MSK Learning Objectives Final Exam .pdf

MSK I Learning Objectives Final Exam Days 2-5 Tissue Physiology and Histology Structure and Functions of Connective Tissue: Structure: Connective tissue is like the glue that holds everything together in our body. It has cells spread out in a background called the extracellular matrix, whi...

MSK I Learning Objectives Final Exam Days 2-5 Tissue Physiology and Histology Structure and Functions of Connective Tissue: Structure: Connective tissue is like the glue that holds everything together in our body. It has cells spread out in a background called the extracellular matrix, which is made up of fibers and a gel-like substance. Bone: osteocytes/osteoblast Cartilage: chondrocytes/chondroblasts CT Proper: fibrocytes, fibroblasts Functions: It supports and binds other tissues, stores nutrients, and helps repair tissues. Three Major Structural Proteins: Collagen: The most common one; it's strong and provides structure type I collagen Elastin: Makes tissues stretchy, like in your skin Reticular Fibers: They form a web-like network that supports tissues type III collagen Structural Protein in Bone: Collagen: It’s the main protein that gives bone its strength. Ground Substance Molecules: Glycosaminoglycans (GAGs): These are long chains that attract water to keep tissues hydrated. Proteoglycans: GAGs attached to proteins; they help the tissue resist compression. Multiadhesive Glycoproteins: Help cells stick to the matrix and each other. Unique Features of Bone’s Extracellular Matrix: Bone: Has a very hard extracellular matrix because it has a lot of minerals (like calcium) mixed with collagen. Other Connective Tissues: Usually softer and more flexible. Cells in Connective Tissue Proper: Fibroblasts: Make the fibers in the matrix. Macrophages: Eat up germs and debris. Adipocytes: Store fat. Cells in Bone: Osteoblasts: Build new bone. Osteocytes: Maintain the bone. Osteoclasts: Break down old bone. Types of Connective Tissue: Loose Connective Tissue: Soft and flexible, with a lot of space between cells (like a cushion). Dense Irregular Connective Tissue: Tough and can handle stress from many directions (like the skin). Dense Regular Connective Tissue: Strong in one direction, like tendons and ligaments. Two Major Types of Bone: Compact Bone: Dense and forms the outer layer of bones. Spongy Bone: Lighter and has a spongy structure inside bones. Haversian System Structure: Haversian System: The structure in compact bone with rings (lamellae) around a central canal that holds blood vessels. Periosteum and Endosteum: Periosteum: A tough membrane covering the outer surface of bones. Endosteum: A thin layer lining the inside of bones. Principal Minerals in Bone: Calcium and Phosphorus: These minerals make bone hard and strong. Bone Hormones: Parathyroid Hormone (PTH): Increases blood calcium by breaking down bone. Calcitonin: Decreases blood calcium by building bone. Macroscopic Bone Structure and Function: Long Bones: Longer than they are wide, like the thigh bone. Short Bones: About as wide as they are long, like wrist bones. Flat Bones: Thin and flat, like the skull. Irregular Bones: Have complex shapes, like the spine. Cortical vs. Cancellous Bone: Cortical Bone: Dense and forms the outer layer. Cancellous Bone: Sponge-like inside the bone. Bone Formation: Intramembranous Ossification: Bone forms directly from a membrane (like the skull). Endochondral Ossification: Bone forms from cartilage (like long bones). Bone Structure During Development: Primary Ossification Center: Where bone first starts forming. Secondary Ossification Centers: Form later, often at the ends of bones. Blood Supply to Bone: Blood travels through small vessels in the Haversian system and outside the bone to keep it healthy. Bone Response to Stress and Fracture: Stress: Bone becomes stronger where it’s used a lot. Fracture: Bone heals by creating new tissue. Microscopic Structure of Cartilage: Cells in Cartilage: Chondrocytes make the cartilage matrix. Glycosaminoglycans (GAGs): Attract water and keep cartilage hydrated. Proteoglycans: Help cartilage resist compression. Multiadhesive Glycoproteins: Help cells stick to cartilage. Major Protein Fiber in Cartilage: Collagen: Provides strength and support to cartilage. Joint Structure and Function Connective Tissue 1. Describe the General Structure and Major Functions of Connective Tissue:  Structure: Connective tissue is like the body’s glue. It has three main parts: cells, fibers (like ropes), and a gel-like background called the extracellular matrix. The cells are spread out and float in the matrix, which helps hold everything together. Functions: Connective tissue supports and connects other body parts, stores important nutrients, and helps repair tissues when they get hurt. Joint Structure and Function 2. Describe the Structure and Function of Joints: Structure: Joints are where two or more bones meet. They are held together by ligaments and may have extra features like cartilage to help them move smoothly. Function: Joints allow bones to move in different ways, which helps us do things like walk, bend, and twist. 3. Compare and Contrast the Structure and Function of Fibrous, Cartilaginous, and Synovial Joints: Fibrous Joints: These are like tight stitches between bones, where they don’t move much (e.g., skull bones). They are strong and connect bones tightly. Cartilaginous Joints: These have cartilage between the bones, allowing a bit more movement (e.g., spine). They cushion and absorb shock. Synovial Joints: These are the most flexible joints with a space between the bones filled with fluid (e.g., knees). They allow for a lot of movement. 4. Describe Movements at Synovial Joints: Flexion: Bending a joint (like bringing your hand to your shoulder). Extension: Straightening a joint (like stretching your arm out). Abduction: Moving a body part away from the middle (like lifting your arm sideways). Adduction: Moving a body part toward the middle (like bringing your arm back down). Supination: Turning your palm up. Pronation: Turning your palm down. 5. Compare and Contrast Hinge, Ball-and-Socket, Plane, and Condyloid Synovial Joints: Hinge Joints: Move back and forth like a door (e.g., elbow). Allows for flexion and extension. Ball-and-Socket Joints: Allow movement in many directions (e.g., shoulder). Can do flexion, extension, abduction, adduction, and rotation. Plane Joints: Slide past each other (e.g., wrist). Allows sliding and gliding movements.  Condyloid Joints: Allow movement but not full rotation (e.g., fingers). Can move side-to-side and up-and-down. 6. Describe the Function of Ligaments in the Musculoskeletal System: Ligaments: These are strong bands of tissue that connect bones to each other. They help stabilize and support the joints, keeping the bones in place. 7. Describe the Characteristics of Normal Synovial Fluid: Synovial Fluid: It’s a slippery liquid inside synovial joints. It helps reduce friction between bones and keeps the joint moving smoothly. It’s mostly water with some proteins and other substances to lubricate the joint. 8. Describe the Structure of a Joint Capsule and the Production of Synovial Fluid: Joint Capsule: It’s like a stretchy bag around the joint. It has two layers: ○ Outer Layer: Tough and helps hold the joint together. ○ Inner Layer: Has cells called synoviocytes that produce synovial fluid. 9. Explain the Role of Synovial Fluid: Role: Synovial fluid acts like oil in a machine. It lubricates the joint, reduces friction, and helps the bones move smoothly against each other. 10. Explain the Microscopic Structure and Function of Articular Cartilage: Articular Cartilage: This is a smooth, slippery layer of cartilage on the ends of bones in a joint. It’s unique because it helps reduce friction and absorb shock, making joint movements smooth and painless. Joints of the Fore and Hind Limbs 11. Identify the Flexor and Extensor Surfaces of Fore and Hind Limb Joints and Describe Their Passive Range of Motion: Flexor Surface: The side of the limb where bending (flexion) happens. Extensor Surface: The side where straightening (extension) happens. Passive Range of Motion: This refers to how far a joint can move without muscle effort, just by stretching or pulling. 