Upper Arm

Question 1

How many muscles are contained within the upper arm?

Answer 1

Four - 3 in the anterior compartment and 1 in the posterior compartment.

Question 2

What are the muscles of the anterior compartment?

Answer 2

• Biceps brachii
• Brachialis
• Coracobrachialis
  Memory Aid: BBC

Question 3

What the muscle in the posterior compartment?

Answer 3

Triceps Brachii.

Question 4

How are the muscles of the anterior compartment innervated?

Answer 4

All innervated by the musculocutaneous nerve.

Question 5

Biceps Brachii: Attachments, Function and Innervation.

Answer 5

Two-headed muscle with a majority of its mass located anteriorly to the humerus.
Origin of long head: supraglenoid tubercle of scapula
Origin of short head: coracoid process of scapula
Insertion: Both heads insert distally into radial tuberosity and the fascia of the forearm via bicipital aponeurosis.
Function: Supination of forearm and flexes arm at elbow and shoulder.
Innervation: Musculocutaneous nerve.

Question 6

Coracobrachialis: Attachments, Function, Innervation.

Answer 6

Lies deep to the biceps brachii.

Origin: Coracoid process of scapula
Insertion: Medial side of the humeral shaft, at the level of the deltoid tubercle.
Function: Flexion of arm at shoulder and weak adduction.
Innervation: Musculocutaneous nerve.

Question 7

Brachialis: Attachments, Function, Innervation.

Answer 7

Lies deep to the biceps brachii and forms floor of cubital fossa.

Origin: Medial and lateral surfaces of the humeral shaft.
Insertion: Ulna tuberosity, just distil of the elbow joint.
Function: Flexion at the elbow.
Innervation: Musculocutaneous Nerve.

Question 8

Triceps Brachii: Attachments, Function, Innervation.

Answer 8

Origin of long head: Infraglenoid tubercle.
Origin of lateral head: humerus, superior to radial groove.
Origin of medial head: humerus, inferior to radial groove.
Insertion: distally, the heads converge onto one tendon and insert into the olecranon of the ulna.
Function: Extension of arm at elbow.
Innervation: Radial nerve.

Question 9

What is the cubital fossa?

Answer 9

An area of transition between the anatomical arm and the forearm.
- Located as a depression on the anterior surface of the elbow joint.

Question 10

What are the borders of the cubital fossa?

Answer 10

Lateral border - medial border brachioradialis muscle.
Medial border - lateral border of the pronator trees muscle.
Superior border - an imaginary line between the epicondyles of the humerus.

Floor of cubital fossa - formed proximally by the brachial and distally by the supinator muscle.

Question 11

What is contained within the cubital fossa?

Answer 11

• Radial Nerve
• Biceps tendon
• Brachial artery
• Median nerve