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Lecture Three: • Describe the 3 main different types of joints found in the body • Provide one example of a fibrous joint and a cartilaginous joint (false joints) • Identify and describe an example of each of the different types of synovial joints (true joints) • Define the terms loose packed and closed packed • Describe the core functions of skeletal muscle • View muscle tissue and tendons in the anatomy laboratory and your own surface anatomy • Define the following terms: origin, insertion, action, prime mover (agonist), antagonist, synergist, fixator, isometric, concentric, eccentric and pennation • Give an example of one of each of the following: a muscle with 2 heads; 3 heads; 4 heads; multiple bellies; a flat muscle; a radially arranged muscle, a convergent muscle and a multi pennate muscle. • Describe the roles of fascia in relation to muscles, tendon sheaths, and  bursae in relation to joint

Classification of Joints: - Structure: o Fibrous = united by fibrous tissue o Cartilaginous = untied by hyaline or fibrocartilage o Synovial = united by a joint capsule that spans and encloses an articular cavity that contains synovial fluid - Connectivity: o False = continuously connected by connective tissue o True = separated by joint space Joint stability provided by four mechanism: - Design/shape of bony surfaces – including articular/hyaline cartilage - Structure that modify joint surfaces (labrum, discs) - Joint capsules and ligaments - Muscles that cross joints Fibrous Joints (False Joints) - Bone – fibrous tissue – Bone o E.g. of a false joint as is continuously connected by connective tissue  Sutures – e.g. skull  Gomphoses – tooth in its socket  Syndesmoses – e.g. interosseous membrane

Cartilaginous Joints - Little movement, shock absorbers, protection - Primary cartilaginous in epiphyseal plate o Bone – Cartilage – Bone - Symphysis or secondary cartilaginous in interverbal disc, symphysis pubis in pelvis  Bone – cartilage – fibrocartilage – cartilage - Bone

Synovial Joints (True Joints) - Bone – Cartilage – Synovial Cavity – Cartilage – Bone o Fluid-filled cavity o Sliding, rolling and twisting movements o Articular surfaces lined by hyaline cartilage Joint capsule  Outer fibrous capsule  Inner synovial membrane o Synovial Fluid o Main moving joints in body o May contain bursae, cartilage or fat pads -

Synovial Fluid: o Nourishes hyaline cartilage o Lubricates articular surfaces o Evenly distributes pressure across articular surfaces

Classification of Synovial Joints 1. Based on shape of articulating surfaces o 6 Classes of Synovial Joints  Plane/Gliding  Hinge  Pivot  Ellipsoidal (condyloid)  Saddle  Ball and Socket

2. Based on movement o Uniaxial –hinge and pivot o Biaxial – at 90 to another : ellipsoid and saddle o Multiaxial – plane gliding, ball and socket Shapes: 1. Plane/gliding joint a. Flattened/ slightly curved surfaces i. E.g. carpal bones at wrist ii. E.g. Tarsal bones in the foot b. Acromioclavicular joint at the top of the shoulder

2. Hinge Joint a. Convex cylinder articulating with a concavity i. E.g. elbow ii. E.g. ankle

3. Pivot Joint a. Cylindrical process lying within ring of bone and or ligament i. E.g. Superior radio-ulnar ii. E.g. Atlanto-axial joint in neck (turning neck)

4. Ellipsoidal or Condyloid Joint a. Convex face in concave depression b. E.g. egg and spoon

5. Saddle Joint a. 2 convex and 2 concave surfaces i. E.g. between trapezium and 1st metacarpal at thumb

6. Ball and Socket Joint a. Round head + cup-shaped depression i. E.g. shoulder ii. E.g. Hip

Joint Terminology - Close-packed position: o Greatest joint contact, stable o Capsule, ligaments taut “locked” o Important in body weight transmission o Think of the ankle joint when standing -

Loose-packed position: o Minimal joint contact o Capsule, ligaments lax, free movements o Unstable, prone to dislocation o Consider ankle ligament tears