12. Describe the Structure and Function of Collateral Ligaments:  Collateral Ligaments: These are ligaments on the sides of joints that help keep them stable by preventing excessive side-to-side movement. Extrinsic Muscles of the Forelimb 1. Describe or Identify the Extrinsic Muscles of the Forelimb, Their Approximate Attachments, and Their Major Actions: Trapezius: ○ Attachment: From the cervical and thoracic vertebrae (spine) to the scapula (shoulder blade). ○ Action: Moves the shoulder blade and helps elevate the forelimb. Latissimus Dorsi: ○ Attachment: From the thoracic and lumbar vertebrae to the humerus (upper arm bone). ○ Action: Pulls the forelimb back and helps with shoulder movement. Brachiocephalicus: ○ Attachment: From the base of the skull and cervical vertebrae to the humerus. ○ Action: Moves the forelimb forward and assists in neck movement. Rhomboid: ○ Attachment: From the cervical and thoracic vertebrae to the scapula. ○ Action: Draws the shoulder blade towards the spine. Serratus Ventralis: ○ Attachment: From the ribs to the scapula. ○ Action: Supports and moves the scapula, aiding in forelimb stability. 2. Differentiate Between Intrinsic and Extrinsic Muscles: Extrinsic Muscles: These start outside the forelimb, often from the trunk or neck, and attach to the forelimb. They primarily control large movements and provide support. Intrinsic Muscles: These are located within the forelimb itself. They control finer movements and stability of the limb. Muscles and Major Non-Muscular Structures of the Ventral Neck in Animals 3. Describe or Identify the Muscles of the Ventral Neck Attaching to the Sternum: Sternohyoid: ○ Attachment: From the sternum to the hyoid bone. ○ Action: Lowers the hyoid bone and assists in swallowing. Sternothyroid: ○ Attachment: From the sternum to the thyroid cartilage.  ○ Action: Lowers the thyroid cartilage and aids in swallowing and vocalization. 4. Describe or Identify the Trachea, Esophagus, Nerve Trunks, and Major Vessels in the Ventral Neck: Trachea: ○ Description: The airway that conducts air from the nose and mouth to the lungs. ○ Location: Located centrally in the neck, just in front of the esophagus. Esophagus: ○ Description: The tube that carries food from the mouth to the stomach. ○ Location: Positioned behind the trachea. Nerve Trunks: ○ Description: Large nerves that transmit signals between the brain and the rest of the body. ○ Location: Located in the neck, these nerves are crucial for controlling movements and sensations. Major Vessels: ○ Description: Important blood vessels that transport blood to and from the heart. ○ Examples: Carotid Arteries: Supply blood to the head. Jugular Veins: Return blood from the head to the heart. Histology of Connective Tissues, Bones, and Joints Describe the Microscopic Features of Connective Tissue in General, and Bones and Joints Specifically: Connective Tissue: Under a microscope, connective tissue looks like a mix of cells and a background called the extracellular matrix. The matrix can be jelly-like, thick, or even hard. The cells can be spread out or packed together depending on the type. Bones: Bones under a microscope show a lot of tiny channels (Haversian systems) with cells and hard layers around them. Joints: In joints, you can see smooth cartilage, synovial fluid, and the connective tissue that holds everything together. 2. List the Cells Found in Connective Tissue Proper and Indicate Which Ones Produce the Extracellular Matrix: Fibroblasts: These cells make and organize the extracellular matrix. Macrophages: These cells clean up waste and germs. Adipocytes: These cells store fat. 3. List the Cells that Make Up Bone and Describe Their Roles in Bone Homeostasis: Osteoblasts: Build new bone. Osteocytes: Maintain the bone, keeping it healthy. Osteoclasts: Break down old bone to make way for new bone. 4. Compare and Contrast Loose Connective Tissue, Dense Irregular Connective Tissue, and Dense Regular Connective Tissue: Loose Connective Tissue: Soft and flexible with a lot of space between cells. It cushions and supports organs. Dense Irregular Connective Tissue: Strong and can handle stress from many directions. It’s found in places like the skin. Dense Regular Connective Tissue: Very strong in one direction, like tendons and ligaments. 5. Compare and Contrast the Microscopic Anatomy of the Two Major Types of Bone: Compact Bone: Dense with tightly packed layers. Looks like a bunch of tiny, nested rings. It’s very strong and forms the outer layer of bones. Spongy Bone: Lighter and has a spongy, honeycomb-like structure inside bones. It helps make bones lighter and contains bone marrow. 6. Describe the Structure of the Haversian System: Haversian System: This is like a tiny tube inside compact bone. It has a central canal that holds blood vessels and nerves, surrounded by layers of bone called lamellae. 7. Describe the Structure, Function, and Location of Periosteum and Endosteum: Periosteum: A tough, outer layer covering the bone. It helps with bone repair and growth. Endosteum: A thin layer lining the inside of bones. It helps with bone maintenance and growth. 8. Identify or Describe the Cell Types or Structures Discussed in the Musculoskeletal System Histology Lab 1 PowerPoint: Since I don’t have access to the PowerPoint, check for specific cells like osteoblasts, osteocytes, and osteoclasts, as well as structures like Haversian systems or synovial fluid. 9. Describe the Microscopic Structure and Function of Cartilage:  Cartilage: Smooth and flexible. It looks like a gel with cells (chondrocytes) inside. It helps reduce friction and cushions joints. 10. Identify the Components of a Synovial Joint Using Light Microscopy: Components: ○ Articular Cartilage: Smooth surface on the bones. ○ Synovial Fluid: Lubricating liquid inside the joint. ○ Joint Capsule: The protective covering around the joint. ○ Ligaments: Connect bones and stabilize the joint. Describe the Structure and Function of Skeletal Muscles and Tendons: Skeletal Muscles: These are long, thin cells (muscle fibers) bundled together. They contract (shorten) to move bones. Muscles have different layers of connective tissue around them: ○ Endomysium: Surrounds each muscle fiber. ○ Perimysium: Groups fibers into bundles called fascicles. ○ Epimysium: Covers the whole muscle. Tendons: These are strong, flexible cords that connect muscles to bones. They help transfer the force from muscles to bones to move the body. 2. Describe the Structure of Muscles Down to Individual Muscle Cells (Fibers) and the Connective Tissue That Surrounds These Structures: Muscle Fibers: Muscle cells are long and thin with many nuclei. Inside, they have special proteins that help them contract. Connective Tissue: ○ Endomysium: Wraps each muscle fiber. ○ Perimysium: Surrounds groups of muscle fibers. ○ Epimysium: Encloses the whole muscle. 3. Explain How Skeletal Muscles Are Attached to Bones: Attachments: Muscles are attached to bones by tendons. One end of the muscle (origin) is usually attached to a fixed point, and the other end (insertion) moves with the muscle's contraction. 4. Compare and Contrast Tendons (and Aponeuroses) to Ligaments: Tendons: Connect muscles to bones and help move the skeleton. Ligaments: Connect bones to other bones and stabilize joints.  Aponeuroses: Similar to tendons but are flat sheets of connective tissue that attach muscles to bones or other muscles. 5. Classify the Attachments of Appendicular Muscles as Origins or Insertions Based on Their Location: Origins: The fixed attachment point of a muscle, often found on a larger, stable bone. Insertions: The movable attachment point of a muscle, usually on a bone that moves when the muscle contracts. 6. Define Agonist and Antagonist in Terms of Muscle Actions: Agonist: The muscle that does most of the work to create a movement (e.g., the biceps when you bend your arm). Antagonist: The muscle that works opposite to the agonist to return the body part to its original position (e.g., the triceps when you straighten your arm). 