Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

Create new article

Filtered (1)Done (clear)

+Systems

×Article Sections

+Sort By

ADVERTISEMENT: Supporters see fewer/no ads

3,050 results found

Abdominal and pelvic anatomy

Abdominal and pelvic anatomy encompasses the anatomy of all structures of the abdominal and pelvic cavities. This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.

Abdominal aorta

The abdominal aorta (plural: aortas or aortae 4) is the main blood vessel in the abdominal cavity that transmits oxygenated blood from the thoracic cavity to the organs within the abdomen and to the lower limbs. Summary origin: continuation of descending thoracic aorta at T12 course: descend...

Abdominal cavity

The abdominal cavity is divided into two major compartments, the peritoneum and retroperitoneum, early in fetal development. The parietal peritoneum is reflected over the peritoneal organs to form a series of supporting peritoneal ligaments, mesenteries and omenta. The peritoneal reflections ca...

Abdominal surface anatomy

Abdominal surface anatomy can be described when viewed from in front of the abdomen in 2 ways: divided into 9 regions by two vertical and two horizontal imaginary planes divided into 4 quadrants by single vertical and horizontal imaginary planes These regions and quadrants are of clinical imp...

Abducens nerve

The abducens nerve is the sixth cranial nerve. It courses from its nucleus located in the dorsal pons to its innervation of the lateral rectus muscle and can be divided into four parts: nucleus and intraparenchymal portion cisternal portion cavernous sinus portion orbital portion Gross anat...

Abducent nucleus

The abducent or abducens nucleus is a small motor nucleus in the pons for the abducens nerve. Gross Anatomy The nucleus is located in the paramedian dorsal lower pons in the floor of the fourth ventricle lateral to the medial longitudinal fasciculus. The nucleus forms a longitudinal paramedian...

Abductor digiti minimi muscle (foot)

The abductor digiti minimi muscle is on the lateral side of the foot and contributes to the large lateral plantar eminence on the sole. Summary origin: lateral and medial processes of calcaneal tuberosity, and band of connective tissue connecting calcaneus with base of metatarsal V insertion:...

Abductor digiti minimi muscle (hand)

The abductor digiti minimi muscle overlies the opponens digiti minimi muscle, within the hypothenar eminence, and is one of the intrinsic muscles of the hand. Occasionally an accessory abductor digiti minimi muscle of the hand is present. Summary origin: pisiform, pisohamate ligament, and tend...

Abductor hallucis muscle

The abductor hallucis muscle forms the medial margin of the foot and contributes to a soft tissue bulge on the medial side of the sole. Summary origin: medial process of calcaneal tuberosity insertion: medial side of base of proximal phalanx of great toe action: abducts and flexes great toe ...

Abductor pollicis brevis muscle

The abductor pollicis brevis muscle is a thin subcutaneous muscle located laterally in the thenar eminence of the hand, and is one of the intrinsic muscles of the hand. Summary origin: mainly from the flexor retinaculum few fibers originate from the tubercles of scaphoid and trapezium and ten...

Abductor pollicis longus muscle

The abductor pollicis longus (APL) muscle is found in the deep layer of the posterior compartment of the forearm. As it descends, it becomes superficial and passes under the extensor retinaculum and through the 1st extensor compartment of the wrist before attaching distally. It is one of the ext...

Aberrant arachnoid granulations

Aberrant arachnoid granulations, also known as arachnoid pits, are arachnoid granulations that penetrated the dura but failed to migrate normally in the venous sinus. They are most often located in the greater wing of the sphenoid bone and may be seen in idiopathic intracranial hypertension. Occ...

Aberrant internal carotid artery

Aberrant internal carotid artery is a variant of the internal carotid artery and represents a collateral pathway resulting from involution of the normal cervical portion (first embryonic segment) of the internal carotid artery 5. Gross anatomy There is consequent enlargement of the usually sma...

Aberrant left pulmonary artery

Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterized by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and esophagus to reach the left lung. It may lea...

Aberrant right subclavian artery

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are one of the commonest of the aortic arch anomalies. Epidemiology The estimated incidence is 0.5-2%. Clinical presentation They are often asymptomatic, but around 10% of people may complain of tracheo-esophageal sym...

