1 LECTURE 07 HIP JOINT + MUSCLES OF HIP UPPER PART OF FEMUR Note

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LECTURE 07 HIP JOINT + MUSCLES OF HIP


UPPER PART OF FEMUR Note the head, which forms about 2/3 of a sphere
   covered with articular cartilage. The head is directed upwards, medially
   and slightly forwards. Note also the neck, the greater and lesser
   trochanter. Note the trochanteric fossa (obturator externus). Posteriorly
   the intertrochanteric crest with the quadrate tubercle in the middle, and
   the linea aspera to which the majority of the thigh muscles attach. Note
   also the gluteal ridge or tuberosity from the linea aspera towards the
   quadrate tubercle (gluteus maximus), the pectineal line from linea aspera
   to lesser trochanter (pectineus), and the spiral line (vastus medialis)
   branching anteriorly to join the intertrochanteric line.



SLIDE OR SKETCH
of upper part of femur
(Williams and Warwick 1980) Fig 3.182
post aspect




ACETABULUM The term acetabulum is derived from L. 'vinegar cup'
   (Arnold's glossary) and was used to describe the cup and ball with which
   clowns entertained people long ago. The ball was connected to the cup with
   a piece of string. In just the same way, the head of the femur is connected
   to the acetabulum by the ligamentum teres. This is not so much a
   ligament as a mesentery, which carries an artery to the head of the femur
   (a branch of the obturator artery). This blood supply is important before the
   epiphysis of the head fuses with the neck (Joseph 1982) p441 about the age
   of 20 (Grant and Basmajian 1980) (p298).




sketch acetabulum
                                                                                   2

HEAD OF FEMUR The head of the femur is not well supplied with blood: until
   the age of 18-20, the epiphysis forming the distal half of the head remains
   unfused, and is separated by the epiphyseal plate from proximal half of the
   head and the neck of the femur. The neck and proximal head receive their
   blood supply from the lateral and medial circumflex arteries, (branches off
   profunda femoris) via the joint capsule; while the head receives its supply
   from a small branch of the obturator artery via ligamentum teres
   (Gardner et al. 1986) p217; (Adams 1978) p208. After fusion, the circumflex
   supply becomes more important (particularly medial circumflex,
   (Williams and Warwick 1980) 391b, and the supply from the ligamentum
   teres is minor. As a result, fractures of the head or neck of the femur in
   the adult may interrupt the blood supply to parts of the head of the femur,
   resulting in slow healing or avascular necrosis. (This also happens in the
   scaphoid and the talus).


SKETCH
blood supply to head of femur
(Gardner et al. 1986) p217




ARTICULAR SURFACES The bony acetabular socket only forms about 1/2 of a
   sphere, but this is extended by the cartilaginous acetabular lip or labrum,
   which helps to retain the head of the femur in the socket. The acetabulum
   is not completely lined with articular cartilage: there is a C-shaped band of
   cartilage around the rim: the gap is called the acetabular notch, nearest
   the obturator foramen. This is bridged by the transverse ligament (which
   forms part of the attachment for the ligamentum teres).


CLOSE PACKING As with all joints, the articular surfaces are not completely
   congruent, although there is one position of the joint where the surfaces fit
   together best, i.e. the position of close-packing, in which the ligaments
   surrounding the joint are taut. In the hip, this position is in full extension
   (and medial rotation? )


LOADING
It appears that under light loads, only a part of the acetabular surface is in
     contact with the femoral head; these are the anterior and posterior thirds,
     or the extremes of the C; the middle of the horseshoe is not in contact
                                                                                      3

    (Greenwald and O'Connor 1971), Fig. 4 but under loads corresponding to
    walking, the whole area is contacted throughout the step cycle.


sketch


CAPSULE AND LIGAMENTS
The capsule is strong, and is thickened by three ligaments, one from each
    component of the hip bone:


1 Iliofemoral - this is like an upside down 'Y', running across the front of the
     hip joint from the AIIS down to the intertrochanteric line. It resists
     hyperextension and medial rotation (Hollinshead and Rosse 1985).
2 Pubofemoral - This is also on the anterior aspect, running from the pubis
     under the medial branch of the iliofemoral to blend with the capsule. It
     resists abduction (Hollinshead and Rosse 1985).
3 Ischiofemoral - This is on the posterior aspect. Like the other ligg., it is taut
     in full extension, i.e. close packing.