7. Compare and Contrast the Blood Supply of Tendons or Ligaments to Muscles and Predict Which Tissue Has Better Healing: Muscles: Have lots of blood vessels, so they heal faster. Tendons/Ligaments: Have fewer blood vessels, so they heal more slowly. 8. Predict the Probable Action of a Muscle Given Its Origin and Insertion: Example: If a muscle originates on the shoulder blade and inserts on the upper arm, it helps move the arm at the shoulder joint. Synovial Bursae and Sheaths 9. Describe the Structure and Function of Synovial Bursae and Sheaths: Synovial Bursae: Small fluid-filled sacs that cushion and reduce friction between bones and soft tissues. Synovial Sheaths: Surround tendons where they pass through narrow spaces, helping them move smoothly. Major Muscles of the Shoulder and Brachium 10. Describe or Identify the Major Intrinsic Muscles of the Shoulder and Brachium, Their Attachments, and Their Major Actions: Supraspinatus: Helps lift the arm.  ○ Origin: Scapula (shoulder blade). ○ Insertion: Humerus (upper arm). Infraspinatus: Helps rotate the arm. ○ Origin: Scapula. ○ Insertion: Humerus. Deltoideus: Moves the arm away from the body. ○ Origin: Scapula and collarbone. ○ Insertion: Humerus. Long Head of the Triceps Brachii: Helps extend the elbow. ○ Origin: Scapula. ○ Insertion: Olecranon (elbow). Biceps Brachii: Helps bend the elbow and rotate the arm. ○ Origin: Scapula. ○ Insertion: Radius (forearm). 11. Describe or Identify the Specific Origins of the Following Muscles: Supraspinatus: From the supraspinous fossa of the scapula. Infraspinatus: From the infraspinous fossa of the scapula. Deltoideus: From the scapula and clavicle. Long Head of the Triceps Brachii: From the scapula. Biceps Brachii: From the scapula. 12. Describe or Identify the Specific Insertions of the Following Muscles: Supraspinatus: Greater tubercle of the humerus. Infraspinatus: Greater tubercle of the humerus. Deltoideus: Deltoid tuberosity of the humerus. Triceps Brachii: Olecranon process of the ulna. 13. Describe or Identify the Transverse Humeral Retinaculum and Its Relationship to the Shoulder Joint and the Tendon of Origin of the Biceps Brachii Muscle: Transverse Humeral Retinaculum: A band of tissue that holds the biceps brachii tendon in place across the shoulder joint. 14. Identify the Infraspinatus and Olecranon Bursae: Infraspinatus Bursa: Located under the infraspinatus muscle to reduce friction. Olecranon Bursa: Located at the back of the elbow to cushion the joint. Blood Vessels and Nerves 15. Describe or Identify the Major Blood Vessels of the Axilla, Shoulder, and Brachium: Axillary Artery and Vein: Supply blood to the shoulder and upper arm. Brachial Artery and Vein: Supply blood to the arm. 16. Describe or Identify the Nerves of the Brachial Plexus (Part 1): Suprascapular Nerve: Controls muscles that help lift and rotate the shoulder. Subscapular Nerve: Controls muscles that rotate the shoulder. Axillary Nerve: Controls the deltoid muscle for arm movement. Radial Nerve: Controls muscles that extend the elbow and wrist. Musculocutaneous Nerve: Controls muscles that flex the elbow. 17. Describe or List the Major Muscles of the Shoulder or Brachium Innervated by the Suprascapular, Axillary, Radial, and Musculocutaneous Nerves: Suprascapular Nerve: Supraspinatus, infraspinatus. Axillary Nerve: Deltoideus, teres minor. Radial Nerve: Triceps brachii, extensor muscles of the forearm. Musculocutaneous Nerve: Biceps brachii, brachialis. 18. Predict the Consequences of Loss of Function of the Suprascapular or Radial Nerves: Suprascapular Nerve Loss: Difficulty lifting the arm and rotating the shoulder. Radial Nerve Loss: Inability to extend the elbow or wrist, leading to a "wrist drop." 19. Deduce the Consequences of Damage to a Brachial Muscle or Its Attachments: Damage to Brachial Muscle: Can lead to weakness or loss of function in arm movement, depending on the muscle and where it's damaged. Muscles of the Antebrachium and Manus Describe or Identify the Major Muscles of the Antebrachium (Forearm) and Manus (Hand/Paw), Their Attachments, and Their Actions: Antebrachium Muscles: ○ Extensor Muscles: These help to straighten the wrist and fingers. Attachment: From the lateral side of the elbow to the back of the paw. Action: Straightens the carpus (wrist) and digits (fingers/toes). ○ Flexor Muscles: These help to bend the wrist and fingers. Attachment: From the medial side of the elbow to the front of the paw. Action: Bends the carpus and digits.  Manus Muscles: ○ Digital Flexors and Extensors: Control the movement of individual digits. 2. Name the Muscles of the Antebrachium Based on Their Distal Attachments and Their Position: Distal Attachments: ○ Flexor Muscles: Attach to the bones in the palm or bottom of the paw. ○ Extensor Muscles: Attach to the bones on the top of the paw. Position: ○ Flexor Muscles: Located on the inner (medial) side of the forearm. ○ Extensor Muscles: Located on the outer (lateral) side of the forearm. 3. Differentiate Between Muscles Acting Only on the Carpus and Those Acting on Both the Carpus and Digits: Carpus Only: ○ These muscles only move the wrist. ○ Example: Some muscles just adjust the angle of the wrist without affecting the fingers. Carpus and Digits: ○ These muscles move both the wrist and the fingers. ○ Example: Muscles that help you grip and release objects. 4. Describe or Identify the Major Attachments of the Digital Extensors and Flexors in Carnivores: Digital Extensors: ○ Attachment: From the lateral side of the elbow to the tips of the claws or toes. ○ Action: Straightens the claws or toes. Digital Flexors: ○ Attachment: From the medial side of the elbow to the pads or tips of the claws. ○ Action: Bends the claws or toes. 5. Compare and Contrast the Antebrachial Muscles Originating From (or Close to) the Medial and Lateral Humeral Epicondyles in Terms of Function and Innervation: Medial Epicondyle Muscles: ○ Function: Mainly flex the wrist and fingers. ○ Innervation: Typically by the median and ulnar nerves. Lateral Epicondyle Muscles: ○ Function: Mainly extend the wrist and fingers.  ○ Innervation: Typically by the radial nerve. 6. Describe or Identify the Flexor Retinaculum of the Carpus: Flexor Retinaculum: ○ Description: A band of connective tissue on the front of the wrist. ○ Function: Keeps the flexor tendons in place as they move. Major Vessels of the Antebrachium 7. Identify the Median Artery and the Cephalic Vein: Median Artery: ○ Location: Runs down the forearm and supplies blood to the front part of the limb. Cephalic Vein: ○ Location: Runs along the outer (lateral) side of the forearm and is used for drawing blood. Nerves of the Brachial Plexus 8. Describe or Identify the Nerves of the Brachial Plexus (Part 2): Ulnar Nerve: ○ Function: Controls some of the muscles that flex the wrist and digits. ○ Location: Runs along the inner side of the forearm. Median Nerve: ○ Function: Controls muscles that flex the wrist and digits. ○ Location: Runs along the middle of the forearm. 9. Describe or Identify Antebrachial Nerves and Their Targets: Radial Nerve: ○ Targets: Muscles that extend the elbow, wrist, and digits. Musculocutaneous Nerve: ○ Targets: Muscles that flex the elbow. Ulnar Nerve: ○ Targets: Muscles that flex the wrist and some of the digits. Median Nerve: ○ Targets: Muscles that flex the wrist and digits. 10. Compare and Contrast the Muscle Groups Innervated by the Radial Nerve and the [Median + Ulnar] Nerves:  Radial Nerve: ○ Muscle Groups: Extensors of the elbow, wrist, and digits. Median and Ulnar Nerves: ○ Muscle Groups: Flexors of the wrist and digits. 11. Predict the Consequences of Loss of Function of the Radial Nerve at the Level of the Elbow: Loss of Radial Nerve Function: ○ Consequences: The animal cannot extend its elbow, wrist, or digits. This results in a "wrist drop" where the paw hangs down and cannot be raised. Imaging 12. Identify and Describe Normal Structures on Radiographic Images of the Fore and Hind Limbs of Domestic Mammals: Forelimbs: Look for bones like the humerus, radius, ulna, and bones of the paw. Hind Limbs: Look for bones like the femur, tibia, fibula, and bones of the foot. 13. Given a Radiographic Image, Describe the View Using the Correct Terminology: DP (Dorsal-Plantar): The view from the top of the paw looking down. Lateral: The side view. Oblique: A tilted view. 14. Describe How to Position a Radiographic Cassette to Radiograph the Carpus and Tarsus of the Horse: Carpus (Wrist): ○ Position: Place the cassette in a way that captures both the front and side views of the carpus. Tarsus (Ankle): ○ Position: Place the cassette to capture the front and side views of the tarsus. 