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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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Trapezius

The [trapezius] is a bilateral muscle belonging to the superficial muscles of the back. On each side it is a flat, thin triangular muscle that spans the neck, shoulders and the superior and middle aspect of the back. When seen together these two triangular muscles form a diamond-shaped quadrangle from which its name derives. The word originates in the Greek [τραπεζι] meaning "a four-legged table" (four sides). This word later evolved into the New Latin [trapezium].

In the midline the trapezius muscle attaches to the inion (external occipital protuberance), the ligamentum nuch?, the spinous processes of the seventh cervical vertebra (vertebra prominens), and the spinous processes of all the thoracic vertebr?.

The trapezius’ muscle fibers have three orientations. From the midline the superior fibers course inferolaterally to attach to the posterior border of the lateral third of the clavicle. The middle fibers course laterally to attach to the medial margin of the acromion, and posterior border of the spine of the scapula. The inferior fibers course superolaterally to attach to the spine of the scapula by way of an aponeurosis.

Because of their attachments, the superior and inferior fibers of the trapezius act coordinatedly to rotate the scapula, while the middle fibers act to retract the scapula. The superior fibers also act to slightly elevate the scapula. The trapezius muscle is sometimes described as an accessory respiratory muscle.

The trapezius muscle receives muscular innervation by way of the spinal accessory nerve (11th Cranial Nerve) which courses on the deep aspect of the muscle along with the  superficial branch of the transverse cervical artery and vein. The muscle also receives sensory innervation by way of nerves arising from the ventral rami of the 3rd and 4th spinal nerves.

Image courtesy of Bartleby.com 

Posterior view of the superficial and intermediate muscle layers of the back (bartleby.com)
Posterior view of the superficial and intermediate muscle layers of the back (bartleby.com)