AP Exam #3 Material

Joints and Muscles

2 types of joint classification

Structural and Functional

Structural Classification

classified by the type of tissue that binds the bones at each junction

Fibrous Joints

dense connective tissue holds the joint together

Syndesmosis Joint

Type of Fibrous Joint

bones bound by interosseous membrane

slight movement is permitted

Sutures

Type of Fibrous Joint

adjacent bones grow together, united by a sutural ligament

Only found between flat bones of the skull

Fontanels

Precursor to a suture (fibrous joint)

Membranous areas that allow for the skull to slightly change shape during childbirth, ‘soft spots’ on an infant

Gomphosis

Type of Fibrous Joint

formed by the union of a cone-shaped bony process in a bony socket

Ex: teeth

Cartilaginous Joint

bones are connected by hyaline cartilage or fibrocartilage

Synchondrosis

bands of hyaline cartilage unite bones

Most are temporary and disappear during growth (Ex: epiphyseal plate)

Permanent: Between the manubrium and the first rib

Symphysis

pad of fibrocartilage between bones

articular surfaces covered by hyaline cartilage

limited movement during compression

Synovial Joint

freely movable

structurally complex

Divided into categories based on axis that permit movement

Nonaxial

Synovial Joint

Sliding and twisting movements only

Ex: carpals

Uniaxial

Synovial Joint

movement in only one plane

Ex: hinge between humerus and ulna in elbow

Biaxial

Synovial Joint

movement in two planes

Ex: saddle in base of thumb

Multiaxial

Synovial Joint

movement in all three places

Ex: Ball and socket in hip

General Structure of a Synovial Joint

Joint Capsule, Fibrous Capsule, Synovial Membrane, Articular Cartilage, Joint Cavity, and Synovial Fluid

Joint Capsule

fibrous capsule plus synovial membrane

Fibrous Capsule

outer layer of the joint capsule

completely encloses the other parts of the joint

dense connective tissue

permits some movements but prevent bones being pulled apart

Synovial Membrane

Inner layer of joint capsule

shiny, vascular lining of loose connective tissue

surrounds synovial cavity

helps fill irregularities of the joint cavity

Articular Cartilage

minimizes friction as joint moves and compresses ends of bone together

Joint Cavity

Filled with Synovial Fluid

Synovial Fluid

clear, viscous fluid which moistens and lubricated the smooth surfaces of the joints

supplies articular cartilage with nutrients from blood vessels within the synovial membrane

contains stem cells which may aid in healing injured ligaments

Ball-and-Socket Joint

bone with an egg shaped head that articulates with the cup-shaped cavity of another bone

Examples of Ball-and-socket Joints

shoulder and hip

Condylar Joint

AKA Ellipsoidal

Examples of Condylar Joint

Metacarpophalangeal Joint (MCP)

Plane Joint

AKA Gliding

Ball-and-socket Joint Movement

Multiaxial movement plus rotation

Condylar Joint

ovoid condyle of one bone fits into the elliptical cavity of another bone

Condylar Joint Movement

Biaxial movement

Plane Joint

Articulating surfaces of these joints are nearly flat or slightly curved

Plane Joint Movement

Nonaxial

Examples of Plane Joints

SI, Carpals, Tarsals, Ribs 2-7

Hinge Joint

convex surface of one bone fits into the concave surface of another bone

Hinge Joint Movement

Uniaxial

Examples of Hinge Joints

Elbow, DIP, PIP, IP

Pivot Joint

cylindrical surface of one bone rotates in a ring formed of bone and a ligament

Pivot Joint Movement

Uniaxial (rotation around a central axis)

Examples of pivot joints 

proximal radioulnar joint, C1/C2

Saddle Joint

forms between bones whose articulating surfaces have both concave and convex regions

Saddle joint movement

Biaxial

Example of Saddle Joint

between the trapezium and first metacarpal

Menisci

fibrocartilage disc that cushions and helps evenly distribute body weight over articulating surfaces

