Describe the Hip Joint
Strong and stable multi axial ball and socket type of joint.
During standing, the entire weight of the upper body is transmitted through the hip bones to the heads and necks of the femur.
What is the Greater Sciatic Foramen?
Formed on the posterolateral pelvic wall and is the major route for structures to pass through the pelvis and the gluteal region and leg
The pisiformis muscle passes out of the pelvis into the gluteal region through the greater sciatic foramen and separates the foramen into two parts.
What structures pass through the greater sciatic foramen?
Above the pisiformis muscle: superior gluteal nerve, artery and vein
Below the pisiformis muscle: sciatic nerve, inferior gluteal nerve, inferior gluteal artery, inferior gluteal vein, pudendal nerve, internal pudendal artery and vein, posterior femoral cutaneous nerve, nerve to obturator internus and superior gemullus muscles, nerve to quadratus femoris and inferior gemullus muscles
What is the Lesser Sciatic Foramen?
Inferior to the greater sciatic foramen on the posterolateral pelvic wall.
It is also inferior to the posterolateral pelvic wall.
It is also inferior to the lateral attachment of the pelvic floor to the pelvic wall and therefore connects the gluteal region to the perineum (nerves and vessels passing through supply the perineum)
What structures pass through the lesser sciatic foramen?
Obturator internus muscle tendon
Pudendal nerve and internal pudendal vessels pass into perineum from gluteal region.
What is the acetabulum?
Large cup-shaped cavity or socket on the lateral aspect of the hip bone that articulates with the head of the femur.
All 3 pelvic bones forming the pelvic bone contribute to the formation of the acetabulum.
What is the Acetabulum labrum?
Lip-shaped fibrocartilaginous rim attached to the margin of the acetabulum, increasing acetabular articular contact area by nearly 10% (deepening the joint).
Helps strengthen the joint.
What is the Transverse Acetabular Ligament?
A continuation of the acetabular labrum, bridges the the acetabular notch.
As a result of the height of the rim and labrum, more than half of the femoral head fits with the acetabulum.
Describe the joint capsules surrounding the hip joints
Formed of a loose external fibrous layer (fibrous capsule and an internal synovial membrane).
The joint capsule covers more of the joint anteriorly than posteriorly.
The joint capsule is strengthened by ligaments which pass in a spiral fashion from the pelvis to the femur.
Extension winds the spiralling ligaments and fibres more tightly, constricting the capsule and drawing the femoral head tightly into the acetabulum. The tightened fibrous layer increases the stability of the joint but restricts extension of the joint to 10-20 degrees behind the vertical position.
Flexion increasingly unwinds the spiralling ligaments and fibres. This permits considerable flexion of the hip joint with increasing mobility.
What are the 3 intrinsic ligaments of the hip joint?
Anteriorly and superiorly Y-shaped Iliofemoral ligament (attached ASIS and acetabuluar rim proximally, the intertrochanteric line distally). Strongest ligament, prevents hyperextension of the hip joint during standing.
Anteriorly and inferiorly is the Pubofemoral ligament which arises from the obturator crest of the public bone and blends with the medial part of the Iliofemoral ligament and tightens during both extension and abduction - prevents overabduction of the hip joint - limits extension and abduction.
Posteriorly is the Ischiofemoral ligament which is the weakest and spirals Superolaterally to the femoral neck - limits extension and medial rotation.
What are the accessory ligaments of the hip joint?
Ligament of head of femur: its wide end attaches to the margins of the acetabular notch and transverse acetabular ligament, its narrow end attaches to the fovea for the ligament of the head. It contains the artery to the head of femur (branch of the obturator nerve)
Transverse acetabular ligament.
What are the flexors of the hip joint?
Tensor fascia latae
Adductor Magnus - anterior-aponeurosis part only
What are the adductors of the hip joint?
What is the Adductor Minimus?
The most superior part of the adductor Magnus is called the adductor minimus if it forms a distinct muscle.
What are the lateral rotators of the hip joint?
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What are the hip extensors?
Gluteus maximus (primary extensor from flexed to standing position and from this point posteriorly, extension is mainly achieved by the hamstrings)
Hamstrings: semitendinosus, semimembranosus, long head of biceps femoris, Posterior part of adductor Magnus
What are the hip abductors?
