The tarsal plates of the eye are formed by dense fibrous tissue representing thickened extensions of the orbital septum, molded to the curvature of the eyeball. Each eye has a superior tarsal plate and an inferior tarsal plate.
The plates anchor the roots of the eyelashes and contain tarsal (M...
The conjunctiva (plural: conjunctivas or conjunctivae) is a transparent membrane is attached at the margins of the cornea. It is loosely attached to the sclera and thence reflected over the inner surface of the eyelids. It is firmly attached to the tarsal plates and blends with the skin at the m...
Tunica is a word used in anatomy to refer to a type of covering.
tunica adventitia (also known as tunica externa)
tunica albuginea (clitoris)
tunica albuginea (ovary)
tunica albuginea (penis)
tunica albuginea (testis)
The reverse Waters view is a modified alternative to the Waters view. However, skull radiographs are rapidly becoming obsolete in general, being replaced by much more sensitive CT scans.
the patient is supin...
The stapediovestibular joint is the fully-functional articulation between the stapes and the oval window. It has a key role in the transmission of sound vibrations in the middle ear to the fluid in the vestibule, and thence in the cochlea 2.
The annular ligament of the stapes, a...
The oval window (or fenestra vestibuli) is a kidney-shaped aperture in the medial wall of the mesotympanum of the middle ear, providing communication with the vestibule of the inner ear. The footplate of the stapes is attached to its rim by the annular ligament 1.
The variability of the size o...
Hiccups (or hiccoughs), medical term singultus (rare plural: singultūs), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating.
Hiccups are a symptom that has prob...
Scleromalacia perforans (or non-inflammatory necrotizing scleritis) is a severe and very rare form of scleritis.
systemic lupus erythematosus
Behçet disease 5
relapsing polychondritis 5
granulomatosis with p...
Senile calcific scleral plaques, also known as senile scleral plaques, are benign degenerations of the ocular sclerae, common in elderly individuals. They are a common incidental finding on CT.
The prevalence of senile scleral plaques increases with age, from ~2.5% at age 60, to 2...
The head and neck cancer therapy response interpretation (Hopkins criteria) is a qualitative system of interpretation for therapy response assessment using PET-CT.
Widely used options for therapy response assessment are clinical examination, histopathology, CT and MR imaging, howeve...
The nasal cycle is a normal physiological process that occurs in the nasal cavity characterized by alternating partial congestion and decongestion of the nasal venous sinusoids of the nasal turbinates.
The nasal cycle is often seen on CT scan of the paranasal sinuses ...
Preauricular sinuses (also known as preauricular pits or preauricular cysts) are common congenital abnormalities that are typically small blind-ended openings near the ascending limb of the helix. These can be a simple pit or have a sinus tract and/or cystic component.
They are mo...
Recessus terminalis is the name given to a blind-ending ethmoid infundibulum. It is an anatomical variant that occurs when the uncinate process inserts more laterally than usual onto the lamina papyracea.
sinonasal disease extending into the recess terminalis may displace the ...
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.
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.
The frontal bullar cells are a subset of variably present frontal recess cells located above the ethmoid bulla.
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...
The lateral lamella (also known as the lamina lateralis) is the name given to the lateral boundary of the cribriform plate of the ethmoid bone. It runs vertically and joins the fovea ethmoidalis inferomedially. It is the thinnest part of the cribriform plate.
The lateral lamel...
The supreme nasal concha or turbinate is one of the conchae in the nose and is a bony projection, arising from the medial surface of the labyrinth of the ethmoid above the superior nasal concha. Its presence is variable and has been reported in up to 52% of subjects 1.
The air passage between t...
The supreme meatus is an air passage of the lateral nasal cavity located between the supreme nasal concha and lateral nasal wall. The ostium of a posterior ethmoidal air cell may be seen in the supreme meatus.
The plural of meatus is meatus (Latin noun of the fourth declension) or ...
The superior meatus is an air passage of the lateral nasal cavity located between the superior nasal concha and lateral nasal wall. The posterior ethmoid air cells and sphenoid sinuses drain into the superior meatus.
The inferior meatus (plural: meatus) is an air passage of the lateral nasal cavity located between the inferior nasal concha and lateral nasal wall. The nasolacrimal duct drains into the inferior meatus, and Woodruff plexus is located posteriorly.