Bursa

fluid-filled sac that cushions and aids in movement of tendons over bony prominences and other tendons

Synarthrotic Joints

Immovable

Amphiarthrotic Joints

slightly movable

Diarthrotic Joints

freely movable

Movement at Synovial Joints

Movement occurs when a muscle contracts and its fibers pull the insertion toward the origin

Flexion

decrease angle at joint

Extension

increase angle at joint

Hyperextension

beyond anatomical position or beyond normal range

Dorsiflexion

toes towards the shins (flexed feet)

Plantar Flexion

toes pointed towards the floor

Abduction

away from the midline

Adduction

towards the midline

Rotation

moving around an axis

Medial/Internal Rotation

moving around an axis anteriorly toward the midline

Lateral/External Rotation

moving around an axis anteriorly away from the midline

Circumduction

end of part follows a circular path

Supination

palm upwards or anteriorly

Pronation

palm downwards or posteriorly

In which position are the radius and ulna overlapped

Pronation

Eversion

bend ankle up on pinky side

Inversion

bend ankle up on big toe side

Protraction

moving a part forward

Retraction

moving a part backwards

Elevation

raising a part

Depression

lowering a part

3 main ligaments of the shoulder joint

coracohumeral, glenohumeral, and transverse humeral ligaments

coracohumeral ligament attachments

coracoid process and greater tubercle of humerus

coracohumeral ligament support

reinforces the superior portion of the shoulder joint

Glenohumeral Ligament attachments

three bands from edge of glenoid cavity to lesser tubercle and anatomical neck of humerus

Glenohumeral ligament support

supports anteriorly of shoulder

Transvers Humeral Ligament Attachments

between the greater and lesser tubercles

Transverse Humeral Ligament Support

foms a canal for the long head of the biceps brachii muscle to pass through

Rotator Cuff Muscles

supraspinatus, Infraspinatus, Teres Minor, Subscapularis

Humeroulnar Joint Classifications

Hinge - flexion and extention

Humeroradial Joint Classifications

plan Joint

Proximal Radioulnar Joint (AKA forearm joint)

Pivot joint

Ligaments of the Elbow

Ulnar Collateral, Radial Collateral, and Anular Ligaments

Ulnar Collateral Ligament (Anterior) Attachments

the medial epicondyle to the coronoid process

Ulnar Collateral Ligament (Posterior) Attachments

connects the medial epicondyle to the olecranon process.

Ulnar Collateral Ligament Support

reinforces the elbow joint medially

Radial Collateral Ligament

extends between the lateral epicondyle and the anular ligament

Radial Collateral Ligament Support

Reinforces the elbow joint laterally

Anular Ligament Attachments

trochlear notch and encircles head of radius

Anular Ligament Support

keeps head of radius in contact with radial notch of ulna

Pulled Elbow

tears anular ligament, radial head is displaces, heal time is usually 2 wks

4 major ligaments of the hip

Iliofemoral, Ligamentous Capitis, Pubofemoral, and Ischiofemoral Ligaments

Iliofemoral Ligament shape

Y-shaped

Iliofemoral Ligament Attachments

Anterior Inferior Iliac Spine to intertrochanteric line (Between the greater and lesser trochanters)

What is the strongest ligament in the body

Iliofemoral

Ligamentum Capitis Attachments

pit of the head of the femur (fovea capitis) to connective tissue in the acetabulum

Pubofemoral Ligament attachments

Extends between the pubis superiorly and the iliofemoral ligament inferiorly

Ischiofemoral Ligament Attachments

ischium and blends with the fibers of the joint capsule

What is the most complex joint in the human body?

Knee

Joint classification between distal femur and patella

Plane Joint

Joint Classification between femur and tibia 

Hinge Joint

Anterior Cruciate Ligament (ACL) Attachments

connects the anterior intercondylar area of the tibia to the lateral condyle of the femur

Anterior Cruciate Ligament (ACL) Support

Strengthens joint capsule and prevents displacement of articulating surfaces