Tensor fasciae latae
Describe the blood supply to the hip joint
Medial and lateral circumflex femoral arteries which are usually branches of the profunda femoris artery but occasionally they arise as branches of the femoral artery.
The artery to the head of femur which is a branch of the obturator artery (via ligament of head of femur)
Main blood supply is from the retinacular arteries arising as branches of the circumflex femoral arteries. Retinacular arteries arising from the medial circumflex artery are most abundant, bringing more blood to the head and neck of the femur because they are able to pass beneath the unattached posterior border of the joint capsule. Retinacular arteries arising from the lateral circumflex femoral artery must penetrate the thick Iliofemoral ligament and are smaller and fewer.
Describe Hip dysplasia/congenital dislocation of the hip joint
Occurs in ~1.5/1000 neonates, bilateral in ~half of cases
Dislocation occurs when the femoral head is not properly located in the acetabulum.
Characteristics: inability to abduct thigh, affected limb appears (and functions as if it is) shorter because the dislocated femoral head is more superior than on the normal side, resulting in a positive Trendelenburg sign (hip appears to drop on one side during walking).
~25% of all cases of arthritis of the hip in adults are the direct result of residual defects from birth.
What problems might there be in Hip Dysplasia?
Problem with bony structures e.g. Acetabulum, head of femur - problems based on abnormal growth of the hip.
Problem could be with supporting joint capsule.
Problems range from subluxation to dislocation, instability
What is a Slipped Upper Femoral Epiphysis?
In children (ages 10-16most affected), fractures that result in separation of the superior femoral epiphysis (growth plate between the femoral head and neck) are also likely to result in an inadequate blood supply to femoral head and in post-traumatic avascular necrosis of the head of the femur.
The rest of the femur rides up and forward in relation to the epiphysis.
As a result, incongruity of the joint surface develops, and growth at the epiphysis is retarded. Such condtions produce hip pain that may radiate to the knee.
Acquired dislocations of the hip are uncommon because the articulation is so strong and stable. Describe posterior dislocations of the hip
A head on collision that caused the knee to strike the dashboard may dislocate the hip when the femoral head is forced out of the acetabulum.
The joint capsule ruptures inferiorly and posteriorly, allowing the femoral head to pass through the tear in the capsule, and over the posterior margin of the acetabulum onto the lateral surface of the ilium, shortening and medially rotating the hip.
Because of the close relationship of the sciatic nerve, it may be injured.
This may result in paralysis of the hamstrings and muscles distal to the knee supplied by the sciatic nerve,
Sensory changes may also occur in the skin over the posterolateral aspects of the leg and much of the foot because of the injury to sensory branches of the sciatic nerve.
Describe an anterior dislocation of the hip joint
Results from a violent injury that forces the hip into extension, abduction and lateral rotation e.g. Catching a ski tip when skiing
The femoral head is inferior to the acetabulum.
Often the acetabular margin fractures, producing a fracture-dislocation of the hip joint.
When the femoral head dislocates, it usually carries the acetabular bone fragment and acetabular labrum with it.
These injuries also occur with posterior dislocations.
What might happen to the head of the femur in some femoral neck fractures?
The artery to the the head of femur may be the only remaining source of blood to the proximal fragment.
The artery is frequently inadequate for maintaining the femoral head; consequently the fragment may undergo avascular necrosis (tissue death).
What does treatment of a femoral neck fracture depend on?
Age and health
If the patient is healthy, the fracture can be fixed (following reduction- realignment). I
f the patient is unhealthy, they might have a replacement (metal prosthesis anchored to the person's femur by bone cement replacing the femoral head and neck. A plastic socket cemented to the hip bone relaxes the acetabulum).
Describe the Trochanteric fractures (between the two trochanters)
Less risk of osteonecrosis
Usually treated with a dynamic hip screw.
Describe the Trochanteric bursa
Situated between gluteus maximus and greater trochanter. Inflammation can occur in arthritis or as a separate entity. May result from repetitive actions such as climbing stairs while carrying heavy objects or running on a steeply elevated treadmill.
These movements involve the gluteus maximus and move the superior tendinous fibres repeatedly back and forth over the bursae of the greater trochanter.
