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.

2,349 results found
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Dorsal columns

The dorsal columns, or posterior columns, are ascending pathways primarily concerned with sensory function. They are responsible for transmitting vibration, conscious proprioception, and fine (discriminative) touch 1,2. The dorsal columns are divided two tracts, which are discussed separately 2...
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Dorsal defect of the patella

Dorsal defect of the patella is a benign subchondral lesion of unknown aetiology and a normal developmental anomaly of the patella, which can be mistaken for a pathological process such as a focus of infection or osteochondritis dissecans. Epidemiology Dorsal defect of patella occurs in males ...
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Dorsal horn

The dorsal horn of the spinal cord is one of the grey longitudinal columns found within the spinal cord. It primarily acts as the termination of primary afferent fibres via the dorsal roots of the spinal nerves. Gross Anatomy On transverse section of the spinal cord the spinal grey matter is d...
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Dorsal interossei (foot)

The four dorsal interossei muscles are the most superior muscles in the sole of the foot and abduct the second to fourth toes relative to the long axis through the second toe. Summary origin sides of metatarsals of toes I to V insertion extensor hoods and bases of proximal phalanges of toes...
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Dorsal interossei muscles (hand)

The interossei muscles as a group consist of four palmar (1st is often rudimentary) and four dorsal muscles. Collectively, the interossei contribute to abduction and adduction of the fingers and also contribute to flexion of the metacarpophalangeal joints (MCPJ) and extension of the interphalan...
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Dorsal nasal artery

The dorsal nasal artery, also known as the dorsonasal artery, is a terminal branch of the ophthalmic artery. Gross anatomy Arising as a terminal branch of the ophthalmic artery, the dorsal nasal artery exits the orbit after piercing the orbital septum above the medial canthal tendon (medial pa...
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Dorsal nerve of penis or clitoris

Dorsal nerve of penis or clitoris is one of the two terminal branches of the pudendal nerve that arises from nerve whilst in the pudendal canal. The other terminal branch is the perineal nerve.  Gross anatomy Course Entering the urogenital triangle of the perineum, the dorsal nerve of penis o...
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Dorsal root ganglion

The dorsal root ganglia are an enlargement of the dorsal root of spinal nerves representing the cell bodies of the primary somatosensory neurons. Gross anatomy Each dorsal root ganglion is oval and proportional in size to its related root. They are usually found just distal to the intervertebr...
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Dorsal scapular artery

The dorsal scapular artery is a branch of either the transverse cervical artery (from the thyrocervical trunk off the first part of the subclavian artery) or an independent branch from the third (or less commonly second) part of the subclavian artery. It accompanies the dorsal scapular nerve, c...
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Dorsal scapular nerve

The dorsal scapular nerve is a branch from the C5 root of the brachial plexus and supplies the rhomboid muscles. Gross anatomy Origin Posterior aspect of the C5 root of the brachial plexus. Course It courses through scalenus medius then accompanies the dorsal scapular vessels inferiorly, de...
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Dorsum sellae

The dorsum sellae is the square shaped process of the sphenoid bone. It ascends superiorly from the posterior part of the sphenoid body to form the posterior wall of the sella turcica. Gross anatomy Relations The dorsum sellae forms the posterior wall of the sella turcica, which houses the pi...
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Double aortic arch

Double aortic arch is the most common symptomatic type of the aortic arch variant. It may account for up to 50-60% of vascular rings. Clinical presentation Double aortic arch is mostly diagnosed in childhood due to of symptoms related to oesophageal and/or tracheal obstruction. Respiratory sym...
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Double retroaortic left renal vein

Double retroaortic left renal vein is a very rare entity that is usually clinically silent and detected incidentally at imaging, surgery or autopsy. The knowledge of anatomical variations helps the surgeon or interventionist to avoid complications during surgery and interventional procedures 4 ...
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Dromedary hump

Dromedary humps are prominent focal bulges on the lateral border of the left kidney. They are normal variants of the renal contour, caused by the splenic impression onto the superolateral left kidney. Dromedary humps are important because they may mimic a renal mass, and as such is considered a...
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Duct of Rivinus

The duct of Rivinus connects the sublingual gland to the floor of the mouth. Despite its name, it is not a single duct, but numerous small ducts all of which open into the floor of the mouth and are collectively termed the duct of Rivinus. The largest of these little ductules is the major duct...
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Ducts of the salivary glands

