Structural KinesiologyKIN172

Functional Anatomy

• The study of muscles, bones, and joints involved in movement

How many bones in the body? - More than ½ in the hands and feet

How many muscles in the body?

Skeletal systems• 206 bones make up the skeletal system, which

provides:

• Bone: matrix of inorganic salts and collagen• Osteocytes: bone cells

– Osteoblasts: cells that create bone

- Osteoclasts: cells that resorb bone

Functions of the Skeleton• Leverage• Support• Protection (brain, internal organs)• Storage (fat and minerals)• Blood cell formation (hematopoiesis)*Critically important for movement

Skeleton may be divided into:

- The Axial skeleton - The Appendicular skeleton

Axial Skeleton

• Forms the axis of the body and supports/ protects the organs of the head, neck, and trunk

Skull Vertebral column Ribs Sternum Auditory ossicles ‘ear bones’

Appendicular Skeleton• Composed of the bones of the upper and lower

extremities and the bony girdles that anchor the joints of the axial skeleton.

• Shoulder and pelvic girdles

Reference Positions

Anatomical Position- All directional terms that describe the relationship of one

body part to another assume the body

is in the anatomical position

Subject standing with upright posture,

feet parallel and close,

palms facing forward Most commonly used

Directional Terminology

• Anterior In front, or front part Ex: The quadriceps is located at the anterior aspect of the thigh

• Posterior Behind, or back part Ex: The triceps are located

at the posterior aspect of the arm

Directional Terminology

• Proximal Nearest the trunk or midline Ex: The elbow is proximal to the wrist

• Distal Further away from the trunk or midline Ex: The distal aspect of the tibia is near

the ankle

Directional Terminology

• Superior Above, higher Ex: The head is superior to the shoulders

• Inferior Below, lower Ex: The shoulders are inferior to the head

Directional Terminology

• Lateral Farther from, outside Ex: The fibula is lateral to the tibia

• Medial Closer to the midline, inside The hip adductors are located medially

Planes of the Human Body

• Sagittal or Anterioposterior Plane Divides the body into left and right halves

• Frontal or Lateral Plane Divides the body into front and

back halves

• Transverse/horizontal plane

Divides the body into top and bottom halves

General Movements

• Abduction- lateral movement away from the midline of the trunk in the frontal plane.

• Adduction- movement medially toward the midline of the trunk in the frontal plane.

• Flexion- bending movement that results in a decrease in joint angle by bring bones together.

• Extension- Straightening movement that results in an increase of the joint angle by moving bones apart.

Movement of the ankle and foot

• Eversion- Turning the sole of the foot outward or laterally in the frontal plane; abduction.

• Inversion- Turning the sole of the foot inward or medially in the frontal plane; adduction.

• Dorsiflexion- Flexion movement of the ankle that results in the top of the foot moving toward the anterior tibia bone in the sagittal plane.

• Plantar flexion- Extension movement of the ankle that results in the foot and/or toes moving away from the body in the sagittal plane.

Types of Bones

• Long Bones- Long cylindrical shaft, which functions as levers

- Phalanges: bones of the toes and fingers- Metatarsals: arch of the foot- Metacarpals: fingers- Tibia and fibula: leg- Femur: thigh- Radius, ulna, humerus: upper arm and forearm

Types of Bones

• Flat Bones- Broad surface for muscle attachments or

protection of underlying organs- Ilium: “hip region”- Ribs, sternum, chest area- Clavicle: shoulder girdle, scapula- Cranial bones: head

Types of Bones

• Short bones- small, transfers forces and absorbs shock

carpals: wrist

tarsals: foot/ankle

• Irregular bones- many physical features for muscle attachments

vertebrae (24), sacrum, spine,

maxilla: facial bones

Muscles

Characteristics of Muscle• Irritability - Ability to respond to stimulation• Contractility - Ability to shorten when it receives

sufficient stimulation

• Extensibility- Ability to stretch/lengthen beyond resting length (protective mechanism)

• Elasticity– Ability to return to resting length after being stretched (protective mechanism)

Functions of Muscle

• Produce movement• Maintain postures and positions• Stabilize joints• Other functions

– Support and protect visceral organs

– Alter and control cavity pressure

– Maintain body temperature

– Control entrances/exits to the body

Gross structure of Muscle

• Epimysium – sheath covering the entire muscle

• Perimysium – sheath covering bundles of muscle fibers

• Endomysium - sheath covering individual fibers

• Myofibrils - strands of contractile filaments within muscle fibers

* Actin (thin filaments) and Myosin (thick filaments)

• Sarcoplasm- Cytoplasm of muscle cell

• Sarcoplasmic reticulum (within the sarcoplasm)

- Specialized endoplasmic reticulum of muscle cells

- Storage site for calcium

Fiber Type• Type I (Slow twitch)

- oxidative

- red (because of high myoglobin content)* myoglobin transfers O2- carried in the blood to mitochondria and act as O2 store in muscles

- fatigue resistant, contract slowly

- endurance athletes

• Type IIa (Fast twitch) - similar to Type 1, - high mitochondria content

- fatigue resistant, increased capacity to produce ATP

- distance runners, and endurance athletes

• Type IIb (Fast twitch)- white, low myoglobin, low mitochondrial content,

- high force production over short period

- high intensity events – weight lifting, sprinters, jumpers

Roles of Muscle

• Agonist: (prime mover) functions to cause a movement

• Antagonist: functions to resist movement

• Stabilizer: functions to fixate an area so another movement can occur

• Synergist: assist another muscle

• Neutralizer: functions to prevent undesired movement

Muscle Contraction

• Isometric: no change in muscle length during contraction

ex. Holding arms out to sides/ pushing against a wall

• Isotonic exercise (change in length )• Concentric: muscle length shortens during contraction

ex. Up phase of a sit-up

• Eccentric: muscle length increases during contraction

ex. Lowering phase of squat

• Isokinetic: speed constant during a movement/contraction