Gross Anatomy
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INTRODUCTION TO THE LIMBS

I. STUDY OF THE LIMBS

  1. Purpose
    1. Provide students with the knowledge base necessary to understand the anatomical basis of limb function.
    2. Give the students an opportunity to demonstrate their ability to utilize this information to solve clinical type problems related to limb function.
  2. Knowledge Base ( Information)
    1. Assigned required readings
      1. Pages in "Principles of Clinical Anatomy" will be assigned
      2. Students expected to complete assigned readings prior to class
      3. Readings constitute primary source of required information
    2. Presentations
      1. Formal lectures
        1. Provide basic information usual not covered in textbook
      2. Simulated Patient Exercises
        1. Based upon Observed Structured Clinical Examination (OSCE) format
        2. Students practice physical examination on simulated patient
        3. Scenario
          1. Found under Case Study Section of course web site
          2. Provides information concerning clinical situations involving the limbs ( Case Study)
        4. Simulated Patient
          1. Found under Case Study Section of course web site
          2. Provides information concerning the symptoms a patient having a given problem should exhibit
        5. Students act as Physician and as Patient
          1. Diagnose condition based upon anatomical knowledge and its application
  3. Handouts
    1. Guide to the topics and activities covered that day
      1. Outline format
      2. Topics covered in textbook will be indicated by the appropriate page numbers
    2. Contains required information needed to understand a topic and / or region
    3. Objectives
      1. Basic information a student needs to understand
      2. Manner in which the information is applied

II. FUNCTION OF THE LIMBS

  1. Bipedialism

    Anatomical changes believed to have first taken place between 3 - 5 million years ago that provided for a division of labor between the limbs.

    1. Upper Limb
      1. Primarily structured for mobility and manipulation
      2. Lost adaptation to support weight ( weight bearing) and/ or locomotion
    2. Lower limb
      1. Primarily structured for locomotion and weight bearing (support)
      2. Slight ability to manipulate
    3. Humans and other hominids are able to stand upright on and move about on 2 limbs
  2. Anatomical Features ( Fig. 1)
    1. Upper Limb
      1. Modified for movement and manipulation
      2. Scapula - designed to allow maximal movement of the upper limb
        1. close to the midline
        2. points outward
      3. Hand
        1. Manipulation
        2. Position of 1st metacarpal
        3. Opposition of the thumb
    2. Vertebral Column
      1. Lumbar curvature
        1. Weight bearing and transmission
    3. Lower Limb
      1. Modified for weight bearing & locomotion
        1. large sized bones
          1. Femur , tibia
      2. Joints
        1. Close pack fit
        2. More limited range of motion
      3. Pelvis
        1. Comprised of 3 bones
          1. Ischium - short
            1. Striding gait
          2. Ilium - broad, flat, flared
            1. attachment of hip stabilizing muscles
      4. Foot
        1. Weight bearing arches
        2. Size and shape of big toe

III. OSTEOLOGY( pgs. 11 -13; 309,310)

  1. Appendicular Skeleton
    1. Upper Limb
      1. Shoulder Girdle
        1. Scapula
        2. Clavicle
        3. Humerus - Proximal
      2. Arm
        1. Humerus
      3. Forearm
        1. Radius (lateral)
        2. Ulna (Medial)
      4. Wrist
        1. Carpal Bones
      5. Hand
        1. Metacarpals
        2. Phalanges
    2. Lower Limb
      1. Pelvic Girdle
        1. Hip (Os Coxae)
          1. Ilium
          2. Ischium
          3. Pubis
      2. Thigh
        1. Femur
      3. Leg
        1. Tibia
        2. Fibula
      4. Foot
        1. Tarsal bones
        2. Metatarsals
        3. Phalanges
  2. Joints
    1. Union ( articulation) between 2 bones
    2. Types
      1. Symphysis
        1. 2 bones united by fibrocartilage
        2. Strong joint with limited movement
        3. Types
          1. Intervertebral joints ; pubic symphysis
      2. Fibrous
        1. Bones united by connective tissue
        2. Little to no movement
        3. Types
          1. Sutures - cranial bones
          2. Syndemosis - radio-ulnar; tibio-fibular
    3. Synovial Joints
      1. Properties
        1. Very mobile
        2. Surrounded by connective capsule
        3. Bathed by synovial fluid- Reduces friction
        4. Apposed articulating surfaces covered with hyaline cartilage
      2. Shapes
        1. Varied
        2. Determine the types of movements available at each joint
        3. Ball and Socket
          1. Most mobile
          2. Glenohumeral ( shoulder) ; hip
        4. Hinge
          1. Flexion-extension
          2. Elbow
        5. Saddle
          1. 1st carpometacarpal joint
          2. Opposability of thumb
        6. Gliding/Planar
          1. Flat surfaces that permit gliding movements
          2. Articular facets of vertebrae

