Dissection Tutorial Videos

Upon completion of this session, the student will be able to:

When writing anatomical terminology, one may save time and space through abbreviation. For instance: 

2. Identify and describe basic tissue types at the gross level.  Appreciate the relationships between development and the adult body structure, and recognize patterns repeated throughout the body.

While dissecting and viewing layers and structures within the human body, pay attention to the tissue types (eg, epithelial, connective, muscle, nervous) and explore their structure.   You should be able to recognize what tissue is found where.  For example: examine the differences in the connective tissue that makes up the deep fascia vs. the connective tissue that makes up the superficial fascia (aka subcutaneous tissue).  Notice the epithelial tissue of the skin vs. the epithelial tissue of the blood vessels.  How is the muscle tissue that makes up the pectoral muscles similar to and different from the muscle tissue that makes up the walls of the blood vessels?   What about the connective tissue that makes up bone?  How is it similar to connective tissue of tendons, fascia, fat, blood, and how is it different?

There are basic patterns that are present throughout the body – begin to notice these patterns and use them to predict what tissue types and what structures are found in specific regions of the body.  For example, epithelial tissue covers and lines structures, so you might predict that you would find epithelial tissue covering the body, lining the inside of blood vessels, and lining the gut tube. How does the function relate to the structure?  Again, using epithelial tissue as an example, the primary functions are protection, secretion, absorption, and filtration.  Does it make sense that you would find epithelial tissue covering and lining structures? 

What kinds of connective tissue do you find?  There is loose connective tissue and dense connective tissue; when would you expect to see what?  What about muscle tissue; what generalizations can you make?  Examples might be:  generally skeletal muscles attach to bone via tendons; the neurovascular structures supplying the muscle (ie, artery, vein, nerve) travel together and enter on the deep side of the muscle; fiber structure and direction relate directly to the function of the muscle.

From what germ layers do tissues develop?  There are three germ layers – ectoderm, mesoderm, and endoderm.  When exploring tissue types in the adult human body, think about their embryological origins – from what germ layer did this specific tissue derive?  For example, the epithelial tissue found in skin derives from ectoderm, while the epithelial tissue that lines the gut derives from endoderm.  What about skeletal muscle?  Connective tissue?  Understanding the development from embryo to adult human structure will inform your understanding of how and why certain patterns are repeated throughout the body.

3. Define "anatomical position". Using conventional anatomical terms, describe the body and the spatial relationships of its parts. 

Anatomy has an international vocabulary that is foundational to medical terminology.  This nomenclature allows precise communication among health professionals —as well as among the basic and applied health sciences— when communicating about issues related to the human body.

All anatomical descriptions are expressed in relation to the anatomical position.  Anatomical position describes a common position for people (regardless of the actual position a person may be in) from which to describe to where in the body one is referring.   The position is as if the person is standing erect with:

• • • head, eyes and toes pointed anteriorly (forward)

    • upper limbs by the sides with palms facing anteriorly

    • lower limbs together with toes directed anteriorly

From this position, one can describe the position of one structure or part of the body relative to other structures or parts.  Examples of directional/description terms are: superficial/deep, medial/lateral, superior/inferior, cranial/caudal, anterior/posterior, proximal/distal, dorsal/ventral.

• • • Medial: indicates that a structure is nearer to the median plane (midpoint) of the body. Lateral: indicates that a structure is farther away from the median plane. (The eyes are lateral to the nose.)

    • Posterior (dorsal): denotes the back surface of the body, or a structure nearer to the back. Anterior (ventral): denotes the front surface of the body, or a structure nearer to the front. (The sternum is anterior to the vertebral or spinal column.)

    • Proximal, distal: are relative terms that are used when contrasting positions with respect to each other. Proximal is nearer and distal is farther. (The wrist is distal to the elbow.)

4. Describe common anatomical planes used to describe the human body. 

There are four imaginary planes that intersect the body in the anatomical position.  They are median, sagittal, frontal, and transverse.

• • • Median plane:  is the vertical plane passing longitudinally through the body midline, dividing into right and left halves.

    • Sagittal planes: are vertical planes passing through the body parallel to the median plane.

    • Frontal (coronal) planes: are vertical planes passing through the body at right angles to the median plane, dividing it into anterior and posterior portions.

    • Transverse (horizontal) planes: are planes passing through the body parallel to the floor (as one stands in anatomical position), dividing the body into superior and inferior portions. 

