Articles
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3,362 results found
Article
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.
Article
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...
Article
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, forming supporting peritoneal ligaments, mesenteries, and omenta.
The peritoneal reflections carry vess...
Article
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...
Article
Abducens nerve
The abducens nerve is the sixth cranial nerve (CN VI). It is a motor nerve responsible for abduction of the eye (TA: nervus abducens or nervus cranialis VI). It courses from the abducens nucleus, located in the dorsal pons, up to the cavernous sinus, via a long cisternal segment that is prone to...
Article
Abducens nucleus
The 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 column of s...
Article
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 the fifth metatarsal
in...
Article
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...
Article
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 ...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
Aberrant right subclavian artery
Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are among the commonest aortic arch anomalies.
Epidemiology
The estimated incidence is 0.5-2% 1.
Associations
as can be expected from the embryological development of the artery, the right recurrent laryngeal nerve...
Article
Abnormal renal rotation
Abnormal renal rotation, also known as 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
...
Article
Absent azygos vein
An absent azygos vein is a very uncommon variant in which the azygos vein fails to develop. In cases of agenesis of the azygos vein, the hemiazygos and accessory hemiazygos veins play an important role in venous drainage, accounting for drainage of both the right and left intercostal veins 1-3.
...
Article
Accessory abductor digiti minimi muscle (hand)
An accessory abductor digiti minimi (ADM) muscle is the most common accessory muscle of the hand and wrist, found in 24% of individuals on the hypothenar eminence. When present it is one of the intrinsic muscles of the hand.
Summary
origin:
antebrachial fascia passing anteriorly to Guyon cana...
Article
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...
Article
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...
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