IV. Vascularity (pgs. 395-6;724 - 25)

  1. Arterial Supply
    1. Oxygenated blood to metabolically active structures of the limbs muscles
      1. bones
    2. Upper Limb
      1. Subclavian
        1. Branch of aortic arch
      2. Axillary
        1. Changes from subclavian after passing 1st. rib
        2. Located in region of arm pit (axilla)
      3. Brachial
        1. Derived from axillary after latter leave axilla
        2. Supplies arm
      4. Radial and Ulnar
        1. Terminal branches of brachial artery
        2. Originate within cubital fossa (anterior elbow)
        3. Supplies forearm, wrist and hand
    3. Lower Limb
      1. Femoral
        1. Continuation of external iliac artery after latter passes distal to inguinal ligament
        2. Supplies thigh
      2. Popliteal
        1. Continuation of femoral after latter enter region of posterior knee (popliteal fossa)
      3. Anterior and Posterior Tibial Arteries
        1. Terminal branches of the popliteal artery
        2. Originate after Popliteal artery leaves popliteal fossa
        3. Supply leg and foot
    4. Integrity of Arterial System
      1. Pulse
        1. Location
          1. Radial - radial ( lateral) side of lower forearm just proximal to wrist
          2. Femoral - below inguinal ligament at start of thigh
          3. Popliteal - posterior knee
          4. Posterior tibial - posterior to medial malleolus
        2. Amplitude
        3. Bilateral symmetry
      2. Allen Test
        1. Functional patency of radial and ulnar arteries
        2. Tight fist to squeeze out blood
        3. Compress either artery and observe refill time
  2. Venous Return
    1. Superficial Veins
      1. Return blood from cutaneous structures
        1. Drain blood into deep veins
      2. Upper Limbs
        1. Basilic Vein
          1. Starts venous arch on dorsum of hand
          2. Drains medial side of limb into brachial vein
        2. Cephalic Vein
          1. Starts venous arch on dorsum of hand
          2. Drains lateral side of limb into axillary vein
        3. Median cubital vein
          1. Branch of cephalic vein
          2. Located in cubital fossa
          3. Drains into basilic vein
          4. Usual site for venipuncture
      3. Lower Limbs
        1. Great saphenous vein
          1. Originates from medial portion of dorsal venous arch of foot
          2. Drains skin from medial leg and thigh into femoral vein
        2. Small saphenous vein
          1. Originates from lateral portion of dorsal venous arch of foot
          2. Drains skin from lateral leg into popliteal vein
    2. Deep Veins
      1. Follow arteries & named for companion artery
      2. Return blood from deeper structures such as muscles and bone
  3. Lymphatics
    1. Return lymph from upper and lower limbs
    2. Tend to follow blood vessels
    3. Routes for metastases and infections
    4. Important nodes
      1. Axillary
        1. Located in axilla
        2. Receive lymph from breast , chest wall and upper limb
        3. Drain into subclavian lymph trunk
      2. Epitrochlea
        1. Located along medial side of elbow
        2. Drains into axillary nodes
      3. Popliteal Nodes
        1. Located near termination of the small saphenous vein
        2. Receive lymph from lateral side of foot and posterior lateral leg
      4. Inguinal nodes
        1. Located along termination of great saphenous vein
        2. Receive lymph perineal region and most of leg and thigh

V. MOVEMENT (pages 11 - 16)

  1. Properties
    1. Limbs designed for mobility, movement and manipulation
    2. Components
      1. Bones
        1. Rigidity
      2. Skeletal muscle
        1. Energy for movement
        2. Connected to bones ( skeleton)
      3. Somatic nerves
        1. Control and coordinate muscle contraction

PRINCIPLES OF MUSCLE CONTRACTION

  1. Parts of a Skeletal Muscle (Fig. 2)
    1. Origin
      1. The fixed and/or proximal attachment of a muscle
    2. Insertion
      1. The moveable and /or distal attachment
    3. 3. Belly
      1. Contains contractile elements
      2. Shape varies
    4. 4. Tendon
      1. Composed of dense connective tissue
      2. Shape
        1. i) Cord like
        2. ii) Aponeurosis
      3. Attaches muscle to bone
        1. i) Origin or insertion ( more common)
      4. Functions
        1. i) Allows action to occur away from belly
        2. ii) Can change direction of motion