5. Describe the general structural plan of the body with regard to the layers one encounters when dissecting from superficial to deep in any particular region.

In your study of human anatomy, you will be studying the structure of the human body.  The structure of the body is the setting in which all of the events (or the functions) of life occur.  The two, structure and function, are intimately linked with one closely informing the other – look for these links throughout your study and use them to create mental maps and a framework for understanding, predicting, and solving when and why things may go wrong.

The study of the structure of the human body can be organized around either the structures within a region or the structures associated with a system.  We will do both.  The curricular structure of the foundational trunk is organized around systems – the study of the body’s organ systems that work together to carry out complex functions.  For example: the integumentary system, the skeletal system, the nervous system, the cardiovascular system, the renal system.  In describing the structure of the human body, you should be able to describe the general structure of the system (and its parts) you are studying; eg, the general structure of the heart and vessels that circulate blood through the body, the general structure of the urinary system including the gross level structure of the kidneys, the ureters, and the bladder.  This view, the study of the structure of organ systems, allows for links between structure and function to be more easily seen.  However, studying anatomy from a regional approach (ie, the structures found in one region of the body) allows you to appreciate and understand the interrelationships between structures and how one system (or structure) can impact the function of another, often because of its proximity or spatial relationship to the other.  This view is particularly important for clinical medicine within the context of physical exam, surgical procedures, image-based diagnosis.  

The body is made up of several regions:  head, neck, trunk (divided into thorax, abdomen, back, pelvis, perineum), upper limbs, and lower limbs.  All of these parts may be further subdivided.  The body is also organized in layers.  The layers, from superficial to deep are:

• • • Skin: The integumentary system has several functions including: protection from water loss, excrete wastes, regulate temperature, synthesize vitamin D, and detect pain, temperature, pressure, sensation. The skin is composed of epidermis and dermis.  The epidermis is the thin, outer, impervious layer of stratified epithelium that provides the initial barrier to the external environment. It contains sensory nerve endings that sense pain, pressure, temperature, and other sensations. The dermis is the deeper, thicker layer that gives skin its strength. It contains hair follicles and the associated sebaceous glands and arrector pili muscles, ducts of sweat glands, blood vessels, and nerve endings.

• • • Subcutaneous tissue or fat (also known as superficial fascia): This layer is composed of loose connective tissue and fat.  It is variable in thickness throughout the individual body and between individuals.  The subcutaneous tissue contains the deep part of sweat glands, blood vessels, lymph vessels, and cutaneous nerves.

    • Deep or investing fascia: This layer, deep to the subcutaneous layer, is made up of dense connective tissue that envelopes the body and extends and invests other structures throughout.  For example, this layer envelopes or surrounds muscles (and sometimes called “muscular fascia”), extends between to compartments of muscles in the limbs to form “intermuscular septa”, surrounds neurovascular structures, and partitions the body into regions and compartments.  Fascial planes are formed between adjacent fascias or between fascial lined structures.  In living people, there is no space in these planes, but there is a potential space that could come to contain something (eg, blood, fluid, infection) and could be used as a route of transportation from one area to another.   Surgeons also use these planes to separate and access structures in the body.

      • • • Neurovascular bundle: veins, arteries, lymphatic vessels, and nerves often travel together in these bundles.  The vessels are wrapped in deep or investing fascia.  They vary in size and do not always have all four elements.

    • Skeleton: The deepest layer in the limbs is the bone.  Bones provide protection, support, and allow for movement.  There are markings on bones that are associated with the stresses applied to the bone via attachments of tendons, ligaments, and/or fascia.  There are also holes (foramina) allowing vessels and nerves to pass through and/or supply the bones themselves.

    • Cavity:  The deepest layer in the trunk is the body cavity. On the deep side of the muscular wall creating the cavity is deep fascia.  This fascia is often named for the region it is in; eg, transversalis fascia, endothoracic fascia.  The cavities are lined with a serous membrane sac.  In the abdomen it is called the peritoneum and in the thorax it is called the pleura (associated with the lungs) and the pericardium (associated with the heart).

Ultimately, your goal, in the study of anatomy, is to know what lies under the skin….

6. Identify bones, parts of bones, and various markings on bones as listed in the Osteology section of the List of Structures.

7. Identify the muscles of the pectoral region, including the general attachments (ie, origin and insertion), function, innervation, and blood supply of each. 

8. Identify the muscles of the superficial back region, including the general attachments (ie, origin and insertion), function, innervation, and blood supply of each.