Sem 1 - T - Arm & Cubital Fossa - Anterior/posterior arm, Brachial artery/elbow joint anastamoses, cubital fossa, bones of upper limb Flashcards
Where is the arm? Which compartment of the arm has the flexors and which has the extensors of the arm?
The arm, anatomically, is located from the shoulder joint to the elbow joint The flexors of the arm is in the anterior compartment The extensors of the arm is in the posterior compartment
What are the muscles of the anterior compartment of the arm? What is the nerve supply to these muscles? What cord of the brachial plexus does this nerve come from and what are its nerve roots?
The muslces of the anteiror compartment of the arm are: Biceps brachii Brachialis Coracobrachialis
The muscles are supplied by the musculocutaneous nerve (C5,6,7) and this is a terminal branch of the lateral cord
WHat are the two different biceps brachii? Where do both heads arise from?
Long head of biceps - arises from the supraglenoid tubercle of the scapula Short head of biceps - arises from the coracoid process of the scapula
What is the insertion point of the biceps brachii? What is the main function of the biceps brachii?
The biceps brachii forms the biceps tendon distally which inserts into the radial tuberosity Small amount of fibres also form the bicipital aponeurosis which is a fascial sheet joining the deep fascia of the forearm Function - Supination of the forearm and weakly flexes the arm
What is the deep fascia of the forearm where the bicipital aponeurosis blends with known as? How does the biceps allow for supination of the forearm? When is the biceps brachii able to flex the arm? What is supination of the forearm?
Deep fascia of the forearm is known as the antebrachial fascia Supination of the forearm refers to the rotation of the radius - supine is when the palms face the sky - allowed by the biceps tendon insertion at the radial tuberosity Flexion of the arm by the biceps brachii only occurs when the arm is supine
Where does the long head of the biceps run? What do the long and short heads of the biceps prevent? What is the nerve supply to the biceps brachii? (state which root valeus specifically of this nerve go to biceps brachii)
Long head of the biceps runs in the bicipital groove to attach to the supraglenoid tubercle of the scapula Long head of the biceps prevents the head of the humerus moving superiorly whilst the short head of the biceps prevents anterior dislocation of the shoulder joint Nerve supply - musculocutaneous nerve via only its C5,6 roots
What are the attachments of the coracobrachialis? What is its function?
Coracobrachialis attaches from the coracoid process of the scapula to the medial shaft of the humerus Its main function is to flex the arm but it also adduct the arm
What is the nerve supply of the coracobrachialis? Biceps brachii had the same nerve supply nut only had the C5,6 roots of the nerve used. Does coracobrachialis differ?
The coracobrachialis is pierced and supplied by the musculocoutaneous nerve (C5-7)
What is the attachments of the brachialis muscles and what muscle does it lie?
The brachialis muscles originates at the distal half of the anterior surface of the humerus and inserts on the ulnar tuberosity and coronoid process of the ulna
What is the nerve supply to the brachialis? Why can it sometimes recieve some fibres from the C7 root of the radial nerve?
The nerve supply to the brachialis is via the musculocutenous nerve (C5,6 roots) As it is a big muscle, it can wrap around the humerus and therefore a small component of lateral fibres from the radial nerve (C7) may also supply this muscle
The arm has 4 muscles 3 anterior * Biceps brachii - Musculocutaneous nerve * Coracobrachialis - Musculocutaneous nerve * Brachialis - Musculocutaneous nerve, lateral fibres of radial nerve State each of the roots of the nerve fibres going to these muscles? What is the muscle in the posterior compartment known as?
Biceps brachii - Musculocutaneous nerve (C5,6) Coracobrachialis - Musculocutaneous nerve (C5-7) Brachialis - Musculocutaneous nerve (C5,6), lateral fibres supplied by radial nerve (C7) Trcieps brachii is the muscle of the posterior compartment of the arm
The triceps brachii has three heads; a long head, a lateral head and a medial head. What is the common distal insertion of the triceps brachii?
Common distal insertion of the triceps brachii is into the olecranon of the ulna Biceps tendon inserts at the radial tuberosity Brachialis inserts at the ulna tuberosity and the coronoid process of the ulna
What is the origin of the three heads of the triceps brachii?
The long head originates form the infraglenoid tubercle of the scapula The lateral head is from the posterior shaft of the humerus superior to the radial groove The medial head sits inferior to the lateral head and inserts on the posterior shaft of humerus inferior to the radial groove
What form the radial groove in the humerus? What is the function of the triceps brachii? What does the long head of the triceps brachii resist?
The radial groove is formed by the radial nerve wrapping around the shaft of the humerus Triceps brachii acts to extend the elbow joint Long head of the triceps prevents dislocation of the shoulder joint
State the attachments of the triceps brachii State the muscles function and its nerve supply
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When is the brachial artery formed?
The brachial artery is formed once the axillary artery crosses the inferior border of the teres major