block

block

 [blok]

obstruction.

1. to obstruct.

regional anesthesia.

2. heart block.

atrioventricular block

1. any interruption of the conduction of electrical impulses from the atria to the ventricles; it can occur at the level of the atria, the atrioventricular node, the bundle of His, or the Purkinje system. See heart block.

2. a type of heart block in which the blocking is at the atrioventricular junction. It is first degree when atrioventricular conduction time is prolonged; it is called second degree or partial when some but not all atrial impulses reach the ventricle; and it is called third degree or complete when no atrial impulses at all reach the ventricle, so that the atria and ventricles act independently of each other.

atrioventricular block, complete see atrioventricular block.

atrioventricular block, first degree see atrioventricular block.

atrioventricular block, partial see atrioventricular block.

atrioventricular block, second degree see atrioventricular block.

atrioventricular block, third degree see atrioventricular block.

AV block atrioventricular block.

Bier block regional anesthesia by intravenous injection, used for surgical procedures on the forearm or the lower leg; performed in a bloodless field maintained by a pneumatic tourniquet that also prevents anesthetic from entering the systemic circulation. Called also intravenous block and IV block.

bifascicular block the combination of complete right bundle branch block with either left anterior fascicular block or left posterior fascicular block. This is an imprecise though commonly used term; specific terms defining the structures involved are preferred.

bundle branch block (BBB) a form of heart block involving delay or failure of conduction in one of the branches in the bundle of His, as determined by an electrocardiogram. It may be complete or incomplete, transient, permanent, or intermittent, and is also named according to involvement of the left or the right bundle branch. It is impossible to determine if bundle branch block is complete or not. When associated with acute anterior wall myocardial infarction, bundle branch block identifies a high-risk patient. See accompanying table.

bundle branch block, bilateral heart block characterized by conduction disturbance in the right and left bundle branches; it may be alternate, intermittent, or permanent. Complete bilateral bundle branch block results in complete (third degree) atrioventricular block.

bundle branch block, complete heart block characterized by absence of conduction in a bundle branch or conduction delay, causing ventricular activation to occur largely or exclusively through the contralateral bundle.

bundle branch block, incomplete heart block characterized by delayed conduction within a bundle branch, resulting in a delay in activation of the ipsilateral ventricle.

bundle branch block, right heart block characterized by a delay or failure of impulse propagation through the right bundle branch; it may be either complete or incomplete. See accompanying table.

caudal block caudal anesthesia.

cervical plexus block regional anesthesia of the neck by injection of a local anesthetic into the cervical plexus.

entrance block a zone of depressed conduction surrounding a pacemaker focus, protecting it from discharge by an extraneous impulse but not necessarily from discharges by electrotonic influences.

epidural block epidural anesthesia.

exit block heart block characterized by failure of an expected impulse to emerge from its focus of origin and propagate; this usually occurs with a parasystolic focus, but is also seen with sinus, junctional, and ventricular rhythms. In cardiac pacing it means that the pacemaker stimulus is not of sufficient amplitude to stimulate the heart, such as when there is a very high threshold.

fascicular block heart block characterized by certain abnormal QRS waveforms ascribed to conduction disturbance in the anterior and posterior divisions of the left bundle branch.

fascicular block, left anterior heart block characterized by delay or interruption of impulse conduction in the anterior superior division of the left bundle branch, resulting in asynchronous activation of the left ventricle.

fascicular block, left posterior heart block characterized by delay or interruption of impulse conduction in the posterior inferior division of the left bundle branch, resulting in asynchronous activation of the left ventricle.

femoral block regional anesthesia of the posterior thigh and the lower leg by injection of a local anesthetic around the femoral nerve just below the inguinal ligament at the lateral border of the fossa ovalis.

field block regional anesthesia by blocking conduction in nerves with chemical or physical agents.

heart block see heart block.

intravenous block Bier block.

intraventricular block impaired conduction within the ventricles due to absence of conduction within the bundle branches, their ramifications, or the ventricles.

intraventricular block, unspecified any heart block characterized by an electrocardiographic pattern of intraventricular conduction disturbance and not qualifying as a bundle branch block or a fascicular block.

interventricular block bundle branch block.

