Articles
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16,879 results found
Article
Accessory brachialis muscle
An accessory brachialis muscle, also known as brachialis accessorius muscle, is a very rare accessory muscle of the elbow and an anatomical variant.
Summary
origin: anterior surface of the lower humeral diaphysis
course: variably medial or lateral to the brachialis muscle
insertion: variable...
Article
Accessory breast tissue
Accessory breast tissue, also known as polymastia, 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 str...
Article
Accessory extensor digiti secundus muscle
The accessory extensor digiti secundus muscle is a rare accessory muscle or tendon of the ankle and an anatomical variant.
Summary
origin: extensor hallucis longus tendon or muscle
insertion: medial phalanx of the second toe adjacent to the second tendon of the extensor digitorum longus muscl...
Article
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...
Article
Accessory flexor carpi ulnaris muscle
The accessory flexor carpi ulnaris (AFCU) is a rare accessory muscle of the forearm and wrist and a normal anatomical variant that can be found in addition to a normal flexor carpi ulnaris muscle.
Epidemiology
The accessory flexor carpi ulnaris muscle is considered very rare 1,2.
Associations...
Article
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...
Article
Accessory flexor digitorum superficialis indicis muscle
An accessory flexor digitorum superficialis indicis muscle is an unusual accessory muscle of the hand and wrist and a normal anatomical variant.
Summary
origin: flexor digitorum superficialis tendon near the transverse carpal ligament
insertion: metacarpal head of the index finger near the A1...
Article
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...
Article
Accessory hepatic sulci
Accessory hepatic grooves (also known as accessory hepatic fissures or accessory hepatic sulci) are a common anatomic variant, with majority of accessory grooves occurring over the diaphragmatic surface of the liver 1,2.
Several hypotheses have been made regarding the process by which an access...
Article
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 ...
Article
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...
Article
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's cave and the middle cranial fossa. It also usually suppli...
Article
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 (...
Article
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, thorax, pelvis, upper and lower limbs.
See also
accessory muscles of respiration
Article
Accessory muscles of respiration
Accessory muscles of respiration refer to muscles that provide assistance to the main breathing muscles, mainly when additional power is needed, for example during exercise or those with airway pathologies (e.g. COPD) 1,2.
During normal quiet breathing, inspiration is an active process primaril...
Article
Accessory muscles of the ankle
Accessory muscles of the ankle are muscular anatomical variants that are usually asymptomatic but rarely cause symptoms or might be encountered on imaging studies.
The following accessory muscles around the ankle have been described 1-4:
posteromedial/flexor compartment
accessory flexor digit...
Article
Accessory muscles of the forearm, wrist and hand
Accessory muscles of the forearm, wrist and hand are muscular, usually asymptomatic, anatomical variants that might be encountered on imaging studies and confused with pathologic conditions.
The following accessory muscles around the forearm, wrist and hand have been described 1-6:
elbow
acc...
Article
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 ...
Article
Accessory navicular syndrome
The accessory navicular syndrome, also known as os naviculare syndrome occurs when a type II accessory navicular becomes painful due to movement across the pseudo-joint between the ossicle and the navicular bone.
Radiographic features
Ultrasound
It can be inferred on musculoskeletal ultrasoun...
Article
Accessory nerve
The accessory nerve, also called the spinal accessory nerve, or historically, the nerve of Willis, is the eleventh cranial nerve (CN XI) and is composed of two parts, the cranial part and the spinal part (TA: nervus accessorius or nervus cranialis XI).
Connections and course
The cranial part (...
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