Introduction to Human Anatomy PDF

Introduction to Human Anatomy By Dr/ Abeer Madkour Mahmoud Lecturer of Human Anatomy and Embryology The human anatomy is the science of studying the various structures of the human body. The anatomical position: The anatomical position: - A person is st...

Introduction to Human Anatomy By Dr/ Abeer Madkour Mahmoud Lecturer of Human Anatomy and Embryology The human anatomy is the science of studying the various structures of the human body. The anatomical position: The anatomical position: - A person is standing erect and facing forward, with the eyes looking forward, - The upper limbs are by the sides, the palms of the hands are directed forward, - The lower limbs are together, the soles of the feet are on the ground, and the toes are pointing forward. The anatomical planes Four geometric planes are applied to the body in the anatomical position: -The median plane (median sagittal plane) is a vertical plane passing through the center of the body, dividing it into equal right and left parts. -A sagittal plane (paramedian) is any vertical plane passing through the body parallel to the median plane. It divides the body into unequal right and left portions. -The coronal (frontal) plane is a vertical plane situated at a right angle to the median plane. The coronal plane divides the body into anterior (front, ventral) and posterior (back, dorsal) parts. -The horizontal (transverse) plane lies at right angles to both the median and the coronal planes. A horizontal plane divides the body into upper (superior) and lower (inferior) parts.  Terms of Relationship and Comparison Median: any structure lying in the median plane.  Terms of Relationship and Comparison The terms anterior and posterior are used to indicate the front or back of the body, respectively. Medial: refers to a structure situated nearer to the median plane of the body than another. Lateral: refers to a structure that lies farther away from the median plane than another. (e.g., in the head, the eyes are lateral to the nose, and the nose is medial to the eyes). Superior: refers to a structure that is nearer to the vertex of the skull. Inferior: refers to a structure that is situated nearer the sole of the foot. Proximal: refers to a structure nearer to the attachment of a limb. Distal: refers to a structure farther from the attachment of a limb. Anterior (ventral) denotes the front surface of the body. Posterior (dorsal) denotes the back surface of the body or nearer to the back.  In describing the hand, the terms palmar and dorsal surfaces are used in place of anterior and posterior, respectively.  In describing the foot, the term plantar surface refers to the sole of the foot and dorsal surface indicates the upper surface. Superficial: refers to a structure closer to the surface. Deep: refers to a structure farther away from the surface. (e.g., the skin is superficial to the ribs, but the heart is deep to the ribs).  The terms internal and external are used to describe locations relative to the center of a structure or space. Internal is inside the structure, whereas external is outside the structure (e.g., the thoracic cavity is an internal space in the trunk of the body, whereas the skin is the external layer of the trunk). Ipsilateral: refers to structures on the same side of the body (e.g. the right thumb and right big toe are ipsilateral). Contralateral: refers to structure on the opposite side of the body relative to another structure (e.g. the right hand is contralateral to the left hand).  Terms Related to Movement: Flexion indicates bending or decreasing the angle between the bones or parts of the body occurring in a sagittal plane. For joints above the knee, flexion involves movement in an anterior direction. Extension indicates straightening or increasing the angle between the bones or parts of the body. Extension usually occurs in a sagittal plane.  Abduction is movement away from the midline of the body in the coronal plane (e.g., when moving an upper limb laterally away from the side of the body).  Adduction is movement toward the midline of the body in the coronal plane (e.g., when moving an upper limb toward the side of the body).  Circumduction is a circular movement that involves sequential flexion, abduction, extension, and adduction (as in the shoulder and hip joints).  Dorsiflexion describes the movement of the foot with flexion at the ankle joint (lifting the top of the foot superiorly).  Plantar flexion describes the movement of the foot with moving the sole of the foot inferiorly, as in standing on the toes.  Inversion and eversion are special terms used to describe certain movements of the foot. Inversion is the movement of the sole of the foot toward the median plane (the sole is facing medially). Eversion is the opposite movement of the sole of the foot away from the median plane, turning the sole laterally. The skin The skin provides:  Protection of the body.  Containment for the body’s structures.  Thermal regulation.  Sensation (e.g., pain) by way of superficial nerves and their sensory endings.  Synthesis and storage of vitamin D. The skin is the largest organ in the body. It is divided into two parts:  The superficial part, the epidermis, and  The deep part, the dermis. The epidermis  It is a keratinized stratified epithelium that provides a protective outer surface.  The epidermis has no blood vessels or lymphatics. The avascular epidermis is nourished by the underlying vascularized dermis. The epidermis  On the palms of the hands and the soles of the feet, the epidermis is extremely thick.  In other areas of the body, such as on the anterior surface of the arm and forearm, it is thin.  The dermis is composed of dense connective tissue containing many blood vessels, lymphatic vessels, collagen and elastic fibers, and nerves. The dermis of the skin is connected to the underlying deep fascia or bones by the superficial fascia. The appendages of the skin: 1- Nails 2- Hair follicles, 3- Sebaceous glands, and 4- Sweat glands. The nails  The nails are keratinized plates on the dorsal surfaces of the tips of the fingers and toes. The proximal edge of the plate is the root of the nail. Except for the distal edge of the plate, the nail is surrounded and overlapped by folds of skin known as nail folds. The surface of skin covered by the nail is the nail bed.  Hairs grow out of follicles, which are invaginations of the epidermis into the dermis. A band of smooth muscle, the errector pili, connects the undersurface of the follicle to the superficial part of the dermis.  Hairs are distributed over the whole surface of the body, except on the lips, the palms of the hands, the sides of the fingers, the glans penis and clitoris, the labia minora and the internal surface of the labia majora, and the soles and sides of the feet and the sides of the toes.  Sebaceous glands secrete an oily material (sebum) onto the shafts of the hairs as they pass up through the necks of the follicles. They are situated on the sloping undersurface of the follicles and lie within the dermis. Sebum is that helps preserve the flexibility of the emerging hair.  Sweat glands are long, spiral, tubular glands distributed over the surface of the body, except on the red margins of the lips, the nail beds, and the glans penis and clitoris