Joints and Muscles PDF

# Joints ## Fibrous Joints - No moving - Bones connected by fibrous tissue - No joint cavity - 3 types: 3 fibrous joints - Sutures - Syndesmoses - Gomphoses ## 3 Types of Fibrous Joints | Type | Sutures | Syndesmoses...

# Joints ## Fibrous Joints - No moving - Bones connected by fibrous tissue - No joint cavity - 3 types: 3 fibrous joints - Sutures - Syndesmoses - Gomphoses ## 3 Types of Fibrous Joints | Type | Sutures | Syndesmoses | Gomphoses | |--------------|---------------------------------------------|------------------------------------------------------------------------|------------------------------------------------------------| | Location | Skull bones | Between long bones (e.g., tibia-fibula) | Tooth socket | | Characteristics| Continuous fibrous tissue | Movement depends on fiber length | Peg-in-socket structure | | | Ossify and fuse with age | Connected by ligaments | Periodontal ligament | | Examples | Coronal suture | Interosseous membrane (radius-ulna) | Teeth in alveolar sockets | ## Cartilaginous Joints - Articulating bones connected by cartilage - Lack a joint cavity - Not highly movable - Has 2 types: - Primary cartilaginous - Secondary cartilaginous ## 2 Types of Cartilaginous Joints | Type | Description | Characteristics | Examples | |----------------------|----------------------------------------------------------------------------|-----------------------------------------------------------------------------------|-----------------------------------------------------------------------------------| | Primary Cartilaginous Joints | Unites the bones with hyaline cartilage | Immovable | Epiphyseal plates | | | | Ossify with age | Manubrium of the sternum | | Secondary Cartilaginous Joints | Resilient shock absorber using a layer of fibrocartilage on hyaline cartilage | Provides strength and flexibility | Intervertebral discs | | | | Slightly movable | Pubic symphysis | ## Synovial joints ### General Structure of Synovial Joints - **Articuler cartilage** - **Joint Cavity:** - Most of the body as a joint - All diarthroses (freely movable) - All contain a fluid-filled joint cavity - Ends of bones have hyaline cartilage - Function: Spondy cushions absorb pressure that occurs during movement or loading (e.g., being crushed) from ends of bones - Protects the bone from being crushed - **Joint Cavity:** - Potential space, a small potential space between the bones that make up the joint - Content: Synovial fluid, a clear or slightly yellowish fluid with lubricant to reduce friction and nourishment for cartilage - Importance: absorb shock, protect against breakdown, and provide flexibility - **Articuler or Joint capsule:** - Dense irregular connective tissue, makes a "fibrous capsule" - Essential part of the synovial joint structure that provides full protection of the joints - Main properties: Two layered, different in structure and function - Outer layer: Fibrous capsule - Strong and fused with periosteum (dense fibrous membrane which covers outer surfaces of the bone) - Provides protection and support - Inner layer: Synovial membrane - Made of loose connective tissue - Lines the inner surface that is not covered by hyaline cartilage - Produces synovial fluid - **Synovial fluid:** - Made of synovial membrane and is a filtrate of blood components - Has a viscous property (special glycoproteins, lubricates cartilage) - Nourishes the cartilage - Lubricates the joint surface to reduce friction between surfaces - Acts as a "weeping lubricant" to maintain continuous lubrication - **Reinforcing ligaments:** Some joints - Most Common: thickened parts - Extracapsular: Outside the articular capsule, provides further support - Intracapsular: Inside the articular capsule, protects synovial fluid ## Nerves - Blood vessels: - Feeds and reduces friction - Detect pain - Monitor stretch - monitor nerve endings of capsule (to inform the body and control his movement) - Rich blood supply: Synovial membrane contains blood vessels - Capillary beds: Extensive capillary beds in the synovial membrane - Blood filtrate (synovial fluid) ## Synovial joints classified by shape: - **Plane Joints:** - Slightly movable, simple gliding movements - Example: - Tarsal bones - Carpal bones - **Hinge Joints:** - Uniaxial movement, flexion and extension - Example: - Knee Joint - Elbow Joint - **Pivot Joints:** - Rotatory movements - Example: - Proximal radioulnar join - Atlantoaxial Joint - **Condyloid joints:** - Biaxial movement, flexion and extension, abduction and adduction - Example: - Wrist joint - Metacarpophalangeal joints - **Saddle Joints:** - Biaxial movement - Example: - Carpometacarpal joint of the thumb - **Ball-and-Socket:** - Multiaxial movement - Example: - Hip Joint - Shoulder Joint ## Shoulder (Glenohumeral) joint and the Rotator cuff muscles - The glenohumeral joint provides great flexibility in movement, but relies on the rotator cuff muscles for stability and injury prevention. - Ball and socket (hip joint) - The "hip joint" is a ball-and-socket joint that allows for a wide range of movement in multiple directions while providing high stability due to its anatomical structure and surrounding ligaments. ## Elbow joint (hinge joint) - Hinge allows for flexion and extension only - Ligaments: - Annular ligament (wraps around the radius) - Radial collateral ligament (strengthens the capsule) - Ulnar collateral ligament (holds the ulna in place) - Muscles crossing the joint: flexion and extension - triceps, biceps, etc. - Trauma: affects movement and stability, injuries include ligament, muscle, and bone tears ## Wrist joint (Condyloid joint) - 2 major joint surfaces with several ligaments stabilize - Radiocarpel joint: - Location: between radius and proximal carpels - Type: Condyloid joint - Movement: flexion, extension, abduction, adduction, circumduction - Intercarpal or midcarpal joint: - Location: between the proximal and distal rows of carpels ## Disorders of joints: - Injuries - Sprains - Dislocations - Torn cartilage - Inflammatory and degenerative conditions: - Bursitis - Tendinitis - Arthritis ## Muscles - The muscular system moves substances throughout the body - Bones of the skeletal system - Food through the digestive system - Blood through the circulatory system - Fluids through the excretory system - Types of muscle tissue - Skeletal muscles - Cardiac muscles - Smooth muscles ### Skeletal muscles - These muscles are attached to bones and help in voluntary movements, like walking, running, lifting. - Striated muscles. ### Cardiac muscles - Found only in the heart, these muscles contract involuntarily to pump blood throughout the body (striated) ### Smooth muscles - Involuntary muscles, found in organs, like the stomach, intestines, and blood vessels. - Help with digestion and regulating blood flow. - Non-striated ☆ Skeletal muscles attach to bones by tendons (connective tissue). ☆ Skeletal muscles, like the biceps muscle and tendon (triceps muscle and tendon). The largest tendon in the body: Achilles tendon ☆ Smooth muscles lines organs and involuntarily move food, empty liquids, control width of blood vessels. ☆ Smooth muscles around the artery allow the artery to regulate blood flow by shrinking and expanding. ☆ Cardiac muscle is only found in the heart. ☆ Pumps blood throughout the body + contains more mitochondria than skeletal muscle cells.