SLIDE
ligaments
Cunningham fig 222
FB1 2-1, 2-2
Gray’s 35 4.64


MOVEMENTS AT THE HIP


flexion to c 120°, extension to c 30°
abduction (40° for slow abduction, 70-80° if kicked out (Joseph 1982) p444
     adduction
internal rotation, external rotation
                                                                                     4

FASCIA
The deep fascia of the thigh is the fascia lata, thickest proximally and laterally.
     It is attached above to the iliac crest and inguinal ligament, and below to
     condyles of the femur and tibia and to the head of the fibula.
Iliotibial tract. On the lateral surface it is thickened to form a strong band, the
     iliotibial tract, found only in man (Kaplan, 1958). This seems to serve as a
     tie from the iliac crest to the knee, which reduces the stress in the femur
     (Pauwels). When the knee is extended, it passes in front of the instant
     centre of rotation; when the knee is flexed, it passes behind it. This means
     that (a) it stabilises the knee in extension but not in flexion and (b) it rubs
     past the lateral epicondyle during running or cycling, and may result in
     bursitis, the iliotibial tract syndrome (Kulund 1988) p462.


MUSCLES
Flexors of the hip joint: Iliacus and psoas.


Psoas major we referred to before as the prevertebral muscle of the lumbar
    region, whose tendon runs between the anterior of the hip joint and behind
    the inguinal ligament, to insert on the lesser trochanter. Proximal
    attachment L1-L5, including TP's, discs and margins of bodies. Lumbar
    plexus located within psoas major, innervated by L1-2. Note also psoas
    minor may be present on front of psoas major.


Iliacus: The tendon of psoas is joined by the fibres of iliacus, a fan shaped
     muscle with its origin in the iliac fossa. Together they are often known as
     the iliopsoas---they have a common action in flexing the thigh on the
     pelvis, but of course it is only the psoas which has the additional action of
     flexing the lumbar vertebral column on the pelvis.



Sketch TS
GM10 Fig 20-16
                                                                                    5

Extensors of the hip joint: Gluteus maximus.
This is a large, strong, coarse muscle lying superficially in the buttock. Its
     fibres run down and laterally, from their
origin on the posterior part of the ilium, just lateral to the PSIS, from the
     sacrum and coccyx, and from the sacrotuberous ligament to the
insertion. This is 1/4 on the gluteal ridge (deeper fibres of lower part of muscle),
     but the main part (3/4) joins with the fascia lata to form the iliotibial tract.
     This runs down to the lateral condyle of the knee, in front of its axis of
     rotation, so that gluteus max. also helps to maintain the knee in extension
     (GM10 p257).


Abductors of the femur: Gluteus medius and minimus, tensor fasciae latae.
The first two are associated with gluteus maximus and lie deep to it; they run
    from the lateral or posterior surface of the blade of the ilium down to the
    greater trochanter. Tensor fasciae latae has its bony insertion into the iliac
    crest between the tubercle and ASIS, and is about the size of a bar of soap.
    It is present in all mammals (Kaplan 1958) even though they do not
    possess an iliotibial tract.


SLIDE FB1 2-5, 1-6
note line of action




(In primates such as the chimpanzee, gluteus medius acts primarily as an
    extensor, since the iliac blades are in the coronal plane, and face
    posteriorly. Only in man do gluteus medius and minimus act significantly
    in lateral balance control--Robinson et al. J. Hum. Evol. (1972) 361-369).