Trochanteric bursitis causes deep diffuse pain in the lateral thigh region.
How is Trochanteric Bursitis characterised?
Characterised by point tenderness over the greater trochanter however the pain radiates along the Iliotibial tract that extends from the iliac tubercle to the tibia.
This thickening of the fascia lata receives tendinous reinforcements from the tensor fasciae latae and gluteus maximus muscles.
The pain from an inflamed Trochanteric bursa, usually located just posterior to the greater trochanter, is usually elicited by manually resisting abduction and lateral rotation of the thigh, while the person is lying on the unaffected side.
Describe the Illiopsoas bursa
In 15% there is communication with hip joint
May present as swelling below inguinal ligament
Describe Ischial bursitis
Recurrent microtrauma resulting from repeated stress (e.g. From cycling, rowing or other activities involving repetitive hip extension while seated) may overwhelm the ability of the ischial bursa to dissipate applied stress.
The recurrent trauma results in inflammation of the bursa.
Ischial bursitis is a friction bursitis resulting from excessive friction between the ischial bursae and the ischial tuberosities.
Localised pain occurs over the bursa and the pain increases with movement of the gluteus maximus.
Calcification may occur in the bursa with chronic bursitis, Because the ischial tuberosities bear the body's weight during sitting, these pressure points may lead to pressure sores in debilitated people, particularly paraplegic persons with poor nursing care.
Describe Osteoarthritis of the hip joint
Grinding - gets worse the more you move.
Mainly cartilaginous damage
Pain is from mechanical grinding
Previous joint injuries may predispose to this condition.
Increased mechanical load makes things worse.
Hip is commonly affected. On x-rays, narrowing stimulate growth of bony spurs.
Describe Rheumatoid Arthritis of the hip joint
Problem starts in the synovium
Joint cartilage is destroyed
Problem then becomes mechanical
Leads to deformities.
What important role does the Gluteus Medius and Minimus have in walking?
Important in stabilising the pelvis whilst walking.
Contraction of gluteus minimus and medius on stance side prevents excessive pelvic tilt during swing phase on opposite side.
Describe the Sciatic Nerve
Largest nerve in the body and is a continuation of the main part of the sacral plexus (L4-S3)
Emerges from the greater sciatic foramen inferior to the piriformis - most lateral structure. Runs Inferolaterally under cover of the gluteus maximus, midway between the greater trochanter and ischial tuberosity. Nerve rests in the ischium and then passes posterior to the obturator internus, quadratus femoris and adductor Magnus.
Has an artery - artery to the sciatic nerve - which is a branch of the inferior gluteal artery.
Does not supply any structures in the gluteal region but supplies the posterior thigh muscles, all leg and foot muscles and the skin of most of the leg and foot. Also supplies the articular branches to all of the lower limb.
The sciatic nerve is actually made up of two nerves, the tibial and common Fibular (Peroneal) nerve. Where does it separate into the two divisions?
Usually separate in the distal thigh, at the apex of thethe popliteal fossa however in ~12% of people, the nerves separate as they leave the pelvis. In these cases, the tibial nerve passes inferior to the piriformis (through the greater sciatic foramen)and the common Fibular nerve pierces this muscle or passes superior to it (through the greater sciatic foramen)
What is the difference between real shortening and apparent shortening?
Real shortening is due to actual loss of bond length e.g. When a femoral fracture has united with a good deal of overriding of the two fragments. Apparent shortening is due to a fixed deformity of the limb e.g. One limb may be apparently shorter than the other due to a gross flexion contracture at the hip.
Describe intramuscular gluteal injections
Common injection site because the muscles are thick and large, consequently they provide a substantial volume for absorption of injected substances by intramuscular veins.
Buttock injections are safely given only in the supero-lateral quadrant of the buttocks or superior to a line extension of the PSIS to the superior border of the greater trochanter (approximately the superior border of the gluteus maximus).
IM injections can also be safely given into the anterolateral part of the thigh, where the needle enters the tensor fasciae latae as it ends distally. The index finger is placed on the ASIS and the fingers are spread posteriorly along the iliac crest until the tubercle of the iliac crest is felt by the middle finger. An IM injection can be made safely in the triangular area between the fingers because it is superior to the sciatic nerve.
