Course Content

I. Introduction to the CourseII. Biomechanical Concepts Related

to Human MovementIII. Anatomical Concepts Related to

Human MovementIV. Applications in Human

Movement

Anatomical Concepts Related to Human Movement

A. The Skeletal SystemB. The Muscular System

The Skeletal System

1. General Structure & Function2. Tissue Level Structure & Function3. System Level Structure &

Function4. Injury to the Skeletal System

System Level Structure & Function

Classification of Joints Accessory Structures System Level Function

System Level Structure & Function

Classification of Joints Accessory Structures System Level Function

Classification of Joints Structure vs. Function

1.Synarthrosis2.Amphiarthrosis3.Diarthrosis

Classification of Joints

1. Synarthrosis (immovable)

a. sutural syndesmosis (fibrous)

b. synchondrosis (cartilaginous)

1-a. Sutural syndesmosis

1-b. Synchondrosis

Temporary

1-b. Synchondrosis

Permanent

Classification of Joints

2. Amphiarthrosis (slightly movable)a. membranous syndesmosis (fibrous)b. symphysis (cartilaginous)

2-a. Membranous Syndesmosis

2-b. Symphysis

Joined by a fibrocartilage disc

2-b. Symphysis

Classification of Joints

3. Diarthrosis (freely movable, synovial)

a. nonaxial b. uniaxialc. biaxiald. triaxial

Diarthrodal Joints 4 common charachteristics:

1) Enclosed by fibrous joint capsule2) Capsule is lined by synovial

membrane3) Joint cavity is filled with synovial

fluid4) Ends of bones are lined with hyaline

articular cartilage

Characteristics of Diarthrodial Joints

3-a. Nonaxial – Gliding, Plane

IT IC

3-a. Nonaxial

TMT, IM

CMC, IMfacet

3-a. Nonaxial

AC

SC

3-b. Uniaxial - Hinge

talocruralIP

humeroulnar

3-b. Uniaxial - Pivot

RUatlantoaxial

3-c. Biaxial – Condyloid & Ellipsoid

condyloid - MP ellipsoid - radiocarpal

3-c. Biaxial - Saddle

SC

3-c. Biaxial - Saddle

calcaneocuboid

1st CMC

3-c. Biaxial – Bicondyloid??

3-d. Triaxial

glenohumeralcoxal

System Level Structure & Function

Classification of Joints Accessory Structures System Level Function

Accessory Joint Structures Tendons Synovial (Tendon) Sheaths Ligaments & Joint Capsules Retinacula Fasciae Articular Discs Bursae Labrums

Tendons

Structure?Function?Active & passive1st line of defense

Synovial Sheaths•Structure?

•Function?Biceps Tendon in Bicipital Groove

Synovial Sheaths

Joint Capsules

•Criss-crossed arrangement

•2 or more layers

•Regular collagenous tissue

Ligaments

StructureFunctionPassive2nd line of defense

Aligned in direction of imposed stress

LigamentsCapsular vs. Noncapsular

Capsular

LigamentsCapsular vs. Noncapsular

Noncapsular

Ligaments

Extracapsular

Noncapsular:Intra vs. Extra

Ligaments

Intracapsular Capsular

Ligaments

Extracapsular

Ligaments – Passive Function

Resists Adduction

Retinacula

•Structure?

•Function?

– Guy Rope

Retinacula– Pulley

Fasciae Fascia – any type of ordinary CT in

a sheet Superficial fascia Deep fascia

Articular Discs

congruence: area over which JRF transmitted

•Fibrocartilage

•Function?

AC jt SC jttibiofemoral radiocarpal

Bursae•Structure?•Function?

Bursae

Labrums

System Level Structure & Function

Classification of Joints Accessory Structures System Level Function

Terminology stability - the ability of a joint to

resist displacement or dislocation; the strength of the bonds between the bones in a joint

mobility - the degree to which the bones are allowed to move before being restricted by surrounding tissues

flexibility - another term for mobility

Measures of Mobility DOF - the angular directions of

movement considered normal for a joint; general measure of mobility

ROM - the angle through which a bone moves about a joint from anatomical position to the extreme limit of a segment motion in a particular direction; a specific measure of joint mobility joint, planar, and direction specific

General Terminology hypermobile - describes a joint

where ROM exceeds normal limits hypomobile - describes a joint

where ROM is less than what would normally be permitted

laxity – the ROM in those directions considered abnormal for a joint; the degree of instability in a joint

General Terminology subluxation – a transient decrease in

the normal area of contact (congruency) between the articular surfaces in a synovial joint

luxation – a transient separation of the articular surfaces in a synovial joint

dislocation – a permanent (in the absence of treatment) separation of the articular surfaces in a synovial joint

Factors Affecting Joint Stability/Mobility 1. Bony Structure 2. Ligament/Capsular restraint

Contact between surfaces creates torque on each bone from JRF of bone.

1. Role of Bony Structure 3rd (& final) line of defense How does bony structure stop

excessive motion?

Flexor torque Adductor torque

Extensor torque

Bony Structure Shape of articular surfaces

determines: when in the ROM the rxn torque is

applied the direction of the rxn force (and

thus, size of moment arm) the amount of the rxn torque

How would a deeper olecranon fossa change:

• where in the ROM Trxn occurred• the direction of

Frxn

• the magnitude of Trxn

• the max ROM

2. Role of Ligaments & Joint Capsules

2nd line of defense Size of moment arm

Angle of attachment Attachment sites

Magnitude of Force Strength

Number of ligaments (net torque)

Flexor torqueAdductor torque

Size of moment arm (angle, attachment site)

Magnitude of force

Tautness Number of

ligaments (net torque)

How can the ligamentous/JC function be changed?

Summary Joints in the body are classified on the

basis of structure and function. Joint structure dictates the function of a

given joint, especially the bony and ligamentous/JC structure about the joint.

Other accessory structures contribute to joint mobility, stability, and longevity as well.