Medial rotators of the femur
There are no specific medial rotators of the hip, but the muscles which carry
   out this function are the anterior fibres of gluteus medius, gluteus
   minimus and tensor fasciae latae (all innervated by the superior gluteal
   nerve). T.f.l. is active during medial rotation (confirmed by palpation,
   electromyography, and electrical stimulation; Kaplan 58). If T.f.l. is
   paralysed, medial rotation, flexion and abduction are slightly weakened
   (Müller-Vahl, 1985).
                                                                                 6

Lateral rotators of the femur
Deep again to the glutei are six muscles which pass around the back of the hip
    joint to insert on the greater trochanter---and so act to laterally rotate the
    thigh. The muscles fan out from their insertions on the greater trochanter
    to their origins as follows:



Muscle                             Origin
Piriformis                        anterior of sacrum
 gemellus sup.                    lesser sciatic foramen, upper margin
Obturator internus (tend.)        obt. membrane (inner surface)
 gemellus inf.                    lesser sciatic foramen, lower margin
Obturator externus                obt. membrane (outer surface)
Quadratus femoris                 ischial tuberosity
                                                                                    7

sketch
e.g. G&S Fig. 7.06
posterior aspect



SLIDE FD1 1-4



All of these muscles are in the gluteal region, which you realise is outside the
     pelvis, on its posterolateral aspect. The main gateway from the inside of
     the pelvis out to the gluteal region is the greater sciatic foramen. Through
     it passes the piriformis muscle, from the anterior aspect of the sacrum
     (inside the pelvis) through the gluteal region to the greater trochanter.


The muscle is most important not for its action, but as the key landmark of the
    gluteal region. Thus the sciatic nerve also emerges from the pelvis
    through the greater sciatic foramen, and appears below the lower border of
    piriformis, with the posterior femoral cutaneous nerve, inferior gluteal
    nerve, and the pudendal nerve.
Note that the peroneal component may split piriformis (cf McMinn &
    Hutchings), while the tibial component emerges below it. It is said that
    spasm of the piriformis may impinge on the sciatic leading to so called
    "piriformis syndrome" Kulund 2 422.
Note also that injections into the buttock should be into the upper lateral
    quadrant of the buttock to avoid the sciatic and gluteal nerves (Platzer p246;
    Snell 2 842).
Superior gluteal nerve and vessels emerge above the muscle
Inferior gluteal nerve and vessels emerge below the muscle
(Internal iliac -> superior + inferior gluteal aa. + nn.


Superior gluteal n. -> gluteus medius, minimus + T.f.l.
inferior gluteal n. -> gluteus maximus etc.
                                                                                     8

CLINICAL ASPECTS OF HIP JOINT


FRACTURES Fracture of the neck of the femur (Snell 2 p586) may be
   subcapital (elderly) or intertrochanteric (young or middle-aged).
   Subcapital occurs in the elderly. The thigh muscles pull the distal
   fragment upward, so that the limb is shortened; the lateral rotators act to
   put the thigh into external rotation (Slide FH1 1-5). Complicated by
   avascular necrosis, (see above) so the best thing is to replace hip rather
   than to hope for it to heal.


PROSTHESES Various kinds, most common are stainless steel ball and high
   density polythene socket (Charnley believed it was necessary to have the
   two bearing surfaces of different hardnesses (Gruebel Lee and Hirsh 1983)
   p229a. Alternative are available in ceramic. Interestingly, the ceramic one
   is aspheric, which is said to have advantages in increasing contact surface
   and lubrication (Grell 81/82). Apparently a case where technology has been
   forced to mimic nature. Teflon doesn't work - it wears quickly in spite of its
   low coefficient of friction, and produces fragments which cause and
   inflammatory reaction (Gruebel Lee and Hirsh 1983).


SLIDES


CONGENITAL DISLOCATION OF THE HIP is one of the commonest
     congenital deformations. It is of particular interest for two reasons:
(1) it is completely curable by conservative treatment provided it is diagnoses
     very early, ideally on the day of birth, and
(2) it suggests that mechanical factors may help to mould the joint, rather as
     mechanical factors contribute to the remodelling of bone.


