This document provides an overview of basic human anatomy, including: 1) The organization of the body into anatomical positions, planes, and directions that are used as a reference. 2) Descriptions of the skeletal, muscular, nervous, and other body systems. 3) Explanations of basic joints, bones, muscles, and movements.

1. Intro To Basic Anatomy
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2. BASIC ANATOMY
Organization of the Body – Direction & Planes
• Anatomical position - body stands erect with
the arms at the sides, palms facing forward
• All body movements and location of anatomical
structures are referenced from this position
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3. Basic Anatomical Positions and Directions
• Inferior – toward the bottom
• Superior – toward the top
• Anterior – toward the front
• Posterior – toward the back
• Medial – toward the midline
• Lateral – away from the midline
• Proximal – closest to the trunk
• Distal – positioned away from the trunk
• Prone – lying face downward
• Supine – lying face upward
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4. • The body is divided into 3 imaginary planes of reference
• Sagittal plane – divides the body into right
and left sides
• Coronal (frontal plane) – divides the body
into front and back sections
• Transverse (horizontal) plane – divides the
body into top and bottom sections
• To determine the plane in which a
movement occurs, follow the bisecting line.
• Movements of flexion and extension
generally occur in the sagittal plane
• Movements of abduction and adduction
generally occur in the coronal plane
• Movement of rotation generally occur in the transverse plane
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5. Skeletal System
• Composed of bones (206), ligaments, and joints
• Main supportive structure of the body
• Axial Skeleton - skull, vertebral column, ribs, sternum, and hyoid bone
• Appendicular Skeleton – upper extremity (scapula, shoulder, arm and hand);
lower extremity (hip, femur, tibia, fibula, foot)
Articular System
• Articulation – a place of union between two or more bones, regardless of the
degree of movement permitted
• Ligaments – attach one bone to another
• Hyaline Cartilage – flexible connective tissue made up of collagen fibers that
line the bones of most joints, aids in smooth articulation of the joint
• Joints – articulating structures within the skeletal system; most serve the
purpose of bearing weight and providing motion
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6. Basic Body Joints
• Shoulder girdle – scapula, clavicle
• Shoulder joint – scapula (glenoid fossa), humerus
• Elbow joint – humerus, radius, ulna
• Wrist joint – radius, ulna, carpal bones
• Vertebral column – facet joints of the vertebrae, body-to-body via discs
• Hip joint – pelvis (acetabulum), femur
• Knee joint – femur, tibia, fibula
• Ankle joint – tibia, fibula, talus
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7. Basic Joint Movements
• Abduction – movement away from the body midline
• Adduction – movement toward the body midline
• Flexion – decreased angle between 2 structures
• Extension – increased angle between 2 structures
• Medial (internal) rotation – rotation of the vertical axis of a bone toward
the body midline
• Lateral (external) rotation – rotation of the vertical axis of a bone away
from the midline
• Circumduction - complete circular movement at the joint
• Pronation – medial rotation of the forearm (palms down position)
• Supination – lateral rotation of the forearm (palms up position)
• Plantar flexion – moving the foot downward , away from the shin
• Dorsiflexion – moving the foot upward, toward the shin
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8. Basic Joint Movements
• Shoulder horizontal abduction – moving the humerus across the body away
from the midline
• Shoulder horizontal adduction – moving the humerus across the body
toward the midline
• Scapular elevation – upward scapula movement (shrugging)
• Scapular depression – downward scapula movement
• Scapular abduction – scapular movement away from the spine
• Scapular adduction – scapular movement toward the spine
• Trunk flexion – anterior movement of the torso toward the pelvis
• Trunk extension – posterior movement of the torso toward the pelvis
• Foot eversion (pronation)– moving the sole of the foot outward at the ankle
• Foot inversion (supination)– moving the sole of the foot inward at the ankle
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9. Muscular System
• Muscles:
• compose 40-60% of body weight
• provide an important mechanism for maintaining joint stability
• Body movements occur as a result of muscle contractions pulling one bony
structure toward another
• Skeletal movement occurs at the joint structures within the body
• Three types of muscle tissue:
• Cardiac – involuntary (cannot be influenced at will)
• Smooth – involuntary
• Skeletal/Striated – voluntary
§ made up of long slender cells (fibers), with length greater than width
§ control body movements and maintain posture.
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10. Muscular System
• Musculoskeletal System – the skeletal and muscular systems working in
concert to provide body stabilization and movement
• Skeletal movement occurs at the joint structures within the body
• Tendon
• Indirect attachment of muscle to bone
• Distal structures of a muscle that transmits the force of the muscle contraction to bone
• Tendon attachments
• Origin – attachment closest to the body midline or axial skeleton
• Generally the fixed portion that provides a stable base during muscle contraction
• Insertion – attachment farthest from the body midline or axial skeleton
• Is drawn toward the origin during muscle contraction
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11.
