L35 Flexor Arm and Forearm Flashcards
What is the dense CT between bones called? Here between the ulna and the radius?
interosseous membrane
What is the purpose of having compartments of the arm?
limits or slows down the spread of infection
aids in muscle function because the CT is not very elastic and keeps muscles in place
What is the main nerve and artery suppling the flexor compartment of the arm?
What is the main action of the flexor arm?
brachial artery
musculocutaneous nerve: motor innervation to all of anterior compartment
forearm flexion and supination
Describe the elbow joint and its action.
What are three ligaments associated with the elbow joint?
synovial hinge joint
humerus, ulna, radius
flexion and extension
radial collateral ligament
ulnar collateral ligament
anular ligament: holds radius in place
What is the proximal radioulnar joint?
synovial pivot joint
radius, ulna
supination and pronation
Biceps brachii
PA: long head: supraglenoid tubercle
short head: coracoid process
DA: radial tuberosity, bicipital aponeurosis
Act: flex and supinates forearm
Inn: musculocutaneous nerve
What is the biceps reflex?
Tests C5, test at elbow
What is special about the medial bicipital groove?
it is where you can palpate the brachial artery
What joints do both heads of the biceps brachii act at?
GH, elbow, radioulnar joints
How can you get tendonitis in the biceps brachii?
What ligament and bursa covers the long head tendon?
repetitive use and inflammation within the intertubercular sulcus can lead to tendonitis and rupture of tendon
“popeye” deformity: rupture of long head tendon
transverse humeral ligament and subdeltoid bursa
Coracobrachialis
PA: coracoid process
DA: humeral midshaft
Act: flexes and adducts
Inn: musculocutaneous nerve pierces
Brachialis
PA: distal humerus
DA: coronoid process, ulnar tuberosity
Act: strong flexor of the forearm
Inn: musculocutaneous nerve
sensory from radial nerve
Where does the brachial artery begin?
What are its branches in the arm?
The brachial artery begins at the inferior border of teres major
Give off first branch which is the deep artery of the arm that travels with the radial nerve and supplies the posterior arm
More inferiorly the brachial artery gives off superior and inferior ulnar collateral arteries
There is also a radial and middle collateral off the deep artery of the arm
What are the 3 main flexor arm nerves?
Musculocutaneous nerve: pierces coracobrachialis, supplies flexor arm
Median nerve: no motor in the arm, travels in flexor compartment with the brachial artery
Ulnar nerve: no innervation in the arm, travels in the flexor compartment more posterior and medial to the brachial artery and median nerve. Give off two cutaneous branches: medial cutaneous nerve of the arm and medial cutaneous nerve of the forearm
What are the boundaries of the cubital fossa?
brachioradialis m
pronator teres m.
line connectin the medial and lateral epicondyles of the humerus
What are the neurovascular contents of the cubital fossa?
brachial artery divides into the radial and ulnar aa. typically in the fossa
radial nerve divides into superficial and deep branches
median nerve runs with the brachial artery
ulnar nerve goes around the posterior side of the joint (medical epicondyle)
What is the most common site for venipuncture?
median cubital vein
What are the main anastomoses of the elbow?
collateral aa. are proximal to the elbow and braches off the brachial artery and deep artery of the arm
recurrent aa. are distal to the elbow, brings blood up to meet the collateral aa. and are branches of the radial and ulnar aa.
radial recurrent off the radial a. anastomoses with the radial collateral
recurrent interosseous anastomoses with the middle collateral a
anterior and posterior ulnar recurrent off the ulnar artery anastomoses with the superior and inferior ulnar collateral aa.
What are the main arteries and nerves supplying the flexor forearm?
What are the main actions of the forearm?
Radial and ulnar aa.
median and ulnar nn.
pronation of the forearm
flexion, abduction, adduction of the wrist
flexion of the digits
What is a common flexor origin?
medial epicondyle of the humerus
Which forearm bone extends more distally?
What does this allow?
