Pectoral and Pelvic Girdles Flashcards
which bones form the pectoral girdle?
scapula and clavicle
what are features of the pectoral girdle?
- attaches the UL to axial skeleton
- augments free movement of limb
- is mobile and moves simultaneously with UL
which bones form the pelvic girdle?
- hip bone (ilium, ischium and pubis)
- sacrum
- coccyx
what are features of the pelvic girdle?
- attaches LL to axial skeleton
- provides an almost rigid, complete ring for weight bearing and child birth
what do both the pectoral and pelvic girdles provide?
- “gateways” for neurovascular structures to pass to and from limbs
- muscle attachment for limb movement
what is the function of the clavicle?
- acts as a strut, holding the upper limb away from the trunk
- transmits forces from the upper limb to the trunk
describe the physical features of the clavicle
lateral end: flat and articulates with acromion
medial end: quadrangular, articulates with manubrium of sternum
medial 1/3 is rounded and convex anteriorly
where does the coraco-clavicular ligament attach?
- conoid tubercle
- trapezoid line
what are features of the scapula?
- triangular bone on the posterolateral aspect of thorax
- suspended in muscles, held in position by clavicle
- overlying the 2nd - 7th ribs
what are the 3 margins of the scapula?
- superior
- medial
- lateral
what is the superior angle of the scapula level with?
2nd rib
what is the inferior angle of the scapula level with?
7th rib
how many fossa feature on the scapula?
3: supraspinous, infraspinous and glenoid
what is the purpose of the glenoid fossa?
to articulate with the humerus
what is the significance of the sternoclavicular joint?
it is the only site of attachment of the pectoral girdle to the body
what are features of the sternoclavicular joint?
- synovial joint with joint capsule and intra-articular disc that is attached to clavicle, manubrium and capsule
how is the capsule of the sternoclavicular joint strenghtened?
- by ligaments anteriorly and posteriorly
- plus interclavicular and costoclavicular ligaments
where does the subacromial bursa lie?
in the narrow “space” between GH joint capsule and acromion, acromioclavicular joint and coraco-acromial ligament
what lies next to the subacromial bursa?
tendon of supraspinatus muscle
how might injury occur to supraspinatus?
due to arthritis in adjacent joints and repetitive strain injury
what are features of a synovial joint?
allows a small range of gliding movement
what makes up the major ligamentous support of the acromioclavicular joint?
conoid and trapezoid parts of the coraco-clavicular ligament
where is the gateway for the pectoral girdle to the upper limbs?
between the clavicle, superior edge of scapula and the first rib
what passes through the pectoral girdle “gateway” to the axilla?
- subclavian vessels
- trunks of brachial nerve plexus
where do the bones of the hip articulate with each other?
pubic symphysis
what is the relationship between the ASIS and pubic tubercle?
on the same coronal plane
what are features of the pubic symphysis?
- secondary cartilaginous/fibrocartilage joint between left and right pubic bodies
- supported by superior and anterior ligaments
- disc between articular surfaces
- limited movement, and shock absorption
what are features of the sacro-iliac joint?
- for weight transfer, extremely limited movement
- synovial anteriorly and supported by anterior sacro-iliac ligament
- fibrous posteriorly, supported by posterior sacro-iliac and interosseous ligaments
which ligaments prevent sacrum tilting forwards?
- sacrospinous
- sacrotuberous
what are the roles of sacrospinous and sacrotuberous ligaments?
- prevent sacrum tilting forward
- convert sciatic notches into GREATER and LESSER sciatic foramina
what structures pass through the greater sciatic foramen?
- sciatic nerve
- gluteal neurovascular bundle
what structures pass through the lesser sciatic foramen?
internal pudendal neurovascular bundle
what gateway does the femoral neurovascular bundle pass through?
the gap between inguinal ligament and pelvic bone
what structures pass through the obturator canal?
obturator neurovascular bundle
where is the safe area for intramuscular injections?
upper, outer quadrant
where does the sciatic nerve emerge?
- into gluteal region
- inferior to piriformis
- midway between ischial tuberosity and greater trochanter
what are the movements of the pectoral girdle?
- elevation and depression
- protraction and retraction
- rotation of the scapula so glenoid fossa faces upwards or downwards (abduction of arm)
what does serratus anterior form?
medial wall of axilla
what nerve descends superficially to serratus anterior?
long thoracic nerve
what is the origin of trapezius?
- superior nuchal line
- external occipital protuberance
- nuchal ligament
- spinous processes of C7-T12
- supraspinous ligaments between C7-T12
what is the insertion of trapezius?
- lateral 1/3 of clavicle
- acromion
- spine of scapula
what muscles act on the pectoral girdle?
- trapezius
- serratus anterior
- pectoralis minor
- subclavius
- levator scapulae
- rhomboid major
- rhomboid minor
