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Joints and Ligaments

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  A.  Proximal femur 
    1.  Head, Neck Trochanters 
    2.  Alignment of the femur
        a.  Angle of Inclination 
           1.  Angle between neck and shaft of femur 
           2.  125- 130 degrees angle in adults 
        b.  Coxa Vara 
           1.  Angle less than 100degrees 
           2.  Results in shortening of limb on affected side 
        c.  Coxa Valga 
           1.  Angle greater than 130 degrees 
           2.  Results lengthening of limb on affected side sulcus 
  B.  Pelvic / Hip Bone (Os Coxa)
    1.  Ilium 
          .  Iliac crest 
                1.  L-4 
           a.  Fossa 
           b.  Anterior Superior Iliac Spine (ASIS) 
                1.  Pelvic alignment 
                2.  Measurement of leg length 
           c.  Posterior Superior Iliac Spine 
                1.  S - 2 
                2.  Location of Sacroiliac joint ( dimples) 

     2.  Pubis 
          .  Symphysis 
              1. strong, slightly moveable joint between right and left
                  pubic bones 
              2. supported by fibrocartilage and ligaments 
          a. Body 
          b. Rami 
              1. Superior ramus 
              2. Inferior ramus 
     3. Ischium 
         . Spine 
              1. Landmark for pudendal vessels and nerve 
        a. Tuberosity 
    4. Obturator Foramen 
         . Opening between ischium and pubis 
         a. Covered by obturator membrane 
     5. Acetabulum 
         . Socket on lateral aspect of pelvic bone 
         a. Formed by parts of all 3 components of the pelvic bone 
         b. Forms socket portion of hip joint with the femoral head 
     6. Notches 
        . Greater sciatic 
             1. Between ilium and ischium 
        a. Lesser sciatic 
             1. Between ischial spine and tuberosity 

     7. Ligaments 
       . Sacrotuberous 
             1. Sacrum to ischial tuberosity 
             2. Weight bearing when seated 
       a. Sacrospinous 
             1. Sacrum to ischial spine 
       b. Sacroiliac 
             1. Bind sacrum to Ilium 
             2. (2) Support sacroiliac joint 


   1.Hilgen Renier Line (HRL) – line connecting the 2 hip joints
   2. Perkin’s Line – vertical line passing the outer edge of acetabulum 

  QUADRANT -  formed ny the HRL and the PL

  Normal, undislocated  femoral head – located in the inferomedial quadrant;
      inner lower quadrant 

  Dislocated head- located in the outer upper quadrant or superolateral

   3. Sheton’s Line – curve line passing the femoral shaft to the
   femoral neck going to the obturator foramen; or obturator
   * if interrupted, hip is dislocated.

   4. Acetabular Index -  oblique line passing or intersecting the
    HRL from the medial to the outer roof of the acetabulum ( lateral );
     measure slope of the acetabulum

      - normal value: less than 30 degrees
      - if greater than 30 degrees = indicates that the 
  acetabular roof is inadequate so the femoral head is not  covered.

   5.  Center Edge Angle of Wilsberg -  formed by the line passing the
        center of the femoral head and by the line passing the the femoral
        head to the outer roof of the acetabulum
  - measures the coverage of the femoral head of the acetabulum
  - normal value: greater than 20 degrees, if less, roof is inadequate

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The thigh is subdivided by the attachments of the fascia lata ( deep
   fascia of the thigh) into 3 functional compartments). Each
   compartment contains a primary functional group of muscles,
   the innervation to theses muscles and a major source of arterial
   blood. It is necessary to understand the attachments, innervation
   and actions of these muscles in order to appreciate how the hip
   functions. The anatomy of the compartments of the thigh are
   covered in the text. The attachments, innervation and functions
   of the thigh muscles are outlined in Chart 1.

