Nasal dermoids (or nasal dermoid sinus cysts) are the most common congenital midline nasal lesion typically presenting in early childhood.
Nasal dermoids are rare and account for only 4-12% of all dermoid cysts of the head and neck, far less common than angular dermoids 1,2. They ...
Cri du chat syndrome is a rare congenital disorder caused by the deletion of the short arm of chromosome 5. A high-pitched monotonous cry is the significant characteristic finding 1.
Cri du chat syndrome is rare with an incidence of 1 in 15,000-50,000 births ref.
The axiolateral oblique mandible view allows for visualisation of the mandibular body, mandibular ramus, condylar process and mentum.
This projection is useful in identifying structural changes and displaced fractures of the mandible in a trauma setting, and in neoplastic or inflam...
Computed tomography of the orbits (CT Orbits) involves the visualisation of bony and soft tissue structures of the orbits. This examination is most commonly performed as a non-contrast scan or reconstructed from other examinations such as a CT head/face. Contrast-enhanced scans are utilised depe...
The CT neck chest-abdomen-pelvis protocol aims to evaluate the neck, thoracic and abdominal structures using contrast in trauma imaging. The use of contrast facilitates the assessment of pathologies globally whilst minimising dose by potentially disregarding a non-contrast scan.
Note: This art...
The foramen caecum of the tongue is the remnant of thyroglossal duct located between the anterior two-thirds and posterior third of the tongue.
The foramen caecum is located in the midline on the surface of the tongue, at the apex of the terminal sulcus, the groove that marks th...
Tympanosclerosis is a descripitve terms which refers to deposition of hyalinised collagen +/- calcium in the tympanic cavity. If it occurs in solely tympanic membrane, it is termed myringosclerosis 1.
It can often be associated with chronic otomastoiditis is which instance it is termed chronic...
A metopic ridge refers to a variation in skull shape, characterised by a midline forehead ridge, which may occur either due to the physiological closure of the metopic suture or as a result of craniosynostosis of this suture 1-3. It is essential to differentiate between the two conditions becaus...
Thyroid atrophy can arise in a number of situations and most with certain chronic thyroiditides such as:
atrophic thyroiditis 1
It can also occur with conditions such as:
prior treatment (e.g. I-131) of hyperactive conditions such as Graves disease 3
The ciliary body is the continuation of the uveal layer of the eye and functions in the production of aqueous humour and the process of lens accommodation.
location: between the vitreous body and posterior chamber of the globe
function: aqueous humour production and accommodati...
The posterior meningeal artery is the largest artery supplying the dura of the posterior cranial fossa. It may arise from the ascending pharyngeal artery, or less commonly, the occipital artery. The artery may enter the cranial vault through the jugular foramen, foramen magnum or the hypoglossal...
The inferior cervical ganglion (plural: ganglia) is the second largest ganglion of the cervical sympathetic trunk and provides autonomic innervation to the head and neck region.
The inferior cervical ganglion is formed by embryologically fused C7 and C8 sympathetic ganglia. It ha...
The middle cervical ganglion (plural: ganglia) is the smallest ganglion of the cervical sympathetic trunk and providing autonomic innervation to the head and neck region.
The middle cervical ganglion is formed by embryologically fused C5 and C6 sympathetic ganglia. It has superio...
The autonomic ganglia and plexuses are a collection of ganglia where autonomic preganglionic neurones arising from the CNS synapse with postganglionic neurones outside the CNS, i.e. in the peripheral nervous system. Many of the ganglia contain nerves of the sympathetic and parasympathetic nervou...
This article lists examples of normal imaging divided by body region and system.
head and neck
Sinonasal carcinomas are a broad group of sinonasal malignant tumours that are of epithelial cell origin/lineage.
Sinonasal carcinomas can be classified into various histological and aetiological subgroups:
sinonasal squamous cell carcinoma: considered the most common histological s...
Protrusion of the infraorbital canal into the maxillary sinus is a type of variant anatomy where the infraorbital canal traverses below the level of the orbital floor and often through the maxillary sinus to varying degrees. It can be detected on sinus CT and cone beam computed tomography and it...
The superior alveolar arteries is a collective term for the following arteries:
posterior superior alveolar artery: branch of the maxillary artery in the pterygopalatine fossa
middle superior alveolar artery: small branch of the infraorbital artery
anterior superior alveolar artery: branch of...
The suspensory ligaments of the middle ear ossicles are ligaments within the middle ear which attach the ossicles to the walls of the mesotympanum 1. The ligaments help the ossicles transmit sound from the tympanic membrane to the oval window.