Joint Movement Motions in Sagittal Planes o Flexion and Extension  Flexion = bending motion that decreases the angle between bone and limb at joint  Extension = lengthening the angle between the bones and limb between joint

Motions in Frontal Planes o Abduction and Adduction o Abduction = the movement of a limb away from midline of body o Adduction = movement towards midline

Motions in Transverse Planes o Medial rotation = the turning of a limb about its axis of rotation toward the midline of the body o Lateral rotation = the turning of a limb towards that lateral side of body Osteoarthritis - A common pathology occurring in weight bearing joints o E.g. metal on metal hip resurfacing for osteoarthritic hip joints  Assists in movability and activity

Properties and Functions of Muscles in the body Functions: - Transform chemical energy into mechanical energy - Movement and stabilization of position - Regulate organ volume - Generate heat - Propel fluids - Propel food matter

Properties: - Electrical excitability - Contractility - Extensibility - Elasticity Muscle Tissue Types: - Skeletal striated muscle -voluntary muscle that move or stabilize - Cardiac striated muscle – involuntary e.g. walls of heart - Smooth muscle – involuntary visceral muscles that lines most vessels and hollow organs in the body Skeletal Muscles: - Bundles of straited muscles fibres - Larges cells with numerous nuclei - Two types of fibres: o Slow twitch o Fast twitch - Muscles have white non-contractile portions e.g. tendo - Nerves supply muscle e.g. motor unit - Contains: o Skeletal muscles tissue o Connective tissues o Blood vessels o Nerves - Affected by age, health, use and body biomechanics - Many act to hold the body upright against gravity o Postural or anti-gravity muscles - 75% water and 20%protein - Age = decrease in muscles mass and increase in fat

Fascia and Septa - Wraps limbs - Divides muscles into groups o Allows movement between compartments - Invests around individual structures - Holds tendons in place - Provides attachment for muscles - Thickens to become retinaculum e.g. at the wrist

Tendons - A white fibrous cord or sheet that attaches a muscle to bone or occasionally to another muscle - Tendons vary in shape and size - Often contribute to the naming of the muscle - An aponeurosis is a sheet like tendon o Abdominal aponeurosis - Sometimes have small bones lying within them o Sesamoid bone - Functional significance of a sesamoid bone: o Bones embedded in tendon o Protect tendon from excessive friction o Act to lengthen effective lever arm

Bursae and Tendon sheaths - Bursae: are closed sacs formed from a membrane that produces synovial fluid - Occur in locations subject to friction - Often under bony prominences - Tendon sheaths: in some areas, e.g. hand and foot, fluid filled tunnels (sheaths) encase tendons to reduce friction and provide tendon protection and nutrition

Muscle terminology - Orientation – rectus = straight - Region of body – gluteal - Structural features o Shape – deltoid – triangular, rhomboid, quadratus o Length – longus/brevis o Size – maximus, minimus o Components – triceps = 3 heads; biceps – 2 heads - Actions – adductor, flexion - Axial – arise on axial skeleton - Appendicular – stabilize/ move appendicular skeleton - Aponeurosis – sheet of tissue Name (meaning) Example Size Maximus (largest) Gluteus Maximus Size Minor (small) Pectorialis minor Size Longus (long) Abductor pollicis longus Shape Rhomboid Rhomboid major and minor Shape Deltoid (triangular) Deltoid Location Pectoralis (chest) Pectorialis major Location Femoris (femur) Quadriceps femoris No. of Heads Triceps (3 heads) Triceps Brachii Brachii = arm region Orientation Rectus (straight) Rectus Abdominis Action Extensor ( extends a joint) Extensor carpi radialis Carpi = wrist

Radialis = relates to radius Muscles – Definitions: o Origin – Muscle attachment = bone/area generally fixed, usually proximal o Insertion – muscle attachment = bone/area generally moves, usually distal o Action – Movement produced o Prime mover/ Agonist – produces main movement o Antagonist = in opposition to agonist o Synergist = assists agonist, prevents unwanted movement (fixator or stabiliser) o Concentric – muscle length shortens with tension  E.g. deltoid shorten to raise arm on abduction o Eccentric – muscle length increases with tension  e.g. deltoid lengthen to lower arm in adduction o Isometric – contraction with constant length  E.g. Deltoid hold arm in abduction

