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...
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
insertion: first or second ribs
blood supply: ascending cervical artery
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...
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
The superior cervical ganglion (plural: ganglia) is the largest ganglion of the cervical sympathetic trunk, providing innervation to the head and neck region 1.
The superior cervical ganglion is formed by embryologically fused C1 to C4 sympathetic ganglia. It is elongated, cylind...
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 esophagus.
These muscles comprise the outer layer of musculature and act to c...
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...
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...
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.
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...
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.
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 fibers 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...
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
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...
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
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 traveling 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 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...
The risorius muscle (TA: musculus risorius) is one of the muscles of the mouth, a subset of the facial muscles. It is often absent and has been described as an accessory muscle.
origin: fascia overlying the parotid, masseter and/or platysma muscles
insertion: modiolus at the angle of...
The levator labii superioris (LLS) muscle (TA synonym: musculus levator labii superioris) is one of the elevators of the upper lip, a subset of the facial muscles.
It is not to be confused with the levator labii superioris alaeque nasalis muscle, which has a very similar name, at least partiall...
A non-recurrent laryngeal nerve is an uncommon anatomical variant in which the recurrent laryngeal nerve takes a course that is deviant to its usual descent into the thorax. The non-recurrent laryngeal nerve rather enters the larynx directly from the cervical Vagus nerve instead of coursing infe...
Cartilage or cartilaginous tissue is a resilient and type of connective tissue of mesodermal origin that forms an integral part within the musculoskeletal system and as a structural component in other organs.
Cartilage can be generally classified into the following main types:
Macrodontia, also known as megadontia or megalodontia, is a rare congenital abnormal enlargement of the teeth that may affect all the dentition or more rarely, only a single tooth.
Macrodontia is very rare. In a review of the panoramic dental radiographs of 1200 patients in Turke...
The respiratory tract refers to the portion of the respiratory system that conducts air into and out of the body. It is conventionally divided into upper and lower tracts.
The upper respiratory tract (URT), also known as the upper airways, is the collective term for the components of the respir...
The root of tongue is the deeper anatomical part of the tongue contained in the oral cavity.
The term root of tongue should not be confused with the base of tongue, which is part of the oropharynx and is the posterior third of the tongue, posterior to the circumvallate papillae.
The uvula (plural: uvulae or uvulas) may refer to several different anatomical structures. When used as a standalone term it is usually understood to refer to the soft palate uvula.
uvula (soft palate)
uvula (male bladder)
History and etymology
Uvula is Latin for 'little ...
The retrotympanum is the posterior compartment of the middle ear cavity (posterior to the tympanic annulus) and contains a number of important recesses.
The midline of the retrotympanum is defined by the pyramidal eminence and styloid eminence 1. The pyramidal eminence is the mos...
The fossula post fenestram is a sac-like evagination of connective tissue within the otic capsule just posterior to the oval window. The region around the fossula is one of the less common areas of predilection for otosclerosis.
It arises from the vestibule and is thus one of three extensions o...
The uvula is a small, conical, pendulous process projected inferiorly from the midline posterior margin of the soft palate. It is primarily formed from the insertions of the two muscles of the uvula and their covering mucosa.
location: posterior midline soft palate
blood supply: from ...
The petrosal fossula refers to a small depression on the inferior surface of the petrous temporal bone. It is located in the ridge between the jugular fossa and external opening of the carotid canal. The petrosal fossula houses the inferior (petrous) ganglion of the glossopharyngeal nerve (origi...
The triticeal cartilage is a small cartilage located within the lateral aspect of the thyrohyoid membrane, that may be bilateral, unilateral or absent. It is considered a laryngeal anatomical variant.
It is found in 33% of an adult cadaver series 2.
The triticeal c...
The condylar process, also called the condyloid process, is the process on the mandible that articulates with the disk of the TMJ.
It consists of two portions:
presents an articular surface for articulation with the articular disk of the temporomandibular joint (TMJ)
Supra bulla frontal cells are an anatomical variant of the paranasal sinuses, included in the International Frontal Sinus Anatomy Classification.
Cell that originates in the supra-bulla region and pneumatizes along the skull base into the posterior region of the frontal sinus. Th...
Supra agger cells are an anatomical variant of the paranasal sinuses, included in the International Frontal Sinus Anatomy Classification.
These are an anterior-lateral ethmoidal cell, located above the agger nasi cell (not pneumatizing into the frontal sinus). The supra agger cel...
Supra bulla cells are an anatomical variant of the paranasal sinuses, included in the International Frontal Sinus Anatomy Classification.
Cell above the bulla ethmoidalis that does not enter the frontal sinus.
The supra agger cells push the drainage pathway anteriorly.
Supra agger frontal cells are an anatomical variant of the paranasal sinuses, included in the International Frontal Sinus Anatomy Classification.
Anterior-lateral ethmoidal cell that extends into the frontal sinus. A small SAFC will only extend into the floor of the frontal sinus...
