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First Edition: 2013

From very early days, teachers in anatomy have been concerned about how and how much of the human body should be dissected by a student within an allotted time frame. At present, the medical curriculum provides only 650 hours for the teaching of anatomy within the first 2 terms of the first-year of the MBBS course. Hence, this dissection manual is programmed in such a way that the dissection of the human body can be completed in a duration of 32 weeks, keeping in mind, the singular need to equip the medical student with clear anatomical concepts rather than getting lost in the intricacies of anatomical details; and, also, to ensure that each student, regardless of the institution attended, will gain fundamental level of competence required for the practice of medical profession.

The authors would like to thank Dr MAM Ramasamy, the Pro-Chancellor; Dr M Ramanathan, the Vice-Chancellor and Dr N Chidambaram, Dean (Faculty of Medicine), Rajah Muthiah Medical College, Annamalai University, Chidambaram, Tamil Nadu, India, for their continued support and encouragement in the preparation of the book.

Structures of the human body are always described in relation to the anatomical position. In this position, the body is assumed to be in the erect posture with the arms by the side and palms facing forwards.

The terms pre-axial and post-axial borders are used in reference to the margins of the limbs. The pre-axial border is in relation to the thumb and big toe while the post-axial border is in relation to the little finger and little toe.

The student engaged in dissecting the human body will come across various structures such as the skin, subcutaneous tissue (superficial fascia), deep fascia, muscles, tendons, blood vessels, lymph vessels and nodes, nerves, bones, etc.

When the deep fascia is removed, the dissectors will bare the ‘flesh’ of the body. This is commonly known as voluntary, skeletal or striated muscle. The muscles contribute to about 50 percent of the body weight. They are composed of muscle fibers.22

The fibers in individual muscles are arranged in different ways so that the muscles are often described as strap-like when the individual fibers are long and arranged in parallel, fusiform when a fleshy belly tapers towards both ends, often ending in tendon, and pennate when there is a resemblance to a feather. Pennate muscles are described as unipennate, bipennate or multipennate. These various types will be encountered during dissection. Muscles are usually connected at their ends to skeletal elements. These attachments of a muscle are usually described as its origin and insertion. The origin is generally the proximal attachment and is usually the fixed point from which the muscle acts so that the skeletal element into which it is inserted distally is able to move. Usually, the origins of muscles are fleshy and their insertions tendinous. The tendons are rounded cord like structures formed by condensations of fibrous tissue and possess great tensile strength. Sometimes, a tendon may be flat and thin and forms a broad sheet called an aponeurosis.

They are of three types—arteries, veins and capillaries. Arteries are thick-walled vessels which carry blood away from the heart to the tissues. Veins return the blood from the tissues to the heart. Intervening between the arterial and venous sides of the circulation are minute vessels called capillaries or exchange vessels as they are involved in exchanges of gases, nutrients and metabolites between blood and tissue. In the cadaver, the arteries appear paler and are palpably thicker, while the veins are bluish or dark in color with thin walls containing blood clot. Veins superficial to the deep fascia often run alone while those deeper to the deep fascia accompany arteries and are called venae comitantes.

The cells constituting the tissues of the body are bathed in fluid called the tissue fluid, which is derived from the blood plasma. The tissue fluid provides a medium for the transport of nutrients to the cells as well as for the removal of their waste products.23

The tissue fluid re-enters the blood circulation by a system of extremely thin walled channels called the lymph capillaries. They unite to form lymph channels which accompany blood vessels. The lymphatic channels lying superficial to the deep fascia generally accompany the superficial veins, while the deeper vessels accompany the arteries. The lymph vessels are not normally seen during dissection. During their course, they are interrupted by lymph nodes which contain discrete aggregation of lymphocytes which are a type of white blood cells. The tissue fluid in the lymph channels after filtering through lymph nodes is carried by lymphatic channels of increasing caliber which ultimately enter the large veins in the neck.

Nerves are usually found together with blood vessels forming what are known as neurovascular bundles. The nerves are actually collections of long process of nerve cells called axons. Axons covered by neurilemmal or Schwann cells which provide support and insulation to these axons are called myelinated nerve fibers. Axons not covered by Schwann cells are called unmyelinated fibers.

They form the major part of the human skeleton which provides the supporting framework for the body. Although they appear to be rigid, they are extremely plastic. During growth and repair, this plasticity is easily seen. Even at normal times there is a continuous turnover of its constituents. Bone is in fact an organ and not merely a tissue, since it has in its matrix, nerves, blood vessels and lymphatics like any other organ of the body.

Since this end of the diaphysis continues to grow in length after the opposite end has ceased its growth, it is called the ‘growing end’ of the bone.

Junctional regions between bones develop into joints. Joints can be classified as fibrous, cartilaginous or synovial, depending on the type of tissue present between the articular ends of the bones. Generally, fibrous joints permit very little movement, while synovial joints provide the greatest degree of freedom of movement. The cartilaginous joints form an intermediate group. However, there are exceptions to these general statements.25