ruptures are most common at the insertions of the intraocular mus...
Article

Globus pharyngeus

Globus pharyngeus is the subjective feeling of a lump in the throat which can have a variety of causes. In modern practice globus is often evaluated by flexible nasoendoscopy in the first instance since many patients present to otolaryngology services. If no cause is identified or if nasoendosco...
Article

Glomus jugulare paraganglioma

Glomus jugulare paraganglioma is a paraganglioma of the head and neck that is confined to the jugular fossa. While it is a rare tumour, it is the most common of the jugular fossa tumours. Epidemiology The relative prevalence of glomus jugulare with respect to other head and neck paraganglioma ...
Article

Glomus tympanicum paraganglioma

Glomus tympanicum paragangliomas (chemodectomas) are the most common middle ear tumour.  Epidemiology There is a female predominance (M:F = 1:3); presentation is most common when patients are more than 40 years old 1,2.  Clinical presentation May be incidental but symptomatic masses produce ...
Article

Glomus vagale tumour

Glomus vagale tumours are glomus tumours that occur along the path of the vagus nerve (CN X). They are a subset of extra-adrenal neuroendocrine tumours that are derived from the nonchromaffin paraganglion cells.  Clinical presentation Typically presents as a painless mass behind the carotid ar...
Article

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...
Article

Glossopharyngeal neuralgia

Glossopharyngeal neuralgia is due to irritation of the glossopharyngeal nerve and presents with repeated episodes of severe pain in the tongue, throat, ear, and tonsils, which can last from a few seconds to a few minutes. It is far less common than trigeminal neuralgia. Epidemiology Glossophar...
Article

Goitre

Goitre refers to enlargement of the thyroid gland. It can occur from multiple conditions. The definition of a goitre depends on age and sex; below are the upper limits of normal for thyroid gland volume 1: adult males: 25 mL adult females: 18 mL 13-14 years: 8-10 mL 3-4 years: 3 mL neonate...
Article

Goldenhar syndrome

Goldenhar syndrome (also known as oculo-auriculo-vertebral spectrum (OAVS), Goldenhar-Gorlin syndrome or facio-auriculo-vertebral dysplasia) is a complex congenital anomaly characterised by abnormalities of the ears, eyes and vertebrae. Epidemiology The estimated incidence is at  1 in 3000-500...
Article

Gorlin-Goltz syndrome

Gorlin-Goltz syndrome, also known as the basal cell naevus syndrome, is a rare phakomatosis characterised by multiple odontogenic keratocysts (KOT), multiple basal cell carcinomas (BCC), and other abnormalities. Epidemiology The condition is thought to occur in ~1 in 60,000 live births while 0...
Article

Gradenigo syndrome

Gradenigo syndrome consists of the triad of: petrous apicitis abducens nerve palsy, secondary to involvement of the nerve as it passes through Dorello canal retro-orbital pain, or pain in the cutaneous distribution of the frontal and maxillary divisions of the trigeminal nerve, due to extensi...
Article

Granulocytic sarcoma

Granulocytic sarcoma (also called myeloid sarcoma and chloroma) is a rare neoplasm comprised of myeloid precursor cells. It can occur in association with: acute myeloid leukaemia (AML) chronic myeloid leukaemia (CML) other myeloproliferative disorders such as myelofibrosis with myeloid meta...
Article

Granulomatosis with polyangiitis (orbital manifestations)

Ophthalmologic manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis), both ocular and orbital, have been reported in 40-50% of GPA patients 1-3 and can occur in either the classic or limited form of the disease. 4 Ophthalmologic disease occasiona...
Article

Granulomatosis with polyangiitis (upper respiratory tract manifestations)

The upper respiratory tract manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis) are common and affect most patients. . Granulomatosis with polyangiitis (Wegener granulomatosis), is a multi-system systemic necrotizing non-caseating granulomatous...
Article

Granulomatous invasive fungal sinusitis

Granulomatous invasive fungal sinusitis, sometimes termed granulomatous invasive fungal sinusitis, is a form of invasive fungal sinusitis. Reports describing the imaging findings have been uncommon 1. Epidemiology It is rare and been mainly reported in Sudan, India, Pakistan and sometimes in t...
Article

Graves disease

Graves disease is an autoimmune thyroid disease and is the most common cause of thyrotoxicosis (up to 85%). Epidemiology There a strong female predilection with the F:M ratio of at least 5:1. Typically presents in middle age. Clinical presentation Patients are thyrotoxic. Extra-thyroid manif...
Article

Greater auricular nerve

The greater auricular nerve is a cutaneous branch of the cervical plexus that innervates the skin of the auricle as well as skin over the parotid gland and mastoid process. The greater auricular nerve also supplies branches that innervate the deep layer of the parotid fascia.   Gross anatomy O...
Article

Greater occipital nerve

The greater occipital nerve is a spinal nerve that innervates the skin of the occiput and upper neck. Gross anatomy Origin The greater occipital nerve arises from the medial branch of the dorsal ramus of C2. Course The greater occipital nerve emerges between axis (C2) and the obliquus capit...
Article

Greater palatine nerve

The greater palatine nerve (or anterior palatine nerve) is a branch of the maxillary division of the trigeminal nerve and contributes to the pterygopalatine ganglion. Gross anatomy The greater palatine nerve divides off the maxillary division just after emerging from the foramen rotundum to en...
Article

Greater wing of sphenoid

The greater wing or ali-sphenoid of the sphenoid bone is a process which projects from either side of the lower part of the sphenoid body, at a common junction with the pterygoid process. 1 It is a paired structure, which curves upward, backward and laterally from each side of the sphenoid body,...
Article

Griesinger sign (mastoid)

Griesinger sign, named after Wilhelm Griesinger, a German psychiatrist and neurologist (1817-1868) refers to oedema of the postauricular soft tissues overlying the mastoid process as a result of thrombosis of the mastoid emissary vein. It is a complication of acute otomastoiditis and may be asso...
Article

Guardsman fracture

A guardsman fracture, also referred to as parade ground fracture, is one of the common forms of mandibular fracture which is caused by a fall on the midpoint of the chin resulting in fracture of the symphysis as well as both condyles. It is usually seen in epileptics, elderly patients and occas...
Article

Guttman sign (larynx)

Guttman sign is a clinical sign relating to the function of the larynx. In normal subjects, frontal pressure on the thyroid cartilage lowers the tone of voice produced and lateral pressure produces a higher tone of voice. The opposite is true with paralysis of the cricothyroid muscle.

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