A.  A. Anterior Compartment 
      1.  Muscles 
            a.  Sartorius 
            b.  Tensor fascia lata 
            c.  Quadriceps femoris 
                    1.  Rectus femoris 
                    2.  Vastus lateralis 
                    3.  Vastus medialis 
                    4.  Vastus intermedius 
            d.  Pectineus 
            e.  Iliopsoas 
                    1.  Iliacus 
                    2.  Psoas 
      2.  Nerve Supply 
           .  Femoral ( L 2,3,4 ) 
                a.  (1) Motor 
                b.  Quadriceps femoris 
                c.  Sartorius 
                d.  Pectineus 
                e.  Sensory 
                f.  Anterior and lateral portion of thigh 
                g.  Medial portion of leg 

      3.  Blood Supply 
           .  Femoral Artery 
                1.  Anterior Abdominal Wall 
                2.  Deep ( profunda ) femoral 
                3.  Muscular to muscles in anterior compartment 
                4.  Descending Genicular 
           a.  Deep ( Profunda ) Femoral 
                1.  Lateral femoral circumflex 
                2.  Medial femoral circumflex 
                3.  Perforating 

  B.  Medial Compartment 
      1.  Muscles 
            .  Pectineus 
           a.  Adductor longus 
           b.  Adductor brevis 
           c.  Adductor magnus 
           d.  Gracilis 

      2.  Nerve Supply 
            .  Obturator ( L 2, 3, 4 ) 
                  1.  Motor to muscles in medial compartment 
                  2.  Sensory to medial portion of thigh 
      3.  Bloody Supply 
            .  Obturator Artery 
                  1.  Muscular branches to muscles in medial 
                        compartment of thigh 
                  2.  Acetabular branch 
                  3.  Head of Femur 
                           0.  Important in children 

  C.  Posterior Compartment 
      1.  Muscles 
            .  Hamstrings 
                  1.  Biceps femoris 
                  2.  Semimembranosus 
                  3.  Semitendinosus 

      2.  Nerve Supply 
             .  Sciatic ( L 4 - S 3 ) 
                   0.  Motor to hamstring muscles 
                   1.  Sensory - see unit on The Leg and Foot 
                   2.  Motor deficits 
      3.  Blood Supply 
             .  Perforating branches of Deep femoral artery 

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Hip Joint

  A.  Type 
        1.  A multiaxial ball and socket synovial joint between 
             the head of the femur and the acetabulum of the coxal
            ( pelvic ) bone. 
  B.  Fibrous Capsule 
        1.  Proximal attachment - encircles rim of acetabulum 
        2. Distal Attachment 
                   a. anterior - greater trochanter, 
                        intertrochanteric line 
                   b. posterior - neck of femur 
                   c. capsule incomplete posteriorly 

  C.  Ligaments 
        1. Iliofemoral 
                   a. Covers hip joint anteriorly 
                   b. Arises from anterior inferior iliac spine 
                   c. Inserts into intertrochanteric line 
        2. Pubofemoral 
                   a. Covers hip joint anteriorly 
                   b. Arises from pubic bone and margin of 
                       obturator foramen 
                   c. Inserts into femoral neck deep to 
                       iliofemoral ligament 
         3. Ischiofemoral 
                   a. Covers hip joint posteriorly 
                   b. Arises from ischium 
                   c. Inserts into greater trochanter of femur 
   4 Functions 
         .  Limit Motion 
         1.  Pubofemoral ligament limits abduction 
         2.  Lateral band of iliofemoral ligament limits 
         3.  Medial band of iliofemoral ligament limits 
              lateral rotation 
         4.  Ischiofemoral ligament limits medial rotation 
          1.  Iliofemoral Ligament becomes taut in extension 
               preventing the femur from moving past
               vertical position ( resists hyperextension) 
          2.  Maintains hip in locked or stable configuration 

  D.  Intracapsular 
          1.  Ligament of the head of the femur 
                        .  Very Weak 
            a.  Conveys branches of obturator artery to head 
                 of femur 

  E.  Retinacula 
          1.  Composed of fibers derived from fibrous capsule 
          2.  Retinacula fibers reflect back along femoral neck 
               towards the femoral head 
          3.  Convey small arteries to head of femur 
                       .  Branches of medial and lateral 
                          femoral circumflex arteries 
                   a.  Main blood supply to femoral head 
                   b.  Commonly found on anterior surface of 
                        femoral neck 

