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.

2,851 results found
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Aortic arch branches (mnemonic)

A useful mnemonic to remember the major branches of the aortic arch is: ABC'S ​Mnemonic A: arch of aorta B: brachiocephalic trunk C: left common carotid artery S: left subclavian artery  
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Aortic hiatus

The aortic hiatus is one of the three major apertures through the diaphragm and lies at the level of T12. Strictly speaking, it is not a real aperture in the diaphragm, but an osseoaponeurotic opening between it and the vertebral column.  The hiatus is situated slightly to the left of the midli...
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Aortic isthmus

The aortic isthmus is the part of the aorta just distal to the origin of the left subclavian artery at the site of the ductus arteriosus. This portion of the aorta is partly constricted in the fetus because of the lack of flow within the aortic sac and ascending aorta. It marks the partial sepa...
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Aortic-pulmonary stripe

The aortic-pulmonary stripe is an uncommon feature of frontal chest radiographs and was first described by Keats in 1972 1. It is formed by the interface of the pleural surface of the anterior segment of the left upper lobe contacting the mediastinal fat that is anterolateral to the pulmonary t...
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Aortic root

The aortic root is the first part of the aorta and connects the heart to the systemic circulation.  Gross anatomy The aortic root lies between the junction of the aortic valve and ascending aorta. It has several subparts 1: three aortic valve leaflets and leaflet attachments three aortic sin...
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Aortic spindle

Aortic spindles are an anatomical variant of the proximal descending thoracic aorta. It occurs just distal to the aortic isthmus and has a circumferential smooth bulging appearance.  Differential diagnosis ductus diverticulum: not circumferential aortic pseudoaneurysm thoracic aortic aneurysm
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Aortic valve

The aortic valve (AV) is one of the four cardiac valves. It is the semilunar valve that allows blood to exit the left ventricle (LV). It opens during systole and closes during diastole. The valve has left, right and posterior cusps, the bases of which attach around the valve orifice to a fibrous...
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Aortomitral continuity

The aortomitral continuity (also known as the aortomitral curtain, aorticomitral junction, intervalvular fibrous body) is a fibrous sheet located between the noncoronary and left coronary leaflets of the aortic valve and anterior leaflet of the mitral valve. It is attached by the left and right ...
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Apical ligament

The apical ligament is a small ligament that joins the apex (tip) of the dens of C2 to the anterior margin (basion) of the foramen magnum. It is the weak, fibrous remnant of the notochord and does not contribute significantly to stability. The more posterior alar and cruciate ligaments are stro...
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Apophysis

The apophyses (singular: apophysis) are the normal bony outgrowths that arise from separate ossification centers and eventually fuse with the bone in time. The apophysis is a site of tendon or ligament attachment, as compared to the epiphysis which contributes to a joint. When unfused, they can...
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Apophysis of the proximal 5th metatarsal

The apophysis of the proximal 5th metatarsal (plural apophyses) lies laterally and is oriented longitudinally parallel to the shaft. Apophysis of the fifth metatarsal base appears on plain radiographs at age 12 for boys and 10 for girls. Fusion of the apophysis to the metatarsal base usually oc...
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Appendicular artery

The appendicular artery is a branch of the ileal or posterior cecal branch of the ileocolic artery, which is from the superior mesenteric artery. It courses posteriorly to the terminal ileum in the free wall of the mesoappendix to supply the appendix.
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Appendicular skeleton

The appendicular skeleton is the portion of the bony skeleton that includes and supports the limbs (the appendages). It includes the pectoral girdle and the bony pelvis, connected to the axial skeleton centrally and is composed of 126 bones in total.  Appendicular bones form from cartilage, by ...
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Appendix

The appendix or vermiform appendix (plural: appendices) is a blind muscular tube that arises from the cecum, which is the first part of the large bowel. Gross anatomy The appendix arises from the posteromedial surface of the cecum, approximately 2-3 cm inferior to the ileocecal valve, where th...
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Arachnoid granulation

Arachnoid granulations, also known as Pacchionian granulations, are projections of the arachnoid membrane (villi) into the dural sinuses that allow CSF to pass from the subarachnoid space into the venous system. Epidemiology They increase in size and number with age and are seen in approximate...
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Arachnoid mater

