field block


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block

 [blok]
1. to obstruct.
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.
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.
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.

field block

regional anesthesia produced by infiltration of local anesthetic solution into tissues surrounding an operative field.

field block

(fēld blok)
Regional anesthesia produced by infiltration of local anesthetic solution into tissues surrounding an operative field.

anaesthesia

general or local loss of sensation, due to pharmacological or pathological suppression of nerve function; the syringe should be aspirated prior to the deposition of injectable anaesthetic
  • ankle block anaesthesia the introduction of local anaesthetic (ILA) to nerve trunks supplying the foot as they cross the ankle joint (deep injections to reach the tibial and deep peroneal nerves, and superficial/subcuticular injections to reach the superficial peroneal, sural and saphenous nerves) to achieve whole-foot anaesthesia (see named sites below)

  • Bier's block anaesthesia ILA into the venous circulation of a limb after the application of pressure cuffs inflated to above systolic pressure to prevent venous drainage of the limb, to achieve whole-limb anaesthesia

  • common peroneal block anaesthesia ILA to subcuticular tissue at neck of fibula, to achieve dorsal foot anaesthesia; this injection also causes footdrop that persists for the duration of anaesthesia

  • deep peroneal block anaesthesia ILA to the deep peroneal nerve where it crosses the anterior ankle joint, deep to the extensor retinaculum, to anaesthetize the dorsal area of the first interdigital cleft; the needle is introduced either between tibialis anterior and extensor hallucis longus tendons, passing through the extensor retinaculum to the anterior tibia; or adjacent to dorsalis pedis pulse where the nerve becomes superficial (injection into the adjacent artery is avoided by aspirating the syringe prior to deposition of LA solution)

  • digital block anaesthesia ILA to digital nerves (dorsal/medial; dorsal/lateral; plantar/medial; plantar/lateral) at the base of the toe, to achieve whole-digit anaesthesia

  • epidural anaesthesia ILA into cerebrospinal fluid to anaesthetize all tissues distal to the injection site

  • field block anaesthesia; regional anaesthesia ILA about all nerves subserving part or all of a limb/body region, to achieve anaesthesia of all tissues distal to the injection sites, e.g. ankle block, digital block, popliteal block, epidural anaesthesia

  • first-ray block anaesthesia; Mayo block anaesthesia ILA to branches of the medial plantar, superficial and deep peroneal nerves at the base of the first metatarsal, to achieve anaesthesia of the distal first ray

  • general anaesthesia; GA central suppression of conscious awareness of pain and other sensations, induced by an intravenous anaesthetic agent, and maintained by inhaled agents, often supplemented with muscle relaxants

  • high saphenous nerve anaesthesia ILA to the saphenous nerve at the medial side of the knee joint to achieve anaesthesia of the medial aspect of the lower leg and the medial longitudinal arch

  • infiltration anaesthesia; local infiltration anaesthesia the introduction of a small volume (e.g. 1 mL) of local anaesthetic solution into the subcuticular tissues underlying a skin lesion, to permit painless treatment of the lesion (see bleb)

  • intermetatarsal anaesthesia ILA to branches of the medial and/or lateral plantar, superficial and deep peroneal nerves at the bases of adjacent lesser metatarsals, to achieve anaesthesia of adjacent rays, interposed soft tissues and distal structures

  • local anaesthesia; LA loss of tissue sensation and pain by the injection or topical application (e.g. Emla) of local anaesthetic agents; LAs cause reversible conduction block of sensory, motor and autonomic nerve fibres

  • local infiltration anaesthesia see infiltration anaesthesia

  • Mayo block anaesthesia see first-ray block anaesthesia

  • medial dorsal cutaneous nerve anaesthesia see superficial peroneal block anaesthesia

  • peroneal block anaesthesia see common peroneal block anaesthesia

  • popliteal block injection ILA to the tibial nerve at the superior lateral area of the popliteal fossa, at a point approximately 5 cm proximal to a line joining the medial and lateral condyles and 1 cm lateral to the vertical bisection of the knee joint, i.e. before the nerve trunk divides to form the sural communicating and tibial nerves, in order to achieve anaesthesia of all parts of the lower leg and foot except the medial longitudinal arch; the deep location of the popliteal nerve is identified by a nerve stimulator

