Muscle Tissue. Isometric Contraction. Isotonic Contractions 11/22/2016. Muscles. Anatomy Two Joints And Movements

Transcription

1 Muscles Anatomy Two Joints And Movements Structure of a Muscle Organ Copyright 2008 by Saunders Muscle Tissue Highly elastic and vascularized, produces movement through elongation and contraction Types of muscle: Smooth Skeletal Cardiac Origin= Most stable attachment Insertion- Most movable attachment Isotonic Contractions Isometric Contraction 1

2 Isotonic (dynamic): tone or tension within a muscle remains the same as the length of the muscle changes Concentric contraction of muscle shortening Eccentric contraction of muscle lengthening Isometric (static): muscle length remains the same while muscle tension increases Muscle Fiber Arrangement A. Parallel B. Convergent C. Fusiform D. Circular E. Unipennate F. Bipennate Body Compass Map of body with respect to anatomical position body erect; facing forward arms at side; palms facing forward; thumbs to the side feet hip distance apart; toes pointing forward Helps you find your way around human body Articulations Synarthroses (fibrous): movement is absent or limited Joints between skull bones Amphiarthroses (cartilaginous): slightly moveable Joints between costals and sternum Diarthroses (synovial): freely moveable joints Shoulder, elbow, hip, and knee Synovial Joints What is an epiphysis? What is another name for diaphysis? What is hyaline cartilage? 2

3 Synovial Joints Articular cartilage decreases friction and helps absorb shock as bones move Joint capsule sleeve around joint Joint cavity inner area lined with synovial membranes filled with synovial fluid Synovial fluid viscous fluid providing nutrition and lubrication Bursae saclike structure lined with synovial membrane and synovial fluid Ligaments Strong cords of dense, white fibrous tissue at most synovial joints. These grow between the bones, lashing them even more firmly together than possible with the joint capsule alone. The cruciate ligaments in the knee prevents the sliding on the tibia and are major stabilizers of the knee. Types of Joints Types of Synovial Joints Ball-and-Socket Joint Ellipsoid Joint Hinge Joint Monoaxial joints Hinge Pivot Only move in one plane Saddle Joint Gliding Joint Pivot Joint Pg. 34 Hinge joints Flexion bends or decreases the angle of a joint Extension straightens or increases the angle of a joint The same joints occur in the toes. 3

4 Plantar flexion toes pointing downward Dorsiflexion toes pointing toward the shin Other Structures of the Ankle and Foot Talocrural Joint Pivot Joints Supination lateral or outward rotation of forearm Pronation medial or inward rotation of forearm Elbow and Forearm (humeroulnar and humeroradial joints elbow, proximal and distal radioulnar joints forearm) Pg. 28 4

5 Rotation circular movement in which bone moves around its central axis Types of Synovial Joints Biaxial joints Ellipsoidal Saddle Move in two planes Ellipsoidal joints Wrist (radiocarpal joint) Allow for flexion and extension, abduction and adduction. Pg. 28 Flexion bends or decreases the angle of a joint Extension straightens or increases the angle of a joint Abduction movement away from the midline Adduction movement toward the midline 5

6 Saddle joint Types of Synovial Joints Triaxial joints Gliding Ball-and-socket Move in all planes Inversion elevation of medial edge of foot; sole is turned inward Eversion elevation of the lateral edge of foot; sole is turned outward Ankle, Foot and Toes (talocrural, talotarsal, midtarsal, tarsometatarsal, metatarsophalangeal and interphalangeal joints) Pg. 31 Gliding (plane) joints Movements of the Body Spine and Thorax (vertebral column) Neck (cervical spine) Pg. 26 6

7 Ball and Socket joints Circumduction distal end moves in a cone-shaped ROM and proximal end is fixed Shoulder (glenohumeral joint) Hip (coxal joint) Pg. 27 Pg. 30 Some other Actions Don t fit neatly into the above ideas either about joints or planes Opposition tip of thumb touches tip of any other finger of same hand Lateral deviation side to side movement The scapulothoracic joint is not a true joint Opposition occurs in an oblique plane 7

8 Protraction movement forward or anteriorly Retraction movement backward or posteriorly Abduction (Protraction) movement forward or anteriorly Adduction (Retraction) movement backward or posteriorly Elevation raising or lifting a body part superiorly Depression lowering or dropping a body part inferiorly Scapula (scapulothoracic joint) Pg. 27 Tips for studying muscles What does the name tell you? Look for clues Do you have a picture in your mind? What joints does it cross? How does it cross those joints? Memorize the origin and insertions Think back to that picture, how is the muscle meeting its attachments? What is its relationship to surrounding muscles? Homework Complete all previous assignments Complete On-Line Handouts 8