MUSCLE ACTIONS

    Types of Muscle Contractions

    1. 1. Isotonic
      1. Active shortening of muscle during contraction
      2. Energy expended
    2. 2. Isometric
      1. Muscle develops tension
      2. Energy expended
      3. No movement ( shortening) occurs

    Types of Isotonic Contractions

    1. 1. Concentric
      1. Muscle shortens upon contraction
      2. Propulsive
      3. Contractions causing a joint to move & / or change direction of movement
    2. 2. Eccentric
      1. Muscle lengthens while it contracts
      2. Restraining
        1. Slow sustained contractions
        2. Helps slow down and control movement

    C. Muscle Function

    1. Prime Mover / Agonist
      1. Muscle or muscle group whose action is mainly responsible for producing a given motion
    2. Synergist
      1. Works with or assists the prime mover(s) to produce a given motion
      2. Works with the prime mover(s) by canceling out an unwanted motion
    3. Fixation Muscles
      1. Act to stabilize joint to enable prime movers to function more effectively
    4. Antagonist
      1. Acts to produce the opposite action of the prime mover
    5. Active
      1. Movement occurs as a result of muscles action directly on a given joint
        1. Action of pectoralis major on the shoulder joint
    6. Passive
      1. Joint moves secondary to other forces
        1. Another individual moves the particular joint
        2. Movement at a given joint occurs secondarily to movement at another joint
          1. Action of pectoralis major on scapula
    7. Resisted Movement
      1. Type of active movement in which muscle is moved against resistance
      2. Used to assess strength of muscle and to compare symmetry

    D. Types of Movements

    1. 1. Flexion
      1. Occurs in a sagittal plane
      2. Movement of 2 bones toward each other
        1. An angle of 90o or less is made between 2 bones
    2. 2. Extension
      1. Occurs in a sagittal plane
      2. Movement of 2 bones away from each other
        1. An angle of 90o or more is made between 2 bones
    3. 3. Abduction
      1. Occurs in a frontal plane
      2. Movement away from the midline
    4. 4. Adduction
      1. Occurs in a frontal plane
      2. Movement towards from the midline
    5. 5. Rotation
      1. Occurs in a transverse plane
      2. Inward = medial
        1. Counter clockwise direction
      3. Outward = lateral
        1. Clockwise direction

Figure 2 MUSCLE SYSTEM

Skeletal muscle is attached to bone. The proximal attachment is the origin while the distal attachment is the insertion. A muscle usually inserts onto the bone by means of a tendon. When a muscle contracts, the distal attachment usually moves towards the origin. Movement of one bone upon another occurs at a joint.


Figure 3 THIRD CLASS LEVER

Most muscles operate as third class levers. In this system, the joint ( fulcrum) is proximal to the insertion of the muscle ( force). The muscle insertion lies between the fulcrum and the weight to be moved ( resistance). The dark arrows indicate the direction of force. Placing the muscle insertion close to the resistance ( dark arrow) enables the contracting muscle to overcome more resistance. Placing the insertion near the joint ( dashed arrow) increases the muscle's range of motion.


Figure 4 Appendicular Skeleton
Name the bones comprising the appendicular skeleton


Figure 5 Arterial Supply of the Limbs
1. Name the major arteries supplying the limbs.

2. Indicate the location of the major lymph nodes draining the limbs.

VIII. OBJECTIVES

  1. Understand the basic organization of the human limbs
    1. Know the components of the appendicular skeleton
    2. Be able to identify the arterial supply and venous drainage to the limbs
      1. Distinguish functionally between superficial and deep veins
      2. Be able to determine if there is adequate blood supply to the limbs.
    3. Be able to differentiate between joints based upon the following features
      1. How the joints are connected
      2. Mobility of joints
      3. Shape
  2. B. Be able to distinguish between the types of muscle contractions
    1. Differentiate between eccentric and concentric contractions
  3. C.Know the different ways in which muscles can act.
    1. Understand the clinical importance of being able to distinguish between active , passive and resisted movements
  4. D. Be able to define the different types of movements that can occur as a result of muscle actions
    1. 1. Know the planes in which each movement occurs
    2. Be able to apply the above information to the analysis of joint movements throughout the Limbs portion of this course.
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