The middle meatus is an air passage of the lateral nasal cavity located between the middle nasal concha and lateral nasal wall. The anterior ethmoid air cells, maxillary and frontal sinuses all drain into the middle meatus.
The uncinate process of the ethmoid bone is a thin hook-like osseous structure of the wall of the lateral nasal cavity.
Together with the ethmoid bulla, it forms the boundaries of the hiatus semilunaris and ethmoid infundibulum.
The course of the free edge of the uncinate proces...
The nasal meatuses are distinct air passages of the lateral nasal cavity located inferior to each nasal conchae.
The plural of meatus is meatus (Latin noun of the fourth declension) or meatuses. Meati is incorrect.
There are three main nasal meatuses:
The basal lamella, also known as basal lamella of the middle turbinate, is an osseous lamella that separates the anterior from the posterior ethmoid sinuses 1.
Internal anterior to posterior partitions of the ethmoid sinuses are called basal lamellae. According to a concept propose...
The lamina papyracea, also known as the orbital lamina of the ethmoid bone, is the principal component of the medial wall of the orbit, and also the lateral surface of the ethmoid air cells.
superiorly with the orbital plate of the frontal bone
inferiorly with t...
The retrobullar recess is a small potential opening (cleft) rather than an actual air cell located superior and posterior to the ethmoid bulla, separating it from the skull base and basal lamella. The ethmoid bulla usually opens posteriorly in the retrobullar recess.
The suprabullar cells are a subset of variably present frontal recess cells located above the ethmoid bulla.
They are nearly identical to frontal bullar cells. The distinguishing features with the latter are that the suprabullar cells are located entirely below the frontal ostium a...
Sinus lateralis is a general term used to described a space behind and/or superior to the ethmoid bulla. As it actually refers to both the suprabullar and retrobullar recesses, the use of these more specific terms is preferred.
The suprabullar recess is a potential opening (cleft) between the bulla lamella and skull base located along the posterior margin of the frontal recess with which it may communicate directly. It is present when the bulla lamella is incomplete superiorly.
The term sinus lateralis i...
Torus ethmoidalis, also known as torus lateralis, is the term given when there is no air cell in the ethmoid bulla (failure of pneumatization). It is encountered in 8% of subjects.
The ethmoid bulla, also known as bulla ethmoidalis, is the largest and most consistent air cell of the anterior ethmoid air cells.
It is located posterior to the frontal recess and enclosed laterally by the lamina papyracea. It forms the roof of the middle meatus.
It can be clas...
A mnemonic to remember the potential anatomic variants to report on pre-functional endoscopic sinus surgery studies is 1:
C: cribriform plate
L: lamina papyracea
O: Onodi cell
S: sphenoid sinus pneumatization
E: ethmoidal artery (anterior)
ostiomeatal complex nar...
The bulla lamella is a structure that, when intact, forms the posterior boundary of the frontal recess. When pneumatized, it forms the ethmoid bulla.
It is frequently incomplete and often does not reach the roof of the ethmoid at the skull base. Under these circumstances, the fro...
Familial medullary thyroid carcinoma (FMTC) is a genetic disorder closely related to multiple endocrine neoplasia type IIa (MEN2a) and multiple endocrine neoplasia type IIb (MEN2b). It is characterized by the development of medullary thyroid cancer.
FMTC is the result of mutations in the RET ...
The frontal recess is an opening in the inferior aspect of the frontal sinuses that allows drainage of the sinus.
The frontal recess is also known as the nasofrontal duct. However, since it does not have bony walls of its own, it is more appropriately referred to as a recess rather...
Frontal intersinus septal cells, also known as interfrontal sinus septal cells, are a subtype of medial frontal recess cells.
The frontal intersinus septal cells lie within the intersinus septum between the frontal sinuses. They usually drain in the medial aspect of the frontal r...
Frontal recess cells are anterior ethmoid air cells that pneumatize 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.
Kuhn classification is an anatomical classification for the subtypes of frontal cells:
type 1 (~37%): a single air cell above the agger nasi cell
type 2 (~19%): two or more air cells above the agger nasi cell
type 3 (~7%): a single large cell above the agger nasi cell that extends into the fr...
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.
functional endoscopic si...