Origins and insertions of the suspen...
Lacrimal gland prolapse, also known as lacrimal gland displacement or lacrimal gland dislocation, is defined as significant herniation of the lacrimal gland outside the lacrimal fossa. It is an underrecognized clinical condition that needs to be differentiated from mass lesions in the preseptal ...
Pseudoproptosis is a situation where the eye can have a proptotic anatomic appearance but without any mass effect from a lesion displacing the globe or any underlying pathology. Instances where this can occur include
buphthalmos: as a result of congenital glaucoma or severe myopia
Elfin facies refers to a characteristic facial appearance seen in certain rare congenital syndromes.
Elfin facies is sometimes used synonymously with Williams syndrome and the latter is occasionally called elfin facies syndrome. However elfin facies is seen with other rare genetic ...
Saturday night retinopathy is an acute ischaemic retinopathy, choroidopathy, and orbitopathy secondary to prolonged ocular pressure during a drug-induced stupor.
While monocular blindness as a complication of prolonged headrest use in prone neurosurgical procedures has been widely...
The bright tongue sign is a radiological sign most commonly described in amyotrophic lateral sclerosis with bulbar involvement 1,2. However, this sign is not pathognomonic, and may be seen with other myopathies or neuropathies with tongue or bulbar involvement (e.g. Kennedy disease, Pompe diseas...
Spontaneous retropharyngeal haemorrhage, also known as spontaneous retropharyngeal haematoma, describes an accumulation of blood in the retropharyngeal space. It is a rare but potentially fatal entity due to potential for acute airway obstruction and/or rapid internal bleeding.
The scalene muscles are a group of three closely related neck muscles.
anterior scalene muscles
middle scalene muscles
posterior scalene muscles
origin: transverse processes of mid to lower cervical vertebrae (C2-C7).
insertion: first or second ribs. The anterior and middle insert...
Oral tori (singular torus) are benign bony outgrowths from the maxilla and mandible:
maxillary tori a.k.a. torus palatinus
mandibular tori a.k.a. torus mandibularis
Oral tori are subcategorised according to their shape 1:
Although not usually called tori, fur...
Internal auditory canal (IAC) exostoses are bony growths that can narrow the IAC lumen, sometimes causing neurological symptoms due to nerve compression.
Unlike their counterpart in the external auditory canal, IAC exostoses are uncommon and can be difficult to detect 1.
Radiation therapy has the potential to cause complications in many organ systems, many of which, especially in the thorax, are important for radiologists to be aware of.
acute radiation syndrome
complications of cranial radiation therapy
radiation-induced cerebral vasculopathy
Salivary duct carcinomas are a subtype of primary salivary gland tumour. Salivary duct carcinomas show high rates of metastasis and recurrence.
Salivary duct carcinomas represent 5-10% of salivary gland malignancies and can arise de novo or out of a pleomorphic adenoma 1,2. They ...
Impacted teeth are common with the third molars most common. Other impacted teeth (e.g. maxillary canines, maxillary second molar, mandibular second premolar, and mandibular second molar) are less common 1,2.
Cone beam CT (CBCT) allows for 1,3:
impacted tooth loc...
Tetanus is a rare vaccine-preventable disease caused by Clostridium tetani, a ubiquitous soil bacterium which contaminates open wounds. It secretes a powerful neurotoxin which degrades neuromuscular junction function, producing muscle spasms and, despite intensive intervention, is often fatal.
Branch retinal artery occlusion (BRAO) refers to the acute obstruction of an arteriolar branch of the central retinal artery, which can lead to retinal ischaemia and transient or permanent visual loss. The distribution affecting a branch distinguishes this disease from central retinal artery occ...
Trigeminal radiofrequency ablation, also known as trigeminal radiofrequency rhizotomy, is a percutaneous interventional procedure used to treat trigeminal neuralgia. It is the most popular technique for trigeminal ablation.
trigeminal neuralgia resistant to traditional medical trea...
Non-arteritic anterior ischaemic optic neuropathy (NAION) is a form of ischaemic optic neuropathy.
It is considered the most common acute optic neuropathy in patients over 50 years of age (especially in those with vasculopathy risk factors (e.g. diabetes mellitus, hypertension, an...
The depressor labii inferioris muscle, also known as quadratus labii inferioris muscle, is one of the facial muscles.
origin: oblique line of the mandible, medial to the mental foramen
modiolus at the angle of the mouth
ascends to medially insert into lower lip
Carotid artery tortuosity is the elongation of the extracranial carotid arteries with redundancy and/or altered course, which may present on imaging as kinking, coiling, and/or looping 1,2.
