Week 3 - Muscles of the Upper Arm

Question 0

Give the origins and insertions of both heads of biceps brachii.

Answer 0

Short head originates at coracoid process
Long head originates at supraglenoid tubercle of scapula
Both insert at the radial tuberosity

Question 1

What muscles make up the anterior compartment of the upper arm, and which nerve supplies them?

Answer 1

BBC -
Biceps brachii
Brachialis
Coracobrachialis
All supplied by the musculocutaneous nerve (C5, C6, C7)
NB - small portion of brachialis innervated by radial nerve

Question 2

Give the action(s) of biceps brachii

Answer 2

Main action = supination of forearm

Also flexes forearm

Question 3

What is the important function of brachialis?

Answer 3

Main flexor of the forearm

Question 4

What is the action of coracobrachialis?

Answer 4

Flexes the arm at the shoulder

Also helps to adduct the arm

Question 5

Which muscles make up the posterior compartment of the arm?

Answer 5

Triceps brachii

Anconeus

Question 6

Which nerve innervates the posterior compartment of the arm, and what are its nerve roots?

Answer 6

The radial nerve - C5, C6, C7, C8, T1

Question 7

What is the action of triceps brachii?

Answer 7

Extension of the forearm at the elbow

Question 8

What is the action of anconeus?

Answer 8

Assists triceps in extending the forearm

Stabilises the elbow joint