Anatomy Flashcards
Types of shoulder joints
-Glenohumeral (glenoid fossa, head of humerus): synovial ball and socket
=Mobility > stability
-Acromioclavicular joint
Ligaments of shoulder
-Glenohumeral: stabilise
=Medial (medial edge to lesser tubercle)
=Superior (apex of glenoid fossa to lesser tubercle)
=Inferior (lower edge to anatomical neck)
-Coracohumeral: strength upper joint capsule
=Superior band (coracoid process to common insertion with supraspinatus tendon on greater tubercle)
=Inferior band (coracoid process to lesser tubercle)
-Coracoacromial (coracoid process to acromion, prevents superior dislocation of humeral head of shoulder joint)
Muscles of the shoulder
-Rotator cuff
=Supraspinatus
=Infraspinatus
=Teres minor
=Subscapularis
-Deltoid
-Pectoralis major
-Teres major
Humerus
-Proximal articulation: glenoid fossa of scapula
-Distal articulations
=Laterally: capitulum with head of radius
=Medially: trochlea with trochlear notch of ulna
-Anatomical neck: attachment of joint capsule
-Surgical neck: inferior to head of humerus
Scapula
-Point of attachment for rotator cuff muscles
-Proximal articulation: the clavicle
-Distal articulation: the head of the humerus
Clavicle
-The clavicle is an S-shaped bone which is contoured by the many muscles which attach to it. It is also the most commonly fractured bone in the body.
-Proximal articulation: the manubrium
-Distal articulation: the acromion of the scapula
Bursae of shoulder
The shoulder joint contains a few fluid-filled sacs called synovial bursae. The function of these is to minimise friction between the articulating surfaces. The bursae located in the shoulder joint include:
-Subacromial-subdeltoid bursa: located between the joint capsule and the deltoid muscle
-Subacromial bursa: located between the joint capsule and the acromion
-Subcoracoid burse: located between the joint capsule and the coracoid process
Rotator cuff muscles
Their main function is to stabilise the shoulder joint and allow its excessive range of motion.
-Supraspinatus
-Infraspinatus
-Teres minor
-Subscapularis
Supraspinatus
-Origin: the supraspinous fossa
-Insertion: the superior facet of the greater tubercle of the humerus
-Function: abduction of the humerus
-Innervation: suprascapular nerve (C5)
-Vascular supply: suprascapular artery
Infraspinatus
-Origin: the infraspinous fossa
-Insertion: the middle facet of the greater tubercle of the humerus
-Function: external rotation of the humerus
-Innervation: suprascapular nerve (C5)
-Vascular supply: suprascapular artery, circumflex scapular artery
Subscapularis
-Origin: the subscapular fossa
-Insertion: the lesser tubercle of the humerus
-Function: internal rotation of the humerus
-Innervation: upper and lower subscapular nerve (C5/6)
-Vascular supply: subscapular artery
Teres minor
-Origin: the lateral border of the scapula
-Insertion: the inferior facet of the greater tubercle of the humerus
-Function: external rotation of the humerus
-Innervation: axillary nerve (C5)
-Vascular supply: posterior circumflex humeral artery, circumflex scapular artery
Deltoid
The deltoid is a large and triangular-shaped muscle. The deltoid muscle plays a significant role in both the range of shoulder joint movement and in preventing joint dislocation when carrying heavy objects.
-Origin: the anterior border of the clavicle, acromion and spine of the scapula
-Insertion: the deltoid tuberosity of the humerus
-Function: abduction, flexion and extension of the shoulder
-Innervation: axillary nerve
-Vascular supply: posterior circumflex humeral artery
Teres major
-Origin: the posterior aspect of the inferior angle of the scapula
-Insertion: the intertubercular sulcus of the humerus
-Function: internal rotation and adduction of the shoulder
-Innervation: lower subscapular nerve
-Vascular supply: subscapular and circumflex scapular artery
Pectoralis major
Pectoralis major is a large muscle located on the anterior chest wall that has several shoulder joint related functions. This muscle works in combination with pectoralis minor which lies underneath it.
-Origin: the clavicular head
-Insertion: the bicipital groove of the humerus
-Function: flexion, adduction and internal rotation of the humerus
-Innervation: lateral and medial pectoral nerve
-Vascular supply: pectoral branch of the thoracoacromial trunk