Quiz 3 Flashcards
Which wrist bone is most commonly fractured?
scaphoid
Which wrist bone is most commonly dislocated?
lunate
What is the sternoclavicular joint? Which ligaments stabilize and prevent excessive movement of it?
The sternoclavicular joint is:
- a fairly stable modified saddle joint
- Convex medial end of clavicle fits into concave manubrium.
- Fibrocartilagenous disc separates the articulating surfaces
- The sternoclavicular ligaments bind the clavicle to the manubrium on both anterior and posterior surfaces.
- The interclavicular ligament binds the medial ends of the right and left clavicles to each other just above the manubrium
- The costoclavicular ligament binds the clavicle to the first rib
What do the sternoclavicular ligaments do?
Part ofthe sternoclavicular joint, the sternoclavicular ligaments bind the clavicle to the manubrium on the anterior and posterior surfaces
What does the interclavicular ligament do?
Part of the sternoclavicular joint, the interclavicular ligament binds the medial ends of the right and left clavicles to each other just above the manubrium.
What does the costoclavicular ligament do?
The costoclavicular ligament binds the clavicle to the first rib in the sternoclavicular joint
Under which ligament can a branch of the brachial plexus get trapped? What happens as a result?
The costoclavicular ligament. It results in pain and muscle weakness, depending upon which branch is trapped.
Are dislocations of the sternoclavicular joint common? What results if there is a posterior dislocation?
No, they are not common. Posterior dislocation can result in trauma to the brachiocephalic veins that are located just posterior to this joint.
What innervates the sternoclavicular joint?
The nerve to the subclavius and the supraclavicular nerve
What supplies the blood to the sternoclavicular joint?
the suprascapular or internal thoracic arteries supply the blood to the sternoclavicular joint
What movements are associated with the sternoclavicular joint?
The sternoclavicular joint increases shoulder ROM and passively moves with scapular motion
Describe the acromioclavicular joint.
- -Synovial joint of Planar type between acromion of scapula and lateral end of clavicle.
- some movement here, but the main function is to bind the clavicle to the scapula in order to support the weight of the upper limb and keep the humerus suspended at the side without using a lot of muscle contraction energy.
What is the main function of the acromioclavicular joint?
bind the clavicle to the scapula in order to support the weight of the upper limb and keep the humerus suspended at the side without using a lot of muscle contraction energy
What provides the main stabilizing force to the acromioclavicular joint?
ligaments.– the acromioclavicular ligament that binds the clavicle to the acromion and the coracoclavicular ligaments, which bind the coracoid process of the scapula to the clavicle.
What two ligaments make up the coracoclavicular ligament?
the conoid and the trapezoid ligaments
When does shoulder separation occur? Describe shoulder separation.
When there is tearing of the coraclavicular ligaments and/or the acromioclavicular ligaments. A greater tear results in greater separation from the clavicle. When this happens, the weight of the upper limb pulls the scapula and the acromion downward. The result is that the clavicle overrides the acromion.
What is the innervation of the acromioclavicular joint?
suprascapular and lateral pectoral nerves
What is the blood supply of the acromioclavicular joint?
suprascapular and thoracoacromial arteries
Describe the glenohumeral joint.
- Most mobile joint in the human body.
- ball and socket synovial joint between head of humerus and concave glenoid fossa of the scapula.
- fibrous capsule that attached from the glenoid cavity to the anatomical neck of the humerus surrounds the joint.
- ligaments reinforce the capsule in all directions except for the inferior portion.
What are the ligaments that reinforce the glenohumeral joint?
1) coracoacromial ligament (which doesn’t actually attach to this joint) connects the coracoid process to the acromion. It reinforces the superior aspect of the shoulder joint and helps prevent upward displacement of the head of the humerus.
2) Coracohumeral ligament– strengenths the superior portion of the capsule and helps resist excessive abduction. It runs from the coracoid process to the lesser tubercle.
3) the transverse humeral ligaments holds the tendon of the long head of the biceps in the bicipital groove. This stabilizes the tendon so that it doesn’t pop out.
4) 3 parts of the glenohumeral ligament, which attach from the upper margin of the glenoid cavity and labrum, strengthen the anterior portion of the capsule.
Ligaments reinforce the fibrous capsule that attaches from the glenoid cavity to the anatomical neck of the humerus in all directions except?
inferior portion
What are the three parts of the glenohumeral ligament?
1) The superior part, which runs over the humeral head to a depression above the lesser tuberosity.
2) The middle part, which runs from in front of the humerus to lower lesser tuberosity
3) the inferior part, which runs to a lower part of the anatomical neck. This ligament is a key stabilizer of the anterior shoulder.
Weakness of which part of the glenohumeral ligament often leads to anterior glenohumeral instability?
The inferior part
What is the glenoid labrum?
rim of fibrocartilage attaching to the outer rim of the glenoid fossa. Superior attachment of the labrum includes the supraglenoid tubercle and the origin of the tendon of the long head of the biceps.
What does the glenoid labrum do?
helps deepen the articulation between the head of the humerus and the glenoid fossa of the scapula. Provides stability to this articulation.
Tears of the glenoid labrum often are associated with…?
glenohumeral dislocations
Describe the capsule of the glenohumeral joint.
