Joints and Muscles

Classification of Joints by Movement• Synarthroses (synarthrotic joints) – non movable

most fibrous joints

e.g. sutures

• Amphiarthroses (amphiarthrotic joints) – semimovable

mostly cartilaginous

e.g. intervertebral disks

• Diarthroses (diarthrotic joints) – movable joints

synovial joints

Classification of Joints by Structure

Fibrous joints – composed of fibrous (inelastic) connective tissue.

sutures – between cranial bones

syndesmoses – e.g. tibia-fibular joint, sternum-clavicle and acromion-clavicle.

Synovial Joints

• movable joints

• contain a joint capsule of synovial membrane

Structure of a SynovialJoint

periosteum

Extracapsular ligament

Fibrous capsule

Synovial membrane

Articular cartilage

Articularcapsule}

Joint cavity

Figure 8.3

Plane or Gliding Joint

Gliding or planar joints – bones slide against one another.

e.g. between carpals or tarsals

Gliding Movement is Non-axial

e.g. elbow, knee.

Hinge Joints

Movements at Uniaxial Joints:

Flexion – decreasing the angle between two bones or parts.

180o

•Begin at anatomical position

•Reduce angle from 180o

Extension– increasing the angle between two bones or parts.

Increase angle back to anatomical position

Return to anatomical

position

Beyond anatomical position is hyperextension

Flexion and Extension of

the VerterbralColumnFlexion

Extension

Hyperextension

When extension proceeds beyond anatomical position it is called hyperextension.

When extension proceeds beyond anatomical position it is called hyperextension.

Flexion and Extension of the Head

FlexionExtension

HyperextensionFlexion

Pivot Joints

e.g. radius with ulna and humerus,

atlas-axis

Rotation of the Head and

Thigh

Rotation of the Radius

Supination – to move palm up

Pronation – to move palm down

Condyloid Joint

Phalange-metacarpal, Carpal-metacarpal,

occipito-atlas and tibia-talus joints.

Saddle Joint

Additional Movements at Biaxial

Joints

Abduction –to move away from the midline or apart.

Adduction –to move toward the midline or together.

Circumduction – a sequence of movements in which one end inscribes a circle.

Ball-and-Socket Joints

Shoulder and hip joint

Movements of the Foot

plantarflexion: point toes down

dorsiflexion: point toes up

Inversion and Eversion

Left foot

Inversion, incorrectly called

supination

Eversion, incorrectly called

pronation

The Elbow Joint

trochlea

Trochlear notch

synovial cavity

Tendon of biceps b.

Tendon of triceps b.

Figure 8.10 a

Articularcartilage

Figure 8.10 b

Annular ligament

Radial (lateral) collateral ligament

Articularcapsule

Figure 8.10 d

Annular ligament

Ulnar (medial) collateral ligament

Elbow radiograph, lateral view

Trochlear notch

Trochlea

Elbow radiograph, dorsal view

Olecranon process

Head of the radius

Sagittal Section of The Right Knee

Articular capsule

Anterior cruciateligament

Posterior cruciateligament

Tibia

Femur Patella

Figure 8.11 a

Patellar ligament

Quadriceps tendon

Anterior View of the Right KneeFigure 8.11 b

Tibia

Fibula

Patellar ligament

Patella

Quadriceps tendon

Medial condyleLateral condyle

Tibial (medial) collateral ligament

Fibular (lateral) collateral ligament

Posterior cruciateligament

Anterior cruciateligament

Lateral meniscus Medial meniscus

Patella

Femur

Tibia Fibula

Condyles

Knee Radiograph

3 Types of Muscle TissueA Comparison

Skeletal Attached to the bones for movement

Muscle TypeLocation Characteristics Control

Long, cynlindricalcells;

multinucleated, striated

Voluntary

Cardiac Muscle of the HeartShort, branching cells, mononucleated, faintly

striated. Forms functional syncytia.

Involuntary

myogenic

Smooth Muscle

Single Unit: GI, Respiratory, &

Genitourinary tract mucous membranes.

Multi-unit: smooth muscle in blood vessel

walls.

Small oblong cells, mononucleated, also may

form a functional syncytium.

Involuntary

myogenic

Skeletal MuscleCharacteristics

Skeletal muscle cells are long multi-nucleated cylinders, separated by connective tissue.

nuclei

Connective endomysiumseparates cells.

Striations are the dark bands Myofibrils fill

cell interiorperpendicular to cell length

Skeletal Muscle photomicrographs

Striations reflect the arrangement of protein myofilaments within the cell. The dark bands are called A-bands, the light areas between are the I-bands.

Z lines run through the middle of each I-band. The unit from one Z line to the next is a sarcomere.Z-line

The sarcolemma is the cell membrane

Structure of a

Skeletal Muscle

Cardiac MuscleCharacteristics

Cardiac muscle cells are faintly striated, branching cells, which connect by means of intercalated disks to form a functional network.

Intercalated disks

nucleus

The action potential travels through all cells connected together in the syncytium causing them to function as a unit.

Cardiac cells are branched, mono-nucleated cells

Smooth Muscle Characteristics

A small spindle-shaped mononucleated smooth muscle cell.

Smooth muscle cells connect to form single-unit syncytiasimilar to cardiac muscle. But impulses and contractions occur much more slowly in smooth than in cardiac muscle.

nucleus

Smooth Muscle Arrangement

In the intestine smooth muscle forms two distinct layers, one running along, the other running around the organ. Together these layers cause wave-like peristalsis which propels the contents.

The longitudinal layer runs along the intestine; it causes wave-like contractions.

The circular layer runs around the intestine and its contraction causessegmentation

Lab Protocol

I. Arthrology

1. Describe and give examples for joint types: synarthroses, amphiarthroses and diarthroses.

2. Relate the types of joints to their structure: fibrous, cartilaginous and synovial.

3. Identify the types of synovial joints with examples and movements. Discuss how these movements can supplement (synergists), oppose (antagonists) or stabilize (fixators) one another.

4. Use cadavers to identify the major structural aspects of selected joints.

II. Muscle Histology

1. Compare structure of skeletal, cardiac and smooth muscle.

2. Identify major anatomical features of each type and relate tofunction.

Assignment to Turn In

1) Complete Review Sheets for Exercise 13.

2) Make a labeled drawing of the three types of muscle from microscopy done in the lab, or from photos available in The Virtual Microscope