Useful mnemonics to remember the branches of the internal carotid artery is:
A VIP'S COMMA
Calming voices make intra operative surgery pleasurable and almost memorable.
A VIP'S COMMA
A: anterior choroidal artery (C7)
V: Vidian artery (C2)
I: inferolateral trunk (C4)
A mnemonic for remembering the branches of the maxillary artery is:
DAM I AM Piss Drunk But Stupid Drunk I Prefer, Must Phone Alcoholics Anonymous
D: deep auricular artery
A: anterior tympanic artery
M: middle meningeal artery
I: inferior alveolar artery
A: accessory meningeal ar...
Useful mnemonics to remember the four branches of the thoracoacromial artery are:
CAlifornia Police Department
Cadavers Are Dead People
B: breast (pectoral)
CAlifornia Police Department
The breast is an apocrine gland seen in both males and females. However, in females it has a specific function which is the production of milk.
The breast has an inhomogeneous structure which is predominantly composed of adipose tissue and glandular tissue. In additi...
Breast hypoplasia is a condition which is characterised by underdevelopment of the breast. Breast hypoplasia can be congenital or acquired.
congenital adrenal hyperplasia
The bregma is the midline bony landmark where the coronal and sagittal sutures meet, between the frontal and two parietal bones.
It is the anterior fontanelle in the neonate and closes in the second 2 (typically around 18 months after birth).
It is one of the skull landmarks, craniometric poin...
The broad ligament(s) are the lateral folds of the parietal peritoneum which reflect over the upper genital tract.
The broad ligament extends from the lateral aspect of the uterus to the lateral pelvic wall and can be divided into three main components - the mesosalpinx, mesovari...
Broca's area (Brodmann area 44) is an area of the lateral frontal lobe in the dominant hemisphere concerned with the production of speech.
Broca's area is located in the posterior inferior frontal gyrus (pars opercularis and pars triangularis) of the dominant hemisphere, anterior...
Brodmann areas are a system to divide the cerebral cortex according to cytoarchitectural organization, and are, despite controversy, still very widely used as a standardised nomenclature which is superimposed on the somewhat variable gyral and sulcal anatomy.
The classification relies on the f...
The bronchial arteries are responsible for only 1% of the lung blood flow but they are the major high-pressure oxygenated blood supplier to the supporting structures of the lung parenchyma including pulmonary arteries. The classic pattern described below of two bronchial arteries on the left and...
The bronchial veins are counterparts to the bronchial arteries and drain the bronchi, hilar structures and the mid-portion of the oesophagus.
There is typically a single bronchial vein at each hilum, formed from the superficial bronchial veins with deep bronchial veins draining i...
Bronchioles are the branches of the tracheobronchial tree that by definition, are lacking in submucosal hyaline cartilage.
The bronchioles typically begin beyond the tertiary segmental bronchi and are described as conducting, terminal or respiratory bronchioles. Following the te...
Bronchopulmonary segmental anatomy describes the division of the lungs into segments based on the tertiary or segmental bronchi.
The trachea divides at the carina forming the left and right main stem bronchi which enter the lung substance to divide further. This initial division ...
Mnemonics to remember the bronchopulmonary segments are:
A PALM Seed Makes Another Little Palm (right lung)
ASIA ALPS (left lung)
'A PALM Seed Makes Another Little Palm'
right upper lobe
A: apical segment
P: posterior segment
A: anterior segment
L: lateral segment
The bronchus intermedius is one of the two bronchi which the right main bronchus bifurcates into, the other being the right upper lobe bronchus.
The bronchus intermedius runs distal to the right upper lobe bifurcation and follows the trajectory of the right main bronchus 1. Its m...
Brown adipose tissue (BAT) is one of two types of adipose tissue (the other one being white fat) important for producing thermal energy (heat, non-shivering thermogenesis) especially in the newborn. It constitutes ~5% of body mass in the newborn and tends to disappear in adulthood. It is importa...
The buccal nerve is the only purely sensory branch of the anterior division of the mandibular division of the trigeminal nerve. It is not to be confused with the buccal branch of the facial nerve.
The buccal nerve divides off the anterior division and passes with the paired nerve...
The buccal space (or buccinator space) is one of the seven suprahyoid deep compartments of the head and neck.
The buccal spaces are paired fat contained spaces on each side of the face forming cheeks. Each space is enveloped by the superficial (investing) layer of the deep cervi...