Carotid artery tortuosity is mostly (~80%) asymptomatic. When symptomatic (~12.5%,...
The superior cervical ganglion (plural: ganglia) is the largest ganglion of the cervical sympathetic trunk, providing autonomic innervation to the head and neck region 1.
The superior cervical ganglion is formed by embryologically fused C1 to C4 sympathetic ganglia. It is elongat...
Orbital apex syndrome, also known as Jacod syndrome, is a constellation of clinical findings, presenting as a result of several potential pathologies that compress or otherwise affect structures passing through the orbital apex.
Presentation is according to the structures...
Hypoglossal nerve palsies, or twelfth nerve palsies, result in weakness of the muscles supplied by the hypoglossal nerve, namely the intrinsic and extrinsic tongue muscles, except for palatoglossus.
The hypoglossal nucleus receives a major component of contralateral corti...
The ciliary muscle (TA: musculus ciliaris) is located within the ciliary body of the eye. It acts to facilitate lens accommodation for near vision, and receives parasympathetic innervation from short ciliary nerves, arising from the oculomotor nerve via the ciliary ganglion.
The dilator pupillae muscle is a ring of contractile cells within the iris. These cells are arranged radially, such that their contraction facilitates pupillary dilation (mydriasis). The dilator pupillae muscle receives innervation from the sympathetic nervous system.
The sphincter pupillae muscle is a circular ring of smooth muscle within the iris responsible for constriction of the pupil (miosis). The structure is stimulated by the parasympathetic nervous system causing the muscle to decrease in diameter as it contracts.
The sphincter pupill...
There are multiple pharyngeal muscles that make up the structure of the pharynx. They comprise circular and longitudinal muscles whose overall function is to propel food into the oesophagus.
These muscles comprise the outer layer of musculature and act to ...
Clival fractures are uncommon skull base fractures resulting from high-energy cranial trauma and are usually associated with other skull vault fractures and brain injuries.
For a general discussion, please refer to the article on basilar fractures of the skull.
Most fractures of ...
An intracochlear schwannoma is a subtype of an intralabyrinthine schwannoma which is a schwannoma arising in relation to the 8th cranial nerve.
Patients may present with unilateral sensorineural hearing loss.
Schwannomas that are confined exclusively to the c...
Periodontitis is an inflammatory disease affecting the supporting tissues of the teeth. It is a common cause of tooth loss, particularly in the adult population.
Different forms of periodontitis are recognised. The terms 'chronic periodontitis' and 'aggressive periodontitis' have b...
A canal-wall-down mastoidectomy comprises a group of mastoidectomies which is more open and extensive than a canal-wall-up mastoidectomy. In addition to traditional forms, various modified forms are now performed (see modified canal wall down mastoidectomy).
They initially comprise the similar ...
Prognathism or mandibular prognathism refers to a type of morphological jaw positional anomaly in which the lower jaw protrudes ahead of the upper jaw. This results in an extended chin and dental malocclusion. It can be associated with certain conditions such as
syphilis - late cong...
The canine space, or infraorbital space, is a paired compartment in the soft tissues of the face, overlying the maxilla near the canine tooth root and covered by the levator labii superioris muscle.
The canine space contains fat and branches of the infraorbital nerve.
Trichilemmal cysts, also known as pilar cysts, are benign accumulations of keratin along the outer hair root sheath, most commonly on the scalp. They are the most common subcutaneous nodule incidentally found on head imaging and are of no clinical relevance when asymptomatic 1. Uncommonly, they ...
Cacosmia refers to a form of olfactory dysfunction where the patient has an inability to "recognise" smells. It can arise from a number of pathologies and can include peripheral sinonasal and central sensorineural components. In this situation, the patient knows there is a smell but cannot disti...
The suboccipital cavernous sinuses are paired venous plexuses that surround the horizontal (distal V3) portion of the vertebral arteries at the craniocervical junction. Its name derives from its resemblance to the cavernous sinus as it is a venous cushion surrounding a large arterial loop at the...
Intraparotid nodal metastases refer to metastatic involvement of intraparotid lymph nodes from either a primary parotid tumour or an extraparotid tumour in the head and neck (e.g. nasopharyngeal carcinoma).
There may be a predilection towards the superficial lobe or tail re...
Age-related macular degeneration (AMD) is an eye disease that affects central vision. It occurs when ageing causes damage to the macula. The macula is responsible for fine detailed vision also known as central vision.