C.D.H. is a spontaneous dislocation of the hip occurring before, during or
    shortly after birth. In Western races, it is one of the commonest congenital
    deformities. If diagnosed at birth, it can be treated effectively by splinting: if
    undiagnosed or poorly treated, the patient may be crippled for life.


Etiology of CDH It is 6 times as common among girls: commoner in the left hip
    than in the right (presumably because of the way the fetus lies in the
    uterus ?): and commoner in people whose ancestors come from parts of
    Eastern Europe.
                                                                                  9

Causes
1) Genetically determined joint laxity. This is basically looseness of the capsule,
    and probably resolves spontaneously.


2) Hormonal joint laxity. In female babies, a ligament-relaxing hormone may
    be secreted by the fetal uterus, in response to oestrone and progesterone
    reaching the fetal circulation. This may also cause temporary instability.


3) Genetically determined dysplasia of the hip. This involves defective
    development of the acetabulum and the femoral head: the roof of the
    acetabulum slopes steeply, and the head of the femur is usually small, so
    that dislocation is likely.


SLIDE 1
FH1 1-4


Diagnosis If tested at birth, a click or thump can be heard or felt as the hips
    are abducted (in the flexed position). This is due to the head of the femur
    snapping back into place in the acetabulum.


Treatment If diagnosed early, the treatment is to keep the baby's hips partially
    abducted with double nappies, for up to 3 months. After this time X-rays
    are easier to diagnose, and most cases, such as those due to laxity of the
    joint capsule, will have resolved by this time. Those involving congenital
    dysplasia of the hip are likely to require further treatment by splinting for
    up to 6 months. If done properly, the head of the femur is held into the
    acetabulum, which then starts to develop normally: presumably the result
    of mechanical factors which determine the configuration of the bony
    socket. The splinting seems to worry the parents much more than the
    baby: the baby manages very well with her hips permanently abducted, and
    some babies even learn to walk like this.


Prognosis The surprising point is that with this treatment, the hip then
    becomes quite indistinguishable from normal. But if left longer than the
    first year, the condition becomes progressively more difficult to treat.
    Redislocation is common, and osteoarthrosis and pain result. After 18
    months of age without treatment, surgery is necessary (Adams Outline of
    Orthopaedics).
                                                                          10

PERTHES’ DISEASE
This is a form of avascular necrosis, occurring most often in boys from 4-8
    years old; often the cause appears to be trauma. If the joint becomes
    inflamed, the increased pressure may occlude the lateral epiphyseal
    vessels running in the retinaculum, which provide the main blood supply
    to the head. Apley & Solomon p258.


References

Adams JC. Outline of fractures, including joint injuries, Churchill
      Livingstone, Edinburgh ; New York, 1978, ix, 320 pp.
Gardner ED, O'Rahilly R, Müller F and Gray DJ. Anatomy : a regional
      study of human structure, Saunders, Philadelphia, 1986, ix, 809
      pp.
Grant JCB and Basmajian JV. Grant's Method of anatomy : by regions,
      descriptive and deductive, Williams & Wilkins, Baltimore, 1980,
      xvii, 625 pp.
Greenwald AS and O'Connor JJ. The transmission of load through the
      human hip joint. J Biomech 1971;4:507-28.
Gruebel Lee DM and Hirsh DM. Disorders of the hip, Lippincott,
      Philadelphia, 1983, xiii, 282 pp.
Hollinshead WH and Rosse C. Textbook of anatomy, Harper & Row,
      Philadelphia, 1985, xii, 1041 pp.
Joseph J. A textbook of regional anatomy, University Park Press,
      Baltimore, 1982, xxii, 519 pp.
Kulund DN. The Injured athlete, Lippincott, Philadelphia, 1988, xviii,
      603 pp.
Williams PL and Warwick R. Gray's Anatomy, Churchill Livingstone,
      Edinburgh, 1980.

				
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