The buccinator artery is a small branch from the second part of the maxillary artery. It runs obliquely forward, between the medial pterygoid and the insertion of the temporalis, to the outer surface of the buccinator, to which it is distributed, anastomosing with branches of the facial artery a...
Buford complex is a congenital glenoid labrum variant where the anterosuperior labrum is absent in the 1-3 o'clock position and the middle glenohumeral ligament is thickened (cord-like) and originates directly from the superior labrum at the base of the biceps tendon and crosses the subscapulari...
The bulbospongiosus is a muscle found in the superficial perineal pouch which covers the bulb of the penis in males and the bulb of the vestibule in females.
origin: median raphe and perineal body
insertion: dorsum of penis/clitoris, perineal membrane
innervation: pudendal nerve
A bunionette, also known as a tailor's bunion, is a bony prominence at the lateral 5th metatarsal head. It is the lateral counterpart of the more common bunion of the first metatarsophalangeal joint.
Bunionettes are visible on clinical examination as an erythematous swel...
Bursae are small fluid-filled sacs lined by synovial membrane with an inner capillary layer of synovial fluid. It provides a cushion between bones and tendons and/or muscles around a joint. This helps to reduce friction between the bones and allows free movement. They may or may not communicate ...
Butterfly vertebra is a type of vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochordal tissue between them.
an anterior spina bifida, with or without an anterior meningocele
can be part of...
The caecum is the first part of the large bowel and lies in the right lower quadrant of the abdomen.
Blind-ending sac of bowel that lies below the ileocaecal valve, above which the large intestine continues as the ascending colon. The caecum measures 6 cm in length and can have ...
The calcaneal inclination angle is drawn on a weightbearing lateral foot radiograph between the calcaneal inclination axis and the supporting surface.
It is a measurement that reflects the height of the foot framework, but is affected by abnormal pronation or supination of the foot:
The calcaneal (Achilles) tendon is the strongest and largest tendon in the foot and even in the human body. But it is commonly injured tendon in the foot owing to scanty vascularity and high pressure upon it. As it carries the whole body weight during standing 2.
The calcaneal te...
Calcaneal vascular remnant is a benign finding that may be seen on MRI of ankle and can be misinterpreted as an alarming bone lesion. It is typically located at the insertion site of sinus tarsi ligaments (cervical and interosseous ligaments).
The focus of signal alteration is believed to be pr...
The calcaneofibular ligament (CFL) is the middle ligament of the lateral collateral ligament complex of the ankle and stabilises both the ankle and subtalar joints.
The CFL is an extracapsular round cord measuring 20-25 mm long x 6-8 mm width. Its origin is distal to the anterior...
Calcaneonavicular coalition is one of the two most common subtypes of tarsal coalition, the other being talocalcaneal coalition. As with any coalition it may be osseous (synostosis), cartilaginous (synchondrosis) or fibrous (syndesmosis).
This type of coalition is more ea...
The calcaneus, also referred to as the calcaneum, is the largest tarsal bone and the major bone in the hindfoot. It articulates with the talus superiorly and the cuboid anteriorly and shares a joint space with the talonavicular joint, appropriately called the talocalcaneonavicular joint. The cal...
The calcar femorale is a normal ridge of dense bone that originates from the postero-medial endosteal surface of the proximal femoral shaft, near the lesser trochanter. It is vertical in orientation, and the ridge projects laterally toward the greater trochanter. This ridge of bone provides mech...
The calcarine artery, named according to its course in the calcarine fissure, is a branch of the posterior cerebral artery, usually from the P3 segment. It may also arise from the parieto-occipital artery or posterior temporal branches. It courses deep in the fissure, giving branches both to th...
The calcarine fissure, or calcarine sulcus, is located on the medial surface of the occipital lobe and divides the visual cortex (a.k.a. calcarine cortex) into two.
The fissure is variable in course (figure 1), but is generally oriented horizontally, anteriorly joining the parieto-occipital fi...
The callosal sulcus is a sulcus of the brain, located on the medial side of each cerebral hemisphere, deep within the medial longitudinal fissure.
The callosal sulcus runs posteriorly from the genu to the splenium of the corpus callosum. It separates the cingulate gyrus dorsally...
The callosomarginal artery (also known as median artery of corpus callosum) is the largest branch of the pericallosal artery. It runs in or posteriorly to the cingulate sulcus and runs a course parallel to the pericallosal artery where it divide to give two or more cortical branches to supply th...
The callososeptal interface is located on the inferior surface of the corpus callosum, when the septum pellucidum abuts it.
