Posterior Arm and Radial Nerve

Question 1

Posterior compartment of the upper contains which muscle

Answer 1

Triceps Brachii

Question 2

Arterial supply to the posterior compartment

Answer 2

Profunda Brachii

Question 3

Attachments of Triceps Brachii

Answer 3

The long head originates from the infraglenoid tubercle, the lateral head originates from the humerus superior to the radial groove, the medial head originates from the humerus inferior to the radial groove. Distally, the heads converge onto one tendon and insert into the olecranon of the ulna

Question 4

Function of Triceps Brachii

Answer 4

Extension of the arm at the elbow

Question 5

Innervation of the Triceps Brachii

Answer 5

Radial nerve.

Question 6

Aconeus Muscle

Answer 6

Small triangular muscle located at the elbow. It originates at the dorsal side of the lateral epicondyle of the humerus and inserts at the olecranon of the ulna.

Question 7

Innervation of the Aconeus Muscle

Answer 7

The radial nerve

Question 8

Action of the Aconeus Muscle

Answer 8

Extension at the elbow joint

Question 9

Nerve roots of the Radial Nerve

Answer 9

C5-T1

Question 10

Sensory function of the radial nerve

Answer 10

Innervates most of the skin on the posterior forearm and the dorsal surface of the lateral side of the palm, and the lateral three and a half digits

Question 11

Motor function of the radial nerve

Answer 11

Innervates the triceps brachii, and the majority of the extensor muscles in the forearm

Question 12

Chord Radial nerve

Answer 12

Posterior chord

Question 13

Anatomical Course of the Radial Nerve in the upper arm

Answer 13

Arises in the axilla where it is posterior to the axillary artery. It exits inferior and supplies branches to the long and medial heads of triceps brachii. It travels down the arm in the radial groove. As it descends it wraps around the humerus laterally and supplies the lateral head of triceps brachii. It is accompanied by the deep branch of the brachial artery.

Question 14

Anatomical course of the radial nerve in the forearm

Answer 14

Anteriorly over the lateral epicondyle of the humerus, through the cubital fossa.

Question 15

Deep branch of the radial nerve

Answer 15

Innervates the muscles in the posterior compartment of the forearm

Question 16

Superficial branch of the radial nerve

Answer 16

Contributes to the cutaneous innervation of the hands and the fingers

Question 17

Injury to the radial nerve

Answer 17

Damaged in the radial groove in midshaft humeral fractures resulting to damage of the wrist flexors (wrist drop)