Ses 2 Hip Anatomy And Disorders Msk Flashcards
Anatomy of hip bones - Look at notion and anki
3 parts to a hip bone:
Ilium
Ischium
Pubis
With sacrum makes pelvic girdle and connects upper body to lower limbs
Hip joint anatomy and roles
Look at notion
Articulation between head of femur and pelvic acetabulum
Ball and socket synovial
Both the acetabulum and head of femur are covered in hyaline cartilage.
The articular surface of the acetabulum is shaped like a horseshoe; it is incomplete inferiorly in the region known as the acetabular notch. The acetabular notch contains fibroelastic fat covered with synovial membrane.
Roles - flexion, extension, abduction, adduction, external rotation, internal rotation and circumduction
Main functions: stability and weight-bearing
• Stability > Mobility so smaller range of movement compared to the shoulder joint.
Factors that stabilise hip joint with brief description
Look at notion
• The cup-shaped acetabulum
• The acetabular labrum, which deepens the acetabulum - Increases the articular contact area by 10% so More than 50% of head of femur fits in
• The capsule - In extension capsule helps pull femoral head into acetabulum. Capsular fibres take a spiral course
Anterior - Attaches at intertrochanteric line
Posteriorly - Lateral part of neck is extra- capsular?
• The ligamentum teres
The extracapsular ligaments: iliofemoral, pubofemoral and ischiofemoral
• The muscles surrounding the hip joint
Identify and describe the anatomy of the muscles which produce movement at the hip joint - look at notability
Identify and describe the anatomy of the neurovascular structures - notion
Describe the blood supply of the head of the femur - look at notion
There is an arterial ring at the base of the femoral neck.( this is why femoral neck fracture can cause avascular necrosis).
Formed posteriorly by the medial femoral circumflex artery and anteriorly by the lateral femoral circumflex artery.
Ascending cervical branches (retinacular arteries) of these supply head of femur.
Main arteries:
1. Profunda femoris artery - MFCA and LFCA branches
2. Obturator artery - ligamentum teres artery branches from this - main source for children until epiphyseal fusion.
Describe the pathology of osteoarthritis - look at notion for X-ray
Degenerative disorder from the breakdown of articular hyaline cartilage. Chronic, not systemic, not inflammatory.
- Swollen due to inc proteoglycan synthesis by inc chondrocytes to repair damage (normal adult chondrocytes do not usually proliferate from chondroprogenitor cells).
- As disease progresses proteoglycan falls - flaking, fibrillation, erosion, loss of joint space.
- Bone responds with vascular invasion and thickened at areas of damage(subchondral sclerosis). Form bone cysts(fluid) and osteophytes.
Secondary factors (e.g. obesity, lead to excessive or uneven loading of the joint which damages hyaline cartilage covering the articular surface.
Describe the risk factors for OA
Primary - cause unknown
Risk factors:
age
sex(female more than male however in hip most common for males over 40)
ethnicity
nutrition
genetics
Secondary causes:
obesity
trauma
Malalignment e.g. Developmental dysplasia (congenital)
Infection e.g. septic arthritis, tuberculosis
Inflammatory arthritis e.g. rheumatoid arthritis
Metabolic disorders affecting the joints (e.g. gout)
Haematological disorders (e.g. haemophilia with bleeding into the joints)
Endocrine abnormalities (e.g. diabetes with neurovascular impairment)
Symptoms of OA,
describe the limitations placed on activities of daily living
Joint stiffness that occurs getting out of bed, after sitting for a long time and rest
Crepitus: A sound and feeling of crunching of bone rubbing against bone
Reduced ability to move the hip to perform routine activities such as putting on a sock, getting in and out of the car, the bath etc.
Pain in the hip, gluteal and groin regions radiating to the knee (via the obturator nerve)
Describe the neck of femur fractures, their radiological appearance, and their complications with regard to adjacent anatomical structures - look at notion
Neck of femur fracture - a fracture of the proximal femur, up to 5cm below the lesser trochanter.
Symptoms:
Reduced mobility
Pain which may be felt in the hip, groin and/or knee
They can be intra or extracapsular
Intracapsular -
Treated by replacement of the femoral head (hemiarthroplasty) or total hip replacement [head and acetabular cup].
Extracapsular - intertrochanteric and subtrochanteric.
Describe the mechanism underlying avascular necrosis of the hip following an intracapsular fracture of the femoral neck
disrupt the ascending cervical (retinacular) branches of the medial femoral circumflex artery.
Ligamentum Teres artery cannot sustain the femoral head so avascular necrosis. Inc risk if the fracture is displaced.
clinical appearance of the limb after a displaced femoral neck fracture, relating to the function of the muscles.
Axis of rotation was oblique through neck but is now longitudinal through GT.
Shortened (rectus femoris, hamstrings and AM), abducted (G med and min) and externally rotated(deep gluteal muscles + iliopsoas + G med and min).
Describe the common mechanisms of traumatic dislocation of the hip, and the typical clinical
appearance, relating the rotation and shortening of the limb to the function of the muscles.
Dislocation - head fully displaced out of acetabulum and on lateral acetabulum.
Posterior - collision with dashboard.
Shortened (gluteus
maximus, hamstrings, adductors)
Internally rotated (anterior
fibres of gluteus medius and minimus)
Adducted
Flexed
Can have sciatic nerve palsy
Anterior
Externally rotated
Abducted
Slightly flexed
Rarely causes damage to femoral nerve
CENTRAL DISLOCATION
head of the femur is driven into the pelvis through the acetabulum.
Always a fracture dislocation
Femoral head palpable on rectum examination
Intrapelvic haemorrhage
Lumbar plexus
The ilioinguinal nerve has the root L1. It innervates the skin of the genitalia and the upper medial thigh.
Genitofemoral - L1 and L2 anterior
Femoral branch innervates skin on the upper anterior thigh.
lateral cutaneous nerve - posterior divisions of the L2 and L3 roots.
sensory function
The obturator nerve is formed from the anterior divisions of the L2, L3 and L4 roots. It innervates the skin over the medial thigh.
The femoral nerve is formed from the posterior divisions of the L2, L3 and L4 roots. It innervates the skin of the anterior thigh.
Lumbosacral plexus
Superior gluteal nerve - L4,5,S1- above piriformis muscle which is in the greater sciatic foramen. Supplies gluteus medius, minimus and tensor fascia lata.
Inferior GN - L5,S1,2 - below piriformis. Supplies gluteus max
Sciatic nerve - L4,5,S1-3 - below piriformis. 2 divisions. Tibulal goes to hamstrings - long head of bicep femoris, semi tendonous and semi membraneous. Fibulal division goes to short head.
Posterior cutaneous- S1-3