15. Correctly Place the Identifying Label on the Cassettes for DP, Lateral, and Oblique Views of the Equine Carpus and Tarsus: DP View: Label the cassette "DP" for the dorsal-plantar view. Lateral View: Label the cassette "Lateral" for the side view. Oblique Views: Label according to the angle, like "DPMLO" (Dorsal-Palmar-Medial-Lateral Oblique). 16. Explain How DPMLO, DPLMO, PDLMO, and PDMLO Views Differ: DPMLO: Dorsal-Plantar-Medial-Lateral Oblique – A view from the top, angled to see the medial and lateral sides. DPLMO: Dorsal-Plantar-Lateral-Medial Oblique – A view from the top, angled to see the lateral and medial sides. PDLMO: Palmar-Dorsal-Lateral-Medial Oblique – A view from the bottom, angled to see the lateral and medial sides. PDMLO: Palmar-Dorsal-Medial-Lateral Oblique – A view from the bottom, angled to see the medial and lateral sides. Cartilage and Ligaments 1. Describe the Function, Structure, and Location of Perichondrium: Function: The perichondrium is a dense layer of connective tissue that surrounds cartilage. It helps provide nutrients to the cartilage and assists in its growth and repair. Structure: It consists of two layers: ○ Outer Layer: Dense and fibrous, contains blood vessels and nerves. ○ Inner Layer: Contains cells that can produce new cartilage. Location: Surrounds most types of cartilage except for the articular cartilage found in joints. 2. Compare and Contrast the Structure, Function, and Location of the 3 Major Types of Cartilage: Hyaline Cartilage: ○ Structure: Smooth and glassy appearance; has a matrix with fine collagen fibers. ○ Function: Provides support and flexibility; reduces friction in joints. ○ Location: Found in the nose, trachea, and at the ends of long bones. Elastic Cartilage: ○ Structure: Similar to hyaline cartilage but contains more elastic fibers, making it more flexible. ○ Function: Provides flexibility and shape retention. ○ Location: Found in the outer ear (pinna) and the epiglottis. Fibrocartilage: ○ Structure: Has thick collagen fibers arranged in bundles; tough and durable. ○ Function: Provides strong support and can absorb shock. ○ Location: Found in intervertebral discs and the pubic symphysis. 3. Differentiate Between the 3 Major Types of Cartilage Using Light Microscopy:  Hyaline Cartilage: Appears smooth and glassy with a homogeneous matrix; chondrocytes are scattered in lacunae. Elastic Cartilage: Contains numerous elastic fibers that appear as dark lines in the matrix; chondrocytes are in lacunae. Fibrocartilage: Shows thick bundles of collagen fibers in the matrix, making it look more fibrous; chondrocytes are in lacunae but less numerous. 4. Identify the Components of a Synovial Joint Using Light Microscopy: Synovial Fluid: Appears as a clear, viscous fluid in the joint cavity. Articular Cartilage: Smooth cartilage covering the ends of bones. Synovial Membrane: Lining of the joint capsule that secretes synovial fluid. Joint Capsule: Surrounds the joint, formed by dense connective tissue. Cellular Transport Day 7 Explain How Molecules Move Across Cell Membranes: Passive Transport: Molecules move across the cell membrane without using energy. This includes: ○ Diffusion: Movement from high to low concentration. ○ Osmosis: Diffusion of water through a selectively permeable membrane. ○ Facilitated Diffusion: Uses proteins to help molecules pass through the membrane. Active Transport: Molecules move against their concentration gradient using energy (usually from ATP). This includes: ○ Pumps: Proteins that move ions or molecules against their gradient (e.g., sodium-potassium pump). ○ Endocytosis: Cells engulf external substances into vesicles. ○ Exocytosis: Cells expel substances by merging vesicles with the membrane. 6. Describe Which Ions Are More Abundant Inside Mammalian Cells and Which Ones Are More Abundant in the Extracellular Fluid: Inside Cells: ○ Potassium (K⁺): Higher concentration inside cells. ○ Phosphate (PO₄³⁻): Higher concentration inside cells. Extracellular Fluid: ○ Sodium (Na⁺): Higher concentration outside cells. ○ Chloride (Cl⁻): Higher concentration outside cells. Resting Membrane Potential 1. Explain How the Resting Cell Membrane Potential Is Generated and Maintained: Generation: The resting membrane potential happens because: ○ Sodium-Potassium Pump: Moves 3 sodium ions out of the cell and 2 potassium ions into the cell, making the inside of the cell more negative. ○ Ion Leakage: Potassium ions leak out of the cell more than sodium ions come in, adding to the negative charge inside. Maintenance: The resting membrane potential is kept stable by: ○ Continuous Operation of the Sodium-Potassium Pump: Keeps the concentration of ions balanced. ○ Selective Permeability of the Membrane: Allows certain ions to pass through at different rates to maintain the potential. 2. Explain the Significance of a Resting Membrane Potential: Importance: The resting membrane potential is essential because it: ○ Action Potentials: Provides the baseline condition needed for nerve impulses and muscle contractions. ○ Cell Communication: Allows cells to respond properly to signals and send messages. 3. Deduce Which Direction Ions Will Flow Across a Cell Membrane Given Their Electrical and Chemical Potential: Chemical Potential: Ions move from where they are in high concentration to where they are in low concentration. Electrical Potential: Ions move towards areas with opposite charges (positive ions go to negative regions and vice versa). Overall Movement: ○ Sodium Ions (Na⁺): Move into the cell because they are more concentrated outside and are attracted to the negative inside. ○ Potassium Ions (K⁺): Move out of the cell because they are more concentrated inside and the outside is less negative compared to the inside. 4. Define the Equilibrium Potential of an Ion: Equilibrium Potential: The voltage at which there is no net movement of a specific ion across the cell membrane. It balances the ion's concentration gradient and electrical gradient. Anatomy of the Large Animal Manus (Part 1) 5. Describe or Identify the Bones and Joints of the Equine and Ruminant Distal Forelimb: Bones: ○ Equine: Includes the radius, ulna, carpal bones, metacarpal bones, and phalanges. ○ Ruminants: Similar bones but may have slight differences in structure and arrangement. Joints: ○ Equine: Includes the carpal joints (antebrachiocarpal, middle carpal, carpometacarpal), metacarpophalangeal joints, and digital joints. ○ Ruminants: Similar joints with minor anatomical differences. 6. Compare and Contrast the Weight-Bearing Digit(s) of Horses and Ruminants: Horses: ○ Weight-Bearing: Mainly the third digit (middle digit) forms the single hoof. Ruminants: ○ Weight-Bearing: Two digits (the third and fourth digits) form cloven hooves. 7. Compare and Contrast the Range of Motion of the Carpal Joints in Horses (Ruminants are Similar): Antebrachiocarpal Joint: Allows the most movement, especially flexion and extension. Middle Carpal Joint: Allows moderate movement; less than the antebrachiocarpal joint. Carpometacarpal Joint: Has limited movement; mainly for stabilization. 8. Describe Which Carpal Joints Communicate in the Horse: Communicating Joints: ○ Antebrachiocarpal and Middle Carpal Joints: Often communicate with each other. ○ Middle Carpal and Carpometacarpal Joints: Generally do not communicate directly. 9. Describe or Identify Where Joint Pouches (= Outpouchings of the Synovial Capsule) of the Metacarpophalangeal Joints Are Palpable: Metacarpophalangeal Joint Pouches: ○ Location: Palpable on the medial and lateral sides of the fetlock joint. 