Abnormal renal rotation

Abnormal renal rotation (renal malrotation) refers to an anatomical variation in the position of the kidneys, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding. Epidemiology Malrotation is...

Accessory abductor digiti minimi muscle (hand)

An accessory abductor digiti minimi (ADM) muscle is the commonest accessory muscle of the hypothenar eminence, found in 24% individuals. When present it is one of the intrinsic muscles of the hand. Summary origin: antebrachial fascia passing anteriorly to Guyon canal occasionally arises from...

Accessory anterior inferior tibiofibular ligament

The accessory anterior inferior tibiofibular ligament (accessory AITFL), also known as Bassett's ligament, is an anatomical variant present in many ankles. Pathological thickening of the accessory ligament is seen in the setting of inversion injury that causing the pain due to mild anterior inst...

Accessory appendicular artery

The accessory appendicular artery, also known as the artery of Seshachalam, is a branch of the posterior cecal artery. It arises from the ileocolic artery, and runs in the mesoappendix. The exact prevalence of this accessory artery and its impact upon the risk of appendicitis varies among studi...

Accessory breast tissue

Accessory breast tissue is a relatively common congenital condition in which abnormal accessory breast tissue is seen in addition to the presence of normal breast tissue. This normal variant can present as a mass anywhere along the course of the embryologic mammary streak (axilla to the inguinal...

Accessory fissures of the lung

Accessory fissures of the lung usually occur at the borders of bronchopulmonary segments. They are common normal variants but are less commonly seen on imaging. Some of the more common accessory fissure include 1: azygos fissure: most commonly seen accessory fissure inferior accessory fissur...

Accessory flexor digitorum longus muscle

The accessory flexor digitorum longus muscle is an accessory muscle in the deep posterior compartment of the leg with a reported prevalence of 6-8%. Unilateral muscles are more common although bilateral cases have been reported. Summary origin: variable; either the medial margin of the tibia a...

Accessory gallbladder

Accessory gallbladders are a rare anatomical variant occurring in 0.03% of cases (approximately 1 in 3000 people). They can arise from either the left or right hepatic ducts or both. Accessory gallbladders arise from a bifid diverticulum of the hepatic duct in the 5th or 6th week of development ...

Accessory hemiazygos vein

The accessory (or superior) hemiazygos vein forms part of the azygos system and along with the hemiazygos vein, it is partially analogous to the right-sided azygos vein. It drains the left superior hemithorax. Terminology Spelling it "hemiazygous" when referring to the vein is incorrect, rega...

Accessory left atrial appendage

An accessory left atrial appendage is a frequent fortuitous finding in cardiac imaging, encountered in ~10% of patients. They are more often seen as a small diverticular structure projecting from the right upper side of the left atrial wall. Differential diagnosis it must not be confused with ...

Accessory maxillary ostium

Accessory maxillary ostia are a common anatomic variant, and are usually found incidentally on CT scans of the paranasal sinuses. Accessory ostia of the maxillary sinus are common, occurring in up to 40% patients 1. No significant association has been found between the presence of accessory osti...

Accessory meningeal artery

The accessory meningeal artery is a branch of the maxillary artery but can also branch from the middle meningeal artery. The artery passes upwards through the foramen ovale to supply the trigeminal ganglion and the dura mater of Meckel cave and the middle cranial fossa. It also usually supplies...

Accessory middle cerebral artery

The accessory middle cerebral artery is a variant of the middle cerebral artery (MCA) that arises from the anterior cerebral artery (ACA). It is different from a duplicated middle cerebral artery, in which the duplicated vessel originates also from the distal end of the internal carotid artery (...

Accessory muscle

Accessory muscles are a form of anatomic variation that refers to supplementary discrete muscles that are found alongside the normal expected musculature. They have been described in the neck, pelvis, upper and lower limbs.

Accessory navicular

An accessory navicular is a large accessory ossicle that can be present adjacent to the medial side of the navicular bone. The tibialis posterior tendon often inserts with a broad attachment into the ossicle. Most cases are asymptomatic but in a small proportion it may cause painful tendinosis d...

Accessory ossicle of the anterior arch of the atlas

The accessory ossicle of the anterior arch of the atlas is a normal variant and is best appreciated on a lateral cervical/sagittal study. It is observed as a circular and corticated osseous density that articulates with the inferior aspect of the anterior arch of the atlas. It is not associate...

