EHS 218 Occupational Ergonomics Anatomy

Basic Anatomic Positions Anatomic Position

Basic Anatomic Positions Anterior = front Posterior = back

Basic Anatomic Positions Medial = toward midline of body Lateral = away from midline of body

Basic Anatomic Positions Proximal = closer to attachment / trunk Distal = farther from attachment / trunk

Basic Anatomic Positions Palmar = palm side Dorsal = back side of hand

Basic Structures and Functions Bones, Ligaments, Tendons, Nerves, Muscles, and Joints

Bones Support weight and protect organs Body movements –1 st, 2 nd, 3 rd class lever systems Blood cell formation Storage of minerals

Ligaments Strong, flexible, stress resistant, somewhat elastic fibrous tissue Connect bone to bone Stabilize joints - resist movement for which joint is not constructed Guide motion

Tendons Connect muscle to bone Transmit force from muscle to bone Continuations of muscle tissue

Nerves Transmit and receive signals for movement and sensation Central nervous system, peripheral nervous system, autonomic nervous system

Muscles Composed of skeletal muscle tissue, nervous tissue, blood, and various connective tissues Only tissue that can shorten and produce tension at ends Generate force Create motion Muscle origins and insertions –origin is usually proximal or stabilizer –insertion is usually distal or mover

Major Muscle Groups Upper extremity Lower extremity Torso

Muscles of the Upper Extremity Shoulder and back –Deltoids –Trapezius –Latissimus dorsi Chest –Pectoralis major/minor Arm –Biceps –Triceps –Lower arm muscles

Deltoid

Trapezius

Pectoralis

Latissimus Dorsi

Biceps Brachii

Triceps Brachii

Lower Arm - Flexors

Lower Arm - Extensors

Muscles of the Lower Extremity Thigh –Quadriceps –Hamstrings –Abductors –Adductors –Gluteals Leg –Calf muscles

Quadriceps

Hamstrings and Gluteals

Calf Muscles

Muscles of the Torso Anterior torso –Abdominals Posterior torso –Erector spinae

Joints Shoulder, Elbow, Wrist/Hand, Hip, Knee, and Spine

Joints When 2 or more bones meet Functional junctions between bones Classified on basis of structure and movement –Fibrous, cartilaginous, synovial –Immovable, slightly moveable, freely moveable

Basic Joint Movements Flexion – angle between segments decreases Extension – angle between segments increases

Basic Joint Movements Abduction – segment moves away from midline of body Adduction – segment moves toward midline of body

Basic Joint Movements Dorsiflexion – point foot up Plantar flexion – point foot down

Basic Joint Movements Inward rotation – rotation toward midline of body Outward rotation – rotation away from midline of body

Basic Joint Movements Supination – palm facing upward Pronation – palm facing downward

Basic Joint Movements Circumduction - complete rotation about segment midline

Upper Extremity - Shoulder Bones - clavicle, acromion, scapula, humerous Muscles - rotator cuff (subscapularis, teres minor, infraspinatus, supraspinatus), deltoids, latissmus dorsi, triceps, biceps, pectoralis Nerves - brachial plexus located deep within the shoulder Type of joint - ball-and-socket (synovial)

Movements of the Shoulder Flexion and extension Horizontal flexion and extension Abduction and adduction Circumduction Internal and external rotation

Upper Extremity - Elbow Bones - humerous, radius, ulna Muscles –Flexors = biceps –Extensors = triceps Nerves - brachial plexus: musculotaneous, radial, ulnar, and median nerves pass through Joint type - hinge between humerous and ulna; sliding joint between humerous and radius (synovial)

Movements of the Elbow Flexion and Extension, Pronation and Supination (at hand)

Upper Extremity – Hand/Wrist Bones - radius, ulna, 8 carpal bones, metacarpals, phalanges Muscles –all originate from distal end of humerous radius/ulna –flexors on anterior side –extensors on posterior side Nerves - brachial plexus: median nerve (lateral side of palm, palmar/dorsal aspects of thumb, index finger, middle finger, 1/2 ring finger); ulnar nerve (little finger and 1/2 ring finger)

Upper Extremity – Hand/Wrist Joint type - gliding joint (synovial) Flexor retinaculum - creates the carpal tunnel between the carpal bones and the retinaculum, through which the flexor tendons and median nerve pass

Movements of the Hand

Movements of the Thumb

Lower Extremity - Hip Bones - Femur and acetabulum of coxal bone Muscles - anterior: flexors, adductors, abductors; posterior: extensors (gluteals) Nerves - Lumbosacral plexus Movement - flexion/extension, abduction/adduction, inward/outward rotation, circumduction Joint type - ball and socket (synovial)

Movements of the Hip Flexion and extension Abduction and adduction Inward and outward rotation Circumduction

Lower Extremity - Knee Bones - femur, tibia, patella Muscles –Flexors = hamstrings (bicep femoris, semitendinosis, semimembrinosis), satrorious, gracilis, popliteus, gastrocnemius –Extensors = quadriceps femoris Nerves - Lumbosacral plexus Join type – synovial (most complex)

Movements of the Knee Flexion and extension Internal and external rotation (in flexion only)

Movements of the Foot Dorsiflexion and plantar flexion Eversion and inversion

Neck and Back Bones - vertebrae, C1-C7, T1-T12, L1-L5, sacrum and coccyx Muscles - erector spinae, abdominals Function of spine - supports head and trunk, protects spinal cord, permits movement Movement – between adjacent segments is limited; but the whole vertebral column has great flexibility

Neck and Back Intervertebral disks –Bands of fibrocartilage with gelatinous core –No blood supply –Nutrition via pressure changes, thus movement is required Curves of spine – “S” shape –thoracic and pelvic concave anteriorly –cervical and lumbar convex anteriorly

Movements of the Neck Flexion and extension Lateral flexion (right and left) Rotation (right and left)

Movements of the Back Flexion and extension (hyperextension) Lateral flexion (right and left) Rotation (right and left)

Nerves Brachial Plexuses

Musculotaneous Ulnar Median Radial