10. Describe or Identify the Ligaments and Tendons of the Equine Distal Forelimb and the Equivalent Structures of the Canine and Feline Digit: Equine:  ○ Deep Digital Flexor Tendon: Runs along the back of the leg and flexes the digit. ○ Superficial Digital Flexor Tendon: Runs along the front of the leg and also flexes the digit. ○ Distal Check Ligament: Supports the deep digital flexor tendon. ○ Interosseous Ligament: Stabilizes the fetlock joint and has extensor branches. ○ Common Digital Extensor Tendon: Extends the digits. Canine and Feline: ○ Digital Flexors and Extensors: Have similar functions but are adapted for different movement patterns. 11. Predict the Structures That Could Be Damaged by a Deep Cut to the Dorsal or Palmar Cannon Region in Horses or Ruminants: Dorsal Cut: ○ Structures: Common digital extensor tendon, interosseous ligament, and possibly the metacarpophalangeal joint. Palmar Cut: ○ Structures: Deep and superficial digital flexor tendons, distal check ligament, and possibly the digital flexor tendons. 12. Describe and Identify the Nerves and Vessels of the Equine Distal Limb: Nerves: ○ Medial and Lateral Palmar Digital Nerves: Located on the sides of the digit. ○ Palmar Nerve: Supplies the palm area. ○ Palmar Metacarpal Nerves: Found deeper near the metacarpal area. Vessels: ○ Medial and Lateral Digital Arteries and Veins: Run along the sides of the digit. ○ Medial and Lateral Digital Nerves: Travel alongside the digital arteries and veins. Anatomy of the Large Animal Manus (Part 2) 1. Describe or Identify the Ligaments and Tendons of the Equine Distal Forelimb: Superficial and Deep Digital Flexor Tendons: ○ Superficial Digital Flexor Tendon: Lies closer to the skin; runs along the front of the leg and helps flex the digits. ○ Deep Digital Flexor Tendon: Lies deeper and behind the superficial flexor tendon; helps flex the digits and is essential for weight bearing. Relationship:  ○ Cannon Region: Both tendons run together but are separate; the superficial is more on the front. ○ Fetlock Region: Both tendons are close but still distinct; the superficial one splits to allow the deep tendon to pass. ○ Pastern Region: The deep tendon is the primary flexor, while the superficial tendon is more involved in stabilizing. 2. Describe or Identify the Insertion of the Common Digital Extensor and the Digital Flexor Tendons: Common Digital Extensor Tendon: Inserts on the dorsal surface of the phalanges (the bones of the digits). Digital Flexor Tendons: ○ Deep Digital Flexor Tendon: Inserts on the palmar surface of the distal phalanx (coffin bone). ○ Superficial Digital Flexor Tendon: Inserts on the palmar surface of the middle phalanx and the distal phalanx indirectly. 3. Describe the Role of the Interosseous Ligament, Its Extensor Branches, and the Distal Sesamoidean Ligaments During Weight Bearing: Interosseous Ligament: Stabilizes the fetlock joint by connecting the sesamoid bones with the metacarpal bone. Extensor Branches: Assist in extending the digits and support the fetlock joint. Distal Sesamoidean Ligaments: Support the fetlock joint during weight bearing and prevent overextension. 4. Describe the Structure and Function of Tendon Sheaths: Structure: Tendon sheaths are tube-like structures that surround tendons and contain synovial fluid. Function: They reduce friction between tendons and surrounding tissues, allowing smooth movement. 5. Describe or Identify the Approximate Location of Tendon Sheaths at the Level of the Carpus and Fetlock in Horses and Cattle: Carpus: Tendon sheaths are located on the front of the leg, surrounding the flexor tendons. Fetlock: Tendon sheaths are around the fetlock joint, enclosing the digital flexor tendons. 6. Predict the Effects That Severely Damaging the Deep Digital Flexor Tendon or Interosseous Ligament Would Have on Weight Bearing:  Deep Digital Flexor Tendon Damage: Can lead to severe difficulty or inability to flex the digits, causing significant weight-bearing issues. Interosseous Ligament Damage: Can result in instability of the fetlock joint, leading to lameness and problems with weight bearing. 7. Describe and Identify the Structures of the Equine and Ruminant Digit Including the Hoof: Navicular Bone: Positioned behind the coffin bone; it sits in the middle of the hoof and is cushioned by the navicular bursa. Phalanges: The bones of the digit, including the coffin bone (distal phalanx), the short pastern bone (middle phalanx), and the long pastern bone (proximal phalanx). Navicular Bursa: Located between the navicular bone and deep digital flexor tendon. 8. Describe or Identify the Walls of the Hoof, the Bulbs of the Heels, the Coronary Band, and Palmar Hoof Structures (Sole, Frog): Walls of the Hoof: The hard outer part of the hoof that protects the internal structures. Bulbs of the Heels: Soft, rounded structures at the back of the hoof. Coronary Band: The area where the hoof wall meets the skin, important for hoof growth. Sole: The concave, bottom part of the hoof that supports weight. Frog: The V-shaped, soft structure in the middle of the hoof that aids in shock absorption. 9. Describe or Identify the Approximate Location of the Navicular Bone Within the Hoof of the Horse: Location: The navicular bone is located at the back of the hoof, underneath the deep digital flexor tendon and above the coffin bone. 10. Describe or Identify the Relationship of the Coffin Bone to the Hoof Wall of the Horse or Claw of Ruminants: Coffin Bone (Horse): The coffin bone is the distal phalanx and fits inside the hoof wall, with the hoof wall providing protection and support. Claw (Ruminants): The coffin bone is located inside the claw and is surrounded by the hard outer claw wall. Anesthesia of the Distal Limb of Large Animals 11. Describe the Location and Effect of Common Local Anesthetic Blocks in the Equine Distal Limb:  Nerve Blocks: ○ Palmar Digital Nerve Block: Numbs the palmar part of the hoof and lower part of the digit. ○ Abaxial Sesamoid Nerve Block: Numbs the entire foot and part of the pastern. ○ High Nerve Block: Numbs the entire limb below the carpus or hock. 12. Explain the Rationales for Performing Local Anesthesia of the Distal Limb of Horses: Purpose: To diagnose lameness by pinpointing the source of pain or to perform surgical procedures with minimal discomfort. 13. Describe the Locations and Effects of the Common Local Nerve Blocks of the Equine Distal Forelimb: Palmar Digital Nerve Block: Affects the palmar digital nerves, blocking pain in the hoof and lower digit. Abaxial Sesamoid Block: Affects both palmar digital nerves and provides more extensive pain relief up to the fetlock. High Nerve Block: Numbs the entire foot, including structures up to the carpus. 14. Deduce the Probable Source of Pain Based on the Results of Local Anesthetic Blocks: Positive Response to Block: Indicates the pain source is in the area affected by the block. No Response: Suggests the pain is from a different area not covered by the block. 15. Place a Needle in the Correct Locations for the Distal Local Anesthetic Blocks on a Fresh (But Dead) Equine Limb: Procedure: Insert the needle at specific landmarks to target the nerves accurately for pain relief. 16. Explain the Rationale for Intravenous Anesthesia of the Distal Limb in Horses and Ruminants: Purpose: To perform procedures on the distal limb with minimal sedation, allowing for more precise and safe operations. The Neuromuscular Junction 1. Describe or Explain the Structure and Function of the Neuromuscular Junction:  Structure: The neuromuscular junction (NMJ) is a specialized connection between a motor neuron and a muscle fiber. It consists of: ○ Presynaptic Terminal: The end of the motor neuron containing vesicles filled with acetylcholine (ACh). ○ Synaptic Cleft: The gap between the neuron and the muscle fiber. ○ Postsynaptic Membrane: The muscle fiber's membrane, which has receptors for ACh. Function: The NMJ transmits signals from the nerve to the muscle, causing muscle contraction. When an action potential reaches the presynaptic terminal, ACh is released into the synaptic cleft, binds to receptors on the postsynaptic membrane, and triggers muscle contraction. 