The radius extends more distally than the ulna, allowing for greater adduction than abduction
What is medial epicondylitis?
inflammation of common flexor origin and periosteum of the medial epicondyle “golfer’s elbow”
What are the 8 carpal bones?
scaphoid, lunate, triquetrum, pisiform
trapezium, trapezoid, capitate, hamate
What are the three bone sets of the hand?
carpals (wrist)
metacarpals (palm)
phalanges (fingers: proximal, middle, distal)
Metacarpals and phalanges have a base, shaft and head
What is special about the pollex or digit 1?
has two sesamoid bones (bones that form within tendon) at the head of MC1
has proximal and distal phalanges only
Describe fracture of the distal ulna and radius.
most common in age 50+, especially women with osteoporosis
fall during wrist extension: colles fracture “dinner fork deformity”
fall during wrist flexion: smiths fracture, bones displaced anteriorly
What is the distal radioulnar joint?
synovial pivot joint
radius, ulna
supination, pronation
What accomodates radial movements?
sacciform recess between radius and ulna
What is the wrist or radiocarpal, RC joint?
synovial condyloid joint
radius, scaphoid, lunate, triquetrium
no ulna: allows greater adduction
flexion, extension, abduction, adduction, circumduction
What are two ligaments associated with the wrist?
dorsal radiocarpal ligament
dorsal radioulnar ligament
They are both also palmar ligaments
What is the 1st carpometacarpal joint? (CMC)
synovial saddle joint
trapezium and 1st MC
flexion, extension, abduction, adduction, opposition, reposition
What is the metacarpophalangeal joint? (MCP)
synovial condyloid joint
MC and proximal phalanx
flexion, extension, abduction, adduction
What is the interphalangeal joints? (IP)
synovial hinge joint
proximal (PIP) and distal (DIP)
flexion and extension
What are three ligaments associated with the phalanges?
deep transverse metacarpal ligaments: restricts abduction
palmar plates or ligaments: joint capsule thickening, protection from tendons
collateral ligaments: medial and lateral reinforcement
What digit is the axis of abduction and adduction for digits 2-5?
3rd digit
can abduct in two directions
Pronator teres
PA: coronoid process, medial epicondyle
DA: radius (lateral midshaft)
Act: pronates and flexes forearm
Inn: median n.
Flexor carpi radialis
PA: medial epicondyle of the humerus
DA: 2nd metacarpal (base)
Act: flexes & abducts hand
Inn: median n
Palmaris longus
PA: medial epicondyle of the humerus
DA: palmar aponeurosis
Act: flexes hand, tenses palmar aponeur.
Inn: median n
Flexor carpi ulnaris
PA: olecranon process (not CFO)
DA: pisiform, hamate, 5th metacarpal
Act: flexes & adducts hand
Inn: ulnar n
Flexor digitorum superficialis
PA: medial epicondyle, radius
DA: middle phalanges 2-5
Act: flexes RC, CMC, MCP, PIP
Inn: median n
Flexor digitorum profundus
PA: ulna, interosseus membrane
DA: distal phalanges 2-5
Act: flexes RC, CMC, MCP, PIP, DIP
Inn: digits 2 & 3: median n
(anterior interosseous branch)
digits 4 & 5: ulnar n
DIP flexion 4&5 is ulnar nerve, not median
Flexor pollicis longus
PA: radius, interosseus membrane
DA: 1st distal phalanx (base)
Act: flexes 1st digit
Inn: median n (ant. inteross. branch)
Pronator quadratus
PA: distal ulna
DA: distal radius
Act: pronates forearm
Inn: median n (ant. inteross. branch)
What is a tendinous chiasm?
FDS tendon splits to allow passage of FDP tendons
What is the fibrous digital sheath?
anchors tendon to bone
prevents bowstringing
has annular and cruciform portions
What are two branches of the ulnar artery right after the elbow?
common interosseus a. that branches into anterior and posterior interosseus arteries. These run along the anterior and posterior sides of the interosseus membrane
What is one function of the deep veins accompanying the arteries? venae comitantes
cooler veins provide thermoregulation
What are the main nerves of the forearm?
Ulnar nerve passes posterior to medial epicondyle in ulnar groove (funny bone). Compression can cause cubital tunnel syndrome. Ulnar nerve than passes wrist within ulnar tunnel or Guyon’s canal. Compression can cause ulnar tunnel syndrome.
Median nerve has a branch called anterior interosseous branch in the forearm. It then passes through the wrist within carpal tunnel. Compression can cause carpal tunnel syndrome
Radial braches in forearm to superficial and deep branches
