Anatomy Unit 2

Articulation

the place where a bone meets another bone, cartilage, teeth.

More mobile means...

Less Stable

2 ways to classify joints

structurally and functionally

Three structural joint classes

1. Fibrous
2. Cartilaginous
3. Synovial

fibrous joints

bones held together by collagen fiber (most immobile)

Cartilage joints

bone held together by cartilage

Synovial joints

bones separated by fluid

Synarthroses

immobile joints (most stable)

Amphiarthroses

Slightly mobile joints

Diarthroses

freely mobile

3 types of fibrous joints

sutures, syndesmoses, gomphoses

Sutures

between skull bones

Gomphoses

teeth to maxilla and mandible

Syndesmoses

between parallel bones (interosseous membrane)

2 types of cartilaginous joints

synchondroses and symphyses

Synchondroses

bones joined by hyaline cartilage (usually immobile)

Symphyses

bones joined by pad of fibrocartilage (slightly mobile)

Items in Synovial Joints (Diarthrotic)

1. Articular Capsule
2. Joint Cavity
3. Synovial Fluid
4.Articular Cartilage
5. Ligaments, nerves, and blood vessels
Freely Mobile

Articular Capsule Layers

-fibrous capsule (outer made of dense regular connective tissue)
-synovial membrane (inner secretes synovial fluid)

joint cavity

-contains synovial fluid
-permits physical separation of articulating bones

synovial fluid

-lubricates articular cartilage
-nourishes the articular cartilage's chondrocytes
-Absorbs shock during compression of joint

articular cartilage

prevents bone-to-bone contact during compression (hyaline cartilage)

Ligaments

connect bone to bone

Nerves

signal when a joint is over stretched

blood vessels

nourish tissues in the joint

Bursae

sacs outside most synovial joints where ligaments, muscles, tendons, and/or bones rub

Tendon sheathes

elongated bursae around tendons, particularly in confined areas (wrist and ankle) where tendons rub each other.

Classifying Synovial Joints

1. Anatomically- shape of articulating surface
2. Physiologically- number of movements (uniaxial, biaxial, multiaxial)

Uniaxial

bones move only one plane

Biaxial

bone moves in two planes

Multiaxial

bone moves in more than two planes

6 classes of synovial joints

1. ball-and-socket (360, hip)
2. condylar (biaxial, phalanges)
3. saddle (biaxial, thumb and carpels)
4. plane (uniaxial, carpals of wrists)
5. hinge (uniaxial, elbow)
6. pivot (uniaxial, dens of axis and atlas vertebrae)

4 types of synovial joint movements

gliding, angular, rotational, special

Gliding

articular surfaces slide back and forth or side to side

Angular

increases or decreases the angle between 2 bones

flexion and extension

Decrease/increase in joint angle (neck, elbow, knee, wrists)

Lateral Flexion

Side-bending left or right

Abduction and Adduction

movement away/into from midline (fingers spread apart, arm, legs, wrist left and right)

Circumduction

circular movement of a limb at the far end (ankle, arm)

Rotational

bone turns along its longitudinal axis

Medial and lateral rotation

anterior surface of humerus moves laterally, turns the anterior surface of humerus medially

Pronation vs Supination

Palm down vs. Palm up

Special

only occur at specific joints

Depression vs. Elevation

- Movement of a body part inferiorly vs superiorly (shoulder joint)

dorsiflexion and plantar flexion

up and down movements of the foot at the ankle

Inversion vs. eversion

sole of foot turns medially vs. sole of foot turns laterally

protraction vs retraction

anterior movement of a body part from the anatomic position vs. posterior movement of body part from anatomic position (chicken head )

Opposition

tip of thumb to tip of pinky finger

Axial

skull, vertebral column, rib cage (80 bones)

Appendicular

shoulder and hip bones and the upper and lower extremities (126 bones)

Skull Bones

Facial: 14 with no brain contact
Cranial: 8 that form cranium and have direct contact with the brain

