“If a man is ignorant of the position of a vital nerve, muscle, artery or important vein, he is more likely to maim his patient or to destroy rather than save life.” Galen, De anatomicis administrationibus (translated by CJ Singer, 1956).
Anatomy is the study of the form of the body. The word “anatomy” is derived from the Greek word ‘anatome’ whose root means “to cut up” (tome) or “to dissect.” Within the context of human anatomy, it is typically applied to the study of cadaver-based morphology and applied in health related professions. Vesalius wrote the book De Fabrica (1543) that is generally recognized as the first anatomical atlas resulting from systematic and repeatable dissection method. He wrote in the text that anatomy “should rightly be regarded as the firm foundation of the whole art of medicine and it is an essential preliminary.” Human dissection remains firmly entrenched in medical education for many important reasons. It facilitates visualization and conveys a mental perception of a patient’s anatomy critical for proper diagnosis. Much of the surface anatomy information applies directly to the living patient and should be related to underlying structures in the cadaver.Interpretation of patient imaging, physical examination and invasive procedures all require a firm understanding of anatomy. The dissection process is particularly valuable in today’s approach of student-directed exploration and life-long learning that many educational programs embrace. Anatomical dissection is a constant process of generating questions and seeking solutions requiring “hands-on” activity. The student must accept responsibility for his/her education. However, cadaveric dissection also contributes other, possibly less obvious, educational values. It establishes a sense of teamwork and camaraderie among students since the exercise requires cooperation and interaction. The study of anatomy provides an important introduction to medical terminology that students will use throughout their careers. Dissection promotes hand-eye coordination requiring patience and meticulous observations that are important faculties for the development of an astute health-care worker. Dissection is the first time many students are exposed to death. The introduction to the human dissection provides an important opportunity for students to discuss death and what it means to each individual.
Gross Anatomy is a subdiscipline of Anatomy in addition to Embryology, Histology & Cell Biology, and Neuroanatomy. For a full appreciation and understanding of Gross Anatomy, the other subdisciplines provide important contextual information. For example, complex relationships of the abdominal peritoneum or the inguinal canal are readily interpreted when considered within the context of embryology. Thus, the student of Gross Anatomy will necessarily call upon critical information from the other anatomical subdisciplines.
Historically, Anatomy has been studied either systematically or regionally. Systematic approaches typically are implemented within integrative curricula where the body is studied according to various physiological systems, e.g. cardiovascular, digestive, neurointegrative, etc. Regional approaches follow contiguous subdivisions of the body, e.g., head and neck, thorax and back, upper limb, etc. This presentation will provide a brief introduction to system based anatomy followed by a regional approach for dissection.
The discipline of Anatomy serves as a cornerstone of the practice of medicine. However, its role in medical education has transformed over the years. Anatomical information provided the major source of knowledge necessary for the diagnosis and treatment of disease in the early days of medicine. However, the relevance of Anatomy has changed as knowledge necessary for the practice of medicine and clinical specialization has increased. Nonetheless, the study of Anatomy remains absolutely essential for the medical and allied medical student to establish a critical knowledge base for correct and safe application of the physical examination as well as delivery of health care through medical specialties. Anatomical conceptualization necessary to achieve these goals remains critically important and is best achieved through human dissection. The purpose of this presentation is to provide a guidebook for cadaveric dissection. It is intended to facilitate dissection that every student should perform.
This course will utilize plastinated specimens to supplement learning issues arising from the dissections. Plastination is a comparatively new tissue preservation method that has gained attention recently. This method functions to replace water and lipids in an anatomical tissue with a plastic polymer that is cured resulting in a highly durable, yet dry and odorless specimen. Numerous specific polymers are used to achieve the desired outcome in terms of tissue color, texture, and flexibility.
The purpose of this text is to achieve a conceptualization of anatomical information through a multimedia delivery system while also providing specific instructions for the corresponding dissection period. Each chapter comprises information representing one laboratory period. Sections are generally divided into the following sections: Objectives; Background, Laboratory Exercises, Assessment. The “Laboratory Exercises” section is performed by a group of students.
