Lecture 5: Arm & Extensor Forearm Flashcards
What are the two compartments of the arm?
Posterior & Anterior
Describe the posterior compartment of the arm
Extensors (generally)
Radian Nerve innervation
Deep brachial artery
Describe the anterior compartment of the arm
Flexors (generally)
Musculocutaneous Nerve
Brachial Artery
What is the cubital fossa?
Triangular depression in the arm
Boundaries of cubital fossa?
Medially: Pronator teres
Laterally: Brachioradialis
What are the contents of the cubital fossa?
Biceps Brachii Tendon
Brachial A
Median N
Describe the posterior compartment of the forearm
Extensors (generally)
Radial Nerve
Posterior interosseous artery
Describe the anterior compartment of the forearm
Flexors (generally)
Median & Ulnar Nerves
Radial & Ulnar arteries
What are the boundaries of the carpal tunnel?
Carpal bones (floor/walls)
Flexor Retinaculum (roof)
What are the contents of the carpal tunnel?
Median Nerve
Tendons
What are the compartments of the hand [5]
Hypothenar
Thenar
Central
Adductor
Interosseous
What is the arterial supply of the upper limb (flow)?
Subclavian –> Axillary –> Brachial Artery
What is the first major branch form the brachial a.?
Deep Brachial a.
What does the brachial artery bifurcate into?
Ulnar & Radial Arteries
The ulnar and radial arteries anastomose and form what?
Superficial & Deep Palmar Arches in the Hand
What does superficial fascia of the arm contain?
Superficial veins, cutaneous nerves, lymphatics
What is another name for deep fascia of the arm?
Brachial fascia
What does brachial fascia do?
Gives off medial & lateral intermuscular septa - this divides the arm into anterior and posterior compartments
What fascia deals with compartment syndrome?
Brachial fascia
What are the contents of the anterior compartment of the arm?
Biceps brachii
Coracobrachialis
Brachialis
Brachial artery and veins
Proximal ½ of ulnar nerve
Median nerve
Musculocutaneous nerve
What are the contents of the posterior compartment of the arm?
Triceps Brachii
Anconeus
Deep Brachial Artery
(almost all of) radial nerve
Distal ½ of ulnar nerve
What are the actions of anterior arm muscles?
Primarily flexors
What is the innervation of anterior arm muscles?
Musculocutaneous n
What is the action of the biceps brachii?
Flexes and supinates elbow (powerful supinator)
What is the action of the coracobrachialis?
Flexes the shoulder
What is the action of the brachialis?
Flexes elbow
What is the difference between supination and pronation?
Supination: Rotation of forearm so palm is pointing anteriorly
Pronation: rotation of forearm so palm is pointing posteriorly
What do posterior arm muscles do?
Primary extensors of elbow
What is the innervation of posterior arm muscles?
Radial N
Action of Triceps Bachii
Extend elbow and shoulder/arm
What is the aconeus
Muscle on posterior elbow, small triangular muscle
What are the contents of the cubital fossa?
Biceps brachii tendon
Brachial artery (dividing into radial and ulnar aa)
Brachial veins
Median nerve
Radial nerve
T/F: The median cubital vein is IN the cubital fossa?
False - it is superficial to the fossa
What type of joint is the elbow?
Hinge
Is the elbow joint stable in adults?
Yes
Is the elbow joint stable in children?
Not really
What is the primary movement at the elbow joint?
Flexion and extension
What ligaments strengthen the elbow joint?
Ulnar (medial) collateral ligament
Radial (lateral( collateral ligaement
What ligament goes from the medial epicondyle to the ulna?
Ulnar (medial) collateral ligament
What ligament goes from the lateral epicondyle to radius?
Radial (lateral) collateral ligament
What ligament goes from the lateral epicondyle to the radius?
Radial (Lateral) collateral ligament
What ligament goes from the lateral epicondyle to the radius?
Radial (lateral) collateral ligament
What ligament Surrounds neck of radius – holds head of radius in place?
Anular ligament
Where do a majority of elbow dislocations occur? (ant or post?)
Posteriorly
Describe “Nursemaid’s elbow”
Subluxation of Head of Radius
Occurs when there is a sudden pull on the pronated forearm - this tears the annular ligament and radial head is pulled out
Children are more prone to get radial head subluxation. Why?
Anular ligament thinner, radial head not fully formed.
What important structure does NOT go through the cubital fossa?
Ulnar N
How many carpal bones do we have? metacarpals? phalanges?
C: 8
M: 5
P: 14
What finger joint is the “knuckles”?
MP (metacarpophalangeal) joints
What finger joint is between proximal and middle phalanges?
PIP (proximal interphalangeal)
What join is between middle and distal phalanges?
DIP (distal interphalangeal)
What joint does the thumb have?
IP (interphalangeal) joint
Describe the interosseous membrane
Fibrous (dense CT) sheet that attaches to interosseous border
What does the interosseous membrane do in the forearm?
Partially subdivides forearm into flexor and extensor compartments
What is the deep fascia of the forearm?
Antebrachial fascia
Where do most muscles of the posterior (extensor) compartment originate?
Common extensor tendon on the lateral epicondyle
The superficial branch of the radial nerve in the extensor compartment is…
Sensory
The deep radial nerve –> posterior interosseous nerve in the extensor compartment is…
Motor
What arteries are noted in the extensor compartment?
Posterior & Anterior interosseous arteries
Function of brachioradialis
Flex elbow during pronation
Function of Extensor carpi radialis longus
Extend and ABduct wrist
Function of Extensor carpi radialis bravis
Extend and ABduct wrist
Function of extensor digitorum
Extend all wrist & MP joints (as well as digits 2-5)
Function of carpi ulnaris
Extend and ADduct wrist
Function of supinator
Supinate
Function of Abductor pollicis longus
ABduct thumb
Function of extensor pollicis longus
Extend wrist & thumb
Function of extensor pollicis brevis
Extend wrist and thumb
Function of extensor indicis
Extend digit 2 independently
Describe the path the radial nerve takes in the arm and forearm
Travels b/t brachialis and brachioradialis (arm) –> through cubital fossa –> in proximal forearm (divides into branches)
Describe the deep branch of the radial nerve
Motor
When does the deep branch of radian n change name?
After it pierces the supinator - it becomes the posterior interosseous N
Describe the superficial branch of raidal N
Sensory (to lateral/dorsal part of hand)
T/F: The superficial branch of the radial nerve travels superficial to brachioradialis
False: Travels deep to brachioradialis