It came to radiological attention when T2 hyperintense lesions affecting this region were believed to be specific for multiple sclerosis. This has, as is usually the case...
Calot triangle is a small (potential) triangular space at the porta hepatis of surgical importance as it is dissected during cholecystectomy. Its contents, the cystic artery and cystic duct must be identified before ligation and division to avoid damaging them during the operation.
The canal of Nuck is an abnormal patent pouch of parietal peritoneum extending anteriorly from the round ligament of the uterus into the labia majora through the inguinal ring into the inguinal canal. Incomplete obliteration of this canal is known as a patent processus vaginalis and can result i...
The canals of Lambert are microscopic collateral airways between the distal bronchiolar tree and adjacent alveoli. They are poorly formed in children, and along with poorly formed pores of Kohn, are thought to be responsible for the high frequency of round pneumonia in that age group.
Cantlie's line is a vertical plane that divides the liver into left and right lobes creating the principal plane used for hepatectomy. It extends from the inferior vena cava posteriorly to the middle of the gallbladder fossa anteriorly.
It contains the middle hepatic vein which divides the live...
The capitate (or os magnum) is the largest of the carpal bones and sits at the centre of the distal carpal row. A distinctive head shaped bone, it has a protected position in the carpus.
The capitate sits in a proximo-distal direction with a waist that is proximal to...
Capito-hamate coalition is the second most common type of carpal coalition and represents congenital fusion of the capitate and the hamate. It represents ~5% of all carpal fusions 1 and is associated with Apert syndrome 2.
A cardiac bronchus is a rare variant of the tracheobronchial tree, arising from the medial aspect of the bronchus intermedius.
This anomaly is rare and is reported in ~0.3% (range 0.09-0.5%) of individuals 3-5. There may be a predilection for males. It is the only recognised true ...
The fibrous skeleton of the heart is a complex set of collagenous rings that connect annuli of all four cardiac valves. Between the four annuli are two trigones (right and left) and the membranous portions of the interatrial, interventricular, and atrioventricular septa. The annuli of the two se...
The cardiac plexus is a plexus of nerves situated at the base of the heart. It is formed by cardiac branches derived from both the sympathetic and parasympathetic nervous systems.
Sympathetic cardiac nerves are derived from T1 to T4 segments and partly from the T5 segment of the ...
The American Heart Association (AHA) has published the nomenclature and segmentation of the left ventricular myocardium (the cardiac segmentation model), now widely used for the description of disease-affected myocardial territories and wall function.
There are 17 segments that have a reasonabl...
The four cardiac valves direct the flow of blood through the heart during the cardiac cycle.
The heart valves are located in the cardiac fibrous skeleton:
two are atrioventricular (AV) valves: the right-sided tricuspid valve and left-sided mitral (bicuspid) valve
open during di...
The carina is part of the trachea and is an important reference point in chest imaging.
The carina is found at the base of the trachea and it is formed as the main bronchi divide into right and left branches.
The carina usually sits in the T4/T5 plane and is at the level of the ...
The caroticotympanic branch (tympanic branch) is a small branch from the C2 segment of the internal carotid artery. It is a vestigial remnant of the hyoid artery.
It passes posterolaterally into the middle ear cavity and anastomoses with the inferior tympanic artery (a branch of the external ca...
The carotid bifurcation is the point at which the common carotid artery terminates. As it does so, it forms the internal and external carotid arteries which go on to supply the head and neck.
It is closely related anatomically to the carotid body, a small group of chemoreceptors and supporting ...
The carotid body is located within the neck, and in close proximity to the carotid bifurcation. It is composed of a number of chemoreceptor cells and supporting matrix and detects changes in the composition of blood in the common carotid as it forms the internal and external carotid arteries.
The carotid canal is a passage within the petrous temporal bone and transmits the internal carotid artery and sympathetic plexus. Its inferior opening is called the carotid foramen and is situated anteriorly to the jugular fossa and medially to the tympanic plate. The carotid canal is initially ...
The carotid cave is a potential dural space formed by the redundant distal dural ring on the medial aspect of the clinoid segment of the internal carotid artery (ICA). It has been reported to be present in ~80% of cadaveric specimens 3.
The clinoid segment of the ICA is bounded b...
The carotid space is one of the seven deep compartments of the head and neck.
The carotid space is a roughly cylindrical space that extends from the skull base through to the aortic arch. It is circumscribed by all three layers of the deep cervical fascia, forming the carotid sh...
