B1W2: Shoulder Region

Question 1

Movements of the upper limb

Answer 1

flexion/extension abduction/adduction medial rotation/lateral rotation (along long axis of limb) protraction, retraction (shoulders) circumduction (combination of all!)

Question 2

aponeuroses

Answer 2

flat sheets that anchor muscle to skeleton, deep fascia or other muscles

Question 3

Origin and insertion of muscles

Answer 3

Origin stays put (proximal attachment), insertion moves (distal attachment)

Question 4

Four types of muscles

Answer 4

Prime mover=agonist, main muscle for producing a specific movement of the body Fixator=steadies the proximal parts of a limb while movements are occuring in distal parts Synergist=helps/assist a prime mover Agonist=opposes action of a prime mover

Question 5

Components of pectoral girdle

Answer 5

Clavicle and scapula

Question 6

General attachments of pectoral girdle

Answer 6

Posteriorly, scapula has no bony connection with the spine Only one bony attachment that attaches the pectoral girdle to the upper limb, and that is the sternoclavicular joint

Question 7

Role of pectoral girdle

Answer 7

Aids in protection, as shock absorber, base for muscles and an interface between the axial/appendicular skeletal components

protection for neurovascular structures

Question 8

Vulnerability of clavicle

Answer 8

Vulnerable in the middle/lateral ttwo thirds; the shoulder drops if broken and limb sags because it protects the brachial plexus, axillary artery and vein If you fracture the clavicle, broken parts can move around

Question 9

Role of clavicle in pectoral girdle

Answer 9

–muscle attachment (6)

–strut: holds upper limb away from trunk

–elevates/depresses at sternoclavicular side

–transfers weight of upper limb to trunk (fulcrum)

Question 10

Attachment of clavicle to body (part of shoulder joint)–sternoclavicular joint

Answer 10

Sternoclavicular joint: joint that connects the sternal (medial) end of clavicle to the shallow end of the sternum(mandirbum); synovial joint; only bony one that connects upper limb to trunk

Has

–costoclavicular ligament connecting to first rib

–sternoclavicular ligament connecting to sternum

–fibrocartilage articular disks between it and sternum

Question 11

Attachment of clavicle to body (part of shoulder joint)–Acromioclavicular joint

Answer 11

Acromion of scapula and acromial (lateral) end of clavicle; synovial joint

Has:

–articular disk

–coracoacromial ligament (acromion to corocoid process)

–acromioclavicular ligament (clavicle to acromion)

–coracoclavicular ligament (trapezoid and concoid ligaments moving medially; clavicle to coracoid process)

–superior transverse scapular ligament

Question 12

Part of shoulder joint: glenohumeral joint

Answer 12

• Head of humerus to scapula
• Large articular surface on head of humerus and shallow articular cup on scapula; only articulation of humerus to pectoral girdle
• Glenoid fossa is the space humerus is trying to attach to
• Glenoid labrium tries to cover area for more surface area by deepening cup
• Humeral head held into glenoid fossa by Musculotendenous Rotator Cuff
• Coracohumeral and glenohumeral ligaments help stabilize

Question 13

Part of shoulder joint: scapulothoracic joint

Answer 13

Gliding of scapula across back of pectoral cage (functional joint only) Causes: Elevation/depression Protraction/retraction Upward rotation/downward rotation

Question 14

What is the role of the scapula?

Answer 14

attachment of 17 muscles

–three sets of attachments that connect it to clavicle; work together as a unit

–spine, acromion, coracoid process all help with muscle attachment

Question 15

What can be damaged by the free ends of a broken clavicle?

Answer 15

–brachial plexus (brachialis artery and vein in limb)

Question 16

Where would humerus be damaged?

Answer 16

Due to osteoporosis, it would detach and fall on forearm or simply break at the surgical neck

RADIAL NERVE is damaged

Question 17

Components of rotator cuff

Answer 17

Subscapularis (anterior) Supraspinatus (above spine, posterior) Infraspinatus Teres minor Rather than being static ligaments, they help stabilize the humerus and still move! Can sense what it’s doing and contract accordingly

Question 18

What is the scapulohumeral rhythm?

Answer 18

Abduction of the upper limb 30 degrees up, supraspinatus – initiate abduction 1:2 ratio between what happens with the scapula and what happens with humerus

Question 19

What muscle is key to moving the scapula?

Answer 19

Serratus anterior

Question 20

What would a downward blow to the shoulder region hurt? (The joint)

Answer 20

Acromialclavicular joint

Question 21

Generalities of the innervation of the shoulder region (will go into more depth later)

Answer 21

Many muscles on dorsal side of the trunk but innervated by branches of the ventral primary rami

Pectoral girdle provides protection for neurovascular structures, like the axillary artery, and especially the brachial plexus

Question 22

Serratus anterior structure/function

Answer 22

long thoracic nerve on surface –attaches scapula to ribs, so if nerve of this muscle was severed you would get winged scapula

Question 23

Posterior/anterior axioappendicular groups of muscles

Answer 23

proximal attachment on trunk, distal attachment on pectoral girdle or humerus

Question 24

Common rotator cuff injuries

Answer 24

tear, attrition due to aging –supraspinatus –most often damaged; most calcified, aged

Question 25

Elderly people who are bowlers sometimes develop soreness to a disease affecting this muscle…

Answer 25

Supraspinatus

Question 26

What can injury to the trapezius muscle cause?

Answer 26

Scapular winging

Question 27

How are the suprascapular nerve and arteries laid out?

Answer 27

Beneath the omohyoid muscle Suprascapular artery is right over suprascapular nerve “army above navy”

Question 28

Attachment of muscles to clavicle

Answer 28

Trapezius

Deltoid

Sternomastoid

Pectoralis major

Subclavius

Question 29

Glenohumeral dislocations

Answer 29

Because of shallow cavity and lax capsule, one of most dislocated things

Mostly anterior; humeral head displaced beneath coracoid process where it could injure axillary or musculocutaneous nerve

Question 30

Bursa

Answer 30

Space enclosed by serous membrane that secretes fluid

Three associated with glenohumeral joint: subacromial, subdeltoid and subscapular

Bursitis=constant moving/inflammation

Question 31

Scapulothoracic joint

Answer 31

funcitonal/physiological joint

Allows movement of scapula

Question 32

Where does the vascular supply for the shoulders originate from?

Answer 32

Subclavian and axillary arteries

Question 33

What is the scapular anastomosis?

Answer 33

Suprascapular artery and dorsal scapular artery anastmose with circumflex scapular artery

–located along medial and lateral borders and w/in infraspinatus fossa

*arterial anastomosis also between anterior and posterior circumflex humeral arteries for

Question 34

Collaterol circulation

Answer 34

Alternative routes of blood supply to structures distal to a blockage that could occur in the main artery, i.e. axillary artery

Question 35

What is the only bony attachment between the pectoral girdle and trunk?

Answer 35

Sternoclavicular joint