What Is Isthmus Of The Bone

Literary meaning of isthmus a narrow strip of land connecting two larger land areas, In anatomy isthmus indicates a narrow anatomical part or passage connecting two larger structures or cavities.

In bone, isthmus refers to the narrowest part of the bony canal.

The location of isthmus varies with the bone.

In femur, for example, it is located approximately at upper third and middle third junction.

Popularity: 1% [?]

What Is Bier Block?

Bier block is intravenous regional anesthesia which was originally introduced by  August K. G. Bier in 1908 and thus the name.

Bier bock  used in surgery of distal part of upper limb like wrist, hand and distal forearm. It is not useful in surgery around the elbow.

The main advantages of this technique are its simplicity and reliability.

Principle

With tourniquet tied intravenous anaesthetic agent like lignocaine is injected in previously exsanguinated limb. There is a  direct diffusion of the local anesthetic from the vessels into the nearby nerves as the drug is not distributed due to circulation blockage by tourniquet.

Peripheral nerve endings of the extremities are nourished by small blood vessels. Injection of a local anesthetic solution into a venous system results in diffusion of the local anesthetic into the nerve endings with the consequent development of anesthesia. The duration of the anesthesia and analgesia are limited by the duration tourniquet. [Read more...]

Popularity: 1% [?]

What Is Hematoma Block?

Hematoma block involves infiltration of local anaesthetic agent within the fracture.  This technique is frequently employed for anesthesia during reduction of distal radius fractures but also in some cases of forearm and leg fractures.

The infiltratiractureon of local anesthetic agent within the fracture serves to block the nerve fibers of the surrounding soft tissues and the periosteum around the fracture. Whenever a bone breaks, bleeding occurs at the site of the fracture and collection is fracture hematoma.

By injecting the local anesthetic into the hematoma, the ends of the broken bone are bathed in the local anesthetic providing  anesthesia to the area of the fracture. [Read more...]

Popularity: 1% [?]

What Is Jackson Table?

Jackson Table System is used to  perform a variety of spinal surgeries to allow patient positioning in supine, prone, lateral positions in a safe manner.

Jackson operating table has  no central table support like in float top tables [ Tables with central base support on which table rests, see video below to see supposrts on both ends of table in case of Jackson table to keep the central area free],  it is really easy to navigate the C arm under the table.

Another peculiarity of the table is being able to place the patient supine position and then flip the patient on the table  to make him/her prone.  This protects the patient from any neurological damage by keeping the spine stable during the turn. [Read more...]

Popularity: 1% [?]

Palmar Tilt of Distal Radius

Palmar Tilt represents the angle between a line joining the dorsal and volar margins of the articular surface and the long axis of the radius on a lateral xray.

Palmar TIlt of Distal Radius

Palmar TIlt of Distal Radius

It is also called Volar Angle or Radial Tilt.

The normal palmar tilt averages 11° and has a range of 2°-20°.

It is an important parameter in treatment of distal radius fractures.

Image Credit
http://www.radiologyassistant.nl/en/476a23436683b

Popularity: 1% [?]

What Is Herbert Screw?

A Herbert screw is a special purpose screw used to compress small fractures fragments. One of the unique feature of the screw is that it is threaded on the both sides. It is also called headless screw.

The screw was invented by Timothy Herbert.

Herbert Screw
Herbert Screw

One end of the screw has cancellous threads while the other end has larger diameter cortical screw threads. The cancellous screw is inserted first and crosses the proximal fracture, screwing into the bone of the distal fragment. As it is screwed in, the proximal cortical portion engages the proximal bone fragment.

Herbert screws are especially useful in articular fractures and small bones like scaphoid.

Because of difference in the pitch and the size of the threads, Each turn of the screw causes the distal end to travel farther into bone than the proximal end resulting in compression of the fracture.

Popularity: 1% [?]

Somato Sensory Evoked Potentials

Evoked potentials are the electrical signals generated by the nervous system in response to sensory stimuli.

Somatosensory evoked potentials consist of a series of responses [presented in wave form] that reflect sequential activation of neural structures along the somatosensory pathways.

Following stimulation sites typically used

  • Median nerve at the wrist
  • Common peroneal nerve at the knee
  • Posterior tibial nerve at the ankle.

The Test

Eectrical stimulation,  a square wave of 0.2- to 2-millisecond duration is delivered to a peripheral nerve by  surface electrodes or needle elctrodest at the usual sites.

Electrodes are placed over the Erb point [site at the lateral root of the brachial plexus located 2–3 cm above the clavicle] for recording upper extremities and  over the lumbosacral spine for lower extremity.

Wave morphology, amplitude, and dispersion is recorded. Depending upon latency of response, the potentials are described as short, middle and long latency somatosensory electric potentials.

Surgical monitoring

SEP monitoring is used during spinal surgeries especially scoliosis correction to recognize any harm caused to the cord. Ischemia of ascending somatosensory pathways produces a drop in amplitude or loss of waveforms, thus warning the surgeon in time to take corrective action.

Use

  • Diagnostic aid in neurological disorders
  • Intraoperative monitoring of surgeries that place parts of the somatosensory pathways at risk.

An abnormal somatosensory evoked potential can be due to problem [dysfunction] of

  • Peripheral nerve
  • Neural plexus
  • Spinal root
  • Spinal cord
  • Brain stem
  • Thalamocortical projections
  • Primary somatosensory cortex.

Diseases of the dorsal columns in which joint position sense and proprioception are impaired invariably are associated with abnormal somatosensory evoked potentials.

Popularity: 1% [?]

Erb’s Point

Also called punctum nervosum, Erb’s point is a a landmark of the brachial plexus on the upper trunk, located about 1 inch (2.5 cm) above the clavicle at about the level of the sixth cervical vertebra.

It is located on the posterior border of the sternocleidomastoid muscle midway between its attachments to the mastoid process, and the sternum and clavicle.

Erb’s point is formed by the union of the C5 and C6 nerve roots, which later converge. Branches of suprascapular nerves and the nerve to the subclavius also merge. The merged nerve divides into the anterior and posterior division of C5 and C6.

Injury to Erb’s point is commonly sustained at birth or from a fall onto the shoulder.

The nerve roots normally involved are C5 and partly C6. [Read more...]

Popularity: 1% [?]

Septicemia

Other term – Sepsis

Septicemia is bacteria in the blood (bacteremia) that often occurs with severe infections.It is a potentially life threatening condition.

It occurs with a known or suspected infection  whose signs and symptoms fulfill at least two of the following criteria of a systemic inflammatory response syndrome (SIRS) – [Read more...]

Popularity: 1% [?]

C Reactive Protein

C-reactive protein (CRP) is a protein found in the blood which rises in level in response to inflammation.

CRP was first discovered as a substance in the serum of patients with acute inflammation that reacted with the C- (capsular) polysaccharide of pneumococcus and thus the name.

It was discovered by Tillett and Francis in 1930 and is synthesized in liver.

 

A rise in CRP occurs as acute phase response  in a wide range of conditions like infections, inflammatory diseases, malignancy and autoimmune disordres. The levels of CRP rapidly increase within 2 hours of acute insult, reaching a peak at 48 hours. [Read more...]

Popularity: 1% [?]