The arachnoid mater forms the middle layer of the meninges and together with the pia mater is sometimes referred to as the leptomeninges.  Gross anatomy The arachnoid mater is a membrane that comes into direct contact with the dura mater and is separated from the pia mater by a CSF-filled spac...
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Arachnoid membranes

Arachnoid membranes represent sheet-like connective tissue that crosses the subarachnoid space, from the pia mater to the arachnoid mater, dividing the subarachnoid space into cisterns. A number of these membranes are named 1: Liliequist membrane: separates the chiasmatic cistern and interpedun...
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Arcade of Frohse

The arcade of Frohse (pronounced "\ˈfʁoːzə \") is also known as the supinator arch. The arcade is formed by a fibrous band between the two heads of the supinator muscle. The deep branch of the radial nerve passes beneath the arcade accompanied by vessels known as the leash of Henry. Radiograph...
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Arc of Barkow

The arc of Barkow is formed by the anastomosis of the right gastroepiploic (a branch of the gastroduodenal artery) and left gastroepiploic (a branch of the splenic artery) arteries. The arc of Barkow supplies the transverse colon via multiple ascending branches. 
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Arc of Riolan

The arc of Riolan, also known as the mesenteric meandering artery (of Moskowitz) or central anastomotic mesenteric artery, is an arterioarterial anastomosis between the superior and inferior mesenteric arteries. Gross anatomy It is an inconstant artery that connects the proximal superior mesen...
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Arcuate foramen

The arcuate foramen (foramen arcuate atlantis, ponticulus posticus or posterior ponticle, or Kimerle anomaly) is a frequently encountered normal variant of the atlas and is easily appreciated on a lateral plain film of the craniocervical junction. Epidemiology Incidence is ~8% (range 1-15%) an...
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Arcuate ligament

The arcuate ligament is part of the posterolateral ligamentous complex of the knee that is variably present, being found in ~65% (range 47.9-71%) of knees. It is a Y-shaped thickening of the posterolateral capsule, which arises from the fibular styloid and divides into two limbs: medial limb: c...
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Arcuate line

The arcuate line or semicircular line of Douglas is located at roughly one-third of the distance from the pubic crest to the umbilicus. It is the demarcation where the internal oblique and transversus abdominis aponeuroses of the rectus sheath start to pass anteriorly to the rectus abdominis mus...
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Area postrema

The area postrema, also known as the chemoreceptor trigger zone is one of the so-called circumventricular organs located on the dorsal inferior surface of the medulla oblongata at the caudal end of the fourth ventricle. The specialized ependymal cells in the area postrema detect toxins in the b...
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Arm

The arm (also known as the upper arm) is part of the upper limb below the pectoral girdle and above the forearm, comprising the humerus.  The elbow joint is inferior and the glenohumeral joint is superior. Arm flexion, extension, abduction, adduction, internal rotation and external rotation occ...
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Arm abduction

Arm abduction represents movement of the arm away from the midline of the body in the coronal plane and, in most cases isolated abduction can be achieved to 160-180°. It is the opposite of arm adduction and contributes to the combined movement of shoulder circumduction. It is produced by: delt...
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Arm adduction

Arm adduction represents movement of the arm towards from the midline of the body in the coronal plane. Most individuals can manage 40° of isolated adduction. It is the opposite of arm abduction and contributes to the combined movement of shoulder circumduction. It is produced by: pectoralis m...
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Arm extension

Arm extension represents the opposite movement to arm flexion where the arm moves posteriorly. Only about 40° of movement posteriorly from the anatomic position is achievable in most individuals. It is the opposite of arm flexion and contributes to the combined movement of shoulder circumduction...
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Arm external rotation

External or lateral rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is externally rotated around the longitudinal plane of the humerus such that the hand moves away from the midline of the body. It is the opposite of arm internal rotation. As wi...
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Arm flexion

Arm flexion represents rotation in the anatomic plane such that the distal humerus moves ventrally. Is represents raising the arm and isolated flexion can achieve approximately 150-170° of movement. The opposite movement is arm extension and contributes to the combined movement of shoulder circu...
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Arm internal rotation

Internal or medial rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is internally rotated around the longitudinal plane of the humerus such that the hand moves towards the midline of the body.   The degree of rotation is dependent on the degree o...
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Arnold's nerve

