Biomechanics -- All Terms

Closer to the head

Superior

Farther from the head

Inferior

Toward the front of the body

Anterior

Toward the back of the body

Posterior

Toward the midline of the body

Medial

Away from the midline of the body

Lateral

Closer to the trunk

Proximal

Away from the trunk

Distal

Toward the surface of the body

Superficial

Inside the body, away from skin surface

Deep

Moving away from midline of body or body part

Abduction

Moving toward the midline of body or body part

Adduction

Moving to the superior position

Elevation

Moving to the inferior position

Depression

Turning about the vertical axis of the bone

Rotation

Rotating forearm laterally (palm faces front of body)

Supination

Rotating forearm medially (palm faces back of body)

Pronation

Turning the foot in toward the center

Inversion

Turning the foot out to the hip

Eversion

Pointing toes

Plantar Flexion

Lifting toes while keeping heel on ground

Dorsiflexion

Circumscribing a conical area, involving flexion, abduction,

extension, and adduction in sequence

Circumduction

Joints connected by fibrous tissue with no joint cavity.

Bony surfaces are immovable or have very little

movement relative to one another. (i.e. tib-fib joint)

Fibrous

Joints in which cartilage (ex. fibrocartilage or sometimes hyaline)

exists at the interface but there is no joint cavity.

Bony surfaces are immovable or have some

movement relative to one another.

Cartilaginous

Allow for a large degree of relative motion

between the opposing bones and contain a joint

cavity. All are diarthrodial (freely moveable).

Synovial

Freely movable joints

Diarthrodial

Synovial joins have a lone of this type of cartilage layering the ends of the involved bones.

Articular

Synovial joinds are encloused by a strong…

Fibrous capsule

This membrane lines the inner surface of a synovial joint capsule

Synovial membrane

T or F: Synovial joints have nerve fibers and blood vessels for the membranes.

True

latin word

meaning “purse” is a

flattened fibrous sac

lined by a synovial

membrane to reduce

friction

Bursa

An elongated bursa that wraps around a tendon

Tendon sheath

Synovial joints, but another name

Diarthrodial

Ball and socket (shoulder)

Enarthrodial

Condylid (wrist)

Ellipsoidal

Gliding (intercarpal joints)

Arthrodial

Hinge joint (elbow, knee)

Ginglymus

Pivot (radius to ulna joint)

Trochoid

Saddle (thumb joint)

Sellar

Type of Cartilage
– Distribution of loads over joint surface

– Improvement of fit of articulating surfaces (femoral

condyles and tibial plateau)

– Limitation of bone slip within joint

– Protection of periphery of articulation

– Lubrication

– Shock absorption

Fibrocartilage

Type of Cartilage
Dense, white connective tissue that provides a protective

lubrication.

– 1-5 mm thick (varies depending on anatomical site)

– Coats the ends of articulating bones in diarthrodial joints

– Load support via the thickness, surface contour, and material

properties

Articular

Type of Cartilage
Larynx, epiglottis, external ear

Elastic

Three main mechanical functions for bones with musculoskeletal system

Structure, protection, movement

Bone material constituents that help with stiffness and compressive strength.

Calcium carbonate; calcium phosphate

Bone material constituents that help with tensile strength.

Collagen

All bone material consituents

Calcium carbonate, calcium phosphate, collagen, water

Compact, mineralized connective tissue with low porisity

Cortical bone

Type of bone tissue most likely found in the shafts of long bones

Cortical

Type of bone tissue categorized by less compact mineralized connective tissue with high porosity.

Trabecular

Type of bone tissue most likely found in the ends of long bones

Trabecular

Type of bone tissue most likely found in the vertebrae

Trabecular

Type of bone tissue that makes up 80% of skeletal mass

Cortical

Type of bone tissue that makes up 20% of skeletal mass

Trabecular

Type of bone tissue that can withstand greater stress

Cortical

Type of bone tissue that can withstand greater strain

Trabecular

Characteristic that describes a material’s different mechanical properties depending on direction

Ansiotropy

Equation for internal stress (Tension)

σ = P/A

Equation for internal stress (Compression)

σ = -P/A

Equation for internal stress (Shear)

τ = V/A

Equation for internal stress (Bending)

σ = Mc/I

Equation for internal stress (Torsion)

τ = Tc / J

“Bone adapts (remodels) in response to the mechanical loads placed on it.”

Wolff’s Law

Number of bones in the adult body

206

Number of bones in the axial skeleton

80

A shallow, dish-shaped depression in a bone that can

serve as an articular surface or as a muscle

attachment.

Fossa

A bony prominence (i.e. the protruding part of the scapula)

Process

A rounded projection of bone to which a ligament,

tendon, or muscle attaches; usually created or

enlarged by the stress of the muscle's pull on that

bone during growth. Usually roughened.

Tuberosity

A rounded process or projection of a bone that

articulates with another bone (i.e. the round part of a “cartoon” bone)

Condyle

A small condyle (usually a site for muscle/ligament

attachment) on or near a condyle

Epicondyle

Blunt irregularly shaped bony projection (femur)

Trochanter

A small, fairly flat, smooth surface of a bone, that is

usually an articular surface

Facet

A hole in a bone through which nerves or vessels pass (i.e. holes in the pelvis)

Foramen

Functions of Muscle

Movement, posture, joint stabilization, heat generation

Muscles aid the skeleton by…

Distributing load, absorbing shock, bone mobility (at joint)

Two types of skeletal muscle activity

Dynamic, static

Static activity

Maintain posture

Dynamic activity

Body movement

Smallest bit of a muscle that can contract

Motor unit

(Less/More) muscle fibers making up a motor movement increases the degree of contractility.

More

Slow Oxidative Fibers

• Aerobic

  • Quick bu

Pennate Fiber Arrangement

• Run obliquely

• Angled & shorter fibers

• Smaller range of shortening

• More powerful

Parallel Fiber Arrangement

• Fibers parallel to muscle

• Greater range of shortening

• Longer fibers

Force transmission of this arrangement is dependant on the angle.

Pennate

Force transmission of this arrangement is always 100%

Parallel

___________ arranged fibers shorten more and have greater range of motion, but the ________ arrangement is more powerful.

Parallel; penate

Concentric

Contracting involving muscle shortening

Isometric

Contraction involving no change in muscle length

Eccentric

Contraction with muscle lengthening

Lowering a weight during a bicep curl.

• Concentric

• Isometric

• Eccentric

Eccentric

Raising a weight during a bicep curl.

• Concentric

• Isometric

• Eccentric

Concentric

Agonist

muscle primarily responsible to cause a movement

Antagonist

opposes prime agonist’s action and cause movement in the opposite direction; act to control or stop a contraction of a primary mover

Agonists and antagonists are typically paired an __________ sides of a joint.

Opposite

Stabilizer

role played by a muscle acting to stabilize a body part/segment against another force (holds a body part immobile while another body part is moving)

Neutralizer

role played by a muscle acting to eliminate an unwanted action produced by an agonist (acts to prevent undesired motion)

Origin

the less moveable attachment of a muscle

Insertion

more moveable attachment of a muscle

The (insertion/origin) is pulled toward the (insertion/origin).

Insertion, origin

The origin is ________ (direction) to the insertion.

Proximal

(Ligaments/Tendons) are weaker and less stiff than (Ligaments/Tendons)

Ligaments, tendons