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Myology Middterm

Three types of joints
Synarthroses (immovable)
Amphiarthroses (slightly movable)
Diarthroses (freely movable)
Synarthroses (immovable) -
3 types = SGS
Suture = skull
Gomphosis = teeth socket
Synchonrosis = growth plate of a bone
Amphiarthroses (slightly movable)
2 types = SS
Syndesmosis = distal jnt. btw. tibia/fibula
Symphysis = IVD btw vertebrae-btw pubic bones and pelvis
Diarthroses (freely movable)
6 Types = B/S, H, G, E, S, P
Ball and Socket, Hinge, Gliding, Ellipsoid, Saddle, Pivot
Ball and socket
one surface is spherical and the other is cup shaped. This allows movement in all directions. Ex: hip and shoulder joints
the convex surface of one bone fits against the concave surface of another bone in a clasping arrangement. Movement is in one plane of flexion and extension. Examples are the elbow, knee, DIP, PIP, and ankle.
both surfaces are essentially flat and movement is limited. Examples intercarpal joints, intertarsal joints, rib-vertebral joint, acromioclavicular joint
an oval shape of one bone fits into an elliptical cavity of the other. Movement in two planes which is flexion/extension and abduction/adduction. Examples are radio-carpal joint and the atlanto-occipital.
both surfaces are saddle shaped. Movement is in two planes flexion/extension andabduction/adduction. Example is the carpo-metacarpal joint of the thumb
a pointed or rounded surface of one bone fits into a ring like structure of another bone. Rotation is the chief movement. Example is atlanto-axial joint.
Production of movement
1. Skeletal muscles produce movement by exerting force on tendons, which in turn pull on bones or other structures such as the skin.
2. Most muscles cross at least one joint and are attached to the articulating bones that form that joint.
3. When this muscle contracts it draws one articulating bone toward the other.
4. The two articulating bones do no move equally; one is held nearly in its original position because opposing muscles contract pulling the bone in the opposite direction.
The attachment of a muscle tendon to the stationary base. The origin is usually proximal in the limbs
The attachment of the other muscle tendon to the moveable bone. Distal in limbs
the fleshy portion of the muscle between the two tendons of the origin and insertion
Types of Lever Systems
3 Basic Types
...1st, 2nd and 3rd classes
1st class lever
The fulcrum is between the effort and the resistance. An example is a see-saw or scissors - head resting on the vertebral column
2nd class lever
The fulcrum is at one end, the effort is at the opposite end, and the resistance is between them. example is a wheelbarrow
3rd class lever
the fulcrum is located at one end, the resistance at the opposite end, and the effort located in-between them.
most common lever located in the bodyexample is flexing the forearm, where the resistance is the weight of the forearm, the fulcrum is the elbow joint, and the effort is the contraction of the biceps muscle.
Most movements require several skeletal muscles acting in groups rather than individually.
Skeletal muscles are arranged in opposing pairs at joints (flexors/extensors, abductors/adductors).
prime mover; a muscle that causes a desired action
: muscle which has an opposite effect on the prime mover
muscle which serves to steady movements thus preventing unwanted movements and also help the prime mover to function more efficiently. Usually located along side the agonist.
muscle which stabilizes the origin of the prime mover so that the prime mover can act more efficiently.
Cranium: Consists of 8 bones
Face: Consists of 14 bones
Cranium: Consists of 8 bones
(1) Frontal Bone
(2) Temporal Bones
(2) Parietal Bones
(1) Occipital Bone
(1) Sphenoid Bone
(1) Ethmoid Bone
Face: Consists of 14 bones
(2) Maxilla
(2) Zygomatic bones
(2) Lacrimal bones
(2) Palatine bones
(2) Nasal bones
(2) Inferior nasal conchae
(1) Vomer
(1) Mandible
Frontal bone landmarks
Squama: flat portion that forms the forehead
Supraorbital margin: ridge under the eyebrow, forming the upper part of the orbit (eye socket)
Supraorbital foramen: small hole within supraorbital margin for blood vessels and nerves
Frontal sinuses: hollow spaces behind the squama, act as sound chambers to give the voice resonance.
Frontal bone landmarks
Temporal Bones Landmarks
Squama: flat portion of the temporal bone forming the anterior and superior part of the temple
External auditory meatus: opening to the ear canal
Mastoid process: bony prominence behind the external auditory meatus
Styloid process: looks like an elephant's tusk located between the mastoid process and the jaw. Acts as a point of attachment for muscles and ligaments.
Temporal Bones Landmarks
Temporal Bones Landmarks
Occiput Landmarks
Foramen magnum: large hole, allowing passage of the spinal cord.
External occipital protuberance (EOP): prominent projection on back of occiput.
Nuchal lines: a superior and inferior line running laterally from the midline, serve as a point of muscle attachment
Occiput Landmarks
Occiput Landmarks
Sphenoid Bone
butterfly-shaped bone at the base of the skull
Sphenoid Bone
Greater wings: large lateral projections of bone that help to form the lateral border of the skull
Lesser wings: smaller lateral projections of bone above the greater wings
Pterygoid processes: two long downward projections from the greater wings that act as a point of muscle attachment.
Sella Turcica: known as the Turkish Saddle which cradles the pituitary gland.
Sphenoid Bone
Ethmoid Bone
forms part of the posterior portion of the nose, the orbit, and the floor of the cranium
Ethmoid Bone