2. Describe How Acetylcholine Acts on the Postsynaptic Membrane and How Its Action Is Terminated: Action: ○ Binding: ACh binds to receptors on the muscle fiber’s postsynaptic membrane, leading to the opening of ion channels and depolarization of the muscle cell, which causes contraction. Termination: ○ Degradation: The action of ACh is terminated by the enzyme acetylcholinesterase, which breaks down ACh in the synaptic cleft. This ensures that the muscle is not continually stimulated. 3. Predict the Effects of Interruption of Acetylcholine Release, Degradation, and/or Reuptake on the Function of the Neuromuscular Junction: Interruption of ACh Release: Prevents muscle contraction because no signal is sent to the muscle fiber. Inhibition of ACh Degradation: Causes prolonged muscle contraction or twitching, as ACh remains in the synaptic cleft too long. Impaired ACh Reuptake: Similar to inhibition of degradation, it may result in sustained muscle contraction or excessive stimulation. Axial and Hind Limb Anatomy 4. Describe or Identify the Major Groups of Epaxial and Sublumbar Muscles: Epaxial Muscles: Located along the spine; responsible for extending and laterally flexing the vertebral column. ○ Examples: Longissimus and iliocostalis.  Sublumbar Muscles (Hypaxial Muscles): Located beneath the lumbar spine; involved in flexing the spine and supporting the abdominal wall. ○ Examples: Psoas major and iliacus. 5. Identify the Thoracolumbar Fascia: Thoracolumbar Fascia: A thick connective tissue covering the muscles of the back and abdomen, providing support and structure to the epaxial and sublumbar muscles. 6. Describe the Functions of Epaxial and Sublumbar Muscles When Acting One-Sided and/or Bilaterally: Epaxial Muscles: ○ One-Sided: Rotate and laterally flex the vertebral column. ○ Bilaterally: Extend the vertebral column (straighten the back). Sublumbar Muscles: ○ One-Sided: Laterally flex the vertebral column. ○ Bilaterally: Flex the lumbar region of the spine and support the abdominal wall. 7. Identify the Iliopsoas Muscle and Its Insertion, and Describe Its Actions: Iliopsoas Muscle: ○ Insertion: Lesser trochanter of the femur. ○ Actions: Flexes the hip joint and helps in bringing the limb forward. 8. Describe or Identify the Nuchal Ligament and Its Parts: Nuchal Ligament: A ligament that supports the head and neck, extending from the skull to the thoracic vertebrae. ○ Parts: Nuchal Ligament Proper: The main part. Funicular Part: The thicker, cord-like section extending from the skull to the spine. 9. Compare and Contrast the Nuchal Ligament of Dogs, Horses, and Ruminants: Dogs: Have a much less developed nuchal ligament; it is not prominent. Horses: Have a well-developed nuchal ligament, providing strong support for the head and neck. Ruminants: Similar to horses but may have variations in thickness and length. 10. Name the Domestic Species Lacking a Nuchal Ligament:  Cats and Pigs do not have a nuchal ligament. 11. Describe the Hip Joint and Its Movements: Hip Joint: A ball-and-socket joint between the femur and the acetabulum of the pelvis. Movements: ○ Flexion: Bringing the thigh towards the abdomen. ○ Extension: Moving the thigh away from the abdomen. ○ Abduction: Moving the leg away from the midline. ○ Adduction: Bringing the leg towards the midline. ○ Rotation: Rotating the thigh internally or externally. 12. Describe or Identify the Lateral, Medial, Deep, and Caudal Muscles and Ligaments of the Croup and Thigh: Lateral Muscles: ○ Gluteal Muscles: Extend and abduct the hip; attach to the greater trochanter of the femur. Medial Muscles: ○ Adductors: Bring the limb towards the body, such as the adductor magnus. Deep Muscles: ○ Hip Flexors: Like the iliopsoas muscle. Caudal Muscles: ○ Hamstring Muscles: Biceps Femoris: Extends the hip, flexes the knee. Semitendinosus: Extends the hip, flexes the knee. Semimembranosus: Extends the hip and stabilizes the knee. 13. Identify the Sacrotuberous Ligament of the Dog (Not Present in Cats!): Sacrotuberous Ligament: Connects the sacrum to the ischial tuberosity; helps stabilize the pelvis. 14. Describe or Identify the Obturator and Sciatic Nerves and the Muscle Groups They Innervate: Obturator Nerve: ○ Innervates: Medial thigh muscles (adductors). Sciatic Nerve: ○ Innervates: Caudal thigh muscles (hamstrings) and the muscles of the lower leg. 15. Based on Their Fields of Innervation, Predict the Loss of Function Resulting from Damage to the Obturator or the Sciatic Nerve:  Obturator Nerve Damage: Results in difficulty with adduction of the limb, leading to instability and possible splaying of the limbs. Sciatic Nerve Damage: Causes loss of function in the hamstrings and the lower leg muscles, affecting hip extension, knee flexion, and overall hind limb movement. 16. Describe or Identify the Major Blood Vessels of the Proximal Pelvic Limb: Femoral Artery and Vein: Major vessels supplying and draining blood from the proximal pelvic limb. Gluteal Arteries and Veins: Supply the gluteal muscles. Imaging the Equine Digit 17. Describe How Radiographs of the Distal Limb of the Horse Are Obtained and Their Nomenclature: Radiograph Views: ○ Dorsal-Palmar (DP): Shows the front-to-back view of the limb. ○ Lateral-Medial (LM): Shows the side view of the limb. ○ Oblique Views: Different angles, such as Dorsal-Palmar-60°Lateral (DPLLO), to visualize specific structures. 18. Identify the Bones of the Equine Digit on Radiographs: Bones: ○ Coffin Bone: Distal phalanx. ○ Navicular Bone: Located behind the coffin bone. ○ Short Pastern Bone: Middle phalanx. ○ Long Pastern Bone: Proximal phalanx. 19. Position an Equine Distal Limb Correctly to Obtain Radiographs of the Digit, Coffin, and Navicular Bones: Positioning: ○ Digit: Place the limb in a standing position with the x-ray beam perpendicular to the hoof. ○ Coffin Bone: Position the limb so the x-ray beam targets the distal phalanx. ○ Navicular Bone: Position the limb in an oblique view to best visualize the navicular bone and its relations. 20. Describe the Path of the X-Ray Beam Given a Labeled Radiograph of the Equine Distal Limb:  X-Ray Beam Path: ○ Dorsal-Palmar View: Beam travels from the front of the limb to the back. ○ Lateral-Medial View: Beam travels from the side of the limb to the other side. ○ Oblique Views: Beam at an angle to capture specific structures, like the navicular bone. Post-Synaptic Events Leading to Muscle Contraction 1. Describe How an Action Potential Is Propagated Along the Muscle Fiber and the Structures That Make This Possible: Propagation: ○ Action Potential: Starts at the neuromuscular junction when ACh binds to receptors on the muscle fiber, leading to a change in membrane potential. ○ T-Tubules: The action potential travels deep into the muscle fiber through transverse tubules (T-tubules), which are extensions of the muscle cell membrane. ○ Sarcolemma: The muscle cell membrane conducts the action potential along its surface. 2. Explain Why a Muscle Action Potential Is an “All or None” Reaction: All or None: Once the action potential reaches a threshold level, it will propagate fully along the muscle fiber without varying in strength. This ensures a consistent and full muscle contraction. 3. Describe the Mechanism of Depolarization of the Muscle Cell Membrane, Including the Channels That Open to Generate an Action Potential: Depolarization: ○ Na⁺ Channels: Voltage-gated sodium channels open in response to the initial depolarization, allowing sodium ions to enter the cell. ○ Membrane Potential: This influx of sodium ions makes the inside of the cell more positive, leading to the propagation of the action potential along the membrane. 4. Propose Ways in Which the Transmission of the Signal from the Motor Nerve Terminal to the Muscle Fiber Can Be Interrupted: Interruptions: ○ Blocking ACh Release: Botulinum toxin prevents ACh release from the nerve terminal. ○ ACh Receptor Blockade: Curare blocks ACh receptors on the muscle fiber.  ○ AChesterase Inhibition: Inhibitors of acetylcholinesterase can disrupt signal termination. 