  • proximal digital block ILA just proximal to the medial and lateral aspects of the metatarsophalangeal joint to achieve anaesthesia of dorsal and plantar digital nerves just before they divide to form the proper plantar and dorsal digital nerves; the needle is introduced at right angles to dorsal skin to one side of the metatarsal neck and a bolus of LA solution deposited, the needle is advanced through the intermetatarsal soft tissues towards the plantar aspect of the foot and a further bolus of LA solution deposited just deep to the dermoepidermal junction; the plantar tissues will blanch on delivery of the plantar LA bolus

  • ray block ILA to the medial and lateral aspects of a metatarsal, as in intermetatarsal anaesthesia, in order to achieve ray anaesthesia

  • regional anaesthesia see field block anaesthesia

  • ring block anaesthesia see digital block anaesthesia

  • saphenous block injection ILA to saphenous nerve as it crosses the medial/ anterior ankle joint, superficial to the extensor retinaculum, in order to achieve anaesthesia of the medial/plantar longitudinal; the needle is introduced subdermally, medial to tibialis anterior tendon and directed towards the medial border of the ankle, parallel to the skin surface; LA is deposited as a 'sausage' in the subcuticular tissue between the anterior ankle and the medial malleolus

  • spinal anaesthesia reversible block of nerve transmission from all distal tissues by the introduction of local anaesthetic solution into the spinal cord subarachnoid space

  • superficial peroneal anaesthesia; medial dorsal cutaneous nerve anaesthesia ILA to the superficial peroneal nerve (medial dorsal cutaneous nerve) as it crosses the anterior ankle joint, superficial to the extensor retinaculum, to achieve anaesthesia of the majority dorsum of the foot (except the dorsal area of the first interdigital cleft); the needle is introduced subdermally adjacent to the extensor digitorum longus tendons, and directed towards the lateral border of the ankle, parallel to the skin surface; LA is deposited as a 'sausage' within the subcuticular tissue along the anterior ankle

  • sural nerve block anaesthesia ILA to the sural nerve as it crosses the lateral/ posterior ankle joint, superficial to the extensor retinaculum, to achieve anaesthesia of the lateral border of the foot and fifth toe; the needle is introduced subdermally behind the lateral malleolus and the tip of the needle aimed in the direction of the hallux

  • tibial block anaesthesia ILA to the tibial nerve in order to achieve anaesthesia of the plantar surface; anaesthetic solution is deposited around the tibial nerve posterior to the medial malleolus; the needle should pass through the retinaculum to the posterior, directing the tip of the needle toward the little toe; injection into the adjacent tibial artery is avoided by aspirating the syringe before depositing LA solution

  • toe block anaesthesia see digital block anaesthesia

field block

(fēld blok)
Regional anesthesia produced by infiltration of local anesthetic solution into tissues surrounding an operative field.

block

1. an obstruction or stoppage.
2. regional anesthesia.

Arthur block
see segmental dorsolumbar epidural block.
bundle-branch block
a form of heart block involving obstruction in one of the branches in the bundle of His.
field block
regional anesthesia obtained by blocking conduction in nerves with chemical or physical agents.
block grazing
see rotational grazing.
heart block
impairment of conduction in heart excitation; often applied specifically to atrioventricular heart block. See also heart block.
inverted L-block
linear infiltration cranial and dorsal to the incision site; used for flank laparotomy in cattle and sheep.
block mating
mating of all the females in a group during a brief period, e.g. within the span of three estral cycles; a characteristic of seasonal animal farming.
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.
nerve block
regional anesthesia secured by injection of an anesthetic in close proximity to the appropriate nerve.
paracervical block
anesthesia of the inferior hypogastric plexus and ganglia produced by injection of the local anesthetic into the lateral fornices of the vagina.
parasacral block
regional anesthesia produced by injection of a local anesthetic around the sacral nerves as they emerge from the sacral foramina.
presacral block
anesthesia produced by injection of the local anesthetic into the sacral nerves on the anterior aspect of the sacrum.
ring block
regional anesthesia by the injection of local anesthetic in a complete circle around a limb of a horse, or the teat of a cow.
sacral block
anesthesia produced by injection of the local anesthetic into the extradural space of the spinal canal.
saddle block
the production of anesthesia in a region 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.
sinus block
sinus arrest.
vagal block, vagus nerve block
blocking of vagal impulses by injection of a solution of local anesthetic into the vagus nerve at its exit from the skull.
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