International Frontal Sinus Anatomy Classification (IFAC) result from an expert consensus, developed to improve the ability of the surgeon to understand the possible variations of the frontal recess and frontal sinus anatomy.
anterior cells: push the drainage pathway of the fron...
Venous lacunae, also known as venous lakes, are enlarged venous spaces within the skull, most often in the parasagittal region. They are normal variants and their primary importance is that they may mimic lytic lesions.
Venous lacunae are the result of focal venous dilatations ...
The optic strut is a paired bony projection that joins the body of the sphenoid bone with the anterior clinoid process of the lesser wing of the sphenoid bone. It separates the optic canal superomedially from the superior orbital fissure inferolaterally 1. It also borders the anterior aspect of ...
The lamina cribrosa sclerae, also known as lamina cribrosa of the sclera, is a net-like structure covering a small hole in the posterior sclera through which the optic nerve (cranial nerve II), central retinal artery and central retinal vein pass.
The lamina cribrosa (rare plural: laminae cribrosae) is an anatomical term that is commonly used for two different structures in the head and neck region:
lamina cribrosa of the ethmoid bone
lamina cribrosa of the sclera
Also note that the macula cribrosa of the vestibule of the inner ear has...
The central retinal vein (CRV) or central vein of the retina, and sometimes shortened to the retinal vein, is the venous counterpart of the central retinal artery.
Each quadrant of the retina is drained by multiple minor retinal veins which coalesce to form a main retinal vein. T...
The cochlear cleft is a curvilinear radiolucent area of incomplete endochondral ossification in the otic capsule adjacent to the cochlea. It is a variant most prominent in children that may also be visible in adults 1.
The cochlear cleft is a C-shaped structure in the otic capsul...
The vestibular or Scarpa's ganglion is the ganglion of the vestibular branch of the vestibulocochlear nerve. It contains the cell bodies of the vestibular nerve as the superior and inferior vestibular branches unite and is located within the nerve as it passes through the lateral aspect of the i...
The anterior condylar confluence is an extracranial venous structure at the base of skull that communicates extensively with regional veins and dural venous sinuses.
It is located immediately anterior to the hypoglossal canal and medial to the jugular vein, just inferior to the jugular bulb an...
The branchial (or pharyngeal) apparatus is the complex region in the developing embryo between the head and chest that develops in the fourth week and provides bilateral ridges and valleys that subsequently develop into numerous anatomic structures of the head, face, palate and anterior neck. Th...
Clival diploic veins are veins that travel through the body of the clivus connecting intracranial venous structures on the inner surface of the skull (e.g. basilar venous plexus, inferior petrosal sinuses, marginal sinus, internal carotid artery venous plexus of Rektorzik, inferior petro-occipit...
The meningo-ophthalmic artery is a variant arterial anatomy in which the entire supply to the ophthalmic artery derives from the middle meningeal artery. This variation represents one extreme of a spectrum of the persistence of the embryologic stapedial artery.
The ice cream cone sign describes the normal appearance of the middle ear ossicles on axial CT scan. The ball of the ice cream is formed by the head of the malleus and cone is formed by the body of the incus, with the tapering conical point formed by the short process pointing towards the aditus...
The petrosphenoidal ligament, also known as Gruber ligament or petroclival ligament, forms the superior border of Dorello canal, the conduit for the abducens nerve.
The ligament has previously been known as the petroclinoid ligament (ligamentum petroclinoideum) but it actually does...
The buccopharyngeal fascia is the component of the middle layer of the deep cervical fascia that invests the outside of the pharyngeal constrictors and buccinator muscles.
The term has been variably used to refer to the entire visceral component of the middle layer of the deep cerv...
Vertebral artery hypoplasia is a congenital anatomical variation characterized by underdevelopment of the vertebral artery.
The prevalence of hypoplastic vertebral arteries is reported to be 2-6% from autopsy and angiograms 1.
These are an asymptomatic anat...
The jugular trunks (TA: truncus jugularis) are small short paired lymphatic trunks, each one draining one side of the head and neck, forming an important terminal part of the lymphatic system 1-3.
the left and right jugular trunks are found in the root of the neck
A high-riding brachiocephalic artery is a rare variant of the neck vessels in which the brachiocephalic artery passes much more superiorly than normally. It is a clinically important variant, as mistaking it for a neck lump and sampling it or neck surgery in the region may cause a devastating he...
The tegmen is the thin osseous plate that separates the middle cranial fossa from the tympanic and mastoid cavities of the temporal bone. It is comprised of two or three parts 1,2:
tegmen tympani (roof of the tympanic cavity)
tegmen mastoideum (roof of the mastoid cavity)
tegmen antri (roof o...
The orbicularis oris muscle, also known as the orbicular muscle of the mouth, (TA: musculus orbicularis oris) is one of the facial muscles and its primary action is as the sphincter of the mouth.
Orbicularis oris muscle comprises both of its own fibers and those lent from the di...