The ducts of the salivary glands allow the passage of salivary juice from the glands to the oral cavity: parotid duct (Stenson duct): connects the parotid gland to the buccal mucosa, adjacent to maxillary second molar submandibular duct (Wharton duct): connects the submandibular gland to the f...
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Ductus arteriosus

The ductus arteriosum (or arteriosus) is the thick short conduit for blood to bypass the non-ventilated lungs in the fetus. It is located between and connects the proximal left pulmonary artery and the undersurface of the aortic arch distal to the origin of the last branch of the arch, at the ao...
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Ductus deferens

The ductus deferens (plural: ducti deferentia or deferentes) forms part of the male internal genitalia where it transports sperm from the epididymis to the ejaculatory duct. In modern anatomic nomenclature, it is no longer referred to as the vas deferens (plural: vasa deferentia or deferentes). ...
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Ductus diverticulum

Aortic ductus diverticulum is a developmental outpouching of the thoracic aorta. Gross anatomy It is usually seen at the anteromedial aspect of the aorta at site of the ligamentum arteriosum, at the aortic isthmus. This is also the site of 90% of post-traumatic aortic injuries as the ligamentu...
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Duodenojejunal flexure

The duodenojejunal (DJ) flexure or junction is the anatomical border between the duodenum and the jejunum. Gross anatomy The DJ flexure is located anterolateral to the aorta at the level of the upper border of the second lumbar vertebra. It makes a sharp turn anteroinferiorly to become the jej...
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Duodenum

The duodenum is the first part of the small intestine and is the continuation of the stomach. Gross anatomy The duodenum is a 20-30 cm C-shaped hollow viscus predominantly on the right hand side of the vertebral column. It lies at the level of L1-3 and the convexity of the duodenum usually enc...
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Duplex appendix

Duplex appendix is a rare anomaly of the appendix and is usually discovered incidentally during surgery for appendicitis. Epidemiology Duplication of the vermiform appendix is extremely rare. It is found in only 1 in 25,000 patients (incidence ~0.004%) operated on for acute appendicitis. Altho...
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Duplicated middle cerebral artery

The duplicated middle cerebral artery is an anatomical variant in which there are two middle cerebral arteries (MCA) originating from the distal end of the internal carotid artery (ICA). Supply The duplicated artery supplies the anterior temporal lobe. Differential diagnosis It should not be...
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Duplication of inferior vena cava

Duplication of the inferior vena cava is a relatively rare vascular anomaly, but this caval abnormality needs to be recognised, especially in association with renal anomalies like crossed fused ectopia or circumaortic renal collar 1-2. Epidemiology The incidence of inferior vena caval duplicat...
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Dural venous sinuses

Dural venous sinuses are venous channels located intracranially between the two layers of dura mater (endosteal layer and meningeal layer). They can be conceptualised as trapped epidural veins. Unlike other veins in the body they run alone, not parallel to arteries. Furthermore, they are valvele...
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Dura mater

The dura mater, also known as the pachymeninx, is the tough outer layer of the meninges that surrounds the central nervous system and is pierced by the cranial nerves, the internal carotid arteries and the vertebral arteries.  Intracranially it is formed by two layers: outer endosteal layer, c...
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Ectopic intracaval liver

Ectopic intracaval liver is a rare congenital abnormality of the liver in which a part of the liver invaginates the inferior vena cava (IVC). Lobar or segmental agenesis, Riedel lobe, and ectopic hepatic lobes have been described as congenital abnormalities 1. The term ectopic intracaval may be ...
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Ectopic kidney

Ectopic kidney (or renal ectopia) is a developmental renal anomaly characterised by abnormal anatomical location of one or both of the kidneys. They can occur in several forms: cross fused renal ectopia ectopic thoracic kidney pelvic kidney Epidemiology The estimated incidence of an ectopi...
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Ectopic pancreatic tissue

Ectopic pancreatic tissue (or heterotopic pancreatic tissue) refers to the situation where rests of pancreatic tissue lie outside and separate to the pancreatic gland. Most patients are completely asymptomatic. Epidemiology It is reportedly relatively common, affecting ~5% (range 1-10%) 1 of p...
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Ectopic posterior pituitary