Lobular capillary haemangioma of the nasal cavity, also known as nasal pyogenic granuloma, is an uncommon benign, rapidly growing vascular neoplasm of the nasal cavity.
The term “pyogenic granuloma” is a misnomer due to its lack of infectious origin according to histological and mi...
The nasal septal cartilage, also known as quadrangular cartilage, forms most of the anterior portion of the nasal septum, and is one of five named nasal cartilaginous components supporting the external nose.
Most of the anterior one-third of the nasal septum is formed by the sept...
Submandibular gland enlargement refers to an increase in the volume of the submandibular gland, exceeding "normal" values of 7.4 ± 1.8 mL 1.
submandibular duct stenosis (e.g. tumour, granulomatous disease)
acute sialadenitis: following...
The salt and pepper sign has been used to describe the MRI appearance of the parotid gland in Sjögren syndrome. This pertains to a combination of punctate regions of calcification (pepper) and fatty replacement (salt) 1.
The salt and pepper sign is used to describe a typical MRI appearance of some highly vascular tumours which contain foci of haemorrhage, typically a paraganglioma 1-3. The appearance is on T1-weighted sequences, and is made up of:
punctate regions of hyperintensity = salt
small flow voids = pe...
The neurocranium (plural: neurocrania) is the name given to the portion of the skull that encloses the brain. It comprises the skull base and the skull vault. The neurocranium and facial bones (viscerocranium) together form the skull.
Hypervascular head and neck lesions are findings that enhance avidly after biphasic injection, on contrast-enhanced CT or MRI of the neck.
ectopic thyroid gland
hyperdense soft tissue mass on non contrast-CT
intense homogeneous enhancement after contrast injection
The nasolacrimal canal is the short bony passage along which the nasolacrimal duct courses in the face.
lacrimal groove of the medial maxilla
lacrimal hook of the lacrimal bone
superiorly: lacrimal bone
inferiorly: lacrimal process of the inferior n...
Chronic otitis media is a form of otitis media where there is a prolonged phase of inflammation in the middle ear with resultant tympanic membrane perforation.
There are a few types of chronic otitis media 1-5:
benign/inactive chronic otitis media: dry tympanic membrane perforation
The oropharyngeal isthmus, a.k.a. isthmus of fauces, is the relative constriction of the anterior oropharynx that borders the oral cavity. The isthmus is sometimes described as the passage that transitions between the oral cavity and pharynx, but strictly speaking, it is part of the oropharynx.
Fibrosing inflammatory pseudotumours are an inflammatory process with histology showing a polymorphous infiltrate with plasma cells, lymphocytes and eosinophils as well as a significant reactive fibrovascular component.
They can occur at various sites of the body including:...
The modiolus (plural: modioli) may refer to one of two different anatomical structures, both in the head and neck region:
History and etymology
The Latin word, "modiolus" means hub of a wheel, and is well-named, as in both the cochlea and at the angle of t...
The modiolus (plural: modioli), also known as the modiolus anguli oris or commissural modiolus, is a small fibromuscular structure at the corner of the mouth where fibres from multiple facial muscles converge, and helps coordinate the action of these muscles.
The convergence of t...
A gomphosis (plural: gomphoses), also known as the dentoalveolar syndesmosis, is the specific name for the fibrous joint between the teeth and the alveolar bone of the maxilla/mandible 1,2.
The incisivus labii inferioris muscle (TA: pars labialis musculi orbicularis oris) is one of the facial muscles. It acts as a supplementary muscle to the orbicularis oris muscle.
The incisivus labii inferioris muscle is often omitted from major anatomical texts or articles on the f...
Osseointegrated implants (OI) are endosteal implants characterised by porous surfaces that allow a direct structural connection between bone and implant without interposed soft tissue and ingrowth and interdigitation of the newly formed lamellar bone.
Osseointegration has been defined as direct...
A commissure (TA: commissura) is a location at which two anatomical structures are united. Though the term most commonly refers to the commissures in the brain, there are a number which exist in the human body:
central nervous system
Multisystemic smooth muscle dysfunction syndrome is a rare genetic disorder caused by mutations in the ACTA2 gene, resulting in intracranial steno-occlusive disease and aortic dissection or aneurysm, among other complications.
Most cases are diagnosed in childhood 1.
Non-pulsatile tinnitus is a form of tinnitus where there is a continuous ringing sensation of the ears. It is thought to have a considerable subjective component in many individuals.
Many factors have been postulated, inclusive of 1-4:
middle ear infection
Auriculocondylar syndrome is a rare congenital syndrome primarily characterised by malformed ears and mandibular condyle aplasia/hypoplasia.