Accessory ossicles

Accessory ossicles are secondary ossification centers that remain separate from the adjacent bone. They are usually round or ovoid in shape, occur in typical locations and have well defined smooth cortical margins on all sides. In most cases, they are congenital in origin, although they may occ...

Accessory ossicles of the foot

Accessory ossicles of the feet are common developmental variants with almost 40 having been described. Some of the more common include 1-4: os peroneum os subfibulare os subtibiale os tibiale externum (accessory navicular) os trigonum os calcaneus secundaris os intermetatarseum pars pero...

Accessory ossicles of the lower limb

There are numerous named and unnamed accessory ossicles of the lower limb. These include: ossicles of the hip os acetabuli ossicles of the knee os fabella cyamella ossicles of the foot os peroneum os subfibulare os subtibiale os tibiale externum os trigonum os calcaneus secundaris o...

Accessory ossicles of the wrist

Accessory ossicles of the wrist are commonly seen on plain radiographs of the wrist and associated cross-sectional imaging. Over 20 were originally described 2, although the more common include 1: lunula: between TFCC and triquetrum os styloideum (carpal boss): on dorsal surface of 2nd or 3rd ...

Accessory parotid gland

Accessory parotid glands are a normal variant and represent ectopic salivary tissue separate from, but usually in close proximity to, the main parotid glands. Epidemiology Accessory parotid glands are commonly picked up incidentally on ultrasound; seen in ~20% of the general population 2. Gro...

Accessory peroneal muscles

Accessory peroneal muscles are a group of accessory muscles that can occur in the foot region as a normal variant in some individuals. The peroneal compartment is known as the lateral compartment of the leg. Peroneus quartus muscle Originally, several accessory muscles were distinguished in th...

Accessory phrenic nerve

The accessory phrenic nerve is an anatomical variant seen in a little over one third of patients (36%). It most commonly arises from the ansa cervicalis, or slightly less commonly, the subclavian nerve. It is unknown as to how much the accessory phrenic nerve contributes to diaphragmatic functio...

Accessory renal artery

Accessory renal arteries are a common variant and are present in ~25% (range 20-30%) and are bilateral in ~10% of the population 1. Their proper identification is of utmost importance for surgical planning prior to live donor transplantation 2,3 and renal artery embolization for various reasons ...

Accessory right inferior hepatic vein

An accessory right inferior hepatic vein is the most common variation of the hepatic veins. It is present in up to 48% of the population and drains the posterior part of the right lobe (mainly segments 6 and 7) directly into the inferior vena cava (IVC). Variations in hepatic vascular anatomy ...

Accessory sacroiliac joint

Accessory sacroiliac joints are a common finding, present on ~15% (range 13-17.5%) of CT studies, and may be unilateral or bilateral. They are an articulation between the medial aspect of the posterior superior iliac spine and the sacrum just lateral to the second dorsal sacral foramen. They may...

Accessory semimembranosus muscle

The accessory semimembranosus muscle is a rare accessory muscle of the posterior compartment of the thigh. It arises from the distal aspect of the semimembranosus muscle belly and courses through the popliteal fossa between it and the semitendinosus muscle medially and the biceps femoris lateral...

Accessory soleus muscle

The accessory soleus muscle is an anatomical variant characterized by an additional distinct muscle encountered along a normal soleus muscle. It is uncommon with a prevalence of ~3% (range 0.7-5.5%). Summary origin: fibula, soleal line of the tibia, or the anterior surface of the soleus muscle...

Accessory superior acetabular notch

An accessory superior acetabular notch is a normal variant of the acetabulum, which can be seen on radiographs. It may lead to diagnostic confusion, especially in younger patients. Radiographic features MRI appear as bilateral symmetric fluid-filled pits in the roof of the acetabulum with sh...

Accessory sutures

The parietal and occipital bones in particular are common regions for accessory sutures because of their multiple ossification centers. It is important to know these anatomic variations, mainly on the head trauma image studies in children, where it could be difficult to differentiate non-depres...

Acetabular foramen

The acetabular foramen is formed by the bony margins of the acetabular notch and completed by the transverse ligament of the hip. From its margins (both transverse ligament and acetabular notch) arises the ligamentum teres. Through it pass nutrient vessels to the femoral head epiphysis.

