MSK - Upper Limb 2 Flashcards
Can you name 16 sites on the humerus? Roughly from proximal -> Distal?
Head - articulates with scapula
Anatomical neck - posterior to head
Greater tubercle - prominence lateral at proximal end
Lesser Tubercle - Prominence medial at proximal end
Intertubecular sulcus - sulcus between tubercles
Surgical Neck - Narrowing between tubercles & shaft
Shaft
Deltoid tuberosity - prominence on ant middle shaft
Radial Groove - Groove on post shaft for radial nerve
Lateral & Medial epicondyles - prominences on medial/lateral distal humerus
Capitulum - rounded prominence on anterolateral distal humerus
Trochlea - prominence on anteromedial distal humerus (articulates with ulna)
Radial fossa - Fossa above capitulum
Coronoid fossa - fossa above trochlea
Olecranon fossa - Fossa above trochlea posteriorly that holds ulnar olecranon process
Heres some points to make it easier to spot the different arm nerves
Ulnar - passes over the medial epicondyle
Median - Tightly follows the brachial artery
Musculocutaneous - Tight to the underside of the biceps
What are the muscles of the anterior (flexor) compartment of the arm?
Biceps Brachii
Coracobrachialis
Brachialis
Describe the attachments of the biceps brachii?
Arises from 2 heads:
- Short head arises from coracoid process of scapula
- Long head arises from supraglenoid tubercle of scapula
Inserts on radial tuberosity distally
What is the action of the biceps brachii?
Flexes shoulder & elbow
Supinates proximal radio-ulnar joint
Nerve supply of the biceps brachii?
Musculocutaneous nerve which arises from the lateral cord or C5-7.
Describe the attachments of the coracobrachialis?
Arises from the tip of the coracoid process (along with the short head of the biceps)
Inserts onto medial humerus at the middle of the shaft.
Actions of the coracobrachialis?
Flexion & Adduction of shoulder
Nerve supply of the coracobrachialis?
Musculocutaneous nerve - Lateral cord (C5-7)
Attachments of the brachialis?
Arises from anterior distal humeral shaft.
Inserts onto coronoid process of ulna
Action of the brachialis?
Flexion of elbow
Innervation of brachialis?
Musculocutaneous
Where does the musculocutaneous arise and travel?
Arises from lateral cord of brachial plexus (C5-7)
It perforates the coraco-brachialis to enter the ant compartment of the arm.
Then descends between biceps & brachialis.
What happens to the musculocutaneous nerve after it supply’s the anterior compartment of the arm with innervation?
It continuous as the lateral cutaneous nerve of the forearm.
What does the musculocutaneous nerve supply?
Ant Muscle compartment of the forearm:
- Brachialis
- Biceps Brachii
- Coracobrachialis
Also cutaneous sensation to the lateral forearm