Glenohumeral & Hip Joints Flashcards
what is the glenohumeral joint?
+ ball (head of humerus) and socket (glenoid cavity of scapula) type joint
+ unstable
+ great mobility
what is the hip joint?
+ ball (head of femur) and socket (acetabulum of hip) type joint
+ stable
+ limited mobility
describe physical features of the GH joint?
+ glenoid fossa is shallow
+ only 1/3 of humeral head is in contact with glenoid
+ held in place by rotator cuff muscles (SITS)
+ surfaces covered by hyaline cartilage
+ fused with tendon of long head of biceps
where does the glenoid labrum attach to?
the edge of the glenoid fossa
what is the function of the glenoid labrum?
to deepen the socket and help stabilise the joint
what are features of the GH joint capsule?
+ joint capsule is loose
- particularly inferiorly, to allow abduction
+ supported by tendons of rotator cuff muscles
+ attached to glenoid fossa margin and labrum and anatomical neck of humerus
+ capsule encloses proximal attachment of long head of biceps
what are the 3 openings on the GH joint capsule?
- biceps tendon passes through to its insertion
- subscapularis bursa
- protects subscapularis tendon from being damaged by edge of glenoid - subacromial bursa
- protects supraspinatus tendon from being injured
what is a bursa?
a sac-like synocial fluid filled cavity near joints which also help facilitate movement
what is bursitis, and what can it lead to?
+ inflammation of the bursa
+ may lead to degenerative changes in associated tendons, resulting in difficulty initiating certain movements
what are the intrinsic (anterior) ligaments of the GH joint?
+ glenohumeral: weak
+ transverse humeral: keeps biceps tendon in bicipital groove
what are the extrinsic (superior) ligaments of the GH joint?
+ coraco-acromial: strong
+ coraco-humeral: strong
what forms the coraco-acromial arch?
+ coronoid process
+ acromion
+ coraco-acromial ligament
what is the function of the coraco-acromial arch?
prevents superior displacement of humerus
what are features of the acetabulum of the hip joint?
+ deep socket, weight bearing, stable
+ acetabular fossa+lunate surface
+ rim is raised by acetabular labrum (may tear and cause pain)
what does the labrum of the acetabulum bridge across the acetabular notch as?
transverse acetabular ligament
what are features of the femoral head of the hip joint?
covered by hyaline cartilage except for fovea of ligament
what is the hip joint capsule attached to?
+ acetabular rim
+ transverse acetabular ligament
+ intertrochanteric line
+ neck of femur
what is the capsule of the hip joint?
a synovial membrane that covers everything except the articular cartilage, and forms a sleeve around the ligament of the head of the femur
what are retinacular fibres?
fibres which the synovial layers of the capsule send medially along the femoral neck towards the head
what are the 3 capsular ligaments of the hip joint?
+ iliofemoral; anterior & superior; strongest
-prevents hyperextension of hip joint during standing
+ pubofemoral; anterior & inferior
- prevents over-abduction of hip joint; tightens during abduction and extension of hip
+ ischiofemoral; posterior; weakest
what are features of the hip joint ligaments?
+ all capsular ligaments of hip joint spiral around joint and attach to femur so that they are taut in extension
- prevent overextension
- stabilize joint
- save energy during standing
what is the zona orbicularis?
annular ligament (orbicular zone)
formed by some deep fibres of fibrous capsule winding circularly around neck of femur
what vascular structures form the cruciate anastomosis?
- medial circumflex femoral artery (retinacular branches)
- lateral circumflex femoral artery (retinacular branches)
- obturator artery
what injury might affect the blood supply of the femoral head?
fracture of femoral neck
what vascular structures supply the hip joint?
- cruciate anastomosis
- trochanteric anastomosis
what vascular structures form the trochanteric anastomosis?
- medial circumflex femoral artery
- lateral circumflex artery
- superior gluteal artery
- inferior gluteal artery
what are the movements of the GH and hip joint?
- flexion & extension
- abduction & adduction
- medial & lateral rotation
- circumduction
what are the FLEXORS of the GH joint?
- pectoralis major
- deltoid (anterior/clavicular fibres)
- biceps brachii
- coracobrachialis
what nerve are coracobrachialis and biceps supplied by?
musculocutaneous
