The arm and cubital fossa

Question 1

Describe the deltoid muscle

Answer 1

Can be divided into three parts anterior middle and posterior fibres. Origin the anatomical horseshoe, inserts into lateral humerus. All the fibres work in different way. Can flex shoulder abbduct and adduct arm depending which are utilised. Needs supraspinatous to do first abduction before middle fibres kick in and are then strong abductors.

Question 2

What is the arrangement of insertions at the inter tubercular groove and where is it

Answer 2

Superior humerus lateral. 
Lady lied between two majors.
Lateral- Pectorals major
Middle- Latissimus dorsi
Medial- teres major

Question 3

What muscle forms the inferior border of axilla

Answer 3

Teres major

Question 4

What are the three muscles that make up the anterior/flexor compartment of the arm

Answer 4

Biceps brachii, brachialis, coracobrachialis.

Question 5

Describe biceps brachii

Answer 5

Two heads- two origins. Short head coracoid process, long head supraglenoid tubercle. Inserts radial tuberosity. Action flex arm at elbow and supinator.
Innervated by musculocutaneous

Question 6

Describe brachialis

Answer 6

Origin anterior surface of distal humerus. Insertion ulna tuberosity. Main elbow flexor. Innervated by musculocutaneous

Question 7

Describe coracobrachialis

Answer 7

Origin coracoid. Inserts medial side of humerus. Adduction/ flexion of shoulder. Stops inferior dislocation (shunt muscle activity). Musculocutaneous nerve passes through this muscle.

Question 8

Describe triceps brachii

Answer 8

Three heads. Long head origin infraglenoid tubercle. Lateral head superior humerus, medial head middle posterior humerus. Medial head workhorse.
All insert into olecranon. Elbow extensors. Innervated by radial nerve.

Question 9

What is the other muscle that is an elbow extensor

Answer 9

Anconeus. Origin lateral epicondyle of humerus.

Question 10

Describe the path of musculocutaneous

Answer 10

Comes off lateral cord. Dives into coracobrachialis. Emerges superficial to coracobrachialis deep to biceps brachii crosses laterally to cross over the lateral epicondyl of the humerus. Become the lateral cutaneous nerve of the forearm.

Question 11

Describe the path of the median nerve

Answer 11

Comes off the lateral and medial cords. Travels lateral to racial artery on the medial side of the arm

Question 12

Describe the path of the ulna nerve

Answer 12

Comes off the medial cord. Travels medial to brachial artery in medial forearm. Travels to elbow where is tracks posterior to the medial epicondyle (funny bone nerve) then comes back anterior to enter anterior compartment of the forearm.

Question 13

What are the borders of the quadrangular space

Answer 13

Teres minor superior. Trees major inferior. Long head of triceps medial. Humerus lateral. The axillary nerve and posterior circumflex artery pass through this space.

Question 14

What are the borders of the triangular interval

Answer 14

Superior-Inferior border of teres major. medial long head of triceps, medial humerus.
The radial nerve and profound brachia artery pass through this space

Question 15

Describe the path of the radial nerve

Answer 15

From posterior cord. travels posteriorly through the triangular interval deep to triceps then goes anterior over lateral epicondyle then back posterior to posterior forearm.