Parotid infantile hemangiomas are the most common parotid tumor of childhood. They usually run a characteristically benign course.
The median age at diagnosis is 4 months 1. There is a female preponderance with a male: female ratio of 1:3.
Presents as an en...
Tumors of the base of skull are histologically varied and are often challenging to preoperatively diagnose and treat.
Exactly which tumors are considered to be tumors of the base of skull is debatable. The broadest definition would include any tumor that involves or abuts the base of skull, thu...
The central base of skull is a region of the skull base centered on the pituitary fossa and includes surrounding structures.
Despite no single universally accepted definition of this region, it is frequently used clinically and is conceptually useful particularly when considering tumors of the ...
The sphenoidal ridge, or sphenoid ridge, is the sharp curving bony edge at the posterior aspect of the lesser wing of the sphenoid bone. It separates the horizontal floor of the anterior cranial fossa in front from the vertical anterior wall of the middle cranial fossa behind 1.
Pediatric nasal cavity masses can occur within the nose or the nasopharynx. These masses are often found incidentally on imaging but can be readily apparent clinically.
The clinical features of these lesions tend to mimic upper respiratory processes and may result in dela...
Nasal septal hematomas arise from ruptures in the small blood vessels in the nasal septum and are largely secondary to trauma. The nasal septum has a rich vascular supply which sources from both the internal and external carotid arteries.
Septal hematomas appear as i...
Paranasal sinuses and facial bones radiography is the radiological investigation of the facial bones and paranasal sinuses. Plain radiography of the facial bones is still often used in the setting of trauma, postoperative assessments and dental radiography.
Skull radiography is the radiological investigation of the skull vault and associated bony structures. Seldom requested in modern medicine, plain radiography of the skull is often the last resort in trauma imaging in the absence of a CT.
Skull radiographs are indicated for a variet...
The ear refers to the entire vestibulocochlear organ and is divided anatomically into:
The posterior auricular vein is tributary of the external jugular vein or retromandibular vein.
Origin and course
It arises over the mastoid process of the temporal bone draining the skin behind the ear and courses anteriorly into the parotid gland, draining into the external ju...
Jugulotympanic paragangliomas (previously known as glomus jugulotympanicum tumors) are jugular paragangliomas that have spread superiorly to involve the middle ear cavity. The term can also be used clinically when a suspected tympanic paraganglioma involves the hypotympanum as its inferior exten...
Supraorbital air cells are an anatomical variant of the paranasal sinuses. They consist of cells originating from the anterior ethmoid air cells extending posteriorly and superiorly over the orbit from the frontal recess. They may mimic septated frontal sinuses as their posterior wall is the sku...
Cerumen, also known as earwax, is a natural secretion produced by and found within the external auditory canal (EAC). It has important roles as part of the first line of defense of the ear from micro-organisms and optimizing function of the tympanic membrane and EAC.
Cerumen is secre...
Brown syndrome refers to a failure of upward gaze while the eye is adducted secondary to an abnormality of the superior oblique tendon sheath complex.
This abnormality is a little counter-intuitive and highlights how the action of the superior oblique is position-dependent and that e...
Anorexia nervosa is a psychiatric disorder characterized by distorted self-perception of body weight leading to starvation, obsession with remaining underweight, and an excessive fear of gaining weight. One in five patients with anorexia dies due to complications of the disease.
Cytomegalovirus retinitis is a late complication of cytomegalovirus (CMV) infection, usually occurring in immunosuppressed patients. It is an acquired immune deficiency syndrome (AIDS) defining illness.
The reported incidence and prevalence of CMV retinitis varies with geographica...
Nelson syndrome is a rare disorder observed in patients with Cushing disease that have undergone bilateral adrenalectomy. It involves enlargement of an existing adrenocorticotropic hormone-secreting pituitary tumor, typically an adenoma, after surgical resection of the adrenal glands.
Descending necrotizing mediastinitis is a severe form of mediastinitis and refers to an acute, polymicrobial infection of the mediastinum that usually spreads downwards from oropharyngeal, cervical, and odontogenic infection.
diabetes: more than one-third of patients...
Dehiscence of the lamina papyracea is an anomaly of the paranasal sinuses represented by a defect of the medial orbital wall. It is thought to be a benign congenital variant of no clinical significance.