Arnold's nerve is the auricular branch, also known as the mastoid branch, of the vagus nerve (CN X). Origin and course Arnold's nerve originates from the superior ganglion of the vagus nerve and also has a small contribution from the inferior ganglion of the glossopharyngeal nerve. It ascends ...
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Arterial anastomosis of the elbow

The periarticular arterial anastomosis of the elbow consists of several arteries that supply the elbow joint and its supporting structures. It functions to allow blood to flow around the elbow joint no matter which position the joint is in. The arteries that contribute include:  from the brachi...
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Arterial supply of the head and neck

The arteries of the head and neck are branches of the common carotid and subclavian arteries. common carotid artery carotid body carotid bifurcation internal carotid artery (segments) caroticotympanic artery persistent stapedial artery ophthalmic artery supraorbital artery lacrimal arte...
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Arterial supply of the lower limb

The arterial supply of the lower limbs originates from the external iliac artery.  The common femoral artery is the direct continuation of the external iliac artery, beginning at the level of the inguinal ligament. The common femoral artery becomes the superficial femoral artery at the point wh...
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Arterial supply of the upper limb

The arterial supply of the upper limb is derived from the subclavian artery. The right subclavian artery originates from the brachiocephalic artery, which is the first branch of the aortic arch. The left subclavian artery originates directly from the aortic arch, being the third branch. The sub...
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Arterial supply to the foot

Arterial supply to the foot can be divided into plantar and dorsal components. Plantar arterial supply Posterior tibial artery  gives off its calcaneal branch  then divides into the medial and lateral plantar arteries Medial plantar artery branch of the posterior tibial artery smaller cal...
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Arterial supply to the hand

The arterial supply to the hand is comprised of a complex vascular network formed from the branches and distal continuations of the radial and ulnar arteries. This rich vascular network can be divided into palmar and dorsal components. Palmar arterial supply The palmar arterial supply can be d...
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Arterial vasocorona

The arterial vasocorona is part of the spinal cord blood supply and is formed by pial anastomoses between the anterior and posterior spinal arteries on the surface of the spinal cord. It encircles the cord and supplies the peripheral lateral aspect of the spinal cord. 
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Artery of Adamkiewicz

The artery of Adamkiewicz, also known as the great anterior radiculomedullary artery or arteria radicularis anterior magna, is the name given to the dominant thoracolumbar segmental artery that supplies the spinal cord. Gross anatomy Origin The artery of Adamkiewicz has a variable origin but ...
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Artery of Bernasconi and Cassinari

The artery of Bernasconi and Cassinari, also known as medial or marginal tentorial artery (of Bernasconi–Cassinari), commonly arises from the cavernous segment of the internal carotid artery. Gross anatomy The artery of Bernasconi and Cassinari is ~2 cm long and is an important branch of the m...
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Artery of Percheron

The artery of Percheron is a rare variant of the posterior cerebral circulation characterized by a solitary arterial trunk that supplies blood to the paramedian thalami and the rostral midbrain bilaterally. From the original classification of arterial patterns at the origin of the paramedian art...
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Artery to the ductus deferens

The artery to the ductus deferens (deferential or vesiculodeferential artery) is a branch of the superior vesical artery, which in turns arises from the internal iliac artery via the umbilical artery. Gross anatomy origin: superior vesical artery main branch: no named branches course: accomp...
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Articularis cubiti muscle

The articularis cubiti muscle lies in the posterior compartment of the arm: origin: posterior surface of the distal humerus insertion: posterior surface of the elbow joint capsule innervation: radial nerve action: tenses the posterior elbow joint capsule during elbow extension
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Articularis genu muscle

The articularis genu is a small flat muscle of the anterior knee. During knee extension it acts to tighten the synovial membrane superiorly thereby preventing impingement of the synovial folds between the femur and the patella. Summary origin: anterior distal femoral shaft insertion: knee joi...
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Aryepiglottic folds

The aryepiglottic folds are two ligamentomuscular structures within the supraglottic larynx that function to protect the airway when swallowing. Gross anatomy Each aryepiglottic fold is comprised of the superior ligamentous edge of the quadrangular membrane and covering mucous membrane 1, the ...
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Arytenoid cartilage

The arytenoid cartilages are paired hyaline cartilages that articulate with the sloping upper border of the lamina of the cricoid cartilage by the cricoarytenoid joint. This joint allows movement of the arytenoid cartilages, which is vital in approximating, tensing and relaxing the vocal folds. ...
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Ascending aorta

