Week 8 - The Hip Joint and Gluteal Region Flashcards
What is the primary function of the hip joint?
To bear weight
What are the articulating surfaces of the hip joint?
Head of femur and acetabulum of the pelvis
- Both are covered in articular cartilage
What is the acetabulum?
A cup-like depression in the lateral side of the pelvis
What is the role of ligaments within the hip joint?
They act in increase stability
What is the intracapsular ligament within the hip joint?
Ligament of head of femur
- A relatively small ligament that runs from the acetabular fossa to the fovea of the femur
- It encloses a branch of the obturator artery
What are the extracapsular ligaments within the hip joint?
- Iliofemoral
- Pubofemoral
- Ischiofemoral
Describe the iliofemoral ligament
- Located anteriorly
- Originates from the ilium, immediately inferior to the anterior inferior iliac spine
- Attaches to the intertrochanteric line in 2 places, giving the ligament a Y-shape
- Prevents hyperextension of the hip joint
Describe the pubofemoral ligament
- Located anteriorly and inferiorly
- Attaches at the pelvis to the iliopubic eminence and obturator membrane
- It then blends with the articular capsule
- It prevents excessive abduction and extension
Describe the ischiofemoral ligament
- Located posteriorly
- Originates from the ischium of the pelvis
- Attaches to the greater trochanter of the femur
- Prevents excessive extension of the femur at the hip joint
Describe the vascular supply to the hip joint
- Medial and lateral circumflex femoral arteries
- – Circumflex arteries are branches of the profound femoris artery
- – They anastomose at the base of the femoral neck to form a ring, from which smaller arteries arise to supply the joint itself
- – The medial circumflex femoral artery is responsible for the majority of the arterial supply
- – The lateral circumflex femoral artery has to penetrate through the thick iliofemoral ligament to reach the hip joint
- Artery to head of femur
- – Branch of the obturator artery
- – Minor supply
What happens if the medial circumflex femoral artery is damaged?
Can result in avascular necrosis of the femoral head
What is the innervation to the hip joint?
- Femoral nerve
- Obturator nerve
- Superior gluteal nerve
- Nerve to quadratus femoris
What are the stabilising factors of the hip joint?
- Acetabulum
- Acetabular labrum
- Extracapsular ligaments
How does the acetabulum act as a stabilising factor in the hip joint?
- Deep
- Encompasses nearly all of the head of the femur
- – This decreases the probability of the head slipping out of the acetabulum and causing a dislocation
How does the acetabular labrum act as a stabilising factor in the hip joint?
- Fibrocartilaginous collar around the acetabulum
- Increases the depth of the acetabulum
- – This provides a large articular surface
How do the extracapsular ligaments act as a stabilising factor in the hip joint?
- Very strong
- They have a unique spiral orientation
- – Causes them to become tighter when the joint is extended
- – It also means less energy is needed to maintain a standing position
- Muscles and ligaments work in a reciprocal fashion
- – Anteriorly, where the ligaments are strongest, the medial flexors are fewer and weaker
- – Posteriorly, where the ligaments are weakest, the medial rotators are greater in number and stronger
Which muscles cause flexion at the hip joint?
- Iliosoas
- Rectus femoris
- Sartorius
What determines the degree to which flexion occurs at the hip joint?
Depends on whether the knee is flexed
- If it is, this relaxes the hamstrings so increases the range of flexion
Which muscles cause extension at the hip joint?
- Gluteus maximus
- Semimembranosus
- Semitendinosus
- Biceps femoris
What limits extension at the hip joint?
- The joint capsule
- The iliofemoral ligament
They become taut during extension to limit further movement
Which muscles cause abduction at the hip joint?
- Gluteus maximus
- Gluteus minimus
- The deep gluteals (performs, gemelli, etc.)
Which muscles cause adduction at the hip joint?
- Adductors longus, brevis and magnus
- Pectineus
- Gracilis
Which muscles cause lateral rotation at the hip joint?