  F.  Fractures/ Dislocation 
           1.  Fracture of femoral neck 
                       .  Could disrupt retinacula and blood 
                          supply to femoral head 
                   a.  Avascular necrosis of femoral head 
                   b.  Limb outwardly rotated 
                       1.  Pull of lateral rotator muscles 
           2.  Dislocation 
                        .  Limb is shortened and inwardly 

  G.  Cruciate anastomosis ( collateral circulation 
       posterior  to hip joint) 
            1.  Deep Femoral 
                        .  Transverse branch of lateral femoral 
                        circumflex artery
                 a.  Medial femoral circumflex a. 
                 b.  Recurrent branch of 1st. perforating a. 
            2.  Inferior gluteal artery 

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 A.  Function 
              1.  Permits standing upright with little expenditure 
                   of energy in the form of muscle contraction 
              2.  Occurs when the head of the femur and the 
                   acetabulum are congruent ( fit tightly together 
                   and the iliofemoral ligament becomes taut. )
 B.  Mechanism 
             1.  Fibrous Capsule 
                  a.  Iliofemoral Ligament 
                      1.  Covers hip joint anteriorly and interiorly 
                      2.  Tightens during hip extension 
                      3.  Prevents femur from moving past vertical 
                           position ( resists hyperextension) 
                 b.  Ischiofemoral ligament 
                      1.  Winds transversely across posterior aspect 
                           of hip 
                      2.  Tightens upon hip extension 
                      3.  Much weaker than iliofemoral ligament 

C.   Process  
             1.  Center of mass of the body falls behind hip joint 
             2.  Gravity forces the hip posteriorly into a position 
                  of extension 
             3.  In the extended position, the hip joint locks 
                      .  The femoral head fits tightly into the 
                      .  Iliofemoral ligament becomes taut 
                         preventing  hyperextension 
            4.  Weight of the body supported by 
                  iliofemoral ligament 


      Properties of the Hip Joint 
           1. Multiaxial ball and socket joint 
           2. Types of Movement - Movements of the lower 
               limb can best be understand if one realizes 
               that different bones will move depending upon 
               whether the limb is in weight bearing or non 
               weight bearing. In either case the movement is 
               the same and the same muscles act. It just that 
               different bones can move given the different 
                   a. Weight bearing (fixed) -foot in contact with 
                       ground and the limb is supporting weight 
                       of body 
                            1. Pelvis moves on a fixed femur 
                            2. Bending down to touch toes 
                   b. Non Weight bearing (free) - foot free of 
                       ground and the limb is up  to support 
                       weight of body 
                            1. Femur free to move on a fixed pelvis 
                            2. Kicking a ball 

 A. Movements at the Hip 
            1. Flexion / Extension 
                  . Occurs in sagittal plane 
                           a. Transverse ( side to side) axis through 
                                head of femur 
           2. Adduction / Abduction 
                  . Occurs in frontal plane 
                           a. Anterior / posterior axis through head 
                               of femur 
           3. Inward / Outward Rotation 
                  . Occurs in transverse plane 
                           a. Vertical axis through head of femur 
                               and lateral femoral condyle 

B. Muscle Actions 

           1. Muscles acting to move the hip include the 
               gluteal muscles, the  iliopsoas , and muscles 
               of the thigh. The Chart lists the movement 
               that can occur at the  hip joint and the 
               muscles acting as prime movers for 
               each motion 