IV block Bier block.

lumbar plexus block regional anesthesia of the anterior and medial aspects of the lower limb by injection of a local anesthetic into the lumbar plexus.

mental block blocking (def. 3).

metabolic block the blocking of a biosynthetic pathway due to a genetic enzyme defect or to inhibition of an enzyme by a drug or other substance.

Mobitz type I block a second degree atrioventricular block in which the P-R interval increases progressively until an atrial impulse is blocked. Called also Wenckebach's phenomenon or block.

Mobitz type II block a second degree atrioventricular block in which the P-R interval is fixed, with periodic blocking of the atrial impulse to the ventricle.

nerve block regional anesthesia by injection of an anesthetic close to the appropriate nerve.

paracervical block regional anesthesia of the inferior hypogastric plexus and ganglia produced by injection of the local anesthetic into the lateral fornices of the vagina.

paraneural block perineural block.

parasacral block regional anesthesia by injection of a local anesthetic around the sacral nerves as they emerge from the sacral foramina.

paravertebral block paravertebral anesthesia.

perineural block regional anesthesia produced by injection of the anesthetic agent close to the nerve. Called also paraneural anesthesia or block and perineural anesthesia.

presacral block regional anesthesia produced by injection of the local anesthetic into the sacral nerves on the anterior aspect of the sacrum.

pudendal block regional anesthesia produced by blocking the pudendal nerves, accomplished by injection of the local anesthetic into the tuberosity of the ischium.

The pudendal block. The pudendal nerves can be effectively blocked by a local anesthetic, thereby anesthetizing the perineum. From Nichols and Zwelling, 1997.

retrobulbar block that performed by injection of a local anesthetic into the retrobulbar space to anesthetize and immobilize the eye.

sacral block regional anesthesia produced by injection of the local anesthetic into the extradural space of the spinal canal.

saddle block regional anesthesia in an area corresponding roughly with the areas of the buttocks, perineum, and inner aspects of the thighs, by introducing the anesthetic agent low in the dural sac. Called also saddle block anesthesia.

sinoatrial block a type of heart block characterized by partial or complete interference with the propagation of impulses from the sinoatrial node to the atria, resulting in delay or absence of the atrial response.

sinus block barosinusitis.

sinoatrial block.

spinal block spinal anesthesia.

subarachnoid block spinal anesthesia (def. 2).

trifascicular block an imprecise term referring to heart block characterized by failure of conduction, partial or complete, in all three of the fascicles of the intraventricular conduction system; i.e., there is simultaneous right bundle branch block, left anterior hemiblock, and left posterior hemiblock. In the setting of acute anterior wall myocardial infarction, this is an ominous sign. More precise terms referring to the specifically involved structures are preferred.

vagal block (vagus nerve block) regional anesthesia produced by blocking of vagal impulses by injection of a solution of local anesthetic into the vagus nerve at its exit from the skull.

Wenckebach block Mobitz type I block.

wrist block regional anesthesia of the hand by injection of a local anesthetic around the median, radial, and ulnar nerves at the wrist.

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

block

(block),

1. To obstruct; to arrest passage through.

2. A condition in which the passage of an electric impulse is arrested, wholly or in part, temporarily or permanently.

3. Synonym(s): atrioventricular block

4. A portion of a polymer structure consisting of constitutional units not present in adjacent regions of that same polymer.

[Fr. bloquer]

Farlex Partner Medical Dictionary © Farlex 2012

block

(blŏk)

n.

