Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community, medical students, and the medical industry. We will post a workweek daily medical or surgical term, its 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

Johann Gottfried Zinn

Johann Gottfried Zinn

Anatomist and botanist, Johann Gottfried Zinn was born on December 6, 1727 in the city of Ansbach, Germany. He started his medical studies in his native city, becoming later a student of Dr.  Albrecht von Hallers at the University of Göttingen, and received his MD in 1749.

He left for Berlin to continue his studies but came back shortly thereafter. He became a professor of anatomy at the University of Göttingen and in 1753 he also became the director of the botanical garden in the same city.

He is known for his anatomical treatise on the anatomy of the human eye: “Descriptio anatomica oculi humani iconibus illustrata”. Because of this, his name has become an eponym in the “Zonule of Zinn”, a ring of strands that forms a fibrous band connecting the ciliary body with the capsule of the lens of the eye. Zonule of Zinn is sometimes referred to as the suspensory ligaments of the lens, or the “ligament of Zinn”. His name is also attached to the anular ring tendon found in the posterior aspect of the eye, the "anular tendon of Zinn". This ring serves as attachment for all the extraocular muscles of the eye and the optic nerve passes through the center of the ring.

Carol Linné (Carolus Linneaus) named a genus of flowers in the family Asteraceae known vernacularly today as “Zinnia” in his honor. Hover your cursor over his portrait to see the flower.

The chapter on orbital anatomy of his anatomy book, taken from the second edition in 1780, has been translated and the first of three parts is published in an issue of “Strabismus”

His book "Catalogus Plantarum Horti Academici Et Agri" can be seen online here.

His life was short, dying at the early age of 32, but his name lives on in the name of a beautiful flower.

1. “Johann Gottfried Zinn" Simonz, HJ Strabismus – 2004, Vol. 12, No. 2, p. 125 
2. "Anatomical Description of the Human Eye" Zinn, JG Strabismus, 13:45–52, 2005 
Images: Public Domain by Wikipedia Commons. 1. Own work I_am Jin, and H. Wilhem Dietz

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The term [aphasia] has Greek origins and means "without speech". This pathology was first described by Paul Broca who called it "aphemia".

Aphasia is a total and complete loss of speech. Lesser presentations of this condition should be called [dysphasias) from the prefix [dys-] meaning "abnormal", and  [phasia], meaning "speech".

Aphasia is the lack of spoken  speech due to cerebral cortex damage in the dominant brain hemisphere, usually the left side in right-handed individuals. There are two main areas of the brain involved in speech: Broca's and Wernicke's. Broca's area is responsible for speech expression (the spoken and written word). Damage to this area causes expressive or motor aphasia (or dysphasia).

Wernicke's area is responsible for the comprehension of speech, the understanding of language. Damage to this area causes receptive orsensory aphasia (or dysphasia). Broca's and Wernicke's areas are connected by an intrahemispheric tract known as the arcuate fasciculus (see image).

Broca and Wernicke's areas in the dominant brain hemisphere

Broca and Wernicke's areas in the dominant brain hemisphere

Complete loss of all communication abilities is called global aphasia. Other dysphasia pathologies are:

• Agraphia / dysgraphia: Incapacity / difficulty in writing
• Anomia / dysnomia: Incapacity / difficulty in naming objects
• Aphrasia / dysphrasia: Incapacity / difficulty forming phrases or sentences. The patient can communicate with single words, but cannot form sentences.

Image under copyleft agreement courtesy of The Brain from Top to Bottom
Thanks to  Margaret P. Tschimperle for suggesting this word.