An ectopic posterior pituitary reflects a disruption of normal embryogenesis of the posterior pituitary and is one of the more common causes of pituitary dwarfism. Although it can be an isolated abnormality, numerous other congenital central nervous system malformations have been identified. Ep...
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Ectopic thyroid

An ectopic thyroid gland is one which is located in a location other than the normal position anterior to the laryngeal cartilages. During embryological development, the thyroid gland migrates down from the foramen caecum at the posterior aspect of the tongue to its permanent location. This nor...
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Ectopic ureter

An ectopic ureter is a congenital renal anomaly that occurs as a result of abnormal caudal migration of the ureteral bud during its insertion to the urinary bladder. Normally the ureter drains via the internal ureteral orifice at the trigone of the urinary bladder.  In females, the most common ...
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Ejaculatory duct

The ejaculatory ducts are paired structures of the male reproductive system and convey seminal fluid. Gross anatomy Each ejaculatory duct is formed by the union of the excretory duct of the seminal vesicle and the ampulla of the ductus deferens and is approximately 2 cm long. They course throu...
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Ejaculatory pathway of sperm (mnemonic)

A useful mnemonic to remember the ejaculatory pathway of sperm is: SEVEN UP Mnemonic S: seminiferous tubules E: epididymis V: vas (ductus) deferens E: ejaculatory duct N: nothing U: urethra P: penis
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Elbow

The elbow is a complex synovial joint formed by the articulations of the humerus, the radius and the ulna.  Gross anatomy Articulations The elbow joint is made up of three articulations 2,3: radiohumeral: capitellum of the humerus with the radial head ulnohumeral: trochlea of the humerus wi...
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Elbow bursae

The elbow bursae are a collection of synovial-lined bursae that exist around the elbow.  They can be divided into bursae around the olecranon and in the cubital fossa. Olecranon Bursae Superficial Olecranon Bursa: Lies between the olecranon and the subcutaneous tissue. Subtendinous Olecranon ...
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Elbow ossification

Elbow ossification occurs at the six elbow ossification centers in a reproducible order. Being familiar with the order of ossification of the elbow is important in not mistaking an epicodylar fracture for a normal ossification center.  Appearance Order The order of appearances of the elbow os...
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Eleventh rib

The atypical 11th rib is one of two floating ribs. Gross anatomy Osteology The 11th rib has a single facet on its head for articulation with the T11 vertebra. It has a short neck and no tubercle. The angle is slight. Its costal groove is shallow. The internal surface of this rib faces slightl...
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Empty sella

An empty sella, also known as an empty pituitary fossa, is a relatively common incidental finding and posed more of a diagnostic problem before modern cross-sectional imaging. In addition to being incidental, a well-established association with benign intracranial hypertension is also recognised...
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Endochondral ossification

Endochondral ossification describes the process of ossification from mesenchymal cells (stem cells) with a cartilaginous template and is involved in the healing process of fractures. Bone formation occurs at centers of ossification (or ossification centres) which are either primary or secondary...
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Endolymph

Endolymph is a one of two type of cochlear fluids, the other being perilymph. It is located in the scala media of the cochlea. It is secreted by the stria vascularis (colloquially called 'battery of the cochlea') on the outer wall of the scala media. It has a high level of potassium (K+) and g...
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Enthesis

An enthesis (pl. entheses) is the connective tissue junction where ligaments and tendons attach to bone. There are two types of entheses: fibrous enthesis fibrocartilage enthesis Histology Fibrous enthesis The ligament or tendon attaches directly to the bone. Fibrocartilage enthesis Ther...
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Entorhinal cortex

The entorhinal cortex (Brodmann area 28) is located in the mesial temporal lobe and acts as the interface between the hippocampus and the neocortex. It has been considered part of the hippocampal formation (along with Ammon’s horn, subiculum and presubiculum), but is difficult to precisely local...
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Eparterial bronchus

The eparterial bronchus is a synonymous term for the right superior lobar bronchus. Its name is derived from the bronchus being the only one originating superior to the level of the pulmonary artery. Conversely, all other bronchi can be referred to by their anatomical relationship to the pulmona...
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Epicardial fat pads

Epicardial (pericardial) fat pads are normal structures that lie in the cardiophrenic, more so on the right. Unsurprisingly, they are more prominent in obese patients. Pathology They can be affected by fat necrosis (see: epipericardial fat necrosis).  Radiographic features Plain radiograph ...
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Epididymal appendix

