Skeletal System Flashcards
Axial Skeleton
Head and trunk of vertebrate
Central axis of human skeleton
Appendicular Skeleton
Portion of the skeleton of vertebrates made up of bones that support appendages
80 bones
Axial Skeleton
126 bones
Appendicular Skeleton
206
Total number of bones
Functions Of Skeletal System
Support and Protection, Body Movement, Produce Blood Cells, Storage of Minerals and Fats
Epiphysis
The epiphyses are named according to their location.
The epiphysis closest to the body’s center is the PROXIMAL epiphysis.
The one that is farthest away is the DISTAL epiphysis.
Diaphysis
shaft of bone
Articular Cartilage
hyaline cartilage, padding
Periosteum
membrane that covers entire bone
Medullary Cavity
hollow chamber filled with bone marrow
Red Bone Marrow Function
blood
Yellow Bone Marrow Function
fat
Compact Bone Tissue
wall of the diaphysis
Spongy Bone Tissue
cancellous, epiphysis - red marrow
Pivot Joint
vertebrae in neck area
At a pivot joint, a rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone and partially by a ligament. The bone rotates within this ring. Since the rotation is around a single axis, pivot joints are functionally classified as a uniaxial joint. An example of a pivot joint is the atlantoaxial joint, found between the C1 (atlas) and C2 (axis) vertebrae. Rotation at this joint allows you to turn your head from side to side.
Hinge Joint
elbow
In a hinge joint, the convex end of one bone articulates with the concave end of the adjoining bone. This type of joint allows only for bending and straightening motions along a single axis, and thus hinge joints are functionally classified as uniaxial joints. A good example is the elbow joint, with the articulation between the trochlea of the humerus and the trochlear notch of the ulna.
Saddle Joint
thumb
At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other. This allows the two bones to fit together like a rider sitting on a saddle. Saddle joints are functionally classified as biaxial joints. The primary example is the first carpometacarpal joint, between the trapezium (a carpal bone) and the first metacarpal bone at the base of the thumb.
Ball and Socket Joint
hip
At a plane joint (gliding joint), the articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other. The motion at this type of joint is usually small and tightly constrained by surrounding ligaments. Based only on their shape, plane joints can allow multiple movements, including rotation. Thus plane joints can be functionally classified as a multiaxial joint.
Condyloid Joint
wrist
at a condyloid joint (ellipsoid joint), the shallow depression at the end of one bone articulates with a rounded structure from an adjacent bone or bones.
Functionally, condyloid joints are biaxial joints that allow for two planes of movement. One movement involves the bending and straightening of the fingers or the anterior-posterior movements of the hand. The second movement is a side-to-side movement, which allows you to spread your fingers apart and bring them together, or to move your hand in a medial-going or lateral-going direction.
Plane Joint
between tarsals
The joint with the greatest range of motion is the ball-and-socket joint. At these joints, the rounded head of one bone (the ball) fits into the concave articulation (the socket) of the adjacent bone. The hip joint and the glenohumeral (shoulder) joint are the only ball-and-socket joints of the body. At the hip joint, the head of the femur articulates with the acetabulum of the hip bone, and at the shoulder joint, the head of the humerus articulates with the glenoid cavity of the scapula. Ball-and-socket joints are classified functionally as multiaxial joints.
Flexion/Extension
Movements that take place within the sagittal plane and involve anterior or posterior movements of the body or limbs. For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward.
Ex: flexing arm
Abduction/Adduction/Circumduction
Adduction (condyloid, saddle, and ball-and-socket joints)
Moves the limb laterally away from the midline of the body
Abduction (condyloid, saddle, and ball-and-socket joints)
Brings the limb toward the body or across the midline
Circumduction (biaxial condyloid, saddle, ball-and-socket)
Movement of a body region in a circular manner, in which one end of the body region being moved stays relatively stationary while the other end describes a circle.
Rotation
Rotation can occur within the vertebral column, at a pivot joint, or at a ball-and-socket joint.
Medial (Internal) Rotation
Movement that brings the anterior surface of the limb toward the midline of the body
Lateral (External) Rotation
Rotation of the limb so that the anterior surface moves away from the midline
Supination/Pronation
Pronation is the motion that moves the forearm from the supinated (anatomical) position to the pronated (palm backward) position.
Supination is the opposite motion, in which rotation of the radius returns the bones to their parallel positions and moves the palm to the anterior facing (supinated) position.
Dorsiflexion/Plantar Flexion
Dorsiflexion and plantar flexion are movements at the ankle joint, which is a hinge joint.
Lifting the front of the foot, so that the top of the foot moves toward the anterior leg is dorsiflexion, while lifting the heel of the foot from the ground or pointing the toes downward is plantar flexion.
Inversion/Eversion
Inversion is the turning of the foot to angle the bottom of the foot toward the midline, while eversion turns the bottom of the foot away from the midline.
Protraction/Retraction
These are anterior-posterior movements of the scapula or mandible.
Protraction of the scapula occurs when the shoulder is moved forward, as when pushing against something or throwing a ball.
Retraction is the opposite motion, with the scapula being pulled posteriorly and medially, toward the vertebral column.
For the mandible, protraction occurs when the lower jaw is pushed forward, to stick out the chin, while retraction pulls the lower jaw backward.
Depression/Elevation
Downward and upward movements of the scapula or mandible.
The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders.
Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth.
Opposition/Reposition
Opposition is the thumb movement that brings the tip of the thumb in contact with the tip of a finger. Thumb opposition is produced by a combination of flexion and abduction of the thumb at this joint.
Returning the thumb to its anatomical position next to the index finger is called reposition.
Number of Bones in Cranium
22 individual bones
Only movable bone in cranium
The 22nd bone is the mandible (lower jaw), which is the only moveable bone of the skull.