Acetabular fossa

The acetabular fossa, also known as the cotyloid fossa, is the central aspect of the medial wall of the acetabulum that hosts the ligamentum teres and the fibrofatty pulvinar. It is the nonarticular portion inside the U-shaped labrum that extends to the acetabular notch 1. The acetabular fossa i...

Acetabular labrum

Acetabular labrum acts to deepen the acetabulum and increase contact between the pelvis and the femoral head. Its exact biomechanical role remains to be fully elucidated. Gross anatomy The acetabular labrum is a C-shaped fibrocartilaginous structure with an opening anteroinferiorly at the site...

Acetabular notch

The acetabular notch is a depression in the margin of the acetabulum located anteroinferiorly. It is bridged by the transverse ligament, and thus forms the acetabular foramen. The ligamentum teres has part of its origin from the acetabular notch.

Acetabulum

The acetabulum (plural: acetabula) is the large cup-shaped cavity on the anterolateral aspect of the pelvis that articulates with the femoral head to form the hip joint. Gross anatomy All three bones of the pelvis (the ilium, ischium, and pubis) together form the acetabulum. The three bones ar...

Acromial types

The shape of the acromion had been initially divided into three types (which was known as the Bigliani classification) 3, to which a fourth has been added 2. They are used as a standardized way of describing the acromion, as well as predicting to a degree the incidence of impingement. Classifi...

Acromioclavicular joint

The acromioclavicular joint (ACJ) is a planar diarthrodial synovial joint of the pectoral girdle. Gross anatomy The acromioclavicular joint is between the small facet of the convex distal clavicle and flat anteromedial acromion. The articular surfaces are lined with fibrocartilage (like the st...

Acromioclavicular joint configuration

There is much variation in acromioclavicular joint configuration, which may be confused with pathology. The relationship of the acromion to the distal clavicle at the AC joint can be described in the coronal plane as 1-3: horizontal: normal low-lying: associated with shoulder impingement (unfo...

Acromion

The acromion (plural: acromia), also known as the acromial process, is a small projection of the scapula that extends anteriorly from the spine of the scapula. Gross anatomy It forms the acromioclavicular joint (ACJ) with the lateral third of the clavicle and also connects with the coracoid p...

Adductor brevis muscle

The adductor brevis muscle is a muscle in the medial compartment of the thigh that lies immediately deep to the pectineus and adductor longus. Summary origin: external surface of body of pubis and inferior pubic ramus insertion: pectineal line and proximal part of linea aspera of femur actio...

Adductor canal

The adductor canal (also known as the Hunter canal or subsartorial canal) is a muscular tunnel in the thigh. It commences at the inferior end of the femoral triangle and terminates at the adductor hiatus. Gross anatomy Boundaries from apex of the femoral triangle to the adductor hiatus an...

Adductor hallucis muscle

The adductor hallucis muscle arises by two heads, an oblique and transverse head. It is responsible for adducting the big toe. Summary origin transverse head: ligaments associated with metatarsophalangeal joints of lateral three toes oblique head: bases of metatarsals II to IV and from sheat...

Adductor longus muscle

The adductor longus muscle is a muscle in the medial compartment of the thigh that lies anterior to the adductor magnus muscle. Summary origin: external surface of body of pubis (triangular depression inferior to pubic crest and lateral to pubic symphysis) insertion: linea aspera on middle o...

Adductor magnus muscle

The adductor magnus muscle is the largest and deepest of the muscles in the medial compartment of the thigh. Like the adductor longus and brevis muscles, the adductor magnus is a triangular or fan-shaped muscle anchored by its apex to the pelvis and attached by its expanded base to the femur. S...

Adductor minimus muscle

The adductor minimus muscle is a small, variably present muscle in the medial compartment of the thigh. Terminology Due to confusion about this muscle over the years it has ended up with a variety of names, which include pars lateralis, adductor quartus muscle, premier faisceau du grand addu...

Adductor pollicis muscle

The adductor pollicis muscle is a large triangular muscle anterior to the plane of the interossei that crosses the palm of the hand. It is deep to the thenar eminence, forming part of the short muscles of the thumb, and the intrinsic muscles of the hand. Summary origin: transverse head: 3rd m...

