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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
(1727–1759)

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.

Sources:
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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Hernia

UPDATED: The definition of hernia is "the protrusion of a deep structure through a superficial weakness of defect".

Herniation has many etiologies, but in all cases a weakness of a superficial containing wall  (usually layered) or a normal or abnormal opening (defect) must be present. A true hernia usually has a deep sac or hernia sac which contains the herniated viscus or viscera. Repair of a hernia is called a hernioplasty or a herniorrhaphy.

Although with exceptions, a herniation with only weakening of the walls and no hernia sac can be called a "prolapse", the suffix for prolapse (or hernia sometimes) is [-ocele].

Indirect inguinal hernia
• Omphalocele: From the Greek [omphalos] meaning "umbilicus", an omphalocele is a herniation through the umbilicus.
• Cystourethocele: A prolapse of the urinary bladder and urethra with a weakened vaginal wall

There are also "internal' hernias, between bodily compartments. Examples are:

Esophageal hiatus hernia: Known as a "hiatal hernia", this hernia is a protrusion of a peritoneal sac with abdominal visceral content into the thorax.
Perineal hernia: The protrusion of abdominopelvic content into the perineal region through a defect in the pelvic diaphragm (levator ani)

A hernia is usually named for the superficial region where it protrudes. An example of this would be a femoral hernia, which starts as an abdominopelvic extrusion, but it ends protruding in the area of the thigh (femoral region). Abdominal or ventral hernias are named according to the abdominal region through which they protrude.

in older times the word "rupture" was used as a synonym for "hernia", as can be seen in a letter written by Dr. Ephraim McDowell in 1829. The image shows an example of an indirect inguinal hernia. 

Original Image courtesy of: nih.gov