Download Anatomy terminology cheat sheet

1
Components of Musculoskeletal System
1.1
Bone
Bone is a living tissue that, because of its high mineral content, is resistant to decomposition and fossilizes
well. The skeletal system has many metabolic functions (producing red blood cells in marrow, acting
as a mineral reservoir), but we are primarily interested in the skeletalmuscle system that supports and
moves the body.
1.2
Joints
Joints are places where bones connect. They can be fixed and immovable (such as the mandibular and
pelvic symphyses, cranial sutures), or they can be capable of movement in a couple or many directions
(elbow and knee; shoulder and hip). The amounts and types of movement at a joint depend on the shapes
of the joint surfaces, the arrangement and action of muscles associated with the joint, and ligaments.
Ligaments are strong fibrous bundles of collagen, which stretch across joints and attach bone to bone like
cables. Joint surfaces are covered with a smooth tissue, cartilage, that cushions and lubricates movement
at the joint.
1.3
Muscle
All bodily movements are produced by the contraction of skeletal muscle across a joint. Muscles attach
to bone either directly or by tendons. Tendons are fibrous connective tissue allowing a bulky muscle to
attach to a small area of bone. Where muscles were attached to bone, they often leave distinctive marks
that provide important information on their size and orientation. Two terms you will often encounter
with respect to muscle anatomy are origin and insertion. Both terms refer to where a muscle attaches to
a bone or to other connective tissue.
2
Anatomical Vocabulary
Certain words must become part of your working vocabulary when describing positions of structures
and orientation of planes through a human body. Basic terms indicating anatomical directions are listed
below as numbered pairs of antonyms.
1. Dorsoventral axis:
(a) Ventral: the lower/belly surface of a body
(b) Dorsal: the upper/back surface of a body
2. Longitudinal axis:
(a) Anterior: towards the front of the body
(b) Posterior: towards the rear of an animal
(c) Cranial: towards the head of an animal
1
(d) Caudal: towards the rear of an animal
3. Transverse axis:
(a) Lateral: towards the side of the body
(b) Medial:towards the interior or middle of the body
4. Any axis:
(a) Proximal: a relative term meaning closer to the trunk of the body
(b) Distal: a relative term meaning further away from the trunk of the body
5. Planes and Sections:
(a) Transverse plane (cross section): from one side to the other
(b) Coronal plane (horizontal section): from head to tail, perpendicular to plane of bilateral
symmetry
(c) Sagittal plane (vertical section): from head to tail, parallel to plane of bilateral symmetry
3
3.1
Classification of Muscle Actions
Flexion/Extension:
Flexion is the term used to describe the bending of a part
or the making of an angle (in the sagittal plane), most easily
visualized in the bending of the knee or elbow. Extension
fundamentally means a straightening. In the anatomical position, most joints are in the extended position.
3.2
Abduction/Adduction:
Abduction is movement away from the central axis of the
body, adduction towards the body (movement in the coronal
plane).
3.3
Medial/Lateral Rotation:
Rotation towards the midplane of the body is medial rotation
and away from the body is lateral rotation.
3.4
Pronation/Supination:
The rotating movement of fore arm and hand. Pronation is
rotation so as to turn the palm downward or backward, while
supination turns the palm upward or forward.
2
Figure 1: Anatomical planes and terms.
3.5
Inversion/Eversion:
Eversion is the rotation of the foot so that the sole turns
outwards, while inversion is the opposite motion.
3.6
Circumduction:
Rotation in a circular motion.
Figure 2: Anatomical planes and terms continued.
3