An epididymal appendix (or alternatively appendix of the epididymis or appendix epididymis) is a testicular appendage that is a developmental remnant of the mesonephric duct (Wolffian duct) which can be found in the head of the epididymis 1. In 78% of the cases, it is stalked and is thus easily ...
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Epididymis

The epididymis (plural epididymides) is situated adjacent to the testis within the scrotal sac. Its primary function is the collection, maturation and transport of sperm via the ductus deferens. Gross anatomy The epididymis is an elongated structure, posterolateral to the testis. It can divide...
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Epiglottis

The epiglottis is a leaf-shaped fibrocartilaginous structure that forms part of the supraglottic larynx and defines the division of the hypopharynx from the larynx.  Gross anatomy The epiglottis projects posterosuperiorly from its stem-like base, which is attached to the thyroid cartilage. It ...
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Epiphysis

The epiphyses (singular: epiphysis) are the rounded portions at the ends of a bone separated from the metaphysis by the physis. The epiphysis contributes to a joint, compared with an apophysis which is a site of tendon or ligament attachment. Once the growth plate has fused, the epiphysis and me...
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Epiploic appendage

Epiploic appendages (or appendix epiploica, plural: appendices epiploicae) are peritoneum-lined protrusions of subserosal fat that arise from the surface of the large bowel.  Gross anatomy Epiploic appendages typically measure 1.5 x 3.5 cm but have been reported to measure up to 15 cm in lengt...
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Epiploic foramen

The epiploic foramen (also called the foramen of Winslow) is a passage between the greater (general peritoneal space) and lesser sac (omental bursa), allowing communication between these two spaces. Gross anatomy Boundaries It has the following borders: anterior: the free edge of the lesser ...
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Episternal ossicles

Episternal (or suprasternal) ossicles are accessory bones and a normal variant of the sternum. They result from supernumerary ossification centers and are seen in ~4% (range 1-7%) of the population. Gross anatomy Episternal ossicles are usually located posterior or superior to the superior bor...
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Epithalamus

The epithalamus is a dorsal posterior segment of the diencephalon which includes the habenula, the stria medullaris and the pineal gland. Its function is the connection between the limbic system to other parts of the brain.
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Epitransverse process of the atlas

Epitransverse process is a rare anatomical variant of the atlas, consisting of a bony exostosis which extends cephalad from from the transverse process of the atlas to articulate with the occipital bone. This process sometimes meets with a paracondylar process, forming a pseudoarthrosis at the i...
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Epitympanum

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 ...
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Erector spinae group

The erector spinae group is the intermediate layer of the intrinsic muscles of the back. This group is made of three subgroups, with the group divisions occurring by location. The iliocostalis group occurs most laterally, followed by the longissimus group, and finally the spinalis as the most me...
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Ethmoidal air cells

The ethmoidal air cells (or less commonly, the ethmoidal sinuses) form one of the four pairs of paranasal sinuses. They are located within the single, midline ethmoid bone. They are present at birth, and they develop rapidly from 0-4-year-old; they further mature from 8-12-year-old during pubert...
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Ethmoidal infundibulum

The ethmoidal 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 frontonasal recess in...
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Ethmoid bone

The ethmoid bone is a single midline facial bone that separates the nasal cavity from the brain and is located at the roof of the nose and between the two orbits. It is a cubical shape and is relatively lightweight because of its spongy construction. It contributes to the anterior cranial fossa....
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Eustachian tube

The Eustachian tube is the channel through which the tympanic cavity communicates with the nasopharynx. It is approximately 36 mm in length and is directed downward, forward, and medially, forming an angle of about 45 degrees with the sagittal plane and one of 30 to 40 degrees with the horizonta...
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Eustachian valve

The Eustachian valve (also known as the "valve of the inferior vena cava") is a ridge of variable thickness in the inferior right atrium. It is a remnant of a fetal structure that directed incoming oxygenated blood to the foramen ovale and away from the right atrium.   Incomplete regression of ...
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Extensor carpi radialis brevis muscle

Extensor carpis radialis brevis (ECRB) is a muscle of superficial layer on posterior compartment of the forearm. It passes through the 2nd extensor compartment of the wrist. ECRB is one of the three muscles forming the mobile wad of Henry. Summary origin: lateral epicondyle of the humerus, ann...
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Extensor carpi radialis longus muscle