Muscular System
• Muscles that control joint movements are aligned as agonists and antagonists
• Agonist – the muscle that causes a movement to occur (ex. biceps brachii
muscle flexes the elbow joint)
• Antagonist – the muscle that directly opposes an agonist muscle action (ex.
triceps brachii extends the elbow joint; must relax for elbow flexion to
occur)
• Reciprocal Inhibition – when an agonist contracts, the antagonist muscle must
relax
• Reciprocal inhibition allows joint movement to occur
• If this does not occur, then tetanus (a state of sustained contraction during
which the muscle does not relax to its initial length or tension) results in no
movement
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12. Muscular System
• Stabilizers – muscles that contract statically in one joint, so that movement
in an adjacent joint can occur
• Example – During walking or running, the hip abductor muscles of the
weight bearing limb contract to stabilize the pelvis so that it does not
drop to the non-weight bearing side
• Synergists – muscles that contract to eliminate an undesired joint action
in another muscle; can also be called "neutralizers" because they help
cancel out, or neutralize, extra motion from the prime mover
• Example – when the gluteus maximus contracts during hip extension, it
also attempts to externally rotate the hip; gluteus minimus and the
tensor fasciae lata contract to neutralize this movement
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13. Muscular System
• Strain –an over stretch or tear of a muscle or tendon
• Acute (instant or recent) strain of the musculo-tendinous structure
occurs at the junction where the muscle transitions into a tendon
• Occur when a muscle over-stretches or over-contracts, as with running or
jumping
• Symptoms may include pain, muscle spasm, loss of strength, and limited
range of motion
• Chronic (long-lasting) strains occur over time, from overuse or
repetitive stress, resulting in tendinitis (inflammation of a tendon)
• Example: tendinitis in the shoulder as the result of constant stress from
repeated tennis serves
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14. Muscular System
• Sprain –the over stretch or tear of a ligament or a joint capsule
• Sprains occur when a joint is forced beyond its normal range of motion,
such as turning or rolling the ankle
• Symptoms may include pain, inflammation, bruising and in some cases,
the inability to move a limb
• Sprains (ligament) and strains (muscle or tendon) are categorized according
to severity
• Grade I (mild) - involves a minor over stretch or minor tear
• Grade II (moderate) - partially torn but still intact
• Grade III (severe) – a complete tear; can result in joint instability
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15. Muscular System
• Hypertrophy – an increase in the cross-sectional size of a muscle fiber
(cell)
• Atrophy – the wasting or reduction of size of muscle, tissues, organs, etc
• Myalgia – muscle pain
• Myositis – inflammation of a muscle
• Fibrositis – inflammation of connective tissue within a muscle
• Tendonitis –inflammation of the tendon
• Fasciculation(muscle twitch) - small, local, involuntary muscle contraction
and relaxation visible under the skin
• Myoclonus - brief, involuntary twitching of a muscle or a group of muscles
• Spasm - a sudden involuntary contraction of a muscle, or a group of
muscles
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16. Muscle Contraction
• Muscle contraction – strength of contraction depends on the number of
motor units activated, stimulation frequency of the motor units, muscle
fiber length, and speed of contraction
• Types of Contraction
• Isometric (static)- muscle tension develops with no change in muscle length
and no joint movement; ex. carrying a heavy object
• Isotonic (dynamic) – muscle tension remains constant, muscle length changes
and movement occurs; contraction can be concentric or eccentric
• Concentric - force generated is sufficient to overcome the resistance, and the
muscle shortens as it contracts; this is what most people think of as a muscle
contraction
• Eccentric – the muscle lengthens as it develops tension, and contracts to control
motion against an external resistance; ex. lowering a load gently rather than
letting it drop
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17. Muscle Fibers
• Skeletal muscle contains a combination of fiber types that are classified as:
• Slow Twitch or Type 1
• Fast Twitch or Type IIa
• Fast Twitch or Type IIx
• Type I (slow twitch) fibers use oxidative metabolism
• Appear red due to the high concentration of myoglobin
• Generate a low level of muscle tension
• Have slow contraction times, are well suited for prolonged, low
intensity work
• Endurance athletes generally have a high quantity of slow-twitch fibers
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18. Muscle Fibers
• Type IIa (fast twitch) use oxidative and glycolytic metabolism
• Type IIa are also red
• An intermediate fast twitch fiber
• Tend to contract with a burst of force, then fatigue
• Can sustain activity for moderate lengths of time at higher intensities
• Examples - Type IIa fibers would be advantageous in gymnastics and
rowing
• Type IIx (fast twitch) use oxidative and glycolytic metabolism
• Type IIx appear white (absence of myoglobin)
• Provide rapid force production, but then fatigue quickly
• Provides greatest potential for power movements that rely on maximal
efforts
• Examples - sprinters, jumpers, shot putters, and Olympic weight
lifters benefit from Type IIx fibers
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19. Muscle Fibers
• Each muscle contains a combination of all three fiber types
• Percentage of fiber distribution varies considerably from muscle to muscle,
and person to person
• Distribution/proportion of fiber types in a given muscle determines that
muscle’s performance capabilities
• Fiber distribution influences how the muscle responds to training, and
ultimately how it develops
• The mode of training application will not alter a person’s fiber distribution;
however specific fibers within the distribution are enhanced by the type of
stimulus applied to the muscle
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20. Muscle Fibers
• When performing a series of repetitions during a resistance exercise
movement (such as a barbell curl) the slow twitch fibers are recruited first
• As the repetitions progress, and the effort becomes more intensive, more
fast twitch fibers are recruited
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21. Nervous System
• Group of tissue composed of highly specialized cells possessing the
characteristics of excitability and conductivity
• Regulates all functions related to human movement, as well as other bodily
functions
• Two types of cells
• Neuroglia – function in supportive, reparative, and metabolic
capacities
• Neurons – basic unit of the nervous system which conducts an
electrical impulse from one part of the body to another
• Two types of processes on each neuron:
• Axon - carries impulse away from the cell body
• Dendrites - carry impulse toward the cell body
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22.