Ampulla (plural: ampullae) is an anatomical term used for tubular structures with a short segmental bulbous dilatation:
ampulla (fallopian tube)
ampulla (lacrimal system)
ampulla (esophagus): a.k.a. phrenic ampulla
ampulla (semicircular ducts)
ampulla of ...
The levator glandulae thyroideae muscle (a.k.a. musculus levator glandulae thyroideae or levator glandulae thyroideae of Soemmerring) is an anatomic variant, consisting of a band of fibrous/fibromuscular tissue, connecting the pyramidal lobe of the thyroid to the hyoid bone. When muscle fibers a...
The tympanomastoid fissure is one of the intrinsic fissures of the temporal bone, located parallel and posterior to the bony external auditory canal, dividing the tympanic part of the temporal bone and mastoid process. Its radiological significance is as a fracture mimic (pseudofracture) 1. Its ...
The planum sphenoidale is a common term for the anterior horizontal part of the superior surface of the body of the sphenoid bone. It is known in the Terminologia Anatomica (2019) as the jugum sphenoideum or sphenoidal yoke 1.
It forms part of the anterior skull base, separating ...
A crus (plural: crura) is an anatomical term used for a structure which resembles a leg.
crus (internal capsule)
crus (semicircular duct)
The cloison sagittale (sagittal partition), also known as Charpy fascia, is a sagittally oriented fascia on either side of the neck that separates the midline deep neck spaces (retropharyngeal space, prevertebral space, and danger space) from the more lateral parapharyngeal space (including caro...
The tensor-vascular-styloid fascia is a part of the middle layer of the deep cervical fascia that has been suggested to divide the prestyloid and poststyloid compartments of the parapharyngeal space. It is an extension of, and previously sometimes referred to as, the tensor veli palatini fascia ...
The deep layer of the deep cervical fascia is one of the three layers of the deep cervical fascia. It encases the paravertebral muscles and forms the perivertebral space. It consists of the perivertebral fascia (the anterior part of which is called the prevertebral fascia) and alar fascia 1-3.
The middle layer of the deep cervical fascia is the one of the three layers of the deep cervical fascia that most closely surrounds the visceral organs. This layer consists anteriorly of the strap muscle fascia (comprised of the sterno-omohyoid and sternothyroid-thyrohyoid layers) and posteriorl...
The superficial layer of the deep cervical fascia, also known as the investing layer, is the one of three layers of the deep cervical fascia that surrounds all of the neck that is deep to the platysma. The layer includes the masticator fascia, submandibular fascia, and sternocleidomastoid-trapez...
The inferior laryngeal artery accompanies the recurrent laryngeal nerve into the larynx, where it anastomoses with the superior laryngeal artery to supply the muscles and mucous membranes of the larynx 1.
origin: branch of the inferior thyroid artery
course: ascends the trachea to en...
The scalene triangle (also known as the interscalene triangle) is located laterally at the root of the neck and is the space through which the roots and trunks of the brachial plexus and the third part of the subclavian artery exit the neck. 1
Its anterior edge is formed by the scalenus anterio...
A mnemonic to remember the contents of the tendinous ring (also known as the annulus of Zinn) from superior to inferior is:
One Canal, Several Orbital Nerves In One Annulus
OC: optic canal
SO: superior division of oculomotor nerve
N: nasociliary nerve
IO: inferior division of ocu...
The anterior ethmoidal notch contains the anterior ethmoidal artery and has significant rates of anatomic variation that put the artery during functional endoscopic sinus surgery (FESS).
The anterior ethmoidal notch lies in the medial wall of the superomedial orbit, adjacent to t...
The incudomalleolar joint, also known as the incudomallear joint, is the joint between the incus and the malleus. The joint is part of the chain of ossicles sending vibrations from the tympanic membrane to the oval window.
dislocations of the joint result in conductive hearin...
The tegmen tympani, also known as the tegmental wall or roof of the tympanic cavity, is a thin plate of the petrous part of the temporal bone that separates the intracranial compartment and middle ear.
Relations and/or Boundaries
anteriorly, roof of the canal for the tensor tymp...
The protympanum (rare plural: protympana) is the compartment of the middle ear cavity located anterior to the coronal plane defined by the anterior margin of the tympanic annulus. Some authors consider the protympanum the anterior part of the mesotympanum rather than a separate compartment or do...
The cog is a coronally oriented bony process in the middle ear cavity of the temporal bone that projects from the tegmen tympani, separating the anterior epitympanic recess from the posterior epitympanum. The cog ends anterosuperior to the head of the malleus and superior to the cochleariform pr...
The internal laryngeal nerve is one of the two branches of the superior laryngeal nerve and provides sensory innervation of the laryngeal mucosa down to the level of the vocal cords (supraglottic larynx).
origin: arises as the larger of the two branches of the superior laryngeal nerve...
The external laryngeal nerve is one of the two branches of the superior laryngeal nerve and supplies the cricothyroid muscle.
origin: arises as the smaller of the two branches of the superior laryngeal nerve at the level of the greater cornu of the hyoid bone