Muscles of the Arm

Question 1

What are the anterior muscles of the arm?

Answer 1

• The bicep brachii
• The coracobrachialis
• the brachialis

Question 2

Bicep brachii - PA, DA, N/S and Action

Answer 2

• Prxomial attachment -
  
  • tip of coracoid process of the scapula (short head)
  • Supraglenoid tubercle of scapula
• Distal attachment - the radial tuberosity of radius & fascia of the forearm via the biciptal aponeurosis
• N/S = Musculocutaneous nerve
• Action: it supinates the forarm, flexes the forearm when its supinated, the short head resists downward dislocation

Question 3

Coracobrachialis - PA, DA, N/S and Action

Answer 3

PA = coracoid process of scapula

DA = middle third of medial humerus

N/S = musculocutaneous nerve

Action = assists in flexion and adduction of the arm, resists shoulder dislocation

Question 4

Brachialis - DA, PA, N/S and action

Answer 4

PA = distal half of anterior surface of humerus

DA = coronoid process and tuberosity of ulna

N/S = musculocutaneous nerve

Action = Flexes forearm in ALL positions

Question 5

What are the posterior muscles of the arm?

Answer 5

The tricep brachii and the anconeus.

Question 6

Triceps Brachii - PA, DA, N/S and action

Answer 6

• PA =
  
  • Long head: infraglenoid tubercle of the scapula
  • Lateral head = posterior surface of the humerus, superior to the radial groove
  • Medial head = post surface of humerus inferior to the radial groove

DA = olecranon process of ulna

N/S = Radial nerve

Action = extension of the forearm, the long head provides downward dislocation of the humerus

Question 7

What are the three heads of the tricep? Where do they proximally attach?

Answer 7

The long head, lateral head, and medial head.

They proximally attach at the infraglenoid tubercle of the scapula, the posterior surface of the humerus, superior to the radial groove, and, the posterior surface of the humerus, inferior to the radial groove.

Question 8

Where is the Anconeus muscle located?

Answer 8

It is located in the posterolateral aspect of the elbow. It looks like a forearm muscle, but its not. ACCEPT IT.

Question 9

Ancenous - PA, DA, N/S and action

Answer 9

PA = Lateral epicondyle of humerus

DA = olecranon of ulna

N/S = Radial nerve

Action = assists triceps in extension of forearm

Question 10

What nerve supplies all the muscles of the anterior arm?

Answer 10

The musculocutaneous nerve.

Question 11

What nerve supplies the posterior arm muscles?

Answer 11

The Radial nerve supplies all of them. They are mainly extensors of the elbow joint.