- Biceps femoris
- Gluteus maximus
- Deep gluteals
Which muscles cause medial rotation at the hip joint?
- Gluteus medius
- Gluteus minimus
- Semitendinosus
- Semimembranosus
What causes a fracture to the neck of the femur?
- In 40 year olds, they are more likely to occur from falls
What happens in a fracture to the neck of the femur?
- Affected limb is laterally rotated
- The arteries arising from the medial circumflex femoral artery are usually torn, disrupting blood supply
- – This can cause avascular necrosis of the femoral head and neck
What happens in a surgical hip replacement?
- A plastic socket is cemented to the hip none to replace the acetabulum
- A stainless steel femoral stem and head replaces the femur
Why are surgical hip replacements performed?
Following:
- Traumatic injury
- Degenerative disease of the joint
What are the 2 types of hip dislocations?
- Acquired
- Congenital
Describe congenital hip dislocations
- More common in girls
- Occurs in ~1.5 per 1000 births, so it is a relatively common abnormality
- During development the femoral head is not placed within the acetabulum, resulting in a dislocated joint
- Common symptoms:
- – Inability to abduct at the hip joint
- – Affected limb is shorter
- – Positive Trendelenburg sign
- Predisposes the patient to arthritis of the hip in later life
Describe acquired hip dislocations
- Quite uncommon, due to the strength and stability of the joint
- Usually occurs during traumatic accidents
- Can be anterior or posterior
- Posterior dislocations:
- – More common type
- – The femoral head is forced posteriorly and tears through the inferior and posterior part of the joint capsule (the weakest part)
- – The affected limb becomes shortened and medially rotated
- – The sciatic nerve can be damaged, which would cause paralysis of the hamstrings and the muscles distal to the knee
- Anterior dislocations
- – A consequence of extension, abduction and lateral rotation
- – The femoral head ends up anterior and inferior to the acetabulum
What can be a consequence of a traumatic hip dislocation in children?
Can disrupt the artery to the head of the femur
- Fractures that result in separation of the superior femoral epiphysis are also likely to result in an inadequate blood supply to the femoral head
- Can cause avascular necrosis of the head of the femur
- Growth at the epiphysis is retarded
- Produces hip pain that may radiate to the knee
What is the route of the sciatic nerve?
- It leaves the pelvis and enters the gluteal region via the greater sciatic foramen
- It leaves the greater sciatic foramen inferior to the piriformis muscle
- It then descends in the plane between the superficial and deep groups of gluteal muscles
- – Posteriorly to the deep gluteal muscles
- – Anteriorly to gluteus maximus and the superficial group of gluteal muscles
- It continues down the posterior thigh, giving rise to motor branches for the hamstring muscles
- When it reaches the apex of the popliteal fossa, it terminates by bifurcating into the tibial and common fibular nerves
Describe how intramuscular injections into the gluteal region are given
- The gluteal region can be divided into quadrants using 2 lines, marked by bony landmarks
- – 1 line descends vertically from the highest point on the iliac crest
- – The other horizontal line passes through the vertical line halfway between the highest point on the iliac crest and ischial tuberosity
- The sciatic nerve passes through the lower medial quadrant
- To avoid damaging the sciatic nerve therefore, intramuscular injections are given only in the upper lateral quadrant of the gluteal region
How are measurements of the lower limb done?
Real shortening = due to actual loss of bone length
- Put both limbs into exactly the same position, where there is no joint fixation
- The length of each limb is then measured from the anterior superior iliac spine to the medial malleolus
Apparent shortening = due to a fixed deformity of the limb
- Patient lies with their legs parallel
- The distance from umbilicus to each medial malleolus
What bursae are there in the hip and where are they found?
- Trochanteric bursa (situated between the gluteus maximus and greater trochanter)
- Iliopsoas bursa (lies deep to iliopsoas)
- Ischiogluteal bursa (situated near ischial tuberosity)
How can the bursae present clinically/become inflamed?