Almost all patients tend to be asymptomatic, according to one study 2...
The occipital condyles are two large protuberances on the undersurface of the occipital bone, located besides the front half of the foramen magnum. It forms the connection between the skull and the vertebral coloumn.
atlas (C1) at the atlanto-occipital joint
A mnemonic to remember the nerve supply to the extraocular muscles:
LR6SO4O3 (mock 'chemical formula')
The letters represent the extraocular muscles and numbers represent their respective cranial nerve supply:
LR6: lateral rectus, innervated by the 6th (abducens) nerve
The vitreous body or vitreous humor is a transparent, avascular gel that occupies ~80% of the globe and helps to maintain the position of the retina and the shape of the globe.
Situated within the globe between the lens and the optic cup, its anterior surface is indented by the ...
The cuneiform cartilages are small, paired accessory laryngeal cartilages that reside in the aryepiglottic fold. They take the form of club-like nodules, visible as elevations beneath the mucosa (the cuneiform tubercle) anterosuperior to the corniculate cartilages. They do not directly articulat...
The Harvard scoring system for rhinosinusitis is, as the name implies, a scoring system based on CT-scan assessment for grading of rhinosinusitis.
0: normal (< 2 mm mucosal thickening on any sinus wall)
1: all unilateral disease or anatomic abnormality
2: bilateral disease limited to...
Sinonasal respiratory epithelial adenomatoid hamartoma (REAH) is a rare benign glandular proliferation of the sinonasal cavities. It is most commonly encountered within the olfactory clefts.
It is most often encountered in middle-aged adults with no definite gender predilection 1,...
Radiation-induced thyroid cancer is an important etiology of thyroid cancer.
Information about radiation-induced thyroid malignancies comes from several long-term cohort studies along with some case-controlled studies and their subsequent meta-analyzes. Although these studies var...
Occipital nerve stimulators are a type of neuromodulation therapy aimed at treating chronic refractory headache and craniofacial pain such as occipital neuralgia 1-3. This form of non-pharmaceutical therapy involves an implantable device composed of an electrode and a pulse generator.
Exudative tracheitis, also known as bacterial tracheitis, membranous croup or membranous laryngotracheobronchitis, is a rare, but potentially life-threatening cause of upper airway obstruction.
Typical age ranges from 6 to 10 years of age.
The internal palpebral arteries, or medial palpebral arteries, are branches of the ophthalmic artery, with superior and inferior medial palpebral branches arising opposite the trochlear of the superior oblique muscle.
The internal palpebral arteries enter the superior and inferio...
Frontal sinus fractures are facial fractures that involve the frontal sinus, either in isolation or more commonly as part of more complex facial fractures. They can result in cosmetic deformity, functional impairment, CSF leak, and/or intracranial infection (e.g. meningitis).
The hiatus semilunaris is a semicircular shaped opening located on the lateral wall of the nasal cavity. It is a component of the ostiomeatal complex and serves as the opening for the frontal and maxillary sinuses and the anterior ethmoid air cells. It is inferior to the ethmoid bulla and the un...
Cutis verticis gyrata is a rare progressive dermatological condition characterized by excessive skin folds in the scalp, resembling the surface of the cerebral cortex.
It occurs more commonly in males, with a male-to-female ratio of approximately 5:1 1.
Benign enhancing foramen magnum lesions, also described as high signal lesions, have been anecdotally seen by radiologists for years but only recently described as an incidental finding on 3D FLAIR MRI in a typical location in the foramen magnum just posterior to the intradural vertebral artery....
The mesotympanum (rare plural: mesotympana) forms the main compartment of the tympanic cavity and contains most of the important structures of the middle ear, including most of the ossicular chain.
The mesotympanum is found in the middle ear.
The tympanic annulus is the thickened edge of the pars tensa of the tympanic membrane, anchoring it in the tympanic sulcus 3.
The tympanic annulus is formed by a fibrocartilaginous thickening of the edge of the pars tensa and has a horseshoe-shaped configuration. It is deficient ...
The hypotympanum refers to the portion of the tympanic cavity lying inferior to the level of the inferior margin of the external acoustic canal (EAC).
The hypotympanum is the smallest of the three compartments that make up the tympanic cavity and is a shallow depression in the fl...
