Tutorial 2: Upper Limb, Dry Lab Flashcards
Look at diagram of humerus (pg 29)
…
What are the muscle compartments of the arm?
Anterior (flexor), posterior (extensor)
What are the muscles of the anterior compartment of the arm?
Biceps brachii
Coracobrachialis
Brachialis
What do the two heads of the biceps brachii arising from the scapula meet and what do they from?
Distal 3rd of the upper arm
Form a short tendon which inserts into the tuberosity of the radius
What joints does the biceps brachii act on?
Shoulder
Elbow
Radio-ulnar joints
What are the 2 heads of the biceps brachii?
Long head
Short head
Where does the short head of the biceps arise from?
The coracoid process of the scapula
Where does the long head of the biceps arise from and where does it later run?
The supraglenoid tubercle
Runs in the bicipital groove
What bone is the supraglenoid tubercle found on?
Scapula
Which bony process on the radius is the tendon of the biceps attached to distally?
Radial tuberosity
What is the action of the biceps on the shoulder joint?
Flexion
What is the action of the biceps on the elbow joint?
Flexion
What is the action of the biceps on the radio-ulnar joint?
Supination
What is the nerve supply to the biceps muscle?
Musculocutaneous muscle
Which segmental fibres mainly innervate the biceps muscle?
C6 (+C5)
From which cords of the brachial plexus is the musculocutaneous nerve a branch of?
Lateral cord (C5, C6, C7 spinal roots)
What is the action of the coracobrachialis muscle on the shoulder joint?
Flexion
What is the nerve supply to the coracobrachialis muscle?
Musculocutaneous nerve
What are the insertions for the coracobrachialis muscle?
Proximal - coracoid process
Distal - medial margin of the humerus at about it’s middle
What are the insertions for the brachialis muscle?
Proximal - anteriorly from the distal half of the humerus
Distal - coronoid process of the ulna
What is the action of the brachialis muscle on the elbow joint?
Flexion
What nerve supplies the brachialis muscle?
Musculocutaneous nerve
What path does the musculocutaneous nerve follow?
It arises from the lateral cord of the brachial plexus
Enters the arm by perforating the coracobrachialis muscle and descends between the biceps and brachialis. After supplying the muscles of the arm it continues as the lateral cutaneous nerve of the forearm
What muscle compartment is supplied by the musculocutaneous nerve?
Anterior compartment of the arm
What are the segmental root values of the musculocutaneous nerve?
C5, C6, C7
What does the musculocutaneous nerve become in the forearm?
Lateral cutaneous nerve - supplies the lateral aspect of the forearm
Does the musculocutaneous nerve supply any of the muscles in the forearm or hand?
No
How could the musculocutaeous nerve be damaged?
Stab to the axilla
What would be the effect of the musculocutaneous nerve being severed?
Paralysis of the biceps, coracobrachialis and brachialis muscles
Loss of sensation on the lateral aspect of the forearm
What does the axillary artery become?
The brachial artery
Where does the brachial run to and from where?
The brachial artery runs from the lower border of the teres major to the cubital fossa
What does the brachial artery divide into?
The radial and ulnar arteries
What is the profunda brachii?
The deep artery of the arm
A branch of the brachial artery
What is the progression of the arteries from the aorta to the forearm?
(Brachiocephalic trunk (L)) Subclavian artery Axillary artery Brachial artery Radial and Ulnar arteries
Which cords of the brachial plexus does the medial nerve in the arm arise from?
Arises from 2 roots: one from the medial cord and one from the lateral cord
What pathway does the median nerve follow?
It descends along the lateral side of the axillary artery and the upper part of the brachial artery. At the middle part of the arm the nerve crosses to the medial side of the brachial artery and enters the cubital fossa. It gives no branches in either the axilla or in the upper arm
What cords of the brachial plexus does the ulnar nerve arise from?
Medial cord
What path does the ulnar nerve follow?
It descends along the medial side of the brachial artery and enters the posterior compartment of the arm through the medial inter muscular septum and runs along the medial head of the triceps and to the back of the medial epichondyle
Do the median or ulnar nerves supply any muscles in the arm?
No
What nerve is most likely to be affected by a fracture to the surgical neck of the humerus?
Axillary nerve
What nerve is most likely to be affected by a fracture to the radial groove of the humerus?
Radial nerve
What nerve is most likely to be affected by a fracture to the medial epichondyle of the humerus?
ulnar nerve
What is the cubital fossa?
The triangular depression in the front of the elbow
What pulse can be felt medially to the tendon of the biceps in the cubital fossa?
Brachial pulse
What are the borders of the cubital fossa?
Base - imaginary line between the 2 epichodyles
Medial border - pronator teres muscle
Lateral border - brachioradialis muscle
What are the contents of the cubital fossa?
Radial nerve
Biceps tendon
Brachial artery
Median nerve
What muscle occupies the posterior compartment of the arm?
Triceps brachii
What are the connections for the triceps brachii?
Long head - scapula
2 shorter heads - lateral and medial from the humerus
Where is the common tendon of the triceps inserted?
Olecranon process of the ulna
What bone are the olecranon and coronoid processed located on?
Ulna
Which head of the triceps has it’s proximal attachment from the infraglenoid tubercle of the scapula?
Long head
What is the main function of the triceps on the elbow?
Extension
What is the action of the anconeus muscle?
Extension of the elbow
What nerve supplies the triceps and anconeus muscles?
Radial nerve
What cord of the brachial plexus is the radial nerve a part of?
Posterior cord
What does the radial nerve provide motor innervation for?
Extensor muscles of the wrist and elbow
What path does the radial nerve follow?
Enters the arm anterior to the long head of the triceps and runs along with the profunda femoris artery and curves around the mid shaft region of the humerus in the RADIAL GROOVE
What are the segmental root values of the radial nerve?
C5-T1
What is a characteristic clinical sign of radial nerve injury?
Wrist drop
What type of joint is the elbow?
Synovial hinge joint
What movements occur at the elbow?
Flexion, Extension
What ligaments are there in the elbow?
Ulnar collateral ligament
Radial collateral ligament
Anular ligament
What muscles flex the elbow joint?
Brachialis, coracobrachialis, biceps brachii
What muscles extend the elbow joint?
Triceps brachii, anconeus
What type of joints are the proximal and distal radio-ulnar joints?
Pivot-type synovial joints
What muscles are involved in the supination of the radio-ulnar joint?
Supinator
Biceps brachii
What muscles are involved in the pronation of the radio-ulnar joint?
Pronator quadratus
Pronator teres