The ascending aorta is the first part of the aorta, and begins at the aortic valve, located obliquely just to the left of the midline at the level of the third intercostal space. It terminates as it exits the fibrous pericardium where it becomes the aortic arch, in the plane of Ludwig, a horizon...
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Ascending cervical artery

The ascending cervical artery is 1 of the 4 branches of the thyrocervical trunk (off the first part of the subclavian artery). It is a small artery that ascends medial to the phrenic nerve on the prevertebral fascia. It contributes many small spinal branches into the intervertebral foramina of ...
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Ascending colon

The ascending colon is the second part of the large bowel. Gross anatomy The ascending colon is the continuation of the cecum superior to the ileocecal valve. It is secondarily retroperitoneal, although it has its own mesentery in approximately 25% of patients and is 15 cm in length 1,2. The ...
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Ascending lumbar communicant vein

The ascending lumbar communicant vein is a communication between the left ascending lumbar vein and the left renal vein. Because of its retroperitoneal location, when dilated, it may be mistaken for a lymph node on non-contrast studies with thick collimation. The image shows the left renal vein...
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Ascending lumbar vein

The ascending lumbar vein is a paired structure which forms a part of the venous drainage of the lumbar vertebral column. Summary location: near midline on the side of the vertebral column in the lumbar region origin and termination: continuation of the lateral sacral veins; joins the subcost...
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Ascending pharyngeal artery

The ascending pharyngeal artery, the smallest branch of the external carotid artery, is a long, slender vessel, deeply seated in the neck, beneath the other branches of the external carotid and under the stylopharyngeus. Summary origin: a branch of the external carotid artery course: vertical...
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Asplenia

Asplenia refers to absence of the spleen thereby leading to deficient splenic function. Epidemiology Seen in 3% of neonates with structural heart disease and in 30% of patients who die from cardiac malposition. The male-to-female ratio is 2:1. Pathology Asplenia can be classified into two  t...
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Association fibers of the brain

Association fibers of the brain, also known as association tracts of the brain or intrahemispheric tracts (cortex-cortex connections 1) are a type of white matter tract that connects different areas in the same hemisphere. There are two types of association fibers: long-range and U-fibers (short...
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Asterion

The asterion is the junction on the side of the posteroinferior calvarium where three sutures meet: parietomastoid suture occipitomastoid suture lambdoid suture It represents the site of the closed mastoid fontanelle. It is located at the posterior end of the parietotemporal suture, whereas ...
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Astrocytes

Astrocytes are cells of the central nervous system which act as both physical and physiological support for the neurons that are embedded between them. They are particularly abundant in the grey matter, where they are the most abundant glial cells 1. They are highly branched and contribute to t...
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Asymmetrically large jugular bulb

Asymmetrically large jugular bulbs are entirely normal and asymptomatic; its only significance is to distinguish it from pathology. The size of the jugular bulbs is variable, with the right side being significantly larger than the left in two-thirds of people. A normal but large bulb will have...
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Asymmetric fatty bone marrow of the petrous apex

Asymmetric pneumatization of petrous apex is a frequent normal anatomic variant resulting in asymmetric fatty bone marrow within the petrous apex. It is a common incidental finding on brain and skull base MRI. Clinical presentation Asymptomatic. Pathology Asymmetric pneumatization of the pet...
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Asymmetry of the lateral ventricles

The lateral ventricles occasionally show small side to side differences in size on CT or MRI of the brain. This asymmetry of the lateral ventricles (ALV) is an anatomic variant in most cases. Epidemiology The prevalence of asymmetry in lateral ventricle size in those without evidence of underl...
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Atlanto-axial articulation

The atlanto-axial articulation is a complex of three synovial joints, which join the atlas (C1) to the axis (C2). Gross anatomy Articulations paired lateral atlanto-axial joints: classified as planar-type joint between the lateral masses of C1 and C2, though somewhat more complex in shape wit...
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Atlanto-occipital articulation

The atlanto-occipital articulation (also known as the C0-C1 joint/articulation) is comprised of a pair of condyloid synovial joints that connect the occipital bone (C0) to the first cervical vertebra (atlas/C1). Gross anatomy Articulations Each joint is comprised of two concave articular surf...
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Atlanto-occipital assimilation

