HUMAN ANAT OMY
Location Terms Anterior and posterior In human anatomical usage, anterior refers to the front of the individual. Similarly, posterior refers to the back of the subject. In standard anatomical position, the palms of the hands point anteriorly. So anterior is used to describe the palm of the hand, and posterior is used to describe the back of the hand and arm. Proximal and Distal The term proximal (Latin proximus; nearest) describes where the appendage joins the body. The term distal (Latin distare; to stand away from) is used for the point furthest from the point of attachment to the body. Since appendages often move independently of (and therefore change position in relation to) the main body, these separate directional terms are used when describing them.
Location Terms Deep & Superficial Deep: it lies deep to further away from the surface of the organism. Thus, the muscular layer is deep to the skin, but superficial to the intestines. Medial towards the midline Lateral away from the midline Superficial: near the outer surface. Thus, skin is superficial to the muscle layer. Intermediate: between two other structures. Thus, the navel is intermediate to (or intermediate between) the left arm and the contralateral (right) leg.
Movement Terms Abduction A motion that pulls a structure or part away from the midline of the body. In the case of fingers and toes adbduction is spreading the digits apart, away from the centerline of the hand or foot). Abduction of the wrist is called radial deviation. Raising the arms laterally is an example of abduction. A good example for the arm is the deltoid. Some leg abductors are the gluteus medius and the gluteus minimus. Adduction A motion that pulls a structure or part toward the midline of the body, or towards the midline of a limb. Dropping the arms to the sides, or bringing the knees together, are examples of adduction. In the case of the fingers or toes, adduction is closing the digits together. Adduction of the wrist is called ulnar deviation. The inner thigh houses some adductors, including the adductor brevis, adductor longus, adductor magnus, and pectineus. The latissimus dorsi is a good example for the arm.
Movement Terms Flexion Flexion Bending movement that decreases the angle between two parts. Bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed. Some knee flexors are the biceps femoris, semitendinosus, and semimembranosus. A couple elbow flexors are the brachialis, biceps brachii, and brachioradialis. Extension Extension The opposite of flexion; a straightening movement that increases the angle between body parts. In a conventional handshake, the fingers are fully extended. When standing up, the knees are extended. Extension of the hip or shoulder moves the limb backward (towards the posterior side of the body). Elbow extensors include the triceps brachii and anconeus. Flexion of the hip or shoulder moves the limb forward (towards the anterior side of the body). Good examples of hip flexors are the rectus femoris, sartorius, iliacus, and psoas. The main muscles that extends the hip is the gluteus maximus. The muscles that extend the knee are the quadriceps. They are the rectus femoris, vastus lateralis, vastus medalis, and vastus intermedius.
Movement Terms Internal Rotation Internal rotation (or medial rotation) of the shoulder or hip would point the toes or the flexed forearm inwards (towards the midline). For example the pectoralis major and subscapularis both medially rotate the humerus. The adductor longus and adductor brevis both medially rotate the thigh. External Rotation External rotation (or lateral rotation) is the opposite of Internal Rotation. It would turn the toes or the flexed forearm outwards (away from the midline). The sartorius laterally rotates the femur. The infraspinatus and teres minor both laterally rotate the humerus.