This is an autosomal dominant genetic disease resulting from GNAI3 or PLCB4 gene defects. This affects facial development especially the 1st an...
The pes anserinus (rare plural: pedes anserini) is the name given to two different anatomical structures:
pes anserinus (facial nerve): a.k.a. parotid plexus
pes anserinus (knee)
Both structures are so named due to their similarity to a goose's foot, which is what 'pes anserinus' means in Lat...
The marginal mandibular nerve (TA: ramus marginalis mandibularis nervi facialis) is a branch of the extratemporal (terminal) segment of the facial nerve. It supplies the depressor anguli oris, depressor labii inferioris and mentalis muscles. It is of greater clinical importance than the other fa...
Odynophagia is the term given for painful swallowing.
It can arise from a number of causes which include
oesophageal inflammation - oesophagitis
dysphagia: difficulty swallowing.
The mentalis muscles (TA: musculus mentalis) are paired muscles, one on each side of the mouth, important as elevators of the chin and lower lip; the muscles are one of the facial muscles.
origin: incisive fossa of the mandible
insertion: skin of the chin
innervation: facial nerve
Auricular perichondritis, also known as perichondritis of the ear or pinna, is an infection or inflammation of the cartilage-bearing part of the external ear.
The term perichondritis, strictly speaking, refers to inflammation involving the perichondrium. However, a distinction is o...
The buccolabial muscles form a subgroup of the facial muscles.
Elevators, retractors and evertors of the upper lip:
levator labii superioris alaeque nasalis (LLSAN) muscle
levator labii superioris muscle
zygomaticus major muscle
zygomaticus minor muscle
levator anguli oris...
A thyrolinguofacial trunk is a very rare pattern of branching of the anterior branches of the external carotid artery. Rather than the facial artery, lingual artery, and superior thyroid artery having their own distinct origins, all three vessels originate from a common trunk of the external car...
A linguofacial trunk is a rare variation of the anterior branches of the external carotid artery. The lingual artery and facial artery share a common trunk rather than branching independently from the external carotid artery 1. Unlike the thyrolingual or thyrolinguofacial variations in which the...
A thyrolingual trunk is an anatomical variant in which the superior thyroid artery and lingual artery share a common trunk 1. This is in contrast to the typical pattern of both vessels emerging independently from the external carotid artery. Other variations of origin include a linguofacial trun...
The submental artery is the largest branch of the facial artery. The vessel supplies the floor of the mouth and sublingual gland while also connecting the circulation of the tongue and the floor of the mouth 1,3.
origin: facial artery 2
course: emerges from the facial artery at the s...
The submasseteric space, also known as the masseteric space, is the inferolateral subcompartment of the masticator space located between the mandible and masseter muscle.
Relations and/or Boundaries
The submasseteric space has the following boundaries 1:
medially: mandible (ram...
The pterygomandibular space is the inferomedial subcompartment of the masticator space located between the mandible and pterygoid muscles.
The pterygomandibular space contains loose areolar tissue, the sphenomandibular ligament, and the following named neurovascular str...
The levator anguli oris muscle, also known as caninus or triangularis labii superioris muscles, is a buccolabial muscle, a subdivision of the facial muscles.
origin: canine fossa of the maxilla
insertion: modiolus and merges with depressor anguli oris muscle
The lesser palatine artery is a small branch of the descending palatine artery (branch of the 3rd part of the maxillary artery). The vessel supplies the soft palate with small branches to the palatine tonsils 1,2. The vessel emerges through the lesser palatine foramen before travelling posterior...
The descending palatine artery is a branch of the maxillary artery that supplies both the soft palate and hard palate as well as the palatine tonsils 1.
origin: 3rd part of the maxillary artery
course: descending through the pterygopalatine fossa before its branches enter either the ...
The CT paranasal sinus protocol serves as an examination for the assessment of the study of the mucosa and bone system of the sinonasal cavities. It is usually performed as a non-contrast study.
NB: This article aims to frame a general concept of a CT protocol for the assessment of the paranasa...
The ascending palatine artery is a branch of the facial artery that supplies part of the soft palate. In addition, the vessel also supplies the tensor veli palatini, uvular muscle, palatine tonsils, and palatopharyngeus 1,2. The posterior branch supplies the posterior and inferior soft palate es...
The frontalis muscle (TA: musculus frontalis) is a paired muscle extending from the supraorbital region to the level of the coronal suture. Flat and quadrilateral in shape, it is one of the facial muscles. Along with the occipitalis muscle, it forms the occipitofrontalis muscle due to a common t...