3 Cranial fossae

anterior - orbital roof (ethmoid, frontal, sphenoid)
middle - middle ear (sphenoid, petrosal/temporal)
posterior - foramen magnum (occipital)

paranasal sinuses

Air-filled spaces in skull bones around nasal cavity
1. Frontal
2. Ethmoid
3. Sphenoid
4. Maxillary

Nasal Septum

separates the left and right airways in the nose
1. Ethmoid
2. Vomer
3. Maxilla
4. Palatine

Deviated Septum

nasal septum is displaced; deviates from the center line

Palate

forms roof of the oral cavity and acts as a barrier to separate it from the nasal cavity
1. Palatine process of maxilla bone
2. Horizontal plate of the palatine bone

Cleft Palate

a congenital split in the roof of the mouth

Curves of the Spine

1. Cervical - anteriorly
2. Thoracic - posteriorly
3. Lumbar - anteriorly
4. Sacral - posteriorly

kyphosis

thoracic curving that causes a bowing or rounding of the back (hunchback)

Lordosis

lumbar curvature that is observed as a protrusion of the abdomen and buttock (sway back)

Scoliosis

abnormal lateral curvature

intervertebral discs

outer ring made of anulus fibrous, and inner region called nucleus pulposus

Herniated "slipped" disc

occurs when gelatinous nucleus pulpous protrudes in or through the anulus fibrous (pinching, painful)

4 Major groups of Appendicular Skeleton

1. Pectoral Girdle (4 bones)
2. Upper Limps (6o bones)
3. Pelvic Girdle (2 bones)
4. Lower Limbs (60 bones)

Upper Limb - Arm

brachial region (area between shoulder and elbow, consist of humerus)

Upper Limb - Forearm

antebrachial region (area between elbow and wrist, radius and ulna)

interosseous membrane

Dense regular connective tissue that maintains distance between radius and ulna and provides pivot point for rotation.

Lower Limb - Thigh

consists of femur, longest, strongest, heaviest bone

Lower Limb - Leg

Crural region (fibula and tibia, connected by interosseous membrane, tibia is weight bearing, fibula articulates with tibia)

Foot Arches

to prevent pinching of muscles, nerves, and blood vessels

3 major arches

1. medial: from heel to hallux (big toe)
2. Lateral : from heel to 5th toe
3. Transverse: perpendicular to other arches, along distal row of tarsals

Polydactyly

extra digits

Ectrodactyly

absence of a digit

syndactyly

webbed fingers or toes

meromelia/amelia

partial or complete absence of limbs

Phocomelia

short, poorly formed limb

3 types of muscles

skeletal, smooth, cardiac

4 properties of muscle tissue

excitability, contractility, extensibility, elasticity

Excitability

ability to respond to stimuli

Contractility

ability to shorten/contract

Elasticity

ability to return to original length

Extensibility

ability to be stretched

Properties of Skeletal Muscle (3)

an organ, contains all tissue types, muscle fibers are striated

What is each muscle composed of?

Muscle fibers

Muscle fibers are organized into what?

fascicles

muscle fibers contain

myofibrils

Myofibrils are composed of

myofilaments

Myofilaments are composed of

actin and myosin

Each muscle has ___ layers of _______

three, concentric connective tissue

Connective Tissue provides?

-protection
-sites for blood vessels and nerves
-attachment of muscle to the skeleton

Endomysium

innermost layer that surrounds and electrically insulates each muscle fiber (cell)

Perimysium

surrounds individual fascicles

Epimysium

surrounds the entire muscle

Deep and superfical fascia

surround each muscle and seperates muscles from each other

All connective tissue merge to form what?

Tendons

Sarcolemma

muscle cell membrane

Sarcoplasm

cytoplasm of a muscle cell

sarcoplasmic reticulum

stores calcium

Transverse tubules (T-tubules)

deep invaginations of the sarcolemma that extend into the sarcoplasm

terminal cisternae

blind sacs at the end of the sarcoplasmic reticulum