5. Describe How Depolarization of T-Tubules Leads to Calcium Release from the Sarcoplasmic Reticulum: Depolarization: ○ T-Tubules: The action potential travels down T-tubules. ○ Sarcoplasmic Reticulum (SR): Depolarization of T-tubules triggers the opening of voltage-sensitive channels in the SR, leading to the release of calcium ions into the muscle cell. 6. Describe the Roles of the T-Tubules and the Sarcoplasmic Reticulum: T-Tubules: Conduct the action potential from the cell surface deep into the muscle fiber. Sarcoplasmic Reticulum: Stores and releases calcium ions, which are essential for muscle contraction. 7. Describe the Roles of the Dihydropyridine (DHPR) and Ryanodine (RyR1) Receptors: DHPR Receptors: Located on the T-tubules, they sense the action potential and trigger the release of calcium from the SR. RyR1 Receptors: Located on the SR, they release calcium ions into the cytoplasm in response to DHPR activation. 8. Describe the Mechanism of Repolarization of the Muscle Membrane: Repolarization: ○ K⁺ Channels: Voltage-gated potassium channels open, allowing potassium ions to leave the cell, which restores the negative membrane potential. ○ Restoration: Sodium-potassium pump helps restore the original ion distribution by moving Na⁺ out of the cell and K⁺ into the cell. 9. Describe the Channels That Open to Repolarize the Muscle Membrane: Channels: Voltage-gated potassium channels open during repolarization to allow K⁺ ions to exit the cell. 10. Describe the Distribution of Electrolytes Between Intracellular and Extracellular Space During Repolarization: Intracellular: Increased potassium (K⁺) inside the cell. Extracellular: Increased sodium (Na⁺) outside the cell.  Repolarization: Restores higher K⁺ inside and higher Na⁺ outside. 11. Propose Ways the Process of Repolarization of the Muscle Membrane Could Be Interrupted: Interruptions: ○ Potassium Channel Blockade: Prevents K⁺ from exiting the cell, disrupting repolarization. ○ Sodium-Potassium Pump Failure: Impairs ion distribution and repolarization. Stifle and Thigh Anatomy 12. Describe the Stifle Joint and Identify Its Components: Stifle Joint: The knee joint in quadrupeds. ○ Components: Femoropatellar Articulation: Between the femur and the patella. Femorotibial Articulation: Between the femur and tibia. 13. Describe or Identify the Ligaments of the Stifle and Their Attachments: Cruciate Ligaments: ○ Cranial Cruciate Ligament: Prevents cranial movement of the tibia relative to the femur. ○ Caudal Cruciate Ligament: Prevents caudal movement of the tibia. Collateral Ligaments: ○ Medial Collateral Ligament: Stabilizes the inner side of the joint. ○ Lateral Collateral Ligament: Stabilizes the outer side of the joint. 14. Describe the Functions of the Cruciate and Collateral Ligaments of the Stifle: Cruciate Ligaments: Stabilize the joint by preventing excessive movement of the tibia relative to the femur. Collateral Ligaments: Provide lateral stability and prevent excessive side-to-side movement. 15. Deduce the Consequences of Damage to the Cruciate or Collateral Ligaments of the Stifle: Cruciate Ligament Damage: Leads to instability and excessive movement of the tibia relative to the femur, causing lameness. Collateral Ligament Damage: Results in instability and increased lateral movement of the joint, affecting normal function. 16. Describe or Identify the Cranial Muscles of the Hip and Thigh, Their Approximate Attachments, and Their Major Actions: Quadriceps Femoris: ○ Rectus Femoris: Originates from the ilium; extends the stifle. ○ Vastus Lateralis, Medialis, and Intermedius: Originate from the femur; also extend the stifle. 17. Identify or Describe the Specific Origin (Proximal Attachment) of the Rectus Femoris Muscle and Contrast Its Actions to the Other Components of the Quadriceps Femoris Muscle: Rectus Femoris: ○ Origin: Anterior inferior iliac spine. ○ Action: Flexes the hip and extends the stifle. Other Quadriceps Muscles: Mainly extend the stifle without hip flexion. 18. Describe or Identify the Femoral and Saphenous Nerves and the Muscle Groups or Areas They Innervate: Femoral Nerve: Innervates the quadriceps muscle and helps extend the stifle. Saphenous Nerve: Provides sensory innervation to the medial aspect of the thigh and leg. 19. Based on Their Fields of Innervation, Predict the Loss of Function Resulting from Damage to the Femoral Nerve: Femoral Nerve Damage: Leads to inability to extend the stifle and difficulty in weight bearing, as the quadriceps is affected. 20. Describe or Identify the Major Blood Vessels of the Proximal Pelvic Limb: Femoral Artery and Vein: Major blood vessels supplying and draining the proximal pelvic limb. Deep Femoral Artery: Provides additional blood supply to the hip region. Live Dog Lab: Identifying Major Clinically Relevant Musculoskeletal Structures 1. Describe the Normal Relationship Between the Tuber Ischium, Dorsal Iliac Crest, and Greater Trochanter: Tuber Ischium: A bony prominence on the pelvis, felt on the rear part of the hip.  Dorsal Iliac Crest: The top edge of the ilium bone of the pelvis, felt on the upper back of the hip. Greater Trochanter: A large bony prominence on the femur, located on the outer side of the hip. Normal Relationship: The tuber ischium is positioned lower and more posterior compared to the dorsal iliac crest. The greater trochanter is located laterally and slightly below the dorsal iliac crest, and it should align with the hip joint. 2. Explain the Significance of Disruption of This Relationship: Disruption: Changes in the normal relationship can indicate hip dysplasia, dislocations, or other pelvic abnormalities. Significance: ○ Hip Dysplasia: Misalignment may suggest hip joint instability or malformation. ○ Pain and Lameness: Disruption can lead to discomfort, reduced mobility, and lameness in the dog. ○ Clinical Assessment: Accurate palpation helps in diagnosing and managing hip and pelvic conditions. Muscle Contraction and Relaxation, Muscle Energetics 1. Muscle Contraction (Cross-Bridge Cycling) and Relaxation: Excitation-Contraction Coupling Steps: 1. Action Potential: A nerve impulse reaches the muscle fiber. 2. Calcium Release: Action potential travels down T-tubules, triggering the sarcoplasmic reticulum to release calcium ions. 3. Cross-Bridge Formation: Calcium binds to troponin, moving tropomyosin away from actin sites, allowing myosin heads to attach to actin. 4. Power Stroke: Myosin heads pull actin filaments towards the center of the sarcomere, causing contraction. 5. Release and Reset: ATP binds to myosin heads, causing them to release actin and reset for another cycle. Sarcomere Length Influence: Optimal Length: Sarcomeres contract most effectively when they are at their optimal length, allowing maximal overlap of actin and myosin filaments. Roles in Muscle Contraction: Actin and Myosin Filaments: Actin provides the binding sites for myosin heads; myosin pulls actin filaments. Troponin and Tropomyosin: Troponin binds calcium and shifts tropomyosin to expose actin binding sites. ATP: Provides energy for myosin heads to perform power strokes and reset. Calcium Ions: Bind to troponin to initiate contraction. Roles in Muscle Relaxation: Sarcoplasmic Reticulum Calcium ATPase (SERCA): Pumps calcium ions back into the sarcoplasmic reticulum, stopping contraction. ATP: Required for SERCA function and to detach myosin heads from actin. Rigor Mortis: Occurs: After death, ATP production ceases, preventing myosin heads from detaching from actin, causing muscle stiffness. Terminated: Eventually, muscle proteins break down and rigor mortis resolves. 2. Energy Sources of Skeletal Muscle: Energy Sources: Immediate Source: ATP (limited supply, used quickly). Short-Term: Creatine phosphate (quickly replenishes ATP). Long-Term: Glycogen (converted to glucose and used in aerobic respiration). Comparison: Availability: ATP and creatine phosphate are rapidly available but limited. Glycogen provides longer-term energy but requires time to process. ATP Supply: Creatine phosphate can quickly regenerate ATP; glycogen requires oxygen and time to convert to ATP. Oxygen Requirements: Glycogen-based energy requires oxygen (aerobic), while ATP and creatine phosphate can work without it (anaerobic). 3. Major Types of Skeletal Muscle Fibers: Type I Fibers (Slow-Twitch): Energy Source: Primarily aerobic (uses oxygen). Speed of Contraction: Slow.  