1. Interruption, especially obstruction, of a normal physiological function.

2. Interruption, complete or partial, permanent or temporary, of the passage of a nervous impulse.

3. Atrioventricular block.

4. Sudden cessation of speech or a thought process without an immediate observable cause, sometimes considered a consequence of repression; mental block.

v.

1. To arrest passage through; obstruct.

2. To interrupt or obstruct the functioning of a physiological process, especially by the use of drugs.

---

block′age (blŏk′ĭj) n.

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

block

Alternative/fringe medicine
See Energy block.
 
Anaesthesiology
Anaesthesia intended to ameliorate locoregional pain (e.g., spinal block).

Biochemistry
See Building block.
 
Cardiology
Impeded electromechanical activity.
 
Drug slang
A regional street term for marijuana.
 
Forensic pathology
See Body block.
 
Gastroenterology
An obstruction.
 
Molecular biology
An ungapped, aligned motif consisting of sequence segments that are clustered to reduce multiple contributions from groups of highly similar or identical sequences.

Neurology
A mental impasse.

Pathology
A paraffin-embedded portion of formalin-fixed and processed tissue, from which a “ribbon” of material is cut, placed on a glass slide and stained, which is used to to establish a histologic diagnosis.
 
Public health
See Sunblock.

Research
Treatment block. A group of patients in a clinical trial of a therapeutic modality that is “blinded” according the study’s protocol, and placed in either the treatment arm or the placebo or “gold standard” arm; each block is analysed individually at the close of the study.

Vox populi
A group, quantity, section or segment that is considered as a unit for some purpose, procedure, process or action.

Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

block

Anesthesiology Anesthesia intended to ameliorate locoregional pain. See Caudal block, Celiac plexus block, Epidural block, Field block, Hemiblock, Nerve block, Neurolytic block, Neurolytic celiac plexus block, Nonneurolytic block, Paracervical block, Pudendal block, Ring block, Spinal block Cardiology Impeded electromechanical activity. See Atrioventricular block, Bundle branch block, Exit block, Heart block, Left bundle-branch block, Möbitz type I block, Möbitz type II block, Mucosal block, Right bundle-branch block Gastroenterology An obstruction Neurology A mental impasse. See Writer's block Public health See Sunblock.

McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

block

(blok)

1. To obstruct; to arrest passage.

2. A condition in which the passage of an electrical impulse is arrested, wholly or in part, temporarily or permanently.

3. Regional anesthesia.

4. Synonym(s): atrioventricular block.

[Fr. bloquer]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

block

(blok)

1. To obstruct; to arrest passage through.

2. A condition in which the passage of an electric impulse is arrested, wholly or in part, temporarily or permanently.

[Fr. bloquer]

Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about block

Q. what does a sun block cream do? and what are a UV rays?

A. It blocks out harmful Ultra violet rays from the skin as the previous entries have related; however it can also block your ability to produce vitamin D. If you live in a northerly area or one that receives limited sunlight, its recommended to get at least 15 minutes of sun a day (this is probably best done with minimal sunblock) and according to personnal sun sensitivity. Another thing to keep in mind is that sunblock works best if applied 20 minutes before sun exposure.

Q. my son is 5 and half yrs old.he is having veezing and 75%block in one nose because of adenod.is is curable he has taken steriods for one and half yrs but with not much relief for veezing. then we switched on to ayur medicines,where he had some pigmentation at some places in his body. so again we are back to allopathy. he has one nasal steriod spray now with few other medicines. in his last test, dr, said he has adenod about 75% blcok in one nose, he has prescribed medicines for one month. he has also said that a small surgery can be done to remove adenod. i would like to know how long this surgry wil take and how much of rest he wil have to take. and if this adenod is removed, wil his other problem like veezing be cured? indira rajesh

A. it's a pretty common surgery from what i remember. most of our family has any kind of nasal problem...sinusitis..adenoids...just name it. the surgery is entering through the mouth (under full sedation) and lasering/curetting - removed. it took about a week to recover , eating soft foods..and it worked!

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