BMS Anatomy Asynchronous Lecture 1 PDF

BMS Anatomy Asynchronous Lecture 1 Introduction to Syndesmology, Arthrology and Muscles Dr. Karyn Lumsden BSc., M.Ed., DC. Fall 2023 Clinically Oriented Anatomy Introduction Chapter Pages 15 - 19 Joint Classification • Arthrology = Joint / Syndesmology = Ligaments • A joint is an articulation bet...

BMS Anatomy Asynchronous Lecture 1 Introduction to Syndesmology, Arthrology and Muscles Dr. Karyn Lumsden BSc., M.Ed., DC. Fall 2023 Clinically Oriented Anatomy Introduction Chapter Pages 15 - 19 Joint Classification • Arthrology = Joint / Syndesmology = Ligaments • A joint is an articulation between 2 bones. Often there is movement produced at a joint. • Movement produced at a joint is determined by the shape of the bony surfaces involved Joint classification: (Either by structure or function) Structure: Based on the material holding the joint together • Fibrous: Joint is held together by fibrous connective tissue • Cartilaginous: Joint held together by cartilage (hyaline or fibrocartilage) • Synovial: Many structures involved in holding the joint together JOINT CLASSIFICATION Function: Based on how much movement is produced at the joint • Synarthrosis: (Little to no Movement) • Amphiarthrosis: (Some Movement) • Diarthrosis: (Freely Moveable) Types of Fibrous Joints: • Suture: Found between the bones of the skull, no movements is produced, known as synarthrodial joint (i.e. between the bones of the cranium) • Syndesmosis: 2 bones are connected by a fibrous connective tissue, some movements will be found, known as amphiarthrodial joints (i.e. between the ulna and radius or fibula and tibia) • Gomphosis: The joint between a tooth and it’s socket (alveolus), no movement, known as a synarthrodial joint. STRUCTURAL CLASSIFICATION Types of Cartilaginous Joints • Synchondrosis: This is a Primary Cartilaginous Joint because the bones are connected by hyaline cartilage, is often a temporary joint (because with age will usually ossify, but not always) located in the metaphyseal area (i.e. epiphyseal growth plate) • Symphysis – This is a Secondary Cartilaginous Joint because the bones are joined by fibrocartilage, strong slightly movable joints, known as amphiarthrodial joints (i.e. IVD between the vertebrae) STRUCTURAL CLASSIFICATION Types of Synovial Joints: • Plane Joint / • Hinge Joint / • Saddle Joint / Pivot Joint Condyloid Joint Ball and Socket Joint Synovial Joint Components Synovial Membrane: encapsulates the ends of each bone Synovial Cavity: space the joint is permitted between the articulations Synovial Fluid: acts as blood in the joint, allows friction free movement (joints don’t have blood) Articular Cartilage: made up of hyaline cartilage - thin strip on either side, protection lining for friction free movement Accessory Ligaments: reinforce the connection between bones and ensure there's not a lot of excess movement Additional Structures found at Synovial Joints Intra-articular discs: Fibrocartilaginous discs found at joints under high stress ◦ TMJ and Sternoclavicular joint Menisci: Fibrocartilaginous disc found between the femur and tibia (The Knee) Planar Synovial Joint • 2 relatively flat, smooth surfaces articulating together (i.e. Tarsal bones) • Allows gliding and sliding motions • Has 1 degree of freedom: (only moves in 1 plane therefore uni-axial movement) - only moves in 1 way of the body Hinge Synovial Joint • Similar to a door hinge • Cylindrical surface fitting into a cylindrical groove (i.e. Elbow joint) • Allows for 1 degree of freedom: Uniaxial movement - flexion and extension Pivot Synovial Joint • A projection fitting into a ring (the ring is usually formed by a ligament) (i.e. Articulation between proximal radius and ulna) • Allows for 1 degree of freedom: Uniaxial movement (rotation, example: forearm) Condyloid Synovial Joint • An egg/oval shaped projection fitting into an elliptical hole (i.e. Wrist joint) • Allows for 2 degrees of freedom: Bi-axial movement. Allows for flexion/extension and adduction/abduction Saddle Synovial Joint • The opposing surfaces are reciprocally concave-convex. (i.e. 1st carpometacarpal joint) • Allows for 2 degrees of freedom: Bi-axial movement. Allows for flexion/extension and adduction/abduction Ball and Socket Synovial Joint • A spherical surface fitting into a bowl shaped socket (i.e. Glenohumeral joint (shoulder joint) • Allows for 3 degrees of freedom: Tri-axial movement. Allows for flexion/extension, adduction/abduction and rotation Ligaments of Joints Ligament: a connective tissue structure that connects bone to bone. • Participate in the stabilization of joints and can limit certain movements within the joint Classified based on their anatomical relationship to the joint capsule: Capsular ligaments = blends in with the joint capsule, or a thickening of the joint capsule; enhance strength of capsule Extracapsular ligaments = separate from the joint capsule but stabilize the joint in close proximity to the capsule Intracapsular ligaments = are found within joint capsules, reinforce the connection between articulating surfaces Ligaments of Joints Vasculature