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 prefix [retro-] has a Latin origin and means "posterior", "backwards", or "behind". The main use of this prefix in human anatomy and surgery is "posterior".

Applications of this prefix include:

retroesternal: posterior to the sternum, such as the heart or the internal thoracic vessels
retropharyngeal: posterior to the pharynx, as in the "retropharyngeal space", a potential space found posterior to the pharynx
retroperitoneal: posterior to the peritoneum, referring to abdominal organs found outside and posterior to the peritoneal sac, such as the aorta and kidneys
retrogastric: posterior to the stomach, as in the "retrogastric space", an area also known as the "lesser bursa"
• retroversion: a posterior rotation or turn. Usually refers to the posterior rotation of the uterus or a joint

Francois Poupart

This article is part of the series "A Moment in History" where we honor those who have contributed to the growth of medical knowledge in the areas of anatomy, medicine, surgery, and medical research.To search all the articles in this series, click here.

François Poupart (1661-1709). Physician, zoologist, entomologist, and anatomist, Francois Poupart was born in Le Mans, France. His origins were very humble and he studied Medicine in Paris as a very poor student.  He had great interest in entomology, studying the anatomy of insects. Poupart obtained his MD a the University of Reims and was a surgeon at the H?tel (hospital) Dieu. A naturalist, Poupart is known for having written a monograph on the anatomy of the leech.

His life is mostly unknown. Poupart died at the age of 48. His name is eponymically associated with the inguinal ligament, which he described in detail in 1705. Although this structure was originally described by Gabrielle Fallopius, it was Poupart who stated the function of the inguinal ligament as an attachment for the three lateral muscles of the abdominal wall.


1. "Two eponymous surgeons: Cowper and Poupart" Ellis, H. Brit J Hosp Med 2009 701:4 225
2. "The Anatomical History of the Leech" Poupart, F. Phil Transact 1697 19:722-726

No image available
*: There is no known image of Francois Poupart that we could find. If you have any source, please let us know through our "Contact Us" form.


The word [pinna] is Latin and means "feather". It also means "wing". The variation [penna] as in the case of [pennate], means "winged". It refer to the external ear, or auricle. It appears that the use of the term [pinna] for ear arises from the ear-like or winged extensions of viking and medieval helmets.

The ear has three components, the internal, middle, and external ear. The external ear is composed of the external acoustic canal and the pinna. The pinna is composed of fibrocartilage covered with skin, and has several ligaments and small muscles related to it. These muscles are  extrinsic (between the pinna and the skull) and intrinsic (within the pinna) All these muscles have limited capabilities in the human.

The pinna receives blood supply from the anterior and posterior auricular arteries, and a small branch of the occipital artery. The nerve supply is by way of the great auricular nerve, the auricular branch of the vagus nerve, the auriculotemporal branch of the mandibular nerve, and the lesser occipital nerve.

Lateral view of the pinnaImages property of: CAA.Inc. Artist: Dr. E. Miranda

The external (lateral) anatomy of the pinna is complicated and very detailed, with potential anatomical variations. Click on the image for a higher detail. The medial aspect of the pinna presents elevations which correspond to the depressions (fossae) on its lateral surface and they are named, eminentia conch?, eminentia triangularis, eminentia scaphoides, etc.


The prefix [circum-] is Latin and means "around" or "about". It is used in medical terms such as:                            

Circumcision: the root term [-cis-] meaning to "cut". To cut around
Circumflex: the root term [flex] for [flexion] meaning to "bend". Bends around
Circumambulation: a patient that walks in circles

Also in everyday terms such as:

Circumlocution: to talk around a subject
Circumnavigation: To sail or navigate around
Circumscribe: to write in circles or around a subject

Flexion / extension

The word [flexion] comes from the Latin [flexere] meaning "to bend". In anatomy, flexion is the reduction in the angle between two bodily components that are communicated by a type of joint.

By contrast, [extension] refers to the opposite action, that is, the increase in the angle between two bodily components that are communicated by a type of joint.

The image shows flexion of the head, the upper extremity, and the lower extremity. Hover over the image to see extension of the same structures. 

Excessive flexion (hyperflexion) or extension (hyperextension) of a joint can lead to potential pathology as would be the case of hyperextension of the neck as a result of a car crash (whiplash injury)

Note that in a human in the anatomical position, flexion of the upper extremity is an anterior movement, while flexion of the lower extremity is a posterior movement. You could make a case that in these image the upper extremity is performing an anteflexion (anterior flexion) while the lower extremity is performing a retroflexion (posterior flexion). 

In the upper and lower extremities there are whole groups of muscles that, because of their action, are called flexors or extensors.

Vermiform appendix

The word [vermis] is Latin and means "worm". The term [vermiform appendix] means "the worm-shaped appendage", and refers to a worm-like appendage that is related to the cecum, a segment of the right colon.

This structure was first described by Jacobo Berengario da Carpi in 1524, and it was Andreas Vesalius who first described it as an appendix, and suggested it looked like a worm. It has been called the [vermix] and the [cecal appendix]

The vermiform appendix1 has the same four layers found in most of the abdominal digestive tract and is attached to the cecum at the point where the three tenia coli (libera, mesenterica, and omentalis) meet. The length of the vermiform appendix is variable. On average about 2.5 to 3 inches, it can be as long as 10 inches in length, with one recorded case of a 13 inch appendix!2

Terminal ileum, cecum, and vermiform appendix (www.bartleby.com)Original image courtesy of www.Bartleby.com

The location of the vermiform appendix is also subject to anatomical variation, being found in a retrocecal position in 65% of the cases. For more information on this organ's anatomical variations, click here.

The vermiform appendix is an intraperitoneal structure, as it has a peritoneal extension called the mesoappendix. Within the mesoappendix are the appendiceal arteries and veins. The appendiceal artery is usually a branch of the ileocolic artery.

1. It is not proper to call this structure the "appendix", as there are many appendices in the human body.
2. Personal note: The longest vermiform appendix I have personally seen was 8 inches (20.3 cm) in length, retrocolic, and the tip of the organ was actually retrohepatic!.  Dr. Miranda.