L3 - Anatomy of the shoulder region Flashcards
What is the pectoral girdle?
The clavicle & scapula
What are the skeletal components of the shoulder region?
Clavicle
Scapula
Humerus
What are the two joints in the shoulder region?
Glenohumeral joint
Acromioclavicular joint
What is the function of the ligaments of the shoulder
To stabilise/support the shoulder (they are very strong)
What are the ligaments of the shoulder?
Coracoclavicular
Acromioclavicular
Coracoacromial
Glenohumeral
How many parts to the coracoclavicular ligament?
Two
Sit at right angles to each other - provides added strength
What is important about the coracoclavicular ligament?
It is a major stabilising ligament of the shoulder
What is the function of the coracoacromial ligament?
Forms an arch
Provides support for the head of the humerus
Prevents superior dislocation of the humerus from the glenohumeral joint
Which ligaments form a triangle?
Coracoclavicular and coracoacromial
Which muscle performs abduction of the arm?
The deltoid (but supraspinatus initiates it)
Describe the shape and composition of the deltoid muscle
Large triangular muscle
Anterior, intermediate and posterior fibres
When the fibres all contract together what happens?
Abduction of the arm
Which muscles perform adduction of the arm?
Latissimus dorsi
Pectoralis major
What is the origin and insertion of latissimus dorsi?
Origin: Thoracolumbar fascia
Insertion: floor of the bicipital groove
What is the origin and insertion of pec major?
Origin: sternum & medial clavicle
Insertion: Lateral lip of the bicipital groove
What increases the range of movement in abduction/adduction of the arm?
Rotation of the scapula
During abduction of the arm, the inferior angle of the scapula rotates in which direction?
Laterally
During adduction of the arm, the inferior angle of the scapula rotates in which direction?
Medially
When we raise our arms above our heads the supraglenoid fossa is brought into which position?
Superior orientation
What is the composition of the trapezius?
Upper, middle and lower fibres
Where do the upper fibres insert?
Acromion
Which muscles contract in order to (abduct &) lift our arms up above our head?
Upper and lower fibres of the trapezius
Inferior digitations of serratus anterior
Which muscles are involved in adducting the arms?
None - adduction of arm mostly due to gravity
Which muscles contract in adduction of the arm against gravity (to bring arms towards horizontal from above our heads)?
Levator scapulae
Rhomboid
Which muscles are involved in flexion of the arm?
Biceps brachii
Anterior fibres of the deltoid
Describe the composition of the biceps brachii
Long head and short head
What is the origin of the long head of the biceps brachii?
Supraglenoid tubercle of scapula (at the top of the glenoid fossa)
What is the origin of the short head of the biceps brachii?
Apex of coracoid process
What movement does the coracobrachialis help with?
Bringing the arm across the torso
What muscle extends the arm?
Triceps brachii
What is the composition of the triceps brachii?
Long, lateral and medial heads
What is the origin of each head of triceps brachii?
Long head: infraglenoid tubercle of scapula
Medial head: posterior surface of shaft of humerus
Lateral head: posterior surface of shaft of humerus