Medical Terminology Daily - Est. 2012

Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community. We post anatomical, medical or surgical terms, their meaning and usage, as well as biographical notes on anatomists, surgeons, and researchers through the ages. Be warned that some of the images used depict human anatomical specimens.

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A Moment in History

William S. Halsted, MD

William S. Halsted, MD
(1852 – 1922)

American anatomist, teacher, and surgeon, William Stewart Halsted was born in New York City, USA to a wealthy family of English origin. His father was involved in charitable work and Governor and trustee to a city hospital. Not a brilliant student initially, Halsted took an undergraduate in Liberal Arts in Yale, CT., after which he entered the Medical College of Physicians at the Columbia College, where he excelled.

As a second-year medical student Halsted applied and obtained a position in surgery at a local hospital. In here he learned about Lister’s antiseptic technique and became an adamant proponent of it to reduce infection. In 1877 Halsted obtained his MD. After a short time as House Physician at the New York Hospital, Halsted traveled to Europe to further his education studying for two years at the Universities of Vienna, Leipzig, and W?rzburg.

Besides being at the forefront of surgical and antiseptic techniques (introducing the use of rubber gloves in surgery), Halsted was extremely concerned with the way medical students were taught in the US. He pioneered bedside clinical round discussions with the medical students after two years of basic sciences studies. Halsted developed the idea of a patient chart; he also developed the residency program for medical students in use today.

Halsted is probably the most influential researcher and surgeon at the turn of the century. He dedicated time to the study of intestinal anastomoses and the use of silk as a suture material. His experimental work in 1887 proved that the inclusion of the submucosa layer in an anastomosis was mandatory, as well that a single layered anastomosis was enough to attain closure. Perhaps Halsted’s most important contribution was the application and use of the scientific method to surgical questions. Halsted’s principles, also known as  "Halsted's Rules of Surgery", set the standards used today in surgical suturing and surgical stapling.

He also pioneered the development and surgical techniques for radical mastectomy as a treatment for breast cancer.

As a side effect of this studied in anesthesia and the use of cocaine for anesthesia, Halsted became addicted to this substance, a problem that followed him through the years. Without impairing his capacity as a researcher and a surgeon, Halsted eventually recovered. He died in Baltimore in 1922 as a complication to surgery.

Sources:
1. Dubay, A. D., & Franz, G. M. (2003). Acute Wound Healing: The Biology of Acute Wound Failure. Surg Clin NA, 83, 463-481.
2. Halsted, W. S. (1887). Circular Suture of the Intestine - An Experimental Study. Am J Med Sci, 436-461.
3. “William Stewart Halsted: his life and contributions to surgery” Osborne, P. Lancet Oncol 2007; 8: 256–65
4. “William Stewart Halsted: Surgical pioneer” Burress, P Endoc Today (2010), 8: (2) 22
5. “William Stewart Halsted (1852–1922) Neurological stamp” Haas, LF J Neurol Neurosurg Psych 2000;69:641
Original image courtesy of "Images from the History of Medicine" at  www.nih.gov


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Normal electrocardiogram - sinus rhythm
Sinus rhythm electrocardiogram

Sinus Rhythm (SR), also known as Normal Sinus Rhythm (NSR) is the term used to denote normal cardiac activity. A normal beating heart is in sinus rhythm.

In the normal beating of the heart the left and right atria contract almost simultaneously, followed by the contraction of the left and right ventricles. These atrial and ventricular contractions are separated by a lag time of 1/10th of a second which allows the atria to relax (atrial diastole) while the ventricles contract (ventricular systole). The addition of the normal action of the four heart valves (tricuspid, mitral, aortic, and pulmonary) allows the heart to work as a blood pump and circulate blood within the heart and through the body and lungs.

NSR is coordinated by a complex set of structures. The first part is the conduction system, composed of heart muscle cells (cardiomyocytes) which are characterized by automaticity. It is important to state here something that is known, but many times ignored: The conduction system is not composed of nerves... it is formed by specialized cardiac muscle cells! The description of this cardiomyocyte-based system can be read in a separate article here.

The second component is the cardiac autonomic nervous system (CANS), which acts as a moderator (accelerating or slowing) the cardiomyocyte-based conduction system. The CANS has two components, an extrinsic component formed by nerves and ganglia outside the heart, and an intrinsic component of nerves and ganglia that forms a complex network within the superficial aspect of the heart muscle and fat surrounding the heart. These are the cardiac ganglionated plexuses, and their dysfunction can cause abnormal heart rhythm.

Both these systems, the conduction system, and the CANS form a complex cardiac rhythm control system. For more information click here.

When these two components and their thousands of cardiac muscle cells, ganglia, and nerves are working property, the heart is in sinus rhythm, and beats between 60 to a 100 times per minute.

Personal note: The term Normal Sinus Rhythm (NSR) is redundant. By definition, if the heart is in SR, it is normal. On the other hand, the term Abnormal Sinus Rhythm is also not correct… if the heartbeat is abnormal, the heart is not in SR! (Dr. Miranda)