Lecture 13: Shoulder Joint Flashcards
What are the two bones involved in the shoulder joint?
Humerus and scapula
The scapula’s supraglenoid tubercle attaches what muscle?
long head bicep brachii
the scapula’s infraglenoid tubercle attaches what muscle?
long head tricep brachii
What is the surgical neck?
the diaphysis of humerus
How many greater tubercles are there?
3
How many lesser tubercles are there?
1
Where does the coracoclavicular ligament insert?
to the coracoid process of the scapula
Apart from the scapula, what are the other bones that interact with the head of the humerus?
Acromion and glenoid labrum (ring)
Where is the synovial capsule attached to?
around the glenoid labrum
What is the extracapsular ligament of the shoulder joint:
coraco-acromial, gaps between the coracoid and acromion
What is the intracapsular ligaments of the shoulder joint:
1) Coroco-humeral
2) Tranverse humeral (between greater and lesser tubercles)
3) Glenohumeral
What does a bursa do?
Prevents friction between bone and soft tissue and acts as a cushion
What are the main tendons involved in the shoulder joint
Subscapularis; supraspinatus; infraspinatus: bicep tendon; subscapularis
What does the sacciform synovial membrane do?
allows bicep brachii tendon to move up and down the humerus.
Explain what the caracoacromial arch does? (give me 2)
acts as a buffer and prevents superior dislocation
What are the rotator cuff muscles? (SIST)
supraspinatus
infraspinatus
subscapularis
teres minor
other than the rotator cuff muscles, what are 3 additional muscles that act on the shoulder joint?
Deltoid Major
teres major
coracobrachialis
which rotator cuff muscle is only seen on the anterior
Supracapsularis
What is the origin and insertion of the supraspinatus?
Origin: supraspinus FOSSA
Insertion: Superior FACET of Greater Tubercle
What is the origin and insertion of the infraspinatus?
Origin: Infraspinatus FOSSA
Insertion: Middle FACET of Greater Tubercle
What is the origin and insertion of the Teres minor?
Origin: Lateral boarder of the scapula
Insertion: Inferior FACET of Greater Tubercle
What is the origin and insertion of the subcapsularis?
Origin: subscapular FOSSA
Insertion: LESSER tubercle
What is the origin and insertion of the Deltoid?
Origin: anatomical horseshoe
Insertion: Deltoid tuberosity
What is the main function of the subscapularis?
Internally rotates arm
What is the main function of the supraspinatus?
Initiates the beginning of ABducts the arm
What is the main function of the infraspinatus?
externally rotates arm
What is the main function of the teres minor?
externally rotates arm
What is the main function of the anterior fibres of the deltoids?
1) flex the shoulder
2) internally rotate arm
What is the main function of the middle fibres (multipennate) of the deltoids? and why?
Adducts the arm. It waits until supraspinatus performs adduction the humerus to 15 degrees from the anatomical position before contracting.
What is the main function of the posterior fibres?
1) extend the shoulder
2) externally rotate arm
What is the origin and insertion of the middle fibres of the deltoid?
Origin: acromion
Insertion: deltoid tuberosity
What two deltoid fibres assist middle fibres with adduction?
anterior and posterior. Its function depends on their spatial orientation of the insertion of the muscle, relative to the axis.
What is the origin and insertion of teres MAJOR?
Origin: inferior angle and lateral border of the scapula (posterior side)
Insertion: anterior aspect of the humerus
What is the main function of teres MAJOR?
1) internally rotates arm
2) extends shoulder
what is the origin and insertion of the coracobrachialis?
Origin: coracoid process (anterior side)
Insertion: medial side of humerus
What is the main function of coracobrachialis?
1) adduction of shoulder
2) its a shunt muscle
what are the muscles that ABDUCT the arm?
supraspinatus
lateral deltoids
What are the muscles that ADDUCT the arm?
7
posterior deltoids anterior deltoids (anterior aspect) pectoralis major (anterior aspect) long head of tricepts coracobrachialis (anterior aspect teres major latissimus dorsi
What are the arm flexors? (4)
anterior deltoids
clavicular head of pectoralis major
coracobrachialis
bicep brachii
What are the arm extensors? (5)
posterior deltoids teres major latissimus dorsi long head of triceps sternocostal portion of pectoralis major
What muscles are responsible for INTERNAL rotation of the ARM?
Pectoralis major anterior deltoid subscapularis latissimus dorsi teres MAJOR
What muscles are responsible for EXTERNAL rotation of the ARM?
posterior deltoids
infraspinatus
teres MINOR
