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Flashcards in pectoral girdle Deck (57)
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1

what does the pectoral girdle include? what are its signature characteristics and the function of these? where does it get support and stabilization?

clavicle and scapula in an incomplete ring (open posteriorly) to allow mobility +independent motion
-support and stabilization by axio-appendicular muscles

2

what is the sternoclavicular joint?

single articulation between the pectoral girdle and the axial skeleton. (scapula has no articulation w/ axial- only attached via muscles)

3

what are the 3 chief characteristics of the clavicle? expand on each.

1.Elongated S shape
--Convex medially (curve protudes anteriorly)
--Concave laterally
2.Enlarged sternal (medial) end
--Articulates with manubrium
--Sternoclavicular joint (SC)
3.Flattened acromial (lateral) end
--Articulates with acromion process
--Acromioclavicular joint (AC)

4

when someone falls on an outstretched arm, where are they likely to have a fracture/break?

weak points: clavicle or wrist

5

when people fall on their shoulder, where will they have a fracture/break? why?

clavicle - it transmits force from the upper limb to the axial skeleton

6

what are the movements of the clavicle?

swinging strut, suspends scapula at corcacoid process . Allows scapula to "glide" on the thoracic wall (scapulothoracic joint)

7

what movements can the scapula do at the scapulothoracic joint?

elevation/depression
protraction/retraction
upward rotation/downward rotation

8

characteristics of scapula structure? Think medial/lateral, anterior/posterior, superior/inferior

Medial, lateral, superior borders
--Suprascapular notch
--Superior transverse scapular ligament
Superior, lateral, inferior angles

Posterior surface divided by spine
--Supraspinous fossa (above spine)
--Infraspinous fossa (below spine)
Acromion- lateral end of spine
--Acromioclavicular (AC) joint

Anterior subscapular fossa: indented region
Coracoid process- looks like little thumb
--Coracoclavicular ligament
Lateral surface bears glenoid fossa
--“Socket” for much larger humeral head

9

what two features create a foramen on the superior border of the scapula?

suprascapular notch and superior transverse scapular ligament

10

how does the acromion project?

anterior and laterally

11

where is the weight of the scapula and upper limb suspended?

center of balance: the strong coracoclavicular ligament- which is attached to the coracoid process on the anterior surface of scapula

12

how does the scapula and humerus counterbalance each other?

the balance of the coracoclavicular ligament but also the pull of the rhomboids against the weight of the limb.

13

posterior axio-appendicular muscles...O,I,A? What do they include?

Originate on axial skeleton
Insert on appendicular skeleton
Move or stabilize pectoral girdle and/or humerus
includes: superficial and deep extrinsic shoulder muscles

14

superficial extrinsic shoulder muscles

trapezius and lat. dorsi

15

deep extrinsic shoulder muscles

rhomboids (major and minor) + levator scapulae

16

scapulohumeral muscles: O,I,A. which muscles are included?

the intrinsic should muscles. O&I on appendicular skeleton. predominantly O on scapula and I on humerus

Act: on glenohumeral (shoulder) joint
-Deltoid
-teres major
-rotator cuff group

17

what muscles are in the rotator cuff group?

"SITS"
supraspinatus
infraspinatus
teres minor
subscapularis

18

Deltoid features, O,I,A, Innerv.?

inverted triangle: anterior, middle, and posterior portions
O- lateral third clavicle, acromion, lateral scapular spine
I-deltoid tuberosity (prominence on humerus)
A-abducts arm after 15degrees
--anterior: flexes
--posterior:extends (when adducted)
innveration:axillary nerve C5, C6 - terminal branch of brachial plexus

19

what abducts arm the first 15degrees?

supraspinatus

20

Teres Major:general location, O,I,A, Innerv.

Forms posterior lateral boundary of axilla, runs very close to latissimus dorsi.
O-posterior surface of inferior scapular angle
I-intertubercular groove of humerus (posteromedial to latissimus dorsi)
Adducts & medially rotates arm
Innervated by lower subscapular nerve (C5, C6)
--(Collateral/preterminal branch of brachial plexus)
NOT THORACODORSAL NERVE

21

what does "teres" mean?

"round" - cylindrical shape of muscle

22

what type of baseball pitch would the teres major help in?

screwball, medial/internal rotation

23

which muscle is not part of the rotator cuff group but does serve to rotate the humerus?

teres major

24

what do the rotator cuff muscles do?

all 4 form a tendinous cuff around glenohumeral joint that stabilizes the oversized humeral head into undersized glenoid fossa - think of thumb and first three finger grabbing onto humeral- they form “ the cuff “
--3 of the 4 serve to rotate the humerus. (supra only ABducts)
--4 muscles provide tendinous support- support on all sides except inferiorly - plays a role in shoulder dislocation

25

what are the placement of the rotator cuff muscles in the finger model?

holding the head of the humerus with the palm as the glenoid fossa
thumb: subascapularis
pointer: supraspinatus
middle: infraspinatus
ring: teres minor

26

supraspinatus: O,I,A, Inner,Blood?

O-supraspinous fossa
I-greater tubercle (superior portion)
A: First 15° abduction of arm
Innervated: suprascapular nerve (C4-6)
---Collateral/preterminal branch of brachial plexus
-blood: suprascapular artery

27

what is the general location of the supraspinatus?

passes under the acromion and under the acromion ligament "bridge"

28

infraspinatus: O,I,A, blood?

O-infraspinous fossa of scapula
I-greater tubercle of humerus (posterior portion)
A: Laterally rotates arm
Innervated: suprascapular nerve (C5-6)
----Collateral/preterminal branch of brachial plexus
blood: suprascapular artery

29

what muscle aids in the curveball pitch?

infraspinatus (lateral rotation)

30

suprascapular nerve and artery: general location

both originate in neck go into the pectorogirdle region