The anatomical position is the body position used as a reference when describing anatomical structures. In this position, the body stands upright, faces forward, and has arms at the side, palms facing forward, legs parallel, and feet pointing forward.
Annular ligament of radius - ligament encircling head of the radius that connects it to the ulna - Origin for forearm extensor muscles
Anterior means in front of. An anterior view shows the front of the structure.
Ex: The sternum is anterior to the heart.
Articulate means to form a joint with another bone.
Ex: The humerus articulates (forms a joint with) the scapula.
A ball-and-socket joint is a synovial joint where the ball-like (spherical) head of one bone fits into a socket (cup-like structure) of another bone.
Ex: Your shoulder is a ball-and-socket joint.
Cervical refers to the neck.
Ex: The cervical vertebrae are in the neck.
Coccygeal refers to the coccyx, also called the tailbone.
Ex: The coccygeal vertebrae comprise the coccyx.
The coccyx, also called the tailbone, is an irregular bone at the very bottom of the spine.
Circumduction is circular motion of a body part.
Ex: Your finger circumducts when it traces the outline of a circle.
Distal means farther from a reference point. The trunk of the body is assumed to be the reference point if none is given.
Distal is the opposite of proximal.
Ex: The radius is distal to the humerus.
Extension is a movement that brings two body parts farther apart in the sagittal plane (aka looking at the body in the anatomical position from the side).
Ex: Extension of the elbow brings the forearm farther from the upper arm.
Flexion is a movement that brings two body parts closer together in the sagittal plane (aka when looking at a body in the anatomical position from the side).
Ex: Flexion of the elbow brings the forearm closer to the upper arm.
Forearm extensors - extend wrist and fingers; assist in supination - Extensor carpi radialis brevis - Extensor digitorium - Extensor digiti minimi - Extensor carpi ulnaris - Anconeus - Supinator
Forearm flexors - flex wrist and fingers; assist in pronation - Flexor carpi ulnaris - Palmaris longus - Flexor carpi radialis - Pronator teres - Flexor digitorum superficialis
A hinge joint is a synovial joint that allows for movement in one plane (typically flexion and extension in the sagittal plane).
Ex: The elbow is a hinge joint that allows flexion and extension of your forearm.
The humerus is the long bone in the upper arm. It extends from the shoulder to the elbow.
Inferior means below. An inferior view shows the bottom of the structure.
Ex: The chest is inferior to the head.
Lateral means away from the midline. A lateral view shows the outer side of the structure, farthest from the body's midline.
Ex: The eyes are lateral to the nose.
Lumbar refers to the lower back, beneath the ribcage.
Ex: The lumbar vertebrae are in your lower back.
Medial means toward the midline. A medial view shows the inner side of the structure, closest to the body's midline.
Ex: The nose is medial to the eyes.
A structure's origin is where it begins. Not all structures have origins.
Ex: Your humerus's origin is your shoulder
The pelvis is the bony structure in your hip region. It connects your spine to your legs and supports the weight of your upper body.
A pivot joint is a synovial joint that allows for rotation.
Ex: The pivot joint between the C1 and C2 vertebrae lets you shake your head "no."
Posterior means behind. A posterior view shows the back of the structure.
Ex: The heart is posterior to the sternum.
Pronation of the hand and forearm is a rotation that makes the palm face downward. Pronation of the foot is the inward rolling of the foot during walking.
Ex: Your hand is pronated when it lays palm-down on a table.
Proximal means closer to a reference point. The trunk of the body is assumed to be the reference point if none is given.
Proximal is the opposite of distal.
Ex: The humerus is proximal to the radius.
Radial Collateral Ligament - ligament on lateral side of elbow running from lateral epicondyle of humerus to the annular ligament of the radius - Stabilizes elbow
The radius is the lateral bone of the forearm in anatomical position. It lies on the same side of the forearm as the thumb does.
Rotation is turning a body part around its long axis.
Ex: Your arm rotates when you turn a doorknob.
Sacral refers to the sacrum, the irregular, triangular bone at the bottom of your spine.
Ex: The sacral vertebrae comprise the sacrum.
The sacrum is an irregular, triangular bone at the bottom of your spine that forms the back of the pelvis.
The sagittal plane divides the body into left and right halves. This plane is commonly used to show movements that go forward and backward, like flexion and extension.
The scapula, also called the shoulder blade, is a flat, triangular-shaped bone in your upper back.
The sternum is a flat bone in the center of your chest that connects the ribs.
Superior means above. A superior view shows the top of the structure.
Ex: The head is superior to the chest.
Supination of the hand and forearm is a rotation that makes the palm face upwards. Supination of the foot is an outward rolling caused by placing weight on the outer edge of the foot during walking.
Ex: Your hand is supinated when it lays palm-up on a table.
A synovial joint is a fluid-filled capsule that connects two bones and allows for a large range of motion.
Thoracic refers to upper part of your torso (your chest and upper/mid-back).
Ex: The thoracic vertebrae are in your upper/mid-back.
The ulna is the medial bone of the forearm in anatomical position. It lies on the same side of the forearm as the pinky does.
Ulnar Collateral Ligament - ligament on medial side of elbow running from medial epicondyle of humerus to coronoid process and olecranon of ulna - Stabilizes elbow
The vertebrae are the bones in your spine. They are grouped into cervical, thoracic, lumbar, sacral, and coccygeal sections and are identified by the first letter from their section (except for coccygeal which is "Co") and their number from the top of the section.
Ex: The T4 vertebra is the fourth vertebra from the top of the thoracic section.