Adductor tubercle

The adductor tubercle is a bony protuberance on the medial condyle of the femur and is located superior to the medial epicondyle. It demarcates the inferior most aspect of the medial supracondylar line. The adductor tubercle is the point of insertion for the adductor minimus and the hamstrings p...

Adenoid tonsil

The adenoid tonsils, or often just simply the adenoids (also known as the nasopharyngeal or pharyngeal tonsils), are paired foci of lymphatic tissue located on the superoposterior wall of the nasopharynx and form part of Waldeyer's ring.

Adnexa (disambiguation)

Adnexa is a general term that refers to the accessory structures of an organ. Adnexa have been described in relation to: cutaneous/skin adnexa hair follicles, sweat glands, nails adnexa mastoidea structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antrum, aditus ad an...

Adrenal arteries

The adrenal glands are highly vascular. Threefold arterial supply includes the: superior adrenal arteries: typically 6-8 in number, arising from the ipsilateral inferior phrenic artery middle adrenal artery: one or more, arising from lateral side of abdominal aorta inferior adrenal artery: o...

Adrenal gland

The adrenal (suprarenal) glands (often shortened to just the adrenals) are paired organs of the endocrine system, often asymmetric in shape. Gross anatomy Each gland is enclosed in the perirenal fascia and each has a body and two limbs: a medial limb and a lateral limb. However, the right adr...

Adrenal veins

The venous drainage of the adrenal (suprarenal) glands is typically comprised of a single vein draining each adrenal gland. Like the gonadal veins each side drains differently: left suprarenal vein drains into the left renal vein 1. right suprarenal vein drains directly into the inferior vena ...

Adventitial bursae

Adventitial bursae are those bursae that develop later in life in response to pressures developed as a result of acquired bony prominences or deformities 1. These bursa can become inflamed resulting in adventitious bursitis.

Agenesis (general)

The biological/medical term agenesis (plural: ageneses) refers to failure of an organ to grow or develop during the embryological period. Examples include: appendiceal agenesis cerebellar agenesis corpus callosum agenesis dental agenesis (anodontia) diaphragmatic agenesis dorsal pancreati...

Agenesis of the appendix

Agenesis of the appendix is extremely rare, with an incidence at surgery of approximately 1 in 100,000 laparotomies 1. It is most commonly due to a sporadic etiology. However in the rare genetic condition, familial apple peel jejunal atresia, absence of the appendix is a recognized feature. Also...

Agenesis of the left hepatic lobe

Agenesis of the left hepatic lobe is a rare variation in liver anatomy. It is clinically asymptomatic and discovered during imaging or surgery. Radiographic features absence of the left hepatic lobe (left of the falciform ligament, Couinaud segments 2 and 3) absence of left hepatic artery, le...

Agenesis of the right hepatic lobe

Agenesis of the right hepatic lobe is a rare variation in liver anatomy. Radiographic features absence of the right hepatic lobe absence of right hepatic artery, right portal vein, and right hepatic biliary system compensatory hypertrophy of the left hepatic lobe and caudate lobe possible r...

Agger nasi cells

Agger nasi air cells are the most anterior ethmoidal air cells lying anterolateral and inferior to the frontal recess and anterior and above the attachment of the middle turbinate. They are located within the lacrimal bone and therefore have as lateral relations the orbit, the lacrimal sac and t...

AICA-PICA dominance

AICA-PICA dominance refers to the principle that the cerebellar vascular territory supplied by the anterior inferior cerebellar artery and posterior inferior cerebellar artery have a reciprocal arrangement. That is the size of the AICA and the subsequent territory it supplies is inversely propor...

Alar fascia

The alar fascia is a thin fibroareolar membrane separating the (anterior) true retropharyngeal space from the (posterior) danger space. It is the ventral component of the deep layer of the deep cervical fascia. Notably, in the well patient, the alar fascia is not usually visible on cross-sectio...

Alar ligament

The alar ligaments join the lateral margins of the sloping upper posterior margin of the dens of C2 to the lateral margins of the foramen magnum (adjacent to the occipital condyles) and lie on either side of the apical ligament. They may be oblique or vertical and are thickest at the occipital a...

Alar thoracic artery

The alar thoracic artery is a rare variant arterial glandular branch of the axillary artery (usually the second part) that supplies the axillary fat, lymph nodes and skin of the axilla.