Atlanto-occipital assimilation is the fusion of the atlas (C1) to the occiput and is one of the transitional vertebrae.  Epidemiology Atlanto-occipital assimilation occurs in approximately 0.5% (range 0.08-3%) of the population 2-5,. It is thought to affect males and females equally. Clinical...
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Atlas (C1)

The atlas (plural: atlases) is the first cervical vertebra, commonly called C1. It is an atypical cervical vertebra with unique features. It articulates with the dens of the axis and the occiput, respectively allowing rotation of the head, and flexion, extension and lateral flexion of the head. ...
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Atlas of Normal Roentgen Variants That May Simulate Disease

The Atlas of Normal Roentgen Variants That May Simulate Disease is a classic radiology text that was first published in 1973, and is now in its ninth edition (2012). The first - and all subsequent - editions, were written by an American radiologist Theodore Eliot Keats (1924-2010) who died durin...
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Atypical cervical vertebrae

Of the cervical vertebrae, the atlas (C1), axis (C2) and vertebra prominens (C7) are considered atypical cervical vertebrae. The atlas (C1) lacks a body or spinous process. It has anterior and posterior arches with lateral masses. Its superior articular surfaces articulate with the occiput at t...
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Atypical lumbar vertebrae

Of the five lumbar vertebrae, L5 is considered atypical due to its shape. The remaining lumbar vertebrae are largely typical. For a basic anatomic description of the structure a generic vertebra, see vertebrae.
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Atypical ribs

Owing to their features, the first, eleventh and twelfth ribs are considered atypical ribs. Of all ribs, the first is the strongest, broadest and most curved. Ribs eleven and twelve are unique, among other reasons, by not being attached to the sternum.
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Atypical thoracic vertebrae

T1 and T9 - T12 are considered atypical thoracic vertebrae. T1 bears some resemblance to low cervical vertebrae. T9 has no inferior demifacet. T10 often, but not always, shares features with T11 and T12.  For a basic anatomic description of the structure a generic vertebra, see vertebrae.
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Auriculotemporal nerve

The auriculotemporal nerve is a sensory branch of the posterior division of the mandibular division of the trigeminal nerve. Gross anatomy The auriculotemporal nerve divides posteriorly from the posterior division of the mandibular division before dividing into two roots separate to encircle t...
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Avascular plane of Brodel

The avascular plane of Brodel is the section of renal parenchyma between 2/3 anterior and 1/3 posterior kidney on the cross-section that is relatively avascular. The reason for its relative avascularity is that it represents the plane where the anterior and posterior segmental renal artery branc...
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Axial skeleton

The axial skeleton is the central portion of the bony skeleton comprising the head, neck and trunk (80 bones in total). It has many functions including housing and protecting the central nervous system as well as the organs of the chest, abdomen and pelvis. It enables movement and supports the u...
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Axilla

The axilla is a space located between the upper limb and thorax, which permits the passage of the major neurovascular structures. Gross anatomy The axilla is pyramidal in shape with its apex opening superiorly towards the base of the neck between the subclavius muscle, first rib, and clavicle....
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Axillary artery

The axillary artery represents the continuation of the subclavian artery and is a major artery of the upper limb. Summary origin: continuation of the subclavian artery as it passes under the midpoint of the clavicle on the outer edge of the first rib  termination: continues as the brachial ar...
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Axillary artery branches (mnemonic)

Useful mnemonics to remember the branches of the axillary artery are: S AL SAP Screw the lawyer, save a patient! Mnemonics S AL SAP The gap between the 'S' and the 'AL' to emphasize that 'S' is 1st part and 'AL' are 2nd part S: superior thoracic artery (from 1st part) A: acromiothoracic (...
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Axillary lymph nodes

The axillary lymph nodes, also known commonly as axillary nodes, are a group of lymph nodes in the axilla and receive lymph from vessels that drain the arm, the walls of the thorax, the breast and the upper walls of the abdomen. Gross anatomy There are five axillary lymph node groups, namely t...
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Axillary nerve

The axillary nerve is one of five terminal branches of the brachial plexus, supplying motor and sensory branches to the shoulder.  Summary origin: posterior cord of the brachial plexus course: passes out of axilla through the quadrangular space to the upper arm major branches: superior later...
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Axillary vein

