Unit 2 - Upper Limb: Joints of the Pectoral Girdle (Ex. II)

Question 1

acromioclavicular (AC) joint

Answer 1

planar synovial joint
acromion –> acromial end of clavicle
articular disk in acromioclavicular surfaces
acromioclavicular ligament –> supports S
coracoclavicular ligament –> extrinsic; anchors clavicle to coracoid process ==> conoid ligament (M) and trapezoid ligament (L)

Question 2

scapulothoracic (ST) joint

Answer 2

NOT A REAL JOINT
functional relationship between serratus anterior and subscapularis (thoracic wall and scapula)
allows scapula to glide and pivot on chest wall

Question 3

glenohumeral (GH) joint

Answer 3

ball-and-socket synovial joint
shallow glenoid cavity of scapula –> large head of humerus
glenoid labrum - fibrocartilage to deepen cavity
fibrous capsule w/ synovial membrane surrounds joint
S, middle, I glenohumeral ligaments - A thickenings of capsule
coracohumeral ligament - S; extends between coracoid process of scapula and lesser tubercle of humerus
synovial membrane lines joint space - tubular sheath (transverse humeral ligament) around tendon of biceps brachii as it passes through joint space; communicates w/ coracoacromial ligament - coracoid process –> acromion; prevents S humeral dislocation
subtendinous bursa of subscapularis - between tendon of subscapularis and neck of scapula; communicates w/ synovial cavity
subacromial bursa - S; under coracoacromial ligament and above supraspinous tendon and GH joint capsule
subdeltoid bursa - L; deep to deltoid and above subscapularis tendon; communicates w/ subacromial bursa

Question 4

sternoclavicular (SC) joint

Answer 4

strong and highly mobile saddle synovial joint (BUT ACTS AS BALL-AND-SOCKET)
only bony articulation between UL and trunk - sternal end of clavicle –> manubrium and 1st costal cartilage
articulating surfaces separated by articular disk
A and P sternoclavicular, costoclavicular, and interclavicular ligaments strengthen
allows clavicle to elevate and rotate in conjunction w/ limb movements