Anterior Compartment of the Arm and Musculocutaneous Nerve Flashcards
- biceps brachii
- brachialis
- musculocutaneous nerve
- coracobrachialis
what is the most superficial muscle of the anterior compartment of the upper limb?
The biceps brachii is the most superficial muscle of the anterior compartment.
what is the origin and insertion of biceps brachii?
It arises from the scapula via. two heads. Both heads unite at the distal third of the upper arm forming a short tendon which inserts onto the radial tuberosity.
It also attaches through the bicipital aponeurosis to the deep fascia of the forearm
where does the short head of the biceps brachii muscle originate from?
coracoid process of the scapula
where does the long head of the biceps muscle originate from?
The long head of the biceps muscle originates from the supraglenoid tubercle of the scapula. Its tendon passes through the shoulder joint and runs down the bicipital groove of the humerus.
what is the action of the biceps muscle?
flexion of shoulder and elbow joint
- At the superior radio-ulnar joint it is involved in supination (the action in which the radius rotates over the ulna)
what is the origin and insertion of the coracobrachialis muscle?
The coracobrachialis slender, rounded muscle passing from its origin at the tip of the coracoid process and inserting to the medial aspect of the mid-shaft of the humerus
what is the action of the coracobrachialis muscle?
Its action is to flex the arm at the shoulder joint
what is the origin and insertion of the brachialis muscle?
The brachialis muscle arises from the anterior surface of the distal shaft of the humerus. It is a deep muscle of the anterior compartment, passing downwards and attaching to the coronoid process of the ulna
what is the main action of the brachialis muscle?
Its main action is to flex the elbow joint
what does the musculocutaneous nerve arise from?
This nerve arises as a terminal branch from the lateral cord of the brachial plexus.
what is the main nerve of the anterior compartment of the arm, supplying all the muscles within this compartment?
median nerve (except for the flexor carpi ulnaris and medial half of flexor digitorum profundus, which are innervated by the ulnar nerve)
what is the course of the musculocutaneous nerve?
It enters the arm by perforating the coracobrachialis, descending distally between the biceps brachii and brachialis muscles. After crossing the elbow joint it gives off its terminal branch to supply the skin as the lateral cutaneous nerve of the forearm.
What is the segmental or root value of the musculocutaneous nerve?
C5-7