Extensor carpis radialis longus (ECRL) is a muscle of the superficial layer in the posterior compartment of the forearm. It passes through the 2nd extensor compartment of the wrist. It is one of the three muscles forming the mobile wad of Henry. Summary origin: lateral supracondyle ridge of hu...
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Extensor carpi ulnaris

Extensor carpis ulnaris (ECU) is a muscle of the superficial layer of the posterior compartment of the forearm. It is separated from the extensor digitorum and the extensor digiti minimi muscles by a distinct intermuscular septum. It is the only forearm extensor that lies in its own fibro-osseou...
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Extensor compartments of the wrist

The extensor tendons at the level of the wrist are divided into six extensor compartments that are designated by Roman numerals from lateral to medial 1: I: extensor pollicis brevis, abductor pollicis longus II: extensor carpi radialis longus, extensor carpi radialis brevis III: extensor poll...
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Extensor digiti minimi

Extensor digiti minimi (EDM) is a muscle of the superficial layer of the posterior compartment of the forearm, and with other extensor muscles arises from a common extensor tendon attached to the lateral epicondyle of the humerus. The EDM represents a medial group of superficial extensor muscles...
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Extensor digitorum

Extensor digitorum (ED), also known as extensor digitorum communis (EDC), is a muscle of the superficial layer of the posterior compartment of the forearm and with other extensor muscles arises from a common tendon attached to the lateral epicondyle of the humerus. ED represents a medial group o...
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Extensor digitorum brevis manus

The extensor digitorum brevis manus (EDBM) muscle is an accessory muscle in the hand and is a normal anatomical variant.  Summary origin: distal radius and posterior radiocarpal ligament insertion: extensor hood of 2nd or 3rd digits (variable) innervation: posterior interosseous nerve actio...
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Extensor digitorum brevis muscle

The extensor digitorum brevis muscle is a muscle on the dorsal surface of the foot which helps extend digits 2 through 4. Summary origin: superolateral surface of calcaneus insertion: lateral sides of the tendons of extensor digitorum longus of toes II to IV action: extension of toes II to I...
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Extensor digitorum longus muscle

Extensor digitorium longus (EDL) is a thin muscle situated in the anterior leg lateral to extensor hallucis longus and extends the lateral four toes. Summary origin: lateral tibial condyle, medial surface of the middle portion of the fibula and superior portion of the anterior surface of the i...
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Extensor hallucis brevis muscle

The extensor hallucis brevis is a muscle on the dorsal surface of the foot which helps to extend the big toe. Summary origin superolateral surface of calcaneus insertion base of proximal phalanx of great toe action extension of metatarsophalangeal joint of great toe arterial supply dors...
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Extensor hallucis longus

Extensor hallucis longus is a thin muscle in the anterior compartment of the leg between tibialis anterior and extensor digitorum longus. Summary origin: anterior surface of the middle portion of the fibula and the interosseous membrane insertion: the dorsal side of the base of the distal pha...
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Extensor indicis

The extensor indicis muscle is an accessory extensor of the 2nd digit. It is located in the deep layer of the posterior compartment of the forearm and its tendon passes through the 4th extensor compartment of the wrist. Summary origin: posterior surface of the ulna (distal to extensor pollicis...
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Extensor mechanism of the knee

The extensor mechanism of the knee comprises of: quadriceps muscle quadriceps tendon medial patellar retinaculum lateral patellar retinaculum patella patellar tendon tibial tuberosity Related pathology extensor mechanism of the knee injuries
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Extensor pollicis brevis

Extensor pollicis brevis (EPB) is one of the muscles of the deep layer of the posterior compartment of the forearm, inserting into the base of the proximal phalynx of the thumb. Along with extensor pollicis longus, it is responsible for extension of the thumb. Along with abductor pollicis longus...
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Extensor pollicis longus

Extensor pollicis longus (EPL) is a muscle of the deep compartment in the posterior compartment of the forearm. It passes through the 3rd extensor compartment of the wrist, then continues medially towards the thumb around Lister's tubercle. The tendon of EPL defines the ulnar border of the Anato...
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Extensor retinaculum

The extensor retinaculum is located at the dorsal aspect of the foot and consists of the superior and inferior extensor retinacula.  Gross anatomy The superior extensor retinaculum is located proximally to the dorsal aspect of the ankle joint and houses the tibialis anterior, extensor digitoru...
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External capsule

