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.