Gross Anatomy instruction at JABSOM occurs during the first 6 units (not including unit 5; click here for general schedule). For dissection sessions, each group should have a ‘reader’ who keeps his/her hands clean and reads the text verbatim and handles the plastinated specimens and computer. The other members of the group are responsible for dissecting and manipulating the anatomical structures with gloved hands. The ‘reader’ function should rotate among members of the group each week. The reader will encounter words in bold font. These structures should be identified either on the cadaver, with the use of prosections (previously dissected specimens) or individual students when considering surface anatomy concepts. Typically, bolded terms can be ‘clicked’ and representative illustrations, schematics, 3D models or animations will be presented. The reader will also encounter italicized terms. These structures are less likely to be seen, but should be conceptualized. Students should be prepared to understand all of the information in the text, but the words in bold font or italicized will aid the organization of concepts and achievement of the learning objectives listed at the beginning of each section. It must be emphasized that students are encouraged to consult multiple anatomy resources to assist in the identification of anatomical structures.
Remember, no two people are the same and you will likely see the “typical” example. However, arteries, nerves, and even bones will display variations on a theme. You are encouraged to view all donors in the lab so that you can begin to appreciate the difference between normal variation and anomalies as well as pathology.
Osteology, the study of bones, forms the basis of human anatomy. A fundamental understand enables learning of muscular function, anatomical spatial relationships of soft tissues and provides an underpinning of many diagnostic and therapeutic treatments. The laboratory is equipped with several skeletons as well as bone boxes at each station containing disarticulated bones. Osteology will not be covered as a separate topic and you are expected to learn the bones as well as their distinctive features and articulations on your own. Be sure to take time to review the corresponding bones of the anatomical region under study prior to initiating your dissection. In this way, you will be able to make more successful cuts and achieve more meaningful understanding. You are encourage to access the Introduction to Osteology component of the xrcore website (click here) and work through the laboratory exercises as indicated.
Surface anatomy is the external morphology of the body as well as projecting internal structures onto the body surface primarily for the purpose of phyhsical diagnosis. In gross anatomy, you should begin your dissection by examining the external surface of the Silent Teacher to identify contusions, surgical scars, and anatomical variations to provide insight into the subsequent dissections.
Percussion of the thorax serves to identify cardiac borders and valves in the living individuals and is an essential component of the physical examination. Trace out the surface projection of the heart visually and tactilely on your Silent Teacher using the pen provided (see the video below for a simple example of this process).
1. Begin by identifying the cadaver’s sternum, clavicle, and ribs 2-6 on the surface of the thoracic wall.
2. Identify and name all intercostal spaces (e.g., ICS 2 is located between ribs 2 and 3).
3. The areola and nipple lie at ICS 4 in the male (more variable in the female).
4. Visually and manually (with your finger) outline the borders of the heart.
5. The right border begins in ICS 2, approximately 2.5 cm lateral to the right sternal margin.
6. Proceed with your line parallel with the body of the sternum and inferiorly to the xiphoid process. This right border represents the lateral borders of the right atrium and ventricle.
7. The inferior border of the heart continues to the left side terminating at the apex of the heart which lies in ICS 5 and about 8-10 cm to the left of the midsternal line. At this point, one finds the point of maximum impulse (PMI) which has an approximate diameter of 2 cm. If larger or displaced left, ventricular hypertrophy, perhaps the result of aortic stenosis, may be indicated.
8. The left border ascends following a line superiorly and medially from the PMI and ending in ICS 2, approximately 2.5 cm from the left sternal margin.
9. A portion of the aortic arch projects onto ICS 1, just to the left of the manubrium.
Auscultation relies on the accurate placement of the stethoscope to detect heart sounds. Although cardiac valves are positioned deep to the sternum, bell placement occurs in adjacent ICSs since sound does not travel directly through bone. Use this illustration to identify the location of the heart valves as well as the correct placement of the bell.
1. This model is derived from an MR scan of a patient with cardiomegaly. Note that the apex is far lateral to the mid-clavicular line. The cardiac chambers have been segmented separately. Rotate the model and identify the structure indicated by #1:
2. This heart specimen is derived from the same Silent Teacher as the segmented heart from question #1. Appreciate the abnormally large oval shape of the heart. Contrast the thickness of the cardiac walls. Structure #2 is a segment of the cardiac wall from the:
3. Identify the structure indicated by #1 in this partially dissected heart.