The pectoral girdle – structure and muscles Learning objectives:  Correctly apply the anatomical terminology relating to the bones of the pectoral girdle • Identify major bony features of the clavicle and scapula • Classify the synovial joints found in the pectoral girdle • Identify and name the main ligaments associated with these joints • Describe and demonstrate the main movements of the pectoral girdle • Identify and describe the main origin, insertion and action of the 5 main muscles that move the pectoral girdle Functions of Upper Limb: - Upper limb is modified to increase: o Range o Direction o Accuracy of placing hand o Stabilisation of hand - Modified to provide greater tactile input and manipulative function - Shoulder girdle – extends rand of movement of limb = reach - Clavicle = acts as a strut - Glenohumeral joint = great mobility for limb placement - Stability vs mobility trade off – glenohumeral joint most mobile and least stable joint - Elbow – angular movements to direct hand placement - Superior and inferior radio-ulnar joints = refine hand placement - Joints of wrists and fingers = dexterity and sensory info Terminology Relating to the shoulder region: - Axilla = arm pit - Brachium = arm (e.g. biceps Brachii) - Clavicle = collar bone - Scapula = shoulder blade Pectoral Girdle Functions: - Extends range of movement of the shoulder - Scapula alight largely flat bone, providing surfaces for muscle attachment and a large degree of movement - Clavicle – acts as a strut - Gives upper limb reach

The Clavicle: - Blunt larger end articulates with sternum - Flatter end located laterally and joins to acromion of the scapular in a joint complex (AC joint) - Smooth superior surface of clavicle - Slight roughening inferior surface for ligament and muscle attachments that anchor the clavicle

Sternoclavicular Joint: - Strong capsule, costoclavicular lig and an articular disc o Strong but also very mobile (saddle joint) o Two joint components due to the presence of an articular disc The Scapula: - Triangular - Flat bone overlying 2-7th ribs - Three fossae (scooped out areas on bone) - Two posterior fossae divided by thick ridge = spine that broadens laterally to form an acromion process - Concave costal anterior surface that hugs the ribs = subscapular fossa - Lateral and slightly forward facing glenoid fossa rimmed with labrum to slightly -

Acromioclavicular (AC) Joint: - Lies between the acromial end of the clavicle and the acromion of the scapula - A joint capsule surrounds the joint and a small disc lies within - Ligament integrity is important to prevent displacement - Commonly injured

Joints of the pectoral girdle: - Ligaments important for stability: o Acromioclavicular lig o Coracoclavicular ligs (trapezoid and conoid) o Coracoacromial lig

Scapula Movements: - Protraction - Retraction - Elevation

- Depression - Medial and lateral rotation Muscles of Pectoral Girdle: Muscle

Origin (Proximal + Fixed)

Insertion (Distal + Moves)

Action

Nerve

Trapezius (posterior)

Off the base of the skill + spinous process of cervical and thoracic vertebrae (i.e. neck and mid back)

Outer clavicle, acromion and spine of scapula

Scapula elevation, retraction and depression

Cranial nerve XI -accessory

Rhomboids (both) (posterior)

Spinous processes from C7-T5 (lower neck and mid back)

Medial Border of Retraction and Scapula medial rotation of scapula stabilizes ++

Dorsal scapular Nerve

Levator Scapulae (posterior)

C1-4 (cervical spineneck region) Transverse processes

Medial border of scapula

Elevates and rotates scapula

Dorsal scapular nerve

Pectoralis minor (anterior) Serratus anterior (anterior)

Ribs 3-5 near costal cartilages

Coracoid process of the scapula Medial boarder of scapula

Scapula protraction

Medial pectoral nerve Long thoracic nerve

Lateral 1st-8th ribs

Protection and rotated scapula, keeping it against chest wall...