What are the complications of improper intramuscular gluteal injection technique?
Sciatic nerve injury
How you measure apparent shortening?
Compare the distance from the umbilicis (belly button) to the medial malleolus on each side. Get patient lying with legs parallel (as if he was standing). If there is a fixed pelvic tilt or fixed joint deformity in one limb, there may be this apparent difference between the lengths of two legs. Adduction apparently shortens the leg. Abduction apparently lengthens the leg.
How would you measure the real length of the limbs?
Put both limbs into exactly the same position; where there is no joint fixation, this means the patient lies with his pelvis square, his legs abducted symmetrically and both lying flat. If however one hip in 60 degrees of fixed flexion, the other hip must be put into this identical position. Measure each limb from ASIS to medial malleolus. Slide the finger upwards along the inguinal ligament and mark the bony point first encountered by the finger. Similarly slide the finger upwards from just distal to the malleolus to determine the apex of this landmark on each side. This is to obtain identical points on each side.
How would you determine if there is real shortening at the hip?
Place the thumb on the ASIS and the index finger on the greater trochanter on each side. A glance should tell you if there is any difference. Nelaton's line joins the ASIS to the ischial tuberosity and should normally lie above the greater trochanter; if the line passes through of below the trochanter, there is shortening at the head or neck of femur, Bryant's triangle; with the patient supine, a perpendicular is dropped from each ASIS and the distance between this line and the greater trochanter trochanter is compared on each side.
How would you determine if there is real shortening at the femur?
Measure the distance from the ASIS (if hip disease has been excluded) of from the greater trochanter to the line of the of the knee joint (not to the patella whose height can be varied by contraction of the quadriceps).
How would you determine if there is real shortening at the tibia?
Compare the distance from the line of the knee of the joint to the medial malleolus on each side.
Describe Injury to the Superior Gluteal Nerve
Results in a disabling gluteus medius limp to compensate for weakened abduction of the thigh by the gluteal medius and minimus. Medial rotation of the thigh is also severely impaired. When in standing position, the patient is asked to lift one foot off the ground and stand on one foot, the gluteus medius and minimus normally contract as soon as the contra-lateral foot leaves the floor, preventing tipping of the pelvis to the unsupported side. With a person who has suffered a lesion to the superior gluteal nerve, the pelvis on the unsupported side descends indicating that the gluteus medius and minimus in the supported side are weak or non functional (positive Trendelenburg test). Other causes of this spring include fracture of the greater trochanter (the distal attachment of the gluteus medius) and dislocation of the hip joint.
What is the gluteal gait, and why may it been in injury to the superior gluteal nerve?
When the pelvis descends on the unsupported side, the lower limb becomes in effect, too long and does not clear the ground when the foot is brought forward in the swing phase of walking. To compensate, the individual leans away from the unsupported side, raising the pelvis to allow adequate room for the foot to clear the ground as it swings forward. This results in a characteristic "waddling" or gluteal gait. Other ways to compensate is to lift the foot higher as it is brought forward, resulting in the so-called steppage gait or to swing the foot outward (laterally), the so-called swing-out gait.
Describe the Nerve Innervation to the Hip Joint
According to Hilton's Law: Flexors innervated by the femoral nerve pass anterior to the hip joint (the anterior aspect of the hip joint is innervated by the femoral nerve - directly and via articular rami of the muscular branches to the pectineus and rectus femoris). Lateral rotators pass inferior and posterior to the hip joint; the inferior aspect of the joint is innervated by the obturator nerve (directly and via articular rami of the muscular branch to the obturator externus) and the posterior aspect is innervated by the nerve to the quadratus femoris, Adductors innervated by the superior gluteal nerve pass superior to the hip joint; the superior aspect of the joint is innervated by the superior gluteal nerve.
Describe Femoral Neck Fractures
Especially common in people > 60 years, particularly in women because their femoral necks more often weak and brittle as a result of osteoporosis.
Fractures of the femoral neck are often intracapsular and realignment of the neck fragments requires internal skeletal fixation.
Shortening and Lateral/external rotation of the lower limb occurs and blood supply to the femoral neck is often disrupted