Week 1: The Pectoral Girdle and Shoulder Flashcards
Where are the 3 large joints in the upper limb?
- shoulder
- elbow
- wrist
What are the 3 neuromuscular ‘spaces’ in the upper limb?
- axilla
- cubital fossa - anterior to elbow
- carpal tunnel
What is the most commonly dislocated joint in the body?
shoulder
What is the ‘pectoral girdle’?
Consists of:
- the clavicle
- the scapula
What is the glenohumeral joint?
- the ‘shoulder joint’
- the head of the humerus articulates with a socket on the scapula called the glenoid fossa
Where is the coracoid process?
on the lateral edge of the superior anterior portion of the scapula
projects anteriorly
Where is the supra spinous fossa?
hollow region on the posterior surface of the scapula, just above the spine of the scapula
What separates the head of the humerus with the greater and lesser tubercles of the humerus?
anatomical neck of the humerus
Why is the shoulder joint incongruent/ a poor fit?
- we get a greater range of movement as the joint is less stable
- we can position our hand where we want it to be
Which features increase the stability of the shoulder joint?
- surrounding muscle
- tendon of long head of biceps brachii muscle
- glenoid labrum (ring of cartilage around the edge of the glenoid fossa which improves the fit for the humeral head)
What are the 4 movements of the scapula?
- Protraction (forwards)
- Retraction (backwards)
- Elevation (shrugging of shoulders and depression)
- Rotation
What are the three muscles of the anterior pectoral girdle?
- Pectoralis Major
- Pectoralis Minor
- Serratus Anterior
Which actions can the pec major perform?
Adduction
medial rotation of shoulder
What bones are attached to the pec major?
humerus
sternum
clavicle
What is the origin point of the pectoralis minor?
ribes 3-5
What is the function of the pec minor
stabilises the scapula and assists in protraction
What structure does the pectoralis minor insert onto?
the coracoid process of the scapula
What is the function of the serratus anterior?
protracts the scapula
Which nerve runs down the serratus anterior?
long thoracic nerve
Which ribs does the serratus anterior run through?
ribs 1-8
What are the 5 muscles of the posterior pectoral girdle?
- Levator scapulae
- Rhomboid minor
- Rhomboid major
- Trapezius
- Latissimus dorsi
What movements of the shoulder is the latissimus dorsi responsible for?
adduction
medial rotation
extension
What movements of the scapula is the trapezius muscle responsible for?
elevation
contraction
depression
Which muscles of the posterior pectoral girdle are deep and which are superficial
deep - levator scapulae, rhomboid major/minor
superficial - latissimus dorsi, trapezius
What happens when the levator scapulae contracts?
it elevates and pulls the scapula up towards the neck
What is the function of the deltoid muscle?
abducts, flexes and extends
What are the attachment and insertion points of the deltoid muscle?
attachment - clavicle and spine of scapula
insertion - deltoid tuberosity
Which nerve innervates the deltoid, teres minor and teres major muscle?
axillary nerve
What are the attachment and insertion points of the teres major?
attachment - posterior scapula
insertion - anterior humerus
What is the function of the teres major?
medially rotates and adducts the shoulder
Where do the rotator cuff muscles originate and insert?
originate from the scapula
insert on the humerus
What are the 4 rotator cuff muscles?
- Supraspinatus
- Infraspinatus
- Subscapularis
- Teres minor
What is the function of the supraspinatus?
starts abduction (first 20*)
Which rotator cuff muscles are lateral rotators of the shoulder?
infraspinatus and teres minor
What is the function of the subscapularis?
adducts and medially rotates the shoulder
Which arteries and veins are found in the pectoral region and shoulder?
- at the axilla, the subclavian artery and vein becomes the axillary artery and vein
- these give rise to the anterior and posterior circumflex humeral arteries
What is the major superficial vein that drains into the axillary vein?
cephalic vein
Where is the cephalic vein?
lies between the deltoid and the pectoralis major in a groove called the deltapectoral groove
What is an avulsed nerve?
when a nerve is pulled away from its origin
What is a common problem associated to the supraspinatus tendon?
the supraspinatus tendon can get trapped (impinged) between the humeral head and the acromion and become inflamed
What causes a ‘winged’ scapula
- shoulder blade protrudes from a persons back abnormally
- injury to the long thoracic nerve, which innervates the serratus anterior
- patient would have problems protracting the scapula
What is the function of the pectoral girdle?
to anchor and secure the upper limb to the axial skeleton
What part of the sternum does the clavicle articulate with?
the manubrium of the sternum (at the sternoclavicular joint)
Which part of the clavicle is the weakest?
- the point between the medial third and lateral third
- between the convexity and concavity of the clavicle
- this is where it tends to fracture
What is a characteristic feature of the posterior aspect of the scapula?
the spine of the scapula - extends upwards and lateral to the acromion
What is a comminuted fracture?
when a fracture has more than two fragments
What is the acromion clavicular joint?
bony articulation between our clavicle and our scapula
What is the function of the rhomboid muscles?
acts as retractor and elevator of the scapula
Which part of the humerus is most commonly fractured?
the surgical neck
Where does the subscapularis muscle insert?
the lesser tubercle of the humerus
Where do the supra spinatus, infraspinatus and teres minor muscles insert?
the greater tubercle of the humerus
What type of joint is the glenohumeral joint?
Synovial
Which ligaments attach the acromion and clavicle to the coracoid process?
- coraco-acromial ligament
- coraco-clavicular ligament
Explain how abduction of the shoulder is carried out
- first 30 degrees by supraspinatus
- 30-90 degrees by deltoid
- 90-180 degrees by trapezius
- GHJ and STJ must be synchronous
What is the maximum range of the following movements:
- Abduction
- Adduction
- Lateral/medial rotation
- Flexion
- Extension
- Abduction - 180
- Adduction - 45
- Lateral/medial rotation - 90
- Flexion - 180
- Extension - 50
Which nerve innervates the supraspinatus and infraspinatus
suprascapula nerve
What is another term for ‘frozen shoulder’?
adhesive capsulitis
What is ‘frozen shoulder’?
- unknown aetiology
- painful global restriction of GH movements in all planes, both active and passive, in the absence of joint degeneration
What are the clinical features of frozen shoulder?
- rare in <40s
- diabetes increases risk
- pain, ache, night pain, spasm, stiffness