The carotid triangle is one of the paired triangles in the anterior triangle of the neck. The triangles of the neck are surgically focussed, first described from early dissection-based anatomical studies which predated cross-sectional anatomical description based on imaging (see deep spaces of t...
The carpal bones are the eight bones of the wrist that form the articulation of the forearm with the hand. They can be divided in two rows:
The names and order of these bones can be rememb...
Mnemonics of the carpal bone are numerous and useful for memorising the order and location carpal bones. They usually describe the position of the carpal bones from latera to medial in the proximal row and then the distal row:
Sam Likes To Push The Toy Car Hard
She Looks Too Pretty Try To Catc...
Carpal coalition refers to fusion of two or more carpal bones, and although the most commonly involved bones are the lunate and triquetrum, most combinations of adjacent bones can be found to be coalesced.
The estimated prevalence is ~0.1% in Caucasian Americans and ~1.5% in Afri...
The carpal tunnel is a fibro-osseous canal that acts as a passageway from the forearm to the anterior hand. It is found in the anterior wrist.
superficial border (roof): flexor retinaculum
deep border (floor): carpal bones
The carpal tunnel contains the fo...
Carrying angle is a small degree of cubitus valgus, formed between the axis of a radially deviated forearm and the axis of the humerus. It helps the arms to swing without hitting the hips while walking.
Normally it is 5-15o away from the body or 165-175o towards the body.
A decreased carrying ...
Cartilaginous joints are a type of joint where the bones are entirely joined by cartilage, either hyaline cartilage or fibrocartilage. These joints generally allow more movement than fibrous joints but less movement than synovial joints.
Primary cartilaginous joint
These cartilaginous joints...
The cauda equina is the collective term given to nerve roots distal to the conus medullaris, which occupy the lumbar cistern.
It's name comes from the Latin for "horse's tail".
Caudate nuclei are paired nuclei which along with the globus pallidus and putamen are referred to as the corpus striatum, and collectively make up the basal ganglia. The caudate nuclei have both motor and behavioural functions, in particular maintaining body and limb posture, as well as controll...
The caudothalamic groove is an important landmark when performing neonatal cranial ultrasound.
As the name suggests, it is located between the caudate nucleus and thalamus, and is a shallow groove projecting from the floor of the lateral ventricle. It is approximately at the leve...
Many caval variants exist, due to the complex embryology of the venous system. These are important for a number of reasons:
not to confuse them with pathology
suggest the presence of frequently associated other abnormalities
planning of vascular intervention or surgery
superior vena ...
The cavernous sinuses are paired dural venous sinuses.
The cavernous sinus (CS) is located on either side of the pituitary fossa and body of the sphenoid bone between the endosteal and meningeal layers of the dura. It spans from the apex of the orbit to the apex of the petrous t...
The superior cavo-atrial junction, generally referred to as simply the cavo-atrial junction (CAJ), is the junction of the right lateral border of the superior vena cava (SVC) and the superior border of the right atrium.
It is an important landmark to recognise because it marks an optimum site f...
Cavum septum pellucidum (CSP), or more grammatically correct cavum septi pellucidi, is a normal variant CSF space between the leaflets of the septum pellucidum.
It is sometimes called the fifth ventricle, but this term is not in current use as a CSP does not have any direct communi...
A cavum veli interpositi (CVI) is a normal variation where there is a dilated CSF space involving the velum interpositum. When larger than 1 cm in axial transverse measurement, with outwardly bowed margins and positive mass effect, the term cyst of the velum interpositum or cavum veli interposit...
The cavum vergae (CV), along with the cavum septum pellucidum (CSP) is a persistence of the embryological fluid-filled space between the leaflets of the septum pellucidum and is a common anatomical variant. The CV is sometimes referred to as the 6th ventricle 3.
The CV is the po...
The central artery of the retina or central retinal artery (CRA) arises from the ophthalmic artery.
The central artery of the retina courses anteriorly and inferior to the optic nerve, It then pierces the dura and the arachnoid of the optic nerve. It then runs in the centre of t...
The central canal is a CSF-filled space which runs the entire length of the spinal cord and represents the most caudal portion of the ventricular system.
The central canal spans the length of the spinal cord from the caudal angle of the fourth ventricle to the conus medullaris. T...
A number of cell groups in the reticular formation of the pons and medulla are responsible for the central control of the respiratory cycle:
inspiratory centre (a.k.a. dorsal respiratory group) - bilateral groups of cells in the region of the nucleus of the tractus solitarius in the dorsum of t...
Central nervous system (CNS) embryology is complex, and below is a brief summary of its development.