The axillary vein is one of the major veins of the upper limb. It is formed by the union of the paired brachial veins and the basilic vein and contributes to the drainage of the axilla, arm and superolateral chest wall. Summary origin: formed by the union of the paired brachial veins and the b...
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Axis (C2)

The axis is the second cervical vertebra, commonly called C2. It is an atypical cervical vertebra with unique features and important relations that make it easily recognisable. Its most prominent feature is the odontoid process (or dens), which is embryologically the body of the atlas (C1) 1,2. ...
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Azygo-esophageal recess

The azygo-esophageal recess (also known as the line/interface) (AER) is a prevertebral space formed by the interface of the posteromedial segments of the right lower lobe and the azygos vein and esophagus 1-3. The AER extends from the azygos arch to the aortic hiatus and has the following border...
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Azygos anterior cerebral artery

An azygos anterior cerebral artery is an uncommon to rare variant of the circle of Willis where the two A1 segments of the anterior cerebral artery (ACA) join to form a single trunk. As a result, there is no anterior communicating artery. This organization is similar to that seen in lower primat...
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Azygos continuation of the inferior vena cava

Azygos continuation of the inferior vena cava (also known as the absence of the hepatic segment of the IVC with azygos continuation) is an uncommon vascular anomaly and is a cause of a dilated azygos vein. Terminology Spelling it "azygous" when referring to the vein is incorrect, regardless of...
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Azygos lobe

An azygos lobe is created when a laterally displaced azygos vein creates a deep pleural fissure into the apical segment of the right upper lobe during embryological development. It is a normal anatomic variant of the right upper lobe due to invagination of the azygos vein and pleura during devel...
Article

Azygos vein

The azygos vein is a unilateral vessel that ascends in the thorax to the right side of the vertebral column, carrying deoxygenated blood from the posterior chest and abdominal walls. It forms part of the azygos venous system. Terminology Spelling it "azygous" when referring to the vein is inco...
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Azygos venous system

The azygos (venous) system is a collective term given to the H-shaped configuration of the azygos, hemiazygos, accessory hemiazygos veins and left superior intercostal vein. It is responsible for draining the thoracic wall and upper lumbar region via the lumbar veins and posterior intercostal v...
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Babcock triangle

Babcock triangle is a relatively radiolucent triangular area seen in the subcapital region of the femoral neck on an anteroposterior radiograph of the hip. In this region, the trabeculae are loosely arranged and surrounded by more radiodense normal bony trabeculae groups. It may be the initial s...
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Ball and socket ankle joint

A ball and socket ankle joint is a variant affecting the ankle where there is a rounded or spherical configuration to the talar dome with the corresponding concavity of the tibial plafond. The distal fibula may or may not be involved. Pathology The etiology has been debated with two theories p...
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Ball and socket joint

Ball and socket joints are a type of synovial joint where the spheroid articular surface of one bone sits within a cup-like depression of another bone. Movements The ball and socket configuration allows for movement with 3 degrees of freedom, which is more than any other type of synovial joint...
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Band of Giacomini

The band of Giacomini, also known as the tail of the dentate gyrus or limbus Giacomini, is the anteromedial continuation of the dentate gyrus, which in turn is part of the hippocampal formation, along with the hippocampus, subicular complex and entorhinal cortex. It is an important anatomical la...
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Bartholin glands

The Bartholin glands, also known as the greater vestibular glands (or vulvovaginal glands) are paired pea-sized structures, lying on either side of the vaginal opening, and are homologous to the bulbourethral (Cowper) glands in the male. They form part of the vulva. Gross anatomy These glands ...
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Basal ganglia

The basal ganglia are a group of grey matter nuclei in the deep aspects of the brain that is interconnected with the cerebral cortex, thalami and brainstem. In a strict anatomical sense, it contains three paired nuclei that together comprise the corpus striatum: caudate nucleus lentiform nucl...
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Basal lamella

The basal lamella, also known as basal lamella of the middle turbinate, is an osseous lamella that separates the anterior from the posterior ethmoid sinuses 1. Terminology Internal anterior to posterior partitions of the ethmoid sinuses are called basal lamellae. According to a concept propose...
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Basal nucleus of Meynert

The basal nucleus of Meynert, also known as the nucleus basalis of Meynert, is formed by a group of cells that lies in the substantia innominata. It is rich in acetylcholine and its degeneration has been correlated to Alzheimer disease. It lies anterior to the anterior commissure. 

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