It is very thin and lax. It attaches to the glenoid beyond the labrum and to the anatomical neck of the humerus. It is strengthened by the muscles of the shoulder: supraspinatus, infraspinatus, teres minor, subscapularis, and the long head of the biceps brachii
What are the openings of the capsule of the glenohumeral joint?
1) between greater and lesser tubercles that allows passage of the long head of the biceps brachii through the shoulder joint.
2) below and anterior to coracoid process, which allows the joint to communicate with the subscapular bursa
3) between joint and bursa under infraspinatus tendon
What bursae are associated with the glenohumeral joint?
1) subscapular, which is between the muscle and the neck of the scapula. It communicates with the shoulder joint.
2) Subacromial or subdeltoid, which is inferior to the acromion and extending distally to area deep to the deltoid muscle, but superficial to the supraspinatus. This normally does not communicate with the joint.
3) above acromion,
4) others with tendons
5) between the coracoid and the capsule
What innervates the glenohumeral joint?
the suprascapular nerve, lateral pectoral nerve, posterior cord of the brachial plexus, and axillary nerve
What arteries supply the glenohumeral joint?
the anterior and posterior humeral circumflex, which goes through the quandrangular space, and the suprascapular artery, which innervates from the posterior.
How would you characterize the stability of the glenohumeral joint?
Very mobile, so stability is reduced.
What muscles/structures contribute to the passive stability of the glenohumeral joint?
The trapezius acts as a postural muscle, keeping the shoulder joint in a retracted and upwardly rotated position. The deltoid prevents dislocation of the humerus from the glenoid cavity by gravity. The ligaments (especially glenohumeral ligament and coracohumeral ligament and glenoid labrum) help stabilize the joint.
If the shoulder droops, which muscle that stabilizes the glenohumeral joint is likely to have been damaged?
trapezius
What is the difference between passive and active stability?
Passive stability involves the factors that keep it stable when it is at rest. Active stability involves those structures that stabilize the joint when motion occurs.
Describe very simply how the structures involved in active stability of the glenohumeral joint do their job.
they pull the head of the humerus into the fossa and pulls the head of the humerus downward, counteracting the tendency of the head of the humerus to move up towards the acromion and compression of the structures between the humeral head and the acromion.
What muscles are responsible for active stability of the glenohumeral joint?
the rotator cuff muscles– a series of 4 muscles that arise from the scapula and insert into the proximal end of the humerus. They rotate the humerus and are active during all types of shoulder joint movements.
What does weakness of rotator cuff muscles result in?
impingement of structures between acromion and head of humerus.
Which rotator cuff muscles is most likely to get injured?
supraspinatus.
what are the movements of the glenohumeral joint?
1) elevation and depression of scapula. Elevation is like shrugging your shoulders. 2) protraction and retraction of scapula– former moves medial part of scapula away from midline, while latter moves medial part of scapula toward midline , 3) upward rotation of scapula (glenoid cavity and acromion face up), downward rotation occurs when inferior angle moves in a medial direction or acromion is drawn downward. 4) flexion/extension, wherein the humerus moves on the glenoid cavity in a sagittal plane. During flexion, the humerus moves anteriorly, while during extension, the humerus moves posteriorly up to 90 degrees , 5) abduction/adduction, wherein the humerus moves away from/toward the midline, 6) inward/medial rotation or outward/lateral rotation. Inward rotation occurs when the anterior portion of the humerus turns toward the midline of the body, outward rotation is the movement of turning the humerus away from the midline. 7) scapulohumeral rhythm– coordinated movements between scapula and humerus to abduct arm (2:1 ratio humeral abduction to scapula upward rotation). First 30 degrees humerus abducts and scapula remains stable, as motion continues scapula undergoes upward rotation. Upward rotation of scapula is result of the combined actions of the trapezius and serratus anterior. Damage to either the trapezius or serratus anterior results in the person not being able to fully abduct the arm, despite the fact that the deltoid is working to raise the humerus.
When the arm is abducted 180 degrees, how much occurs by rotation of the scapula, and how much by rotation of the humerus at the shoulder joint?
60 degrees by scapula rotation and 120 degrees by rotation of humerus at the shoulder joint.
At what degree would extension of the humerus in the glenohumeral joint be considered hyperextension?
beyond 90 degrees behind the body
What is shoulder impingement?
– overuse injury in which repetitive motion results in fatigue of rotator cuff muscles.
What type of movement reduces the contact between the humeral head and the glenoid fossa and makes the glenohumeral joint less stable than it is at rest?
any type of movement.
What type of motion renders the glenohumeral joint particulary unstable and why? Which muscles are especially responsible for counteracting this instability? What does their action in particular prevent?
abduction (especially full abduction), because there is minimal contact between the articulating bones. The rotator cuff muscles (especially subscapularis, infraspinatus, and teres minor) become active during shoulder abduction. They pull the head of the humerus downward and into the glenoid cavity. Their action prevents the humerus from riding up and pressing the supraspinatus tendon between the acromion and greater tubercle of the humerus.
What happens when the teres minor, subscapularis, and infraspinatus fatigue? What is the primary symptom of this?
The humerus moves towards the acromion and the supraspinatus tendon becomes rubbed between the acromion and greater tubercle, irritating the tendon. The primary symