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Comprehensive Notes on the Knee Joint and Related Anatomical Concepts

  • Personal Reflections and Life Shifts

    • The instructor is currently going through stages comparable to grief, compartmentalizing aspects of life.

    • Compartmentalization Analogy: As a foreign language (German) student, they would switch entirely to German thought mode, leading to academic success (A's).

    • Current Shift: Transition from a household with three people (grandchild, child, and self) to an empty house, as the grandson's schedule means he is gone before the instructor wakes and is not present when he goes to bed.

    • This represents another major shift in life, leading to a need to readjust and recalibrate.

    • The new "compartment" is currently filled primarily with doctor's appointments, a stark contrast to previous family-focused compartments.

    • Medical Updates:

      • An echocardiogram was normal, confirming a heart valve is working.

      • Noted a 65\% efficiency in the left ventricle, which requires further research but is not surprising at his age.

      • Upcoming appointments include a neurologist and an orthopedist for a frozen, painful shoulder, anticipating potential surgery.

    • Family Dynamics: Now sees his son and grandson significantly less frequently due to independent schedules, reducing previous daily interaction to weekly visits.

    • Lack of Worry for Grandson: Expresses no worry because the grandson avoids drugs, sex, alcohol, and smoking, (except for potentially a "heavy foot" while driving, which he jokingly leaves to God).

    • Coping Mechanisms: Reorders life, uses hobbies (basketball, football) to enter "fan mode" and momentarily distract from the vacuum.

    • Learning Styles: Acknowledges different learning styles, some prefer detailed, ordered notes, while others (like him) prefer compartmentalizing and working from different "compartments." The latter is described as normal.

  • Course and Exam Information

    • Course Progress: After today's lecture, one-third (\frac{1}{3}) of the course is completed, covering up to Chapter 8.

    • Upcoming Lecture Exam: Next week, there will be a lecture exam focused solely on bones.

    • Lab Exam Focus: The only articulation model on the lab exam will be the knee model. Shoulder and hip models are not included.

    • Combined Exam Content: The exam will cover skeletal tissue (axial and appendicular skeleton) and the knee joint (articulation), encompassing Chapters 6, 7, and 8.

    • Exam Difficulty: This is historically the hardest test of the semester, and the instructor does not curve it. It's intended to "slap you upside the head" and refocus students as the course approaches its halfway point.

    • Preparation Advice:

      • Do intense preparation and create condensed notes.

      • Focus on how bones relate to each other: arrangement, connection, location (e.g., wrist and ankle bones, what sits next to/above/below what).

    • Instructor as Resource: Students are encouraged to use the instructor as a resource for test preparation. He knows what will be on the test and how it will be delivered, but students rarely ask.

    • Next Module: Starting Monday and Wednesday next week, the course will be 100\% focused on muscles. The instructor will then be unavailable for two weeks after Monday.

  • The Knee Joint: Anatomy, Injuries, and Treatment

    • Classification: The knee is a freely movable (diarthritic) joint.

    • Personal Experience: The instructor, a former basketball player, experienced significant knee problems from an early age due to extensive physical activity (suicides, bleacher laps, diving for loose balls), resulting in very noisy (squeaky) knees by high school graduation.

    • Joint Capsule: The knee is a "closed capsule" system, its own world. It contains:

      • Cartilage

      • Synovial fluid (acting like "WD-40", viscous for lubrication)

      • Articular cartilage on the ends of the tibia, fibula, and femur

      • Tendons

      • Ligaments

    • Orientation for Models: Crucially, understand that the tibia is medial (big toe side) and the fibula is lateral when examining a knee model.

    • Ligaments (Outside/Collateral): These are near the skin surface with good blood supply, allowing for relatively good healing (<3 months recovery).

      • Medial Collateral Ligament (MCL) / Tibial Collateral Ligament (TCL): Number 6 on the model. A complete tear causes the leg to tend medially, losing medial control.

      • Lateral Collateral Ligament (LCL) / Fibular Collateral Ligament (FCL): Number 7 on the model. A complete tear causes the leg to tend laterally, leading to instability.

      • Cause of Tears: Typically result from external forces, such as someone landing on a bent leg.

    • Ligaments (Inside/Cruciate): These are deep within the joint capsule with poor blood supply, leading to long recovery times (minimum 6 months, more likely 1 year) and intense physical therapy.

      • Crux/Crus Analogy: The term "cruciate" comes from Roman Latin "crux" or "crus", meaning "cross", visually representing their crossing pattern.

      • Anterior Cruciate Ligament (ACL): Number 8 on the model. A tear causes the knee to collapse and slide forward.

      • Posterior Cruciate Ligament (PCL): Number 9 on the model. A tear causes the leg to want to go backward.

      • Consequence of Tears: Unlike collateral ligament tears, which might allow limping, cruciate ligament tears prevent sustained movement.

    • Menisci:

      • Medial Meniscus: Number 5 on the model.

      • Lateral Meniscus: Number 13 on the model.

      • Function: Located in the center, they divide the joint capsule and are made of cartilage, similar to articular cartilage.

      • Injury (Incomplete Tear): A common injury involves a small piece of meniscus cartilage coming loose but still attached, causing a "click click click" sound with movement, rather than significant pain. This is compared to a "Y-shaped cheese slicer" shaving.

      • Surgery (Meniscectomy): An outpatient arthroscopic procedure with three small holes, irrigation, microscope, and mini forceps to remove the loose piece. Recovery is quick, often <3 weeks, using immobilization like a walking boot or knee wrap. The instructor has had this 2-3 times.

    • Other Protective Structures:

      • Fat Pads: Around the joint, they protect the knee and serve as energy storage.

      • Bursae: Fluid-filled sacs (like "water balloons") around the joint that act as shock absorbers. Inflammation is called bursitis (e.g., "tennis elbow"). These can rupture from trauma (like diving for loose balls).

    • Preventive Measures: Joggers need special shoes, inserts, and correct running techniques to protect their knees from high impact.

    • Fluid Drainage: The instructor's personal experience includes having synovial fluid drawn from his knee with a syringe at 13 years old due to trauma, necessitating being strapped down during the procedure.

  • Types of Joints and Movements

    • General Definition: A joint occurs wherever two bones meet.

    • Joint Classifications:

      • Immovable (Synarthrotic): No movement (e.g., skull sutures, teeth in sockets).

      • Slightly Movable (Amphiarthrotic): Limited movement (e.g., tibia and fibula, although radius and ulna in the upper arm have more rotation).

      • Freely Movable (Diarthrotic) / Synovial Joints: Extensive movement (e.g., fingers, wrist, elbow, shoulder, hip, knee, ankle).

    • Characteristics of Synovial Joints:

      • Hyaline (articular) cartilage on bone ends.

      • Synovial fluid within the joint cavity.

      • Joint capsule.

      • Ligaments on the outside to anchor and stabilize the joint.

      • Synovial membrane lining the capsule to produce fluid.

      • Periosteum continues from the bone to cover ligaments, forming a continuous sheet of connective tissue. Bone itself is connective tissue.

    • Range of Motion (Planes):

      • Monoaxial: Movement in one plane (e.g., elbow: extension/flexion; ankle).

      • Biaxial: Movement in two planes (e.g., wrist: side-to-side and up/down).

      • Triaxial: Movement in three or more planes (e.g., shoulder, hip: high degree of rotation and various movements around the head of the femur/humerus).

    • Lab Focus: The lab will primarily focus on identifying synovial/diarthritic joints and their key components, rather than detailed classification of movement planes.

    • Knee X-ray Interpretation: A healthy joint will show a "shadow" representing articular cartilage on an X-ray. "Bone on bone" indicates a lack of cartilage, leading to a "crunch crunch crunch" sound, similar to "rice krispies."

  • Future of Joint Treatment: Stem Cell Therapy

    • Traditional Knee Replacement: The instructor describes the procedure as surgically removing the ends of the tibia and femur, drilling holes, and implanting artificial components (like "pegs" secured with "superglue"), a process likened to "working with wood." This is considered "irrelevant" by current standards due to new research.

    • Stem Cell Therapy: Peer-reviewed research is now focusing on stem cell therapy for younger patients (up to 50 years old). This treatment aims to replace all cartilage in the knee with the patient's own stem cells, avoiding surgery and potentially rebuilding the knee to its original state. This is projected to be available within 5 years, offering athletes an alternative to steroid shots.

  • Patellar Ligament and Quadriceps

    • Patellar Ligament: Connects the kneecap (patella) to the tibia.

    • Quadriceps Muscles (Quads): The instructor emphasizes the importance of the quads for knee strength. He "prehabbed" (strengthened) his quads before knee surgery, which allowed him to get up and move independently shortly after surgery, much to the "annoyance" of nurses who expected him to use a call button.

  • Military Service Anecdote (Vietnam War Era)

    • Draft System: The instructor registered for the draft on his 18^{th} birthday, as was required for males at the time.

    • ASVAB Exam: Scored in the 99^{th} percentile on the ASVAB exam.

    • Refusal of OCS (Officer Candidate School): Despite high scores, he declined OCS based on advice from three cousins who served in Vietnam. He preferred to be a "sniper" (behind the lines/leadership) rather than a "butter bar" (second lieutenant) on the front lines, citing the repeated and dangerous task of retaking hills.

    • Draft Physical: On March 17, 1972 (St. Patrick's Day), during his army physical with 400 other recruits, only 2 failed, and he was one of them. He failed due to trauma to his knees from basketball.

    • Reflection on Vietnam: Acknowledges the difficulties faced by returning veterans, who were sometimes called "baby killers," cursed at, and suffered psychological trauma, highlighting his support for the military but questioning specific war strategies.

  • Muscle Movements (Preview for Next Week)

    • The next lectures will cover various muscle movements, determined by their origins and insertions.

    • Examples:

      • Inversion: Foot forced inward (causes ankle twists).

      • Eversion: Foot forced outward (less common for injury).

      • Dorsiflexion: Toes up, towards the back (used to alleviate cramps).

      • Plantarflexion: Toes down (e.g., dancing on tiptoes).

    • Other actions include contraction, retraction, elevation, and compression.

    • Students understanding bone anatomy now will find the muscle portion (muscle etiology) easier if they combine their knowledge. The instructor will explain these movements on Monday and Wednesday.