Shoulder and arm Flashcards
Trapezius - attachments
Proximal: external occipital protuberance, occipital bone, ligamentum nuchae, spinous processes of cervical and thoracic vertebrae
Distal: Posterior border of lateral third of clavicle, medial margin of acromion, posterior border of scapular spine
Trapezius - innervation
Motor supply - accessory nerve (CNXI)
Proprioceptive fibres - C3, C4
Trapezius - action
Elevation, depression and retraction of scapula
Latissimus dorsi - attachments
Proximal: Aponeurosis of posterior layer of thoracocolumnar fascia, spinous processes of lower 6 thoracic vertebrae, most inferior 3/4 ribs (may also attach to iliac crest)
Distal: intertubercular groove of humerus in between insertion points of pec major and teres major.
Latissimus dorsi - innervation
Thoracodorsal nerve (C6-C8)
Latissimus dorsi - action
Extends, adducts and medially rotates the humerus
Levator scapulae - attachments
Proximal: Transverse processes of C1-C4
Distal: Superior portion of medial border of scapula
Levator scapulae - innervation
C3 and C4 - cervical plexus
Branch of dorsal scapular nerve (C5) (lower fibres)
Levator scapulae - action
Elevates the scapula
Deltoid - attachments
Proximal: Lateral third of clavicle, superior surface of acromion, spine of scapula
Distal: Fibres converge into tendon which is attached to deltoid tuberosity (lateral aspect of shaft of humerus)
Deltoid - innervation
Axillary nerve (C5, C6)
Deltoid - action
Abduction, flexion and extension of the humerus
Supraspinatus - attachments
Proximal: Medial 2/3 of supraspinatus fossa from supraspinatus fascia
Distal: Fibres converge to form tendon which inserts into greater tubercle of humerus
Supraspinatus - innervation
Suprascapular nerve (C5, C6)
Supraspinatus - action
Abduction of arm and stabilises humerus (works with deltoid)
Infraspinatus - innervation
Suprascapular nerve (C5, C6)
Infraspinatus - action and attachments
Lateral rotation of humerus and braces head of humerus in glenoid fossa
Proximal: Medial 2/3 of infraspinatus fossa from infraspinatus fascia
Distal: Fibres converge to form tendon which inserts into greater tubercle of humerus
Teres minor - attachments
Proximal: Lateral border of scapula
Distal: Greater tubercle of humerus
Teres minor - innervation
Axillary nerve (C5, C6)
Teres minor - action
One of four rotator cuff muscles
Stabilises shoulder joint
Teres minor - action
One of four rotator cuff muscles - Stabilises shoulder joint
Lateral rotation and weak adduction of arm
Teres major - innervation
Lower subscapular nerve (C6, C7)
Teres major - action
Extension of arm from flexed position
Adduction and medial rotation of arm
Subscapularis - attachments
Proximal: Medial 2/3 of subscapular fossa + lower 2/3 of lateral border of scapula
Distal: Fibres converge into tendon which inserts into lesser tubercle of humerus and anterior portion of shoulder joint capsule
Subscapularis - innervation
Upper and lower subscapular nerves (C5, C6)
Subscapularis - action
One of four rotator cuff muscles
Stabilises shoulder joint, preventing anterior displacement of humerus
Medial rotation and adduction of humerus at shoulder
Pectoralis major - attachments
Proximal: Sternal half of clavicle, upper half of sternum, aponeurosis of external oblique muscle
Distal: All 3 parts of muscle end as a flat tendon inserted into the inter tubercular groove of the humerus
Pectorals major - innervation
Medial and lateral pectoral nerves (C5-C8)
Pectoralis major - action
Adduction, medial rotation, flexion of humerus
Biceps brachii - attachments
Proximal: Short head - apex of coracoid process
Long head - supraglenoid tubercle of scapula
Distal: Both muscle allies join to form a flattened tendon that is inserted into the radial tuberosity
Biceps brachii - innervation
Musculocutaenous nerve (C5, C6)
Biceps brachii - action
Supinator of forearm (with forearm partially flexed)
Flexor of supinated forearm
Coracobrachialis - attachments
Proximal: Apex of coracoid process of scapula
Distal: Middle of medial surface and border of humerus
Coracobrachialis - innervation
Musculocutaneous nerve (C6, C7)
Coracobrachialis - action
Flexes and adducts the arm at the shoulder
Brachialis - attachments
Proximal: Arises from distal half of the anterior humerus
Distal: Inserts into the tuberosity and anterior surface of the coranoid process of ulna
Brachialis - innervation
Musculocutaneous nerve (C5, C6)
Brachialis - action
Flexor of forearm at elbow
Triceps brachii - attachments
Proximal: Long head - infraglenoid tubercle of scapula
Lateral head/Medial head - posterior surface of humerus
Distal: All head insert by common tendon into posterior portion of proximal olecranon of ulna
Triceps brachii - innervation
Radial nerve (C7, C8)
Triceps brachii - action
Extension of forearm at elbow
Long head - extension of humerus
Anconeous - attachments
Proximal: Lateral epicondyle of the humerus
Distal: Lateral aspect of olecranon and upper dorsal surface of body of ulna
Anconeus - innervation
Radial nerve (C7, C8)
Anconeus - action
Extension of forearm at elbow
