muscles of the arm

Question 1

how many flexor muscles are in the arm and how many extensor muscles?

Answer 1

3 flexor muscles are in the anterior compartment :

-biceps brachii (two heads), brachialis, coracobrachialis (all supplied my musculocutaneous nerve)

1 three headed extensor lies in the posterior compartment :
-triceps brachii (supplied by radial nerve)

also a small triangular on the posterior aspect of the elbow :

-The anconeus : covers the posterior aspect of the ulna proximally

Question 2

Answer 2

Biceps Brachii

Proximal attachment :

short head: tip of coracoid process of scapula

long head: supraglenoid tubercle of scapula

distal attachment: tuberosity of radius and fascia of forearm via bicipital aponeurosis

main action: supinates forearm, and when it is supinated, flexes elbow joint; flexes shoulder joint and short head resists dislocation of shoulder

innervation : musculocutaneous nerve (C5,C6)

Question 3

Aponeurosis

Answer 3

a flat sheet or ribbon of tendonlike material that anchors a muscle or connects it with the part that the muscle moves

Question 4

Answer 4

Brachialis

Proximal attachment : distal half of anterior surface of humerus

distal attachment : coronoid process and tuberosity of ulna

main action : flexes elbow joint in all positions

innervation : musculocutaneous nerve (C5, C6)

Question 5

Answer 5

Coracobrachialis

proximal attachment: tip of coracoid process of scapula

distal attachment : middle third of medial surface of humerus

main action: helps flex and adduct shoulder joint; resists dislocation of shoulder

innervation: musculocutaneous nerve (C5,C6,C7)

Question 6

Answer 6

Triceps Brachii

Proximal attachment

long head : infraglenoid tubercle of scapula

lateral head : posterior surface of humerus, superior to radial groove

medial head: posterior surface of humerus, inferior to radial groove

distal attachment: proximal end of olecranon of ulna and fascia of forearm

main action : chief extensor of elbow joint : long head extends shoulder joint and resists dislocation of humorous (especially important during abduction)

innervation : radial nerve (C6, C7, C8)

Question 7

Answer 7

anconeus

proximal attachment : lateral epicondyle of humerus

distal attachment : lateral surface of olecranon and superior part of posterior surface of ulna

main action : assists triceps in extending elbow joint; stabilizes elbow joint; abducts ulna during pronation

innervation : radial nerve (C7, C8, T1)

Question 8

tendon of biceps brachi

Answer 8

helps supinate

Question 9

bicipital aponeurosis

Answer 9

located in the cubital fossa of the elbow and separates superficial from deep structures in much of the fossa. The bicipital aponeurosis originates from the distal insertion of the biceps brachii

Question 10

what muscles attach to the coracoid process?

Answer 10

pec minor, biceps brachi (short head) and coracobrachialis