Energy Use: More efficient and fatigue-resistant. Fatigability: Low. Type II Fibers (Fast-Twitch): Energy Source: Primarily anaerobic (less reliance on oxygen). Speed of Contraction: Fast. Energy Use: Less efficient but generate more power quickly. Fatigability: High. Role of Myoglobin: Function: Stores oxygen in muscle cells, supporting aerobic respiration. Motor Unit: Structure: A motor neuron and all the muscle fibers it innervates. Function: Coordinates muscle contractions. Muscle Fibers in Motor Units: Types: Motor units can include both Type I and Type II muscle fibers. Anatomy 1. Clinically Relevant Aspects of the Hock Joint: Range of Motion: Greatest to Least: Tarsocrural > Proximal Intertarsal > Distal Intertarsal > Tarsometatarsal. Joint Communication: Horses: Tarsocrural and Proximal Intertarsal joints often communicate. Dogs: Generally less communication between joints compared to horses. 2. Major Muscles of the Crus: Craniolateral Muscles: Actions: Extend the digits and flex the hock. Innervation: Common fibular nerve. Caudal Muscles:  Actions: Flex the digits and extend the hock. Innervation: Tibial nerve. Long Digital Extensor: Origin: Lateral aspect of the femur. Insertion: Extensor process of the distal phalanx. Gastrocnemius: Insertion: Calcaneal tuberosity (via the common calcanean tendon). Muscles Contributing to the Common Calcanean Tendon: Gastrocnemius, Superficial Digital Flexor, and Deep Digital Flexor. 3. Major Vessels and Nerves of the Crus: Tibial and Fibular Nerves: Tibial Nerve: Carries sensory information from the plantar surface of the foot. Fibular Nerve: Carries sensory information from the dorsal surface of the foot. 4. Damage Predictions: Tibial Nerve Damage: Effects: Loss of ability to extend the hock and flex the digits. Fibular Nerve Damage: Effects: Loss of ability to flex the hock and extend the digits. 5. Major Landmarks and Structures: Sacrotuberous Ligament (Dog vs. Large Animals): Dog: Sacrotuberous ligament is present. Cats: Sacrotuberous ligament is absent. Large Animals: Sacrosciatic ligament is present (broader version of sacrotuberous). Stay Apparatus (Horses and Ruminants): Locking Mechanism: Equine and bovine stifle locking mechanisms stabilize the limb for resting.  Reciprocal Apparatus: Links the stifle and hock joints, ensuring coordinated movement. Effects of Ligament or Tendon Damage: Patellar Ligament, Peroneus Tertius, or Calcanean Tendon Damage: Effects: Compromises the ability to lock the stifle or extend the hock, affecting weight-bearing and movement. Anatomy 1. Ventrolateral Muscles of the Abdominal Wall: Muscles and Aponeuroses: External Oblique: The most superficial layer. It attaches from the ribs (5-12) and the thoracolumbar fascia to the iliac crest and pubic tubercle. Its aponeurosis contributes to the formation of the linea alba. Internal Oblique: Intermediate layer, attaching from the iliac crest and lumbar fascia to the lower ribs and linea alba. Its aponeurosis also forms part of the linea alba. Transversus Abdominis: Deepest layer, extending from the lower ribs, iliac crest, and lumbar fascia to the linea alba. It is covered by the aponeurosis that contributes to the linea alba. Rectus Abdominis: Runs vertically from the pubic bone to the costal cartilages and xiphoid process. It is enclosed in the rectus sheath formed by the aponeuroses of the external and internal obliques and transversus abdominis. Cutaneous Trunci Muscle: Function: Allows twitching of the skin. Innervation: Lateral thoracic nerve. Muscles of the Abdominal Wall (Superficial to Deep): 1. Flank Region: ○ External Oblique ○ Internal Oblique ○ Transversus Abdominis ○ Rectus Abdominis (more medial) 2. Adjacent to the Linea Alba (Superficial to Deep): ○ External Oblique ○ Internal Oblique ○ Transversus Abdominis  ○ Rectus Abdominis Attachments: External Oblique: From ribs 5-12 to the iliac crest and pubic tubercle. Internal Oblique: From iliac crest and lumbar fascia to the lower ribs and linea alba. Transversus Abdominis: From the lower ribs, iliac crest, and lumbar fascia to the linea alba. Rectus Abdominis: From the pubic bone to the xiphoid process and costal cartilages. Innervation: Skin of the Flank: Innervated by the dorsal and ventral branches of the spinal nerves. Abdominal Muscles: Innervated by lower intercostal nerves, iliohypogastric nerve, and ilioinguinal nerve. 2. Major Bones and Muscles of the Head: Muscles of Mastication: Masseter: Elevates the mandible for chewing. Temporalis: Elevates and retracts the mandible. Pterygoids: Assist in grinding movements of the jaw. Muscles of Facial Expression: Orbicularis Oris: Encircles the mouth; helps in closing and puckering the lips. Orbicularis Oculi: Encircles the eyes; helps in closing the eyelids. Buccinator: Compresses the cheek against the teeth, aiding in chewing. 3. Gait and Lameness: Domestic Mammals Standing and Moving: Weight Bearing: The forelimbs support about 60% of the body weight in quadrupeds. Stances: ○ Plantigrade: Walking on the entire foot (humans). ○ Digitigrade: Walking on the toes (dogs, cats). ○ Unguligrade: Walking on the tip of the hoof (horses). Common Quadruped Gaits: Walk: Four-beat gait with a consistent rhythm. Amble/Pace: Two-beat gait with paired limb movements.  Trot: Two-beat diagonal gait with alternating diagonal pairs. Canter: Three-beat gait with a distinct lead. Gallop: Four-beat, fast gait with an extended stride. Adaptations for Speed: Carnivores: Tend to have flexible spines and long limbs for sprinting. Horses and Small Ruminants: Adapted for endurance with elongated limbs and specialized hooves. Identifying Lameness: Leg Causing Lameness: Observe the animal's gait and stance. Look for uneven movement or reluctance to bear weight on one leg. Criteria for Determining Lameness: Evaluate the symmetry of the gait, the rhythm, and the response to palpation and hoof testing. Intramuscular Injection Sites Small Animals: Lateral (Outer) Quadrant of the Rear Leg: Located in the vastus lateralis muscle of the thigh. Epaxial Muscles: Located along the dorsal aspect of the spine, typically between the last rib and the iliac crest. Triceps Muscle: On the upper rear part of the front leg. Ruminants: Cervical Region: In the large muscle mass of the neck, avoiding the jugular vein. Lateral Muscles of the Neck: Just behind the shoulder, in the large muscle mass of the neck. Muscles of the Hip: Specifically the gluteal muscles, avoiding the sciatic nerve. Horses: Cervical Region: In the large muscle mass of the neck, avoiding the jugular vein. Gluteal Muscles: Located on the hindquarters, avoid the sciatic nerve. Pectoral Muscles: Located in the chest area, but less commonly used. Performing an IM Injection: Small Animals:  1. Position: Secure the animal in a comfortable position. 2. Site: Locate the chosen site (e.g., vastus lateralis). 3. Technique: Insert the needle at a 90-degree angle and aspirate to ensure the needle is not in a blood vessel. Inject the medication and withdraw the needle. Equine: 1. Position: Ensure the horse is calm and secure. 2. Site: Locate the cervical or gluteal muscles. 3. Technique: Insert the needle at a 90-degree angle, aspirate, and inject the medication. Withdraw the needle and apply gentle pressure. Bovine: 1. Position: Secure the animal, preferably in a squeeze chute. 2. Site: Locate the cervical region or lateral muscles of the neck. 3. Technique: Insert the needle at a 90-degree angle, aspirate, inject the medication, and withdraw the needle. Communicating Medical Information Use precise and accurate terminology to describe conditions, procedures, and anatomical structures. Document findings clearly and concisely in reports or discussions, using standard medical terms and nomenclature. Radiographic Images of Limbs Normal Structures: Forelimbs: Include the scapula, humerus, radius, ulna, carpal bones, metacarpals, and phalanges. Hindlimbs: Include the pelvis, femur, patella, tibia, fibula, tarsal bones, metatarsals, and phalanges. Major Deviations: Fractures: Breaks in bones, evident as discontinuities. Dislocations: Misalignment of joints. Osteoarthritis: Joint space narrowing and bone spurs. Soft Tissue Abnormalities: Abnormal densities indicating swelling or foreign objects.