The shoulder Flashcards
Appendicular skeleton
Limbs, scapula, hip bones
Axial skeleton
Skull, sternum, ribs, vertebral column
What is the acromium?
Point of the shoulder
What are the joints of the shoulder girdle?
Sternoclavicular joint
acromioclavicular joint
glenohumeral joint
What is the one joint that joins the appendicular skeleton to the axial skeleton? Why are they only joined at one point?
Sternoclavicular joint
So bones can move freely around the thorax
What is the difference between the functions of the upper limbs compared to the lower limbs?
Upper limbs are built for flexibility whereas lower limbs are built for stability as they have to support the weight of the body
Protraction of scapula
Bad posture- bringing scapula round to the front
Retraction of scapula
Good posture- taking scapula backwards to bring shoulder blades together
What is protraction and retraction of the scapula important for?
Pushing and pulling objects
What is the scapula attached to the trunk by? Where does it originate?
Trapezius
Back of the head to the thoracic spine
Superior part of trapezius direction and action
Points upwards to neck and head
Elevates the scapula
Middle part of trapezius direction and action
Goes across the back horizontally
Retraction- pulls shoulder blades together
Inferior part of traapezius direction and action
Comes down the back vertically
Depression of the scapula
Levator scapulae
Elevates the scapula and joins the top corner of it to the neck
Rhomboid minor and major
Minor is at the top and major is at the bottom, fibres run similar to middle of trapezius so they help with retraction
Serratus anterior
Comes from underneath the scapula and attaches its medial edge to the ribs
Important for protraction and upwards rotation
What nerve supplies the trapezius?
Accessory nerve
What nerve supplies rhomboid major and minor?
Dorsal scapula nerve
What nerve supplies serratus anterior?
Long thoracic nerve
Subclavius and pectoralis minor
Round the front of the shoulder, pulls scapula downwards so is involved in protraction and depression
What nerve supplies levator scapulae?
Dorsal scapular nerve
What nerve supplies the subclavius and pectoralis minor?
Medial pectoral nerve
What are the superior rotators?
Serratus anterior and superior part of trapezius
What are the inferior rotators?
Rhomboid major, rhomboid minor and levator scapulae
Why does the glenohumeral joint have a lot of mobility?
Glenoid fossa is much smaller than the head of the humerus which allows it a large amount of space to move around
Synovial joint
Has a capsule, ligaments, synovial membrane with synovial fluid in the joint cavity and cartilage
What type of joint is the glenohumeral joint?
Synovial ball and socket joint
Abduction
Arm taken away from the trunk and lifted up
Adduction
Arm brought back down next to the trunk
Flexion and extension
Bringing arm up in front of you
Bringing arm back down
Hyperextension
Going backwards behind you
Medial rotation
Going towards the midline
Lateral rotation
Going away from the midline
Circumduction
Going round in a big circle both forwards and backwards
Deltoids location
Fastens in like a horseshoe around the clavicle and spine of the scapula and the acromium
Comes down and inserts into the humerus
Middle portion of deltoid
Abducts the arm
Front and back portions of the deltoid
Make abduction by the middle portion smoother by guiding it
If the front acts on its own it flexes the arm
If the back acts on its own it extends the arm
Latissimus dorsi
Comes upwards and inserts into the humerus
Important for adduction and extendion of the arms
Teres major
Short fat muscle on the side and has same function as latissimus dorsi
Pectoralis major
Attaches to clavicle and sternum
Adducts and medially rotates the arm
What nerve supplies the pectoralis major?
Medial and laterla pectoral nerves
What stabilises the glenohumeral joint? How?
Glenoid labrum and the tendon of biceps brachii
Goes up and over the joint cavity and fastens to the top of the glenoid fossa to stop it moving upwards
What are the rotator cuff muscles?
Supraspinatus, infraspinatus, teres minor and subscapularis
What is the function of the rotator cuff muscles?
Attaching the scapula to the humerus and providing dynamic stabilisation
What is another function of the supraspinatus?
Assists in abducting the arm
Which rotator cuff muscles attach to the greater tuberosity?
Supraspinatus, infraspinatus and teres minor
What nerve supplies the supraspinatus and infraspinatus?
Suprascapular nerve
What nerve supplies the teres minor?
Axillary nerve
Where is subscapularis located?
Between the scapula and ribcage
Inserts onto the lesser tuberosity of humerus
