Anatomy:Joints and Muscles

Joint cavity

Fluid filled space

Fibrous Joint

Adjacent bones are United by fibrous connective tissue

Cartilaginous Joint

Bones are joined by hyaline cartilage or fibrocartilage

Synovial joint

Articulating surfaces of bones are not directly connected

Synovial joint characteristics

Come into contact within joint cavity filled with lubricating fluid, allow for free movement between bones, most common type of joint

Synarthrosis

Immobile joint

Sutures

Fibrous joints between bones of skull

Manubriosternal joint

Cartilaginous joint that unites manubrium and body of sternum(protects the heart)

Amphorarthrosis

Slightly moveable joint

Intervertebral joints

Fibrocartilaginous intervertebral discs allow limited motion

Pubic symphysis

Confers weight-bearing stability to pelvis

Diarthrosis

Freely moveable joint,most found in appendicular skeleton, limbs wide range of motion

Vniaxial joint

Allows for motion within a single plane ( example, elbow joint)

Biaxial joint

Allows for motion within two planes (example: metacarpophalangeal joints (knuckles)

Multiaxial joint (polyaxial, triaxial)

Allows for several directions of movement ( example: hip and shoulder joints)

Syndesmosis

Fibrous joint in which two parallel bones are united by fibrous connective tissue

Narrow gaps

Bones joined by ligaments

Wide gaps

Bones joined by broad sheet of connective tissue called introsseous

Fontanelles

Provides flexibility of skull during birthing process, allows for rapid growth of skull and enlargement of brain after birth

Synostosis

Ossified sutures

Synchondrosis

Bones are joined together by hyaline cartilage(example, first sternocostal joint)

Gomphosis

Specialized fibrous joint anchors root of tooth into its bony socket

Periodontal ligament

Short bands of dense connective tissue span from bony walls of socket to root of tooth

Symphysis

Bones joined together by fibrocartilage (growing together)

Synovial joints

Most common joint in the body, presence of joint cavity and lack of direct connection between bones

Articulate capsule

Fibrous connective tissue attached to each bone just outside areas of bones articulating surfaces, forms walls of joint cavity

Articulate cartilage

Thin layer of hyaline cartilage covers entire articulating surface of each bone, prevents friction

Synovial membrane

Outer layer formed of connective tissue (fibrous,adipose,areolar) inner layer (aka intima) consists of sheet of cells; thinner than piece of paper, secretion of synovial fluid, synovial fluid supplies nourishment to articular cartilage

Ligaments

Strong bands of fibrous connective tissue anchor bands together and prevent separation, resist range of motion to prevent excessive or abnormal joint movements

Extrinsic ligament

Located outside articulate capsule

Intrinsic ligament

Fused or incorporated into wall of articular capsule

Intracapsular ligament

Located inside articular capsule

Tendons

Dense connective tissue structure attaches muscles to a bone, dynamic ligaments to resist forces and support joint

Articular disc

Small oval shaped fibrocartilage structure located between articulating bones

Meniscus

Larger c shaped fibricartilaginous structure, strongly unite bones of joint to each other, provide shock absorption and cushioning

Bursa

Thin connective tissue sack with lubricating liquid located in regions when skin, ligaments, muscles, or muscle tendons can rub against each other

Subcutaneous bursa

Located between skin and underlying bone

Submuscular bursa

Found between muscle and underlying bone between adjacent muscles

Trochanteric bursa

Bursa located at lateral hip between greater trochanter of femur and overlying gluteus Maximus muscle

Subtendinous bursa

Found between tendon and bone

Tendon sheath

similar in structure to bursa but smaller connective tissue that surrounds muscle tendon at places where tendon crosses joint

Pivot joint

Rounded portion of bone enclosed within ring formed partially by articulation with another bone and

Atlantoaxial joint

Articulation of atlas and axis allows head to turn from side to side

Hinge joint

Convex end of one bone articulates with concave end of adjoining bone (ex:elbow joint)

Saddle joint

Both bones have a saddle shape: concave in one direction and convex in the other (ex: sternoclavicular joint, opposable thumbs)

Plane joint (gliding joint)

Articulating surfaces of bones are flat or slightly curved and are approximately the same size, motion is tightly restrained by ligaments (ex:inter tarsal and inter carpal joints)

Ball and socket joint

Rounded head of one bone fits into the concave articulation of adjacent bone, full range of motion (ex:hip)

Shoulder (glenohumeral joint)

Largest range of motion in body, high mobility but decreased stability

Rotator cuff composition

Supraspinatous, infraspinatous, teres minor, subscapularis

Shoulder joint common injuries

Inflammation of tendon or bursa, torn rotator cuff tendons

Elbow joint

Prevents side to side movement and hyper extension

Ulnar collateral ligament

arises from medial epicondyle of humerus and attaches to medial side of proximal ulna

Radial collateral ligament

Arises from lateral epicondyle of humerus and blends into lateral side of annular ligament

Annular ligament

Encircles head of radius, supports radial head

Knee joint

Largest joint in body, consists of three different articulations, femoropatellar joint, medial and lateral tibiofemoral joint, medial and lateral meniscus

Femoropatellar joint

Patella articulates with distal femur

Medial and lateral tibiofemoral joint

During flexion and extension, condoles roll and glide over surface of tibia, rolling produces flexion and extension

Medial and lateral meniscus

C shaped fibrocartilage structure is thin along inside margin and thick along outer margin

Knee joint supporting ligaments: extrinsic ligaments

Fibular collateral ligament; located on lateral side of knee, tibial collateral ligament;located on medial side of the knee, helps with stability and supports extended knee

Knee joint supporting ligaments: intracapsular ligaments

Anterior and posterior cruciate ligaments, posterior cruciate ligament is stronger, anterior cruciate ligament helps to resist hyper extension

knee joint common injuries

Terrible triad injury (powerful blow to lateral knee, damage to meniscus, rupture of ACL, tearing of tibial collateral ligament)

Arthritis

Inflammation among joints (joint pain, swelling,stiffness, and reduced joint mobility

Three types of muscles

Cardiac, smooth, skeletal

Characteristics of all muscles

Excitability, contractability,elasticity, extensibility

Myofilaments

Actin and myosin

Skeletal muscle functions

Producing and stopping movements, maintain skeletal stability, protection of internal organs

Individual muscle is organ with integrated tissues

Muscle fibers,blood vessels, nerve fibers, connective tissue

How many nuclei do smooth muscles cells have

One

Skeletal muscle structure: epimysium

Dense irregular connective tissue covers muscle as a whole

Skeletal muscle structure: perimysium

Layer of connective tissue bundles of muscles called fascicles

Skeletal muscle structure:endomysium

Layer of collagen and reticular fibers surrounding individual muscle fibers

Sarcomere

Functional unit of muscle fiber

A band

Darker in color due to overlapping myosin and actin

I band

Lighter in color due to actin only present

Z disc

Narrow,dense line running through I band

Sarcolemma

Plasma membrane

Sarcoplasm

Cytoplasm

Specialized smooth endoplasmic reticulum

Sarcoplasmic reticulum

Actin

Along with shield proteins, projects from a disc, toward center of sarcomere

Myosin

With numerous strands and multiple heads, projects from center of sarcomere towards but not all the way to z discs

Titin

Structural protein that helps align contractile proteins

Nebulin

Structural protein that helps align contractile proteins (runs length of thin filament and stabilizes it)