The epitympanum, also known as the attic or epitympanic recess, is the most superior portion of the tympanic cavity. It is that portion of the tympanic cavity superior to the axial plane between the tip of the scutum and the tympanic segment of the facial nerve 1,3.
Posteriorly the epitympanum ...
The anterior epitympanic recess, also known as the supratubal recess, is a small discrete space in the epitympanum anterior to the malleus. It is separated from the epitympanum proper by the cog.
Vagal nerve stimulators are an implantable device used to treat a number of conditions although the mechanism of action has not been completely elucidated.
Vagal nerve stimulators are indicated in patients with 1:
Lennox-Gastaut syndrome (off-label)
The cochleariform process is the thin osseous projection in the anterior wall of the middle ear cavity that acts as the fulcrum for the tendon of the tensor tympani.
The cochleariform process is located 2,3:
at the posterior termination of the semicanal for tensor tym...
The ethmoid infundibulum is a curved cleft of the ethmoid bone which leads into the anterior portion of the hiatus semilunaris. It is bordered medially by the uncinate process and laterally by the orbital plate of the ethmoid. The infundibulum is often continuous with the frontal recess into whi...
Benign paroxysmal positional vertigo (BPPV) is one of the most common causes of vertigo. It occurs secondary to change in posture and typically is associated with nystagmus. The etiology is thought to be due to changes of position of the otoliths in the inner ear, most commonly into the posterio...
The maxillary ostium or maxillary hiatus is an opening that forms the drainage channel of the maxillary sinus and is also one of the components of the ostiomeatal unit. It is located posteriorly and medially near the roof of the maxillary sinus measuring approximately 2-4 mm. It drains into the ...
The anterior tympanic artery is the second named branch of the first part of the maxillary artery. The vessel passes through the petrotympanic fissure to supply the tympanic membrane and lining of the middle ear. It accompanies the chorda tympani and the anterior ligament of malleus in its course.
The deep auricular artery is the first named branch of the maxillary artery and passes through the bony or cartilaginous wall of the external acoustic meatus to supply the skin of that canal and part of the tympanic membrane. It can sometimes contribute a small branch to the arterial supply of t...
The greater palatine artery is a branch of the descending palatine artery (branch of the 3rd part of the maxillary artery) 4. The blood vessel supplies the hard palate mucosa, gingival tissue, and palatine tonsils 5. The greater palatine artery also contributes to the Kiesselbach plexus of the n...
Duane syndrome, also known as Duane retraction syndrome, is a rare congenital disease characterized by non-progressive strabismus. It is caused by a variable degree of abnormal development of one or both 6th cranial nerves (CN VI).
It presents during childhood and it accounts for ...
Petrous temporal bone fractures are classically divided into longitudinal, transverse or mixed fracture patterns, depending on the direction of fracture plane with respect to the long axis of the petrous temporal bone. Some features may aid in distinguishing them.
Longitudinal petrous temporal ...
Nervus intermedius neuralgia, or geniculate neuralgia, corresponds to a clinical manifestation of sudden paroxysms of excruciating otalgia which usually lasts a few seconds to a few minutes, involving the nervus intermedius (intermediate nerve of Wrisberg).
Nervus intermedius neur...
The sack of marbles sign, also known as the marbles in a bag sign, refers to aggregations of multiple small globules of fat within a cyst mimicking marble spheres within a sack. They appear hyperechoic on ultrasound, fat attenuation on CT, and high signal on T1WI and T2WI on MRI. It is considere...
Paranasal sinuses are air-filled cavities surrounding the nasal cavity proper which includes maxillary sinus, sphenoid sinus, frontal sinus and ethmoid sinus. Trauma to the superior and middle thirds of the face can often lead to in paranasal sinus fractures involving one or more paranasal sinus...
Thyroseq® is an expanded gene classifier test designed for further evaluation of indeterminate thyroid nodules on fine needle aspiration (FNA). In particular, it is designed to further evaluate nodules that show atypia of undetermined significance/follicular lesion of undetermined significance (...
Lagophthalmos refers to the inability of an individual to completely close the eyelids and can result in drying of the eyes and irritation, and even permanent damage.
most common in facial nerve palsies (e.g. Bell palsy)
Ramsay Hunt syndrome 4
trauma/surgery: scarring of...