week 2. The pelvis and hip joint Flashcards
what is the purpose of the pelvic girdle?
connects the vertbral column to the femurs
protects the organs, vessels and nerves in the pelvic region
Compare the pelvic girdle to the shoulder girdle
It is much stronger but less flexible
what are the 3 joints that make up the pelvic gihirlde?
2 sacroiliac joints and the pubic symphysis joint
what is the hip bone (innominate bone) made of?
the ilium, the pubis and the ischium
How does the ilium, pubis and ischium develop?
The develop seperately but then fuse to form the acetabulum
what does the acetabulum do?
it is the socket that attatches and articulates with the femoral head –> forming the hip joint
what type of joint is the hip joint?
ball and socket
Synovial joint –> covered by synovial membrane
what provides stability to the hip joint?
Acetabular anatomy
Fibrous capsule
Ligaments :
Ileofemoral
Pubofemoral
Ischiofemoral
what are the features of the acetabulum that stables the hip joint?
The articular surface is smooth and crescent shaped – ‘lunate surface’
It is deficient inferiorly - acetabular notch
The acetabular notch is bridged by the transverse acetabular ligament
Acetabular labrum –> a rim / lip of cartilage –> deepens the articular surface
how does the fibrous capsule stable the hip joint?
The articular capsule is strong and dense. –> Loose enough to help the joint move
what are the attachments of the fibrous capsule of the hip joint?
Proximal attachment encircles rim of acetabulum
Distal attachment is to the femoral neck–> intertrochanteric line and greater trochanter
How do the hip ligaments stabalise the hip joint?
Spiral around the hip joint
Taut when hip is extended
Pull the femoral head into the acetabulum
Improves stability
what does the illeofemoral ligament do? What is its attachment?
Covers hip joint superiorly and anteriorly
Strongest ligament
Prevents hyperextension of the hip during standing - ‘screws in’ the femoral head
Attaches to the ilium proximally and femur distally
what does the pubofemoral ligament do? What are the attachments?
Covers hip joint inferiorly and anteriorly
Prevents excessive abduction
Attaches to the pubis proximally and femur distally
what does the ischiumfemoral ligament do? What are the attachments?
Covers hip joint posteriorly
Weakest ligament
Attaches to the ischium proximally and femur distally
what is the anatomical name of the hip bone?
innominate bone
what caues the fracture of the pubic rami?
lateral force –> large amount of force
how does the limb apear after a posterior dislocation?
Limb appears shortened and internally rotated
what type of incident would cause a posterior dislocation?
Anterior blow to the knee when the hip is –> flexed, internally rotated and adducted. So in the seat position
Car crash from behind –> knees hit the dashboard and push the femoral head out posteriorly from the acetabulum
what can be damaged by a posterior dislocation?
Sciatic nerve injury may result
May be associated acetabular fracture
how does anterior dislocation occur?
Occurs when force is applied during extreme abduction with external rotation of hip
what is the position of the femoral head after a anterior dislocation?
Femoral head is levered out anteriorly
how does the limb look after a anteiror dislocation?
Limb appears externally rotated, abducted and flexed
what is more common posterior or anterior dislocation?
posterior
what can get damaged in anterior dislocation?
sciatic nerve is posterior so does not get damaged
However femoral artery and vein do get damaged as it is positioned anteriorly
what occurs when there is lack of blood supply to the femoral head?
avascular necrosis occurs to the femoral head
What occurs in development dysplasia of the hip?
Occurs in children
Umbrella term where there is sublaxation due to the loosening of the ligaments.
The ball can sometimes be slightly or completely dislocate from the socket.
what is the problem with development dysplasia of the hip in children?
have trouble walking and get a kid with a limp
If the femoral head and acetabulum are not attached from the start –> neither one will develop properly
They need to articulate to develop properly –> Can cause later problems
What does the pelvic girdle provide?
A stable ans stong support for the lower limbs
What are the articulations of each of the innominate bones?
Each one articualtes with the sacrum posteriorly at the sacroiliac joint and with each other anteriorly at the pubic symphysis
What is another name for the innominate bone?
Hip bone –> single
What are the functions of pelvis
Contain and support bladder, rectum, anal canal and reproductive tract
Bear the weight of the upper body when sitting and standing
Provide attachment for powerful muscle invovled in locomotion, posture and those of adominal wall for standing.
Contains and protects the abdominopelvic and pelvic visera.
What is the difference in male and female pelvis in terms of general stuctures and the greater and less pelvis?
General structure
M–> thick and heavy
F–> thin and light
Greater pelvis
M–> deep
F–> shallow
Lesser pelvis
M–> narrow and deep
F–> wide and shallow
What is the difference in male and female pelvis in relation to the pelvic inlet/outlet?
Pelvic inlet
M–> heart shaped, narrow
F –> oval and rounded; wide
Outlet
M –> compartively small
F–> compartively large
What What is the difference in male and female pelvis in relation to the pubic arch and greater sciatic notch?
Pubic arch
M –> narrow, it is between 50-60
F–> wide, it’s between 80-90
Greater sciatic notch
M–> narrow less than 70
F–> almost 90
What ligaments strengthen the pelvic girdle?
What are there attachments
The sacrotuberois ligament –> Attach the sacrum to the ischial tuberosity
The sacrospinous ligament attaches the sacrum to the ischial spine
Whata re the movements possible at the hip joint?
Flexion/extension
Abduction and adduction
External and internal rotation
Circumduction
What are the chief abductor at the hip joint?
Gluteus medius and minmus
Where does piriformis lie?
Deep to gluteus maximus
Where is a safe site to do intramuscular injection?
Gluteal muscle is a large mass of muscle so therefore used.
Specifically the upper outer quadrant of the gluteal region is used to ensure not damaging the sciatic nerve
Why is the location of piriformis important?
It is a key reference point for identification of vesels and nerve which are superior and inferior to piriformis and pass through the greater sciatic foramen
What vessels and nerves pass superior to piriformis?
The superior gluteal nerves and vessels pass through the foramen above the piriformis.
What vessels and nerves pass inferior to piriformis?
Passing through the foramen below the piriformis are: Inferior gluteal nerves and vessels
Sciatic nerve
Pudendal nerve
Internal pudendal vessels
Posterior femoral cutaneous nerves
The nerves to the obturator internus and quadratus femoris muscles.
How many fractures can occur on the pubic rami?
2 –>Superiorly and inferiorly
What occurs in the open book pelvic fracture?
There is disruption in the pubic symphysis joint.
What is a medial dislocation/ acetabular fracture?
It is when the femoral head pierces through the acetebulum
How is the acetabular fracture caused?
Caused by falling from a height –> the femur goe upwards need a lot of force
What is the complications of a acetabular fracture
Can damage the bladder and/or uterus in females.
Damage to the plexus of arteries, nerves and veins.
Can cause bleeding and death
Disruption of the blood supply to the femoral head can be caused by?
Blood vessels being torn or stretched
Some branches may remain kinked or compressed until the hip is reduced
So what are the different severity of development dysplasia of the hio
Normal, sublaxation, low dislocation and high dislocation
How does sublaxation and low/high dislocation occur in DDH?
The ligaments surrounding the hip joint are loosened allowing sublaxation of the hip joint. The femoral head is no longer in the center of the joint.
Get slight or complete dislocation of the socket.
Other than strengthening the pelvic girdle what else do the sacrotuberous and sacrospinous ligament do?
They convert the greater and lesser sciatic notches into the greater and lesser sciatic foramen
what is the Iliotibial Tract?
The iliotibial tract is a longitudinal thickening of the fascia lata, which is strengthened posteriorly by fibres from the gluteus maximus.
It is located laterally in the thigh
Extending from the iliac tubercle to the lateral tibial condyle.
What are the functions of the iliotibal tract?
Movement: acts as an extensor, abductor and lateral rotator of the hip, with an additional role in providing lateral stabilisation to the knee joint.
Compartmentalisation: The deepest aspect of ITT extends centrally to form the lateral intermuscular septum of the thigh and attaches to the femur. Muscular sheath – forms a sheath for the tensor fascia lata muscle.
What are the chief abductors at the hip joint?
Gluteus medius and minimus
Why is the gluteal region used for IM injection?
Gluteal muscles constitute a large mass of muscle
What muscle divides the greater sciatic foramen into two parts?
Piriformis.
Structures run above or below the piriformis as they run through the greater sciatic foramen
What passess through the lesser sciatic foramen?
Internal pudendal artery and vein
Pudendal nerve
Nerve to obturator internus
The tendon of obturator internus