Alveoli

The alveoli (singular: alveolus) are tiny hollow air sacs that comprise the basic unit of respiration. Gross Anatomy Alveoli are found within the lung parenchyma and are found at the terminal ends of the respiratory tree, clustered around alveolar sacs and alveolar ducts. Each alveolus is app...

Amastia

Amastia is a rare congenital condition characterized by the absence of breast tissue, nipple and areola. This may occur unilaterally or bilaterally. Pathology During embryological development, breasts first appear as ectoderm ridges during the 6th week of gestation. This ridge grows thicker an...

Amazia

Amazia is a rare congenital condition defined by the absence of glandular parenchyma in either one or both of the breasts and a normal nipple and areola complex. Epidemiology This is a very rare entity and the true prevalence is not known. Although there are strict definition criteria, the di...

Ambient cistern

The ambient cistern is part of the subarachnoid cisterns, filled with CSF. Gross anatomy The ambient cistern is a thin, sheet-like extension of the quadrigeminal cistern that extends laterally around the midbrain and posterior to the thalami. It acts as the connection between the quadrigeminal...

Amnion

Amnion refers to a membranous structure which covers and protects the embryo. It forms inside the chorion. The amnion usually fuses with the outer chorion by around 14 weeks of gestation. Radiographic features Ultrasound The amnion can be visualized in most pregnancies before the 12th week of...

Amphiarthroses

Amphiarthroses are a functional class of joint that permit a small amount of movement under normal conditions. Examples symphyses (secondary cartilaginous joints) symphysis pubis intervertebral discs sternomanubrial joint See also synarthroses diarthroses

Ampulla (disambiguation)

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) ampulla (rectum) ampulla (semicircular ducts) ampulla (spleen) ampulla of Vater ampulla (vas defe...

Ampulla of Vater

The ampulla of Vater is a conical structure at the confluence of the common bile duct (CBD) and the main pancreatic duct that protrudes at the major duodenal papilla into the medial aspect of the descending duodenum. The entire structure is encased by smooth muscle fibers that compose the sphinc...

Amygdala

The amygdala (plural: amygdalae) is a very well studied part of the limbic system and forms part of the mesial temporal lobe. Gross anatomy The amygdala is a complex grey matter structure located anterior and superior to the temporal horn of the lateral ventricle and head of the hippocampus. ...

Anal canal

The anal canal is the terminal part of the gastrointestinal tract, whilst the anus (plural: anuses or ani) specifically refers to the opening separating the anal canal from the outside, at the distal most aspect of the anal verge. Anatomically, the anal canal is referred to as the terminal alime...

Anal margin

Anal margin or perianal skin is arbitrarily defined as a skin tissue with a radius of 5 cm from the anal verge, consisting of keratinizing squamous epithelial tissue containing hair follicles. A radius of 5 cm approximately equates to a circle of area of 78.5 cm2 centered on the anal verge. See...

Anal sphincter

The anal sphincter is divided into internal and external anal sphincters. It surrounds the anal canal. Gross anatomy Internal anal sphincter continuation of inner rectal muscle thickened, circular muscle fibers, up to 5 mm thick composed of visceral muscle External anal sphincter Compose...

Anal triangle

The anal triangle forms the posterior half of the diamond-shaped perineum. The triangle's three corners are defined by the tip of the coccyx posteriorly and both ischial tuberosities anterolaterally. The anterior border is the transverse perineal muscles and the posterolateral borders are the sa...

Anal verge

The anal verge is part of the anal region and consists of a band of squamous epithelial tissue which lacks hair follicles and extends from the inter-sphincteric groove to the perianal skin.

Anastamoses between internal and external carotid arteries

Multiple, highly-variable anastamoses exist between the internal and external carotid arteries. These anastamoses may not be evident on non-invasive imaging or even catheter angiography, and may only be demonstrable with elevated intra-arterial pressures or high-flow states. ICA-ECA collaterals ...

Anatomical snuff box

The anatomical snuff box is a surface anatomy feature. It appears as a triangular depression on the lateral surface of the wrist on full extension of the thumb. Gross anatomy Boundaries medial: tendons of the extensor pollicis longus lateral: tendons of the extensor pollicis brevis and mor...

Updating… Please wait.

Unable to process the form. Check for errors and try again.

Thank you for updating your details.