Nervous System
• Neurons (cont.)
• Two types of functions:
• Afferent (sensory) – convey impulses from receptor cells in the
skin , tissues, or other organs to the spinal cord and brain
• Efferent (motor) - carry impulses from the spinal cord and
brain to effector cells (muscle fibers)
• Major Branches of the Nervous System
• Central Nervous System (CNS) – brain and spinal cord
• Peripheral Nervous System (PNS) – cranial and spinal nerves
• Autonomic Nervous System (ANS) – portions of the CNS and
peripheral nervous system, regulates organ function, blood flow, and
other involuntary functions
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23.
Nervous System
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24.
Central Nervous System
• Brain – largest mass of nervous tissue in the body, located in skull
• Cerebrum - largest portion of the brain which contains nerve centers
governing all sensory and motor activities
• Partially divided by median longitudinal fissure into two
hemispheres
• Each hemisphere divided by fissures into four major lobes: frontal,
parietal, occipital, temporal
• Cerebellum – occupies the posterior cranial fossa and consists of three
lobes
• Anterior: controls posture
• Posterior: controls coordination and movement
• Flocculonodular: controls equilibrium
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25.
Central Nervous System
• Spinal Cord – contains all ascending (afferent) and descending (efferent)
fiber tracts connecting PNS and ANS, and brain
• Anterior gray matter contains cell bodies from which efferent (motor)
fibers of the spinal nerves arise
• Posterior gray contains cell bodies from which afferent (sensory) fibers
pass toward brain
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26. Peripheral Nervous System
• Cranial Nerves – 12 pairs of symmetrically arranged nerves attached to the
brain
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27.
Peripheral Nervous System
• Spinal Nerves – 31 pairs:
• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal
• Four plexuses:
• cervical (C-1,2,3,4)
• brachial (C5,6,7,8,&T1)
• lumbar (L1,2,3,4)
• sacral (L4,5,S1,2,3)
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28. Dermatomes
• An area of skin
supplied by one pair
of spinal nerves
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29. Reflexes
• Reflex – an involuntary and nearly instantaneous movement in response to
a sensory stimulus
• Can be superficial (cutaneous stimulation), deep (tendon or
vascular tissue stimulation), visceral (organs), or pathologic
(abnormal)
• Generally serve to protect the body
• Indirect reflex arc – sensory impulse that is processed by a mediating or
internuncial neuron before being passed on to an anterior motor neuron
• Most reflexes are this type
• Example: receptors detect tension applied to a tendon by muscle
contraction; reflex arc results in inhibition of further contraction
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30. Reflexes
• Direct Reflex Arc – sensory impulse that passes directly to the anterior
motor neuron
• Monosynaptic (i.e. only one sensory and one motor neuron is
involved)
• Example: stretch or myotatic reflex
• Most important and prominent
• Leads to contraction of the muscle
• Prevents overstretching of the muscle
• Ex. knee jerk (stimulation of patellar tendon)
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31. Autonomic Nervous System
• Controls the visceral functions of the body
• Generally considered to be involuntary
• Links the control centers of the brain with the effector organs
• Overall function is to maintain homeostasis of the internal environment and
provide the “fight or flight” response
• Divided into the sympathetic and parasympathetic nervous divisions
• Sympathetic – more primitive, constricts blood vessels, involved in
“fight or flight”, stimulates activity
• Parasympathetic – more advanced, acts principally on smooth muscles
and glands in the gut, concerned with restorative processes, inhibits
activity
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32. BASIC ANATOMY
• Suggested Readings :
• 1. Jacob, SW and Francone, CA, Structure and Function in Man. W.B
Saunders, 5th Ed. 1982
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