The external capsule is a series of white matter tracts in the brain situated between the putamen and claustrum. It is composed of claustrocortical fibres dorsally and the combined mass of the uncinate fasciculus and inferior frontal occipital fasciculus ventrally.  Relationships The putamen s...
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External carotid artery

The external carotid artery (ECA) is one of the two terminal branches of the common carotid artery. The other terminal branch is the internal carotid (ICA), which is somewhat larger than the ECA. Summary origin: bifurcation of the common carotid artery course: under the submandibular gland an...
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External ear

The external ear comprises the auricle (or pinna), the external auditory meatus, and the tympanum (eardrum). The pinna concentrates and amplifies sound waves and funnels them through the outer acoustic pore into the external auditory meatus, which carries them to the tympanic membrane. Gross an...
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External iliac artery

The external iliac artery is the larger of the two terminal branches of the common iliac artery. Gross anatomy Origin The common iliac artery bifurcates into the internal iliac artery and external iliac artery at the level of the pelvic brim anterior to the sacroiliac joint.  Course The ext...
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External iliac vein

The external iliac vein (EIV) is located along the pelvic brim between the inguinal ligament and the sacroiliac joint.  Gross anatomy Origin posterior to inguinal ligament within lacuna vasorum 1 as continuation of femoral vein Termination The external iliac vein unites with the internal il...
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External intercostal muscle

The external (or outermost) intercostal muscles are important muscles of respiration. They number eleven on each side and are located in the intercostal space, expanding the transverse dimension of the thoracic cavity during inspiration. Gross anatomy The external intercostal muscles are the o...
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External jugular vein

The external jugular vein (EJV) drains the head, face and part of the pectoral region. Gross anatomy Origin and course The posterior division of the retromandibular vein and posterior auricular vein unite to form the external jugular vein at the angle of the mandible. It courses inferiorly in...
Article

External oblique muscle

The external oblique muscle (EOM) is one of the muscles that forms the anterior abdominal wall. Its free inferior border forms the inguinal ligament, and its aponeurotic part contributes to the anterior wall of the inguinal canal.  Summary origin: outer surface of the shaft of the lower 8 ribs...
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External petrosal nerve

The external petrosal nerve is one of the three branches from the geniculate ganglion. It carries sympathetic fibers to the middle meningeal artery.
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Extraconal orbital compartment

The extraconal orbital compartment or extraconal space is the space within the orbit outside the musculofascial cone. The base of which is anterior and is formed by the orbital septum that surrounds the equator of the globe. The external sides are formed by the bones of the orbit and their perio...
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Extradural space

The extradural (epidural) space is a potential space between the cranial bones and the endosteal layer of the dura mater, which is otherwise adherent to the cranial bone.  Gross anatomy The extradural space is a potential space inside the cranial vault and is not normally appreciable unless th...
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Extramural air cell

An extramural air cell is one that is not contained within its named parent bone. So, the infraorbital ethmoidal air cells that lie within the maxilla rather than the ethmoidal bone are an example of extramural air cells.
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Extra-ocular muscle nerve supply (mnemonic)

Mnemonics for extra-ocular muscle nerve supply include: LR6SO4O3 (mock 'chemical formula') Where the letters represent the extra-ocular muscles and numbers represent their respective cranial nerve supply: LR6: Lateral Rectus, innervated by the 6th (abducens) nerve SO4: Superior Oblique, inne...
Article

Extra-ocular muscles

The extra-ocular muscles are the six muscles that insert onto the eye and hence control eye movements: superior rectus: elevation superior oblique: intorsion medial rectus: adduction lateral rectus: abduction inferior oblique: extorsion inferior rectus: depression Associated pathology op...
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Extrapyramidal system

The extrapyramidal system is the part of the motor system involved in modulation and regulation of movement. As its name suggests, it is distinct from the motor fibres that are relayed through the pyramids of the medulla oblongata (corticospinal and corticobulbar tracts). It is composed of nerv...
Article

Extrarenal pelvis

Extrarenal pelvis refers to the presence of the renal pelvis outside the confines of the renal hilum. It is a normal variant that is found in ~10% of the population 2.  The renal pelvis is formed by all the major calyces. An extarenal pelvis usually appears dilated giving a false indication of ...

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