Arm and Forearm Flashcards
What is the single long bone of the upper arm?
Humerus
Where does the deltoid muscle insert?
The deltoid tuberosity on the humerus
On the distal end of the humerus, the _________ articulates with the ulna, while the _________ articulates with the radius.
Trochlea articulates with the ulna while the capitulum articulates with the radius
What is the fascia of the arm called?
The brachial fascia
Name the upper arm compartments.
Anterior, posterior
Where does the triceps muscle insert?
The olecranon of the ulna
Which nerve innervates the posterior arm compartment?
Radial nerve
Name the muscles of the posterior arm compartment.
Triceps, that’s it!
Name the muscles of the anterior arm compartment.
Coracobrachialis
Biceps brachii
Brachialis
Which nerve innervates the anterior arm compartment? Is it classified as a preaxial, or postaxial nerve?
Musculocutaneous nerve. Preaxial nerve because it is a innervates flexor muscles.
As the musculocutaneous nerve travels distally into the lateral forearm, it supplies cutaneous innervation to the ________ and is renamed the _________ _________ nerve of the forearm.
supplies cutaneous innervation to the lateral forearm and is renamed the lateral cutaneous nerve of the forearm! That is why it is called the musculo cutaneous nerve!
What are the compartments of the forearm?
Anterior and posterior
The deep fascia of the forearm separates the anterior from the posterior compartments and at the wrist forms a fibrous flexor and extensor _________ similar to the ankle joint. In the palm, the deep fascia forms the palmar _________.
extensor retinacula
palmar aponeurosis
Name the subdivisions of the anterior/flexor forearm compartment muscles.
Deep, intermediate, superficial
The middle and deep muscles of the anterior/flexor compartment of the forearm act to _______ the ________.
flex the digits
The superficial muscles of the anterior/flexor compartment of the forearm act to ______ the ______.
flex the wrist
Name the muscles of the deep muscle group of the anterior/flexor forearm compartment.
Flexor digitorum profundus and flexor pollicis longus.
Name the muscle of the intermediate muscle group of the anterior/flexor forearm compartment.
Flexor digitorum superficialis
Name the muscles of the superficial muscle group of the anterior/flexor forearm compartment.
Pronator teres, flexor carpi radialis, flexor palmaris longus, flexor carpi ulnaris
What nerve supplies the anterior/flexor forearm compartment muscles?
Trick question! It isn’t that easy!
Superficial: Flexor carpi radialis and palmaris longus are supplied by median nerve. Flexor carpi ulnaris is supplied by ulnar nerve.
Intermediate: Flexor digitorum superficialis is supplied by the median nerve.
Deep: Flexor pollicis longus is supplied by the median nerve. The radial half of flexor digitorum profundus is supplied by the median nerve and the ulnar half is supplied by the ulnar nerve.
How am I going to remember the innervation of the anterior forearm?
The median nerve supplies everything except 1.5 muscles: The flexor carpalis ulnaris and the ulnar half of the flexor digitorum profundus.
Name the three major arteries of the forearm.
- Radial artery
- Ulnar artery
- Anterior interosseous artery
Which arteries travel distally into the hand from the forearm to become the palmar arches?
The radial and ulnar arteries
Which artery supplies the deep flexor muscles?
Anterior interosseous artery - it runs deep to the muscles along the interosseous membrane
What are the subdivisions of the extensor/posterior forearm muscles?
Superficial, deep
There are ____ superficial posterior/extensor forearm muscles and ____ deep posterior/extensor muscles. (how many?)
8
4
Which nerve innervates the extensor/posterior muscles of the forearm?
Radial nerve innervates all of them!
The brachioradialis muscle is a member of the _______ forearm compartment. It crosses the ______ joint and acts to ______ the elbow.
member of the posterior forearm compartment. Crosses the elbow joint and acts to flex the elbow.
Which muscle is the “beer drinker’s muscle?”
Brachioradialis
Aside from brachioradialis, what is the other posterior forearm muscle that crosses the elbow joint?
Anconeus
What happens to the radial nerve as it travels distally down the forearm?
It divides into a superficial (cutaneous) branch and a deep (motor) branch also known as the posterior interosseous nerve.
If a patient has “wrist drop” (can’t extend the hand and digits), then which nerve is likely damaged?
Radial nerve
Carpal tunnel syndrome results from compression of which nerve?
Median nerve
Which nerve is affected by cubital tunnel syndrome?
Ulnar nerve
Erb’s palsy is characterized by an injury to the _____ and _____ nerve roots of the brachial plexus. It can happen during childbirth.
C5, C6
Klumpke’s palsy results from injury to the ____ and ____ nerve roots of the brachial plexus.
C8, T1
What is the “carrying angle?” What is a normal carrying angle?
angle between humerus
and ulna – normally 10-15 degrees
What is a Colles’ fracture? What is a Smith’s fracture?
Colles’ fracture is a distal radius fracture from falling on an extended wrist. The distal radius is displaced posteriorly. Results in a dinner fork deformity.
Smith’s fracture is a distal radius fracture from falling on a flexed wrist. The distal radius is displaced anteriorly.
Does the scaphoid heal easily? Why or why not?
No, poor blood flow.
List the posterior/extensor muscles of the forearm (8 superficial, 4 deep).
Superficial group:
- Brachoradialis
- Anconeus
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor carpi ulnaris
- Extensor digitorum
- Extensor digiti minimi
- Supinator
Deep group:
- Extensor indicis
- Extensor pollicis longus
- Extensor pollicis brevis
- Abductor pollicis longus
The flexor carpi radialis tendon in the wrist is used to locate which artery? Where does this artery lie in relation to the tendon?
The radial artery lies lateral to the flexor carpi radialis tendon.
The ______ artery is an often used arterial puncture for blood gas analysis.
radial
Lateral epicondylitis (tennis elbow) is caused by chronic inflammation of the common tendon of the ________ muscles.
extensor muscles
Golfer’s elbow (medial epicondylitis) is caused by irritation and inflammation of the _______ muscles of the forearm. Which nerve is at risk for compression from inflammation of these tendons?
flexor muscle inflammation can compress the ulnar nerve
Why doesn’t paresthesia occur over the thenar eminence of the skin in the setting of carpal tunnel syndrome?
This area is supplied by the palmar cutaneous branch of the median nerve that branches off before the carpal tunnel.
Through which muscle does the deep branch of the radial nerve travel through in the posterior forearm?
The supinator