and Innervation of Joints • Joints receive their blood supply from articular arteries, located in the joint capsule • Joints also have a rich nerve supply, the nerve endings are found in the joint capsule • Joints provide sensory information to the brain about proprioception via proprioceptive receptors (awareness of the position of the joint in space) • Joints also have pain receptors, however not all structures within a joint will be pain sensitive OVERVIEW OF MUSCLE TISSUE • There are three types of muscle tissue • Skeletal muscle tissue is primarily attached to bones. It is voluntary. • Movement of the body • Movement at joints • Cardiac muscle tissue forms the wall of the heart. It is involuntary. • Beating of the heart to pump blood • Smooth (visceral) muscle tissue is located in the walls of organs (viscera) It is involuntary. • Movement of food through GI system • Secretion of fluids from glands Skeletal Muscle •attaches to bone, skin or fascia •voluntary control of contraction & relaxation •Each skeletal muscle is supplied by a motor and sensory nerve The Muscular System Introduction • The voluntarily controlled muscles of the body make up the muscular system. • Muscles are the motors of the skeletal system • Allow bones to move or change position • Unique ability to contract actively and produce tension • Muscle pulls with equal force on both attachments (origin and insertion) • What determines the direction of pull is the FIBRE DIRECTION of the muscle belly Muscle Attachment Sites: Origin and Insertion • Skeletal muscles shorten & pull on the bones they are attached to Origin: the point at which muscle attaches to a bone (usually) or another muscle. The structure that the origin is attached to USUALLY is not moved by the contraction of the muscle Insertion: the point a muscle attaches to the skin, a bone, or another muscle. The insertion attaches to the structure that will be moved by contraction of the muscle • Fleshy portion of the muscle in between attachment sites = belly Types of Muscular actions • Isometric – the muscle contracts, produces force, but no gross movement of the muscle occurs (stability) • Concentric – the muscle shortens while contracting, producing acceleration of body segments. • Eccentric – the muscle lengthens while contracting. Eccentric contractions decelerate body segments and provide shock absorption, such as when landing from a jump. Role of Muscles in the Body Agonist/Prime Mover • Principle muscle producing a joint motion or maintaining a posture • Always contracts actively to produce a concentric, isometric, or eccentric contraction Antagonist • Is the muscle that has the opposite anatomic action of the agonist • Usually is a muscle that neither assists nor resists but that passively elongates or shortens to permit the motion to occur Synergist (helpers) • The muscle that contracts at the same time as the agonist • The action may be identical or nearly identical to the agonists Stabilizer/Fixator/Supporter • Muscles that are active isometrically to keep a limb from moving when the agonist muscle contracts HOW ARE SKELETAL MUSCLES NAMED Based on several types of characteristics. (640 skeletal muscles) • These characteristics may be reflected in the name of the muscle. • The most important characteristics include the direction in which the muscle fibers run, the size, shape, action, numbers of origins, and location of the muscle, and the sites of origin and insertion of the muscle Examples from Table 11.2 • triceps brachii -- 3 sites of origin • quadratus femoris -- square shape • serratus anterior -- saw-toothed edge Tendon ● Tendons and aponeuroses are extensions of connective tissue that attach muscle to bone or other muscle • A tendon is a cord of dense connective tissue that attaches a muscle to the bone , or to the skin or to another muscle Aponeurosis, Ligament • An aponeurosis is a sheet tendon that extends as a broad, flat layer Tendon Sheaths Tube like structure made by connective tissue wrap around tendons of the muscles at wrist and ankle where many tendons come together in a confined space Fascia • Superficial fascia is loose connective tissue & fat underlying the skin. It is homologous to hypoderm in skin. It contains the superficial veins and sensory nerves. • Deep fascia: Dense irregular connective tissue under the superficial fascia that wraps the body. It is well defined in limbs. Introduction to Nerves • A nerve is an enclosed, cable-like bundle of dendrites or axons • Sensory nerves are nerves that receive sensory stimuli, such as how something feels and if it is painful • Motor nerves allow the brain to stimulate muscle contraction. A motor nerve is exclusively contains the axons of the neurons which innervates skeletal muscles or glands • The term spinal nerve generally refers to the mixed sensory and motor spinal nerves, which comes out of the spinal cord. They innervate most of the skeletal muscles in our body • Cranial nerves are nerves that emerge directly from the brain. They contain sensory and motor nerve fibers and innervates some of the head and neck muscles Spinal & Cranial Nerves