            A. Actions of the Hip Joint During Gait
                1. Acceleration and Heel Strike 
                    a. Restraining the forward movement of 
                        the lower limb occurs during this 
                        interval through the eccentric 
                        contractions of hamstring and gluteus 
                        maximum muscles acting on the hip joint. 
                        This restraining action leaves the hip in a 
                        flexed position. 
                    b. The gluteus medius and gluteus 
                        minimus contract concentricly abducting  
                        the reference limb from a weight bearing 
                        position. This involves  moving the iliac 
                        crest of the reference limb away from
                        the midline (abduction). The iliac crest 
                        moves instead of the femur because 
                        at  heel strike, the foot of the reference
                        limb is in contact with the ground and 
                        in a weight bearing position. The femur 
                        can not move  so the muscles act on 
                        the iliac crest which can move. 
                        Concomitantly,  the non weight 
                        bearing hip is "hiked" upward 
                        counterbalancing the effect that gravity 
                        wants to exert on the non reference 
                        limb which  is about to attain a non
                       weight bearing position .Without the 
                       concentric contraction of the hip 
                       abductors on the weight bearing reference 
                       limb, the opposite hip would tilt downward 
                       making it very difficult to swing the
                       limb forward in order to take a step. 
                       This type of gait is called "Trendelenburg 
                 2. Heel Strike to Midstance 
                      . The torso is being pulled over the center 
                        of the reference limb as the non 
                        reference limb swings forward. This 
                        puts the hip in a neutral position 
                        without any direct actions of muscles 
                        acting on the hip. 
                3. Midstance to Toe Off 
                       . The non reference limb is in a non 
                         weight bearing stage and is swinging 
                         forward as a step is taken. This process 
                         "drags" the torso in front of the reference 
                         limb forcing the hip joint of the  weight
                         bearing reference limb into an extended 
                         position. Once again, this occurs without
                         the direct action of the muscles acting 
                         on the reference limb. 

               4. Toe Off to Acceleration 

                                . During this interval, the reference 
                     limb goes from a weight bearing to a 
                     non weight bearing position as the 
                     reference limb begins to swing forward 
                     ahead of the torso as a step is being taken. 
                     Powerful concentric contractions of the hip 
                     flexors, mainly the iliopsoas muscle 
                     with help from the adductor muscles bring 
                     the hip into a position of flexion. 
                 a. The hip adductors also helps the swinging 
                     limb move in an inward direction. This 
                     enables the foot to be placed under the 
                     pelvis rather than in a position that would 
                     be parallel with the shoulder. 

           B. The Effect of Nerve Lesions on the Hip Joint
                During Gait 
                1. Superior gluteal nerve 
                          . Trendelenburg Gait 
                                   1. Marked downward tilting of the 
                                       hip on the non weight bearing 
                                       side due to inability of the gluteus 
                                       medius and minimus to actively 
                                       abduct the hip on the weight 
                                       bearing side during walking 
                         a. Trendelenburg Sign 
                                   1. Clinical test to determine the 
                                       integrity of the superior gluteal 
                                   2. Patient's hip tilts down when the 
                                       limb is non weight bearing 
                                       because of superior gluteal nerve
                                       is damaged on weight bearing 
                2. Obturator nerve 
                         . "Waddling gait" 
                                   1. Hip is in a marked abducted 
                                       position due to paralysis of hip 
                                       adductor muscles.
                                   2. When walking, the foot on the 
                                       affected side, can not be placed 
                                       under  pelvis. Patient has to 
                                       "throw" their weight laterally 
                                        when taking a step thus, 
                                       waddling to the affected side. 

           C. Lumbar and Lumbosacral Nerve Root I
               1. L 1,2 
                             . These roots are mainly involved 
                       with innervating the iliopsoas muscle. 
                       Damage to these roots would result in 
                       very weak hip flexion 
                      a. To test for the integrity of these roots, 
                      ask the patient to sit. Then have them 
                      try and flex the hip from a sitting position. 
                      Weak hip flexion indicates a problem with 
                      the L 1,2 nerve roots 

                2. L 2,3 
                             . These roots are concerned with the 
                      innervation of the hip abductors. Damage 
                      to these roots can lead to a waddling type 
                      of gait. 

                      a. To test for the integrity of these roots, 
                      have the patient lie on the side with their 
                      body in a straight line. Place the upper hip 
                      into abduction and place each hand on the 
                      inside of each thigh.  Have the patient try 
                      and bring the hips into adduction. 
                      Weakness could indicate a lesion of the 
                      L 2,3 nerve roots 

               3. L 5 
                            . This is the main root innervating the 
                      gluteus medius and minimus muscles. A 
                      positive. Trendelenburg Sign could 
                      indicate damage to this root.
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