The early CNS begins as a simple neural plate that folds to form a groove then tube, open initially at each end. Within the neural tube stem cells generate the two major classes of cells that m...
The central sulcus (of Rolando) is a very important landmark in both anatomical and functional neuroanatomy.
The central sulcus separates the frontal lobe from the parietal lobe, and also separates the primary motor cortex anteriorly from the primary somatosensory cortex posterio...
The muscle fibres of the diaphragm converge and attach to the central tendon of the diaphragm. It is a thin but strong layer of aponeurosis which forms an intergral part of respiration.
The central tendon of the diaphragm is located near the centre of the diaphragmatic muscle bu...
The centrilobular region, in context of the lungs and HRCT, refers to the central portion of the secondary pulmonary lobule, around the central pulmonary artery and bronchiole.
The centrum semiovale is a mass of white matter, superior to the lateral ventricles/corpus callosum, present in each of the cerebral hemispheres under cerebral cortex.
It has a semi-oval shape and contains projection, commissural, and association fibers. Inferiorly these fibres are continuous w...
The cephalic vein, along with the basilic vein, is one of the primary superficial veins that drain the upper limb 1. It courses through both the forearm and arm and terminates by draining into the axillary vein.
origin: radial aspect of the superficial venous network of the dorsum of...
Cerebellar agenesis is a rare congenital abnormality which can result from failure to develop normal cerebellar tissue or destruction of normally developed tissue.
For a more general overview of cerebellar malformations, please refer to the article on classification systems for malformations of...
The cerebellar nuclei comprise of 4 paired deep grey matter deep within the cerebellum near the fourth ventricle. They are arranged in the following order:
dentate nuclei (the largest and most lateral)
fastigial nuclei (most medial)
They receive inhibitory...
The cerebellar tonsils are ovoid structures on the inferiormedial surface of each cerebellar hemisphere. They are attached to the underlying cerebellum by the tonsillar peduncle 1-4.
medial: uvula of the vermis
superior: flocculonodular lobe
anterior: posterior surfa...
The cerebellopontine angle cistern is a triangular subarachnoid space that lies between the anterior surface of the cerebellum and the lateral surface of the pons.
superior: tentorium cerebelli
posterior: anterior surface of cerebellum
inferior: lower cranial nerves...
The cerebral aqueduct (of Sylvius) is the structure within the brainstem that connects the third ventricle to the fourth. It is located within the midbrain, surrounded by periacqueductal grey matter (PAG) with the tectum of midbrain located posteriorly and the tegmentum anteriorly.
It is filled...
There are two cerebral hemispheres, divided in the midline in the sagittal plane by the interhemispheric fissure. Together they fill most the intra-cranial cavity.
The medial surface of each cerebral hemisphere is flat, the inferior surface is irregular and even slightly concave ...
The cerebral meninges surround the brain and is made up of three layers (from outermost to innermost):
The dura mater can also be known as pachymeninx. The arachnoid mater and pia mater are collectively known as the leptomeninges 3. The spinal meninges ar...
The cerebral peduncles (also known as the cerebral crus) are the part of the midbrain that link the remainder of the brainstem to the thalami and thereby, the cerebrum. They are the most anterior structure in the midbrain and contain the large ascending and descending tracts that run to and from...
Cerebral sulci and fissures are grooves between the adjacent gyri on the surface of the cerebral hemispheres. By allowing the cortex to invaginate to form sulci and gyri the surface area of the cortex is is increased threefold 4. The result is that the surface area of the human cortex is 2200 cm...
An understanding of cerebral vascular territories is important in understanding stroke and complications from surgery and endovascular procedures.
Although one could be excused for thinking that within the brain, such a carefully organised organ, blood supply would be constant, the truth is th...
The cerebral veins drain the brain parenchyma and are located in the subarachnoid space. They pierce the meninges and drain further into the cranial venous sinuses.
The cerebral veins lack muscular tissue and valves. The cerebral venous system can be divided into:
superficial (cortical) cerebr...
The cerebral venous system, somewhat unlike the majority of the rest of the body, does not even remotely follow the cerebral arterial system.
The cortical veins lie superficially, unlike cortical arteries, and are adherent to the deep surface of the arachnoid mater so that they keep the sulci o...
The cerebrum, or telencephalon, is paired structure composed of two cerebral hemispheres (left and right) each containing a central space, the lateral ventricle.
The cerebrum takes up most of the intracranial cavity and lies above the tentorium cerebelli. The cerebrum includes: