Shoulder Anatomy Flashcards
what is the shoulder?
- ball and socket joint that moves in all 3 planes
- most mobile and least stable joint
the shoulder is made up of 3 bones, what are they?
- scapula
- humerus
- clavicle
what is the scapula?
- large flat bone
- sits between the humerus and clavicle
- responsible for stabilizing the upper arm bone
what is the humerus?
- bone of upper arm
- top of humerus is rounded and fits into the shallow socket of the scapula
the top of the humerus is rounded and fits into the shallow socket of the scapula, this is called the?
genoid cavity
what is the clavicle?
- long, thin bone located between the shoulder and top of the ribcage
- helps support and keep the arm in place when away from the body
what is the glenoid labrum?
- fibrocartilage ring attached to the rim of the glenoid fossa, which deepens the cavity
function of the glenoid labrum?
- keep the head of the humerus in place
- ensure smooth movement of the ball-and- socket joint
scapula land mark?
- glenoid labrum
surgical neck of the humerus?
- where the head meets the body
anatomical neck of the humerus?
- where the head meets the tubercles
what is the greater tubercle/tuberosity?
- large projection lateral to the head
what muscles attach to the greater tubercle? (3)
- supraspinatus
- infraspinatus
- teres minor
what is the lesser tubercle?
- smaller projection on the anterior surface
what muscle attaches to the lesser tubercle?
- subscapularis
what is the deltoid tuberosity?
- lateral side
- near midpint
- deltoid attaches here
what is the bicipital groove?
- location
- what does it contain
- groove between the tubercles
- contains the long head of the biceps tendon
what is the subacromial space?
- space bewteen the head of the humerus and acromion process of the scapula where soft tissues of the shoulder can be compressed
what 4 things are in the subacromial space?
- supraspinatus tendon
- long head biceps tendon
- subacromial bursa
- superior border of capsule
biceps bracii: origin, insertion, and action?
origin: scapula
insertion: radius
Action: flexes and supinates forearm at elbow
biceps bracii: origin, insertion, and action?
origin: scapula
insertion: radius
Action: flexes and supinates forearm at elbow
tricep brachii: orgin, action, and insertion?
origin: scapula and humerus
action: elbow extension and shoulder extension
insertion: ulna
anterior deltoid origin, insertion, action?
origin: front and top of lateral 3rd of clavicle
insertion: deltoid tuberosity on outer surface of humeral shaft
action: forward flexes and internally rotates humerus
lateral deltoid: origin, insertion, action?
O: Lateral border of acromion process of scapula
I: deltoid tuberosity on outer surface of humeral shaft
A: abducts humerus following initiation of movement by supraspinatus muscle of rotator cuff
posterior deltoid: origin, insertion, action?
O: spine of scpula
I: deltoid tuberosity on outer surface of humeral shaft
A: extends and externally rotates humerus
what is the pectoralis major? where does it originate? where does it insert?
- chest muscle
- originates along the sternum and clavicle
- inserts on the humerus
function of the pectoralis major? (3)
- adduct
- flex
- medially rotate the arm
what is the trapezius? Where does it originate?
- large, triangular muscle
- starts at base of skull, runs out to tip of shoulder and down to the 12th thoracic vertebrae
function of trapezius?
- shrug and square shoulders
whats are rhomboids?
0 group of 2 muscles that run diagonally from the spine to the medial border of the scapula
rhomboids function?
- retract the scapula
what is the latissimus dorsi?
- “lats”
- gives wing like apperance to sides
- starts along the thoracic vertebrae of back and inserts on the anterior aspect of humerus
function of latissimus dorsi? (3)
- extend
- addect
- medially rotate arm
whats the teres major?
- little helper of lats
- runs from axillary boarder of the scapula to the lesser tubercle of the humerus
Coracobrachialis location?
attaches to the coracoid process and the arm or brachium
Coracobrachialis function?
- stabalizes humerus in the fossa
what is the most frequently injured group of muscles and tendons within the shoulder?
- rotator cuff
where does the rotator cuff originate?
- at the scapula and attaches to the head of the humerus
rotator cuff function?
- stabilizes the glenohumeral joint by hugging the rounded humeral head to the concave glenoid cavity
the roator cuff consists of how may muscles?
4 muscles and their tendons
The four rotator cuff muscles cover what?
the humeral head and hold the head against the glenoid fossa
what are the 4 rotator cuff muscles?
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
what is the supraspinatus muscle? location and function?
- anterior superior shoulder
- superior to the spine of the scapula
function: abduction
infraspinatus location and function?
- posterior inferior shoulder
- inferior to the spine of the scapula
function: external rotation
teres minor location and function?
- posterior shoulder
function: adduction
subscapularic location and function?
- anterior shoulder
function: internal rotation
glenohumeral joint?
- static stabilizers
- dynamic stabilizers
- shallow
static stabilizers: glenohumeral ligaments, glenoid lebrum, and capsule
dynamic stabilizers: rotaor cuff muscles
scapular stabilizers? (4)
- trapezius
- leavator scapulae
- serratus anterior
- rhomboids
3 ligaments of the shoulder?
- glenohumeral lig.
- coracohumeral lig.
- transverse humeral lig.
Glenohumeral ligaments function ?
- 3 ligemets that reunforce the front of the shoulder’s henohumeral joint
glenohumeral ligament location?
- spans from the edge of the glenoid cavity to the neck of the humerus
coracohumeral ligament function?
- strong and broad banf
- strengthens the upper aspect of the bicep brachii muscle
transverse humeral ligament location?
- attaches to 2 different points at the top of the humerus
- creates an arched tunnel for the bicep tendon to pass under
what is a bursa?
- small, fluid-filled sac that reduces friction between bone and soft tissue
2 primary bursae in the shoulder?
- subscapular bursa
2. subacromial bursa
subscapular bursa location?
- located between the glenohumeral joint and the subscapularis muscle
subacromial bura location?
- located directly under the acromion on top of the scapula
subacromial bura function?
- helps rotator cuff funtion
- most susceptible to injury and is often the cause of shoulder impingement
functions or articular cartilage in the shoulder?
- allows 2 bones to move or glide against each other
- cushions bones- acts as shock absorber
articular cartilage is often thinner in the shoulder than it is in weight-bearing joints, such as the knees and hips T or F?
True
what is osteoarthritis?
- damage and loss of articular cartilage
in the shoulder where is osteoarthritis most common?
- glenohumeral joint and scromioclavicular joint are susceptible to this
in the shoulder where is osteoarthritis most common?
- glenohumeral joint and scromioclavicular joint are susceptible to this
GH movements that sacifices stability for mobility? (6)
Flexion Extension Abduction Adduction Internal Rotation External Rotation
primary muscle for abduction?
deltoid
primary muscles for adduction? (2)
- pectoralis major
- latissimus dorsi
primary muscles for flextion? (2)
- pec major
- anterior fibers of the deltoid
primary muscles for extension? (2)
- latissimus dorsi
- teres major
primary muscles for internal rotation? (3)
- subscapularis
- latissimus dorsi
- pec major