They can be inflamed by repetitive strain or direct trauma
- Trochanteric: inflammation occurs in disorders such as rheumatoid arthritis and in patients with gait disturbances)
- Iliopsoas: may present as swelling below inguinal ligament
- Ischiogluteal: can be inflamed by sitting down
- May result in pain in movement and pain on direct pressure
Describe arthritis to the hip
Inflammation of the joint in the synovium
- Damage to cartilage
- Usually pain early on is due to inflammation
Describe osteoarthritis
- 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
Describe rheumatoid arthritis
- Problem starts in synovium
- Essentially inflammatory
- Joint cartilage is destroyed
- Problem then becomes mechanical
What is the gluteal region?
An anatomical area located posteriorly to the pelvic girdle at the proximal end of the femur
What are the 2 groups of muscles found in the gluteal region?
Superficial abductors and extenders
- A group of large muscles that abduct and extend the femur
- It includes the gluteus maximus, gluteus medius and gluteus minimus
Deep lateral rotators
- A group of smaller muscles that mainly act to laterally rotate the femur
- Includes the quadratus femoris, performs, gemellus superior, gemellus inferior and obturator internus
Where is the gluteus maximus found?
- Originates from the posterior surface of the ilium, sacrum and coccyx
- Slopes across the buttock at a 45 degree angle
- Inserts into the iliotibial tract and gluteal trochanter
What are the actions of the gluteus maximus?
- Main extensor of the thigh
- Assists with lateral rotation
- Only used when force is required (such as running or climbing)
What is the innervation of the gluteus maximus?
Inferior gluteal nerve
Where is the gluteus medius found?
- Lies between the gluteus maximus and minimus
- Originates from the gluteal surface of the ilium
- Inserts into the lateral surface of the greater trochanter
What are the actions of the gluteus medius?
- Abducts and medially rotates the lower limb
- During locomotion it secures the pelvis, preventing pelvic drop of the opposite limb
What is the innervation of the gluteus medius?
Superior gluteal nerve
Where is the gluteus minimus found?
- The deepest and smallest of the superficial gluteal muscles
- Originates from the ilium and converges to form a tend
- Inserts to the anterior side of the greater trochanter
What are the actions of the gluteus minimus?
- Abducts and medially rotates the lower limb
- During locomotion it secures the pelvis, preventing pelvic drop of the opposite limb
What is the innervation of the gluteus minimus?
Superior gluteal nerve
What is the main action of the deep gluteal muscles?
Laterally rotate the lower limb
- Also stabilise the hip joint by ‘pulling’ the femoral head into the acetabulum of the pelvis
Where is the piriformis found?
- Originates from the anterior surface of the sacrum
- Then travels infero-laterally through the greater sciatic foramen
- Inserts into the greater trochanter of the femur
What are the actions of the piriformis?
- Lateral rotation
- Abduction
What is the innervation of the piriformis?
Nerve to piriformis
Where is the obturator internus found?
- Forms the lateral walls of the pelvic cavity
- Originates from the pubis and ischium at the obturator foramen
- Travels through the lesser sciatic foramen
- Attaches to the greater trochanter of the femur
What are the actions of the obturator internus?
- Lateral rotation
- Abduction
What is the innervation of the obturator internus?
Nerve to obturator internus
Where are the gemelli found?
- The superior gemellus muscle originates from the ischial spine
- The inferior originates from the ischial tuberosity
What are the gemelli?
2 narrow and triangular muscles
- They are separated by the obturator internus tendon
What are the actions of the gemelli?
- Lateral rotation
- Abduction
What innervates the gemelli?
- Superior: nerve to obturator internus
- Inferior: nerve to quadratus femoris
What are the actions of the quadratus femoris?
Lateral rotation
Where is the quadratus femoris found?
- Originates from the lateral side of the ischial tuberosity
- Attaches to the quadrate tuberosity on the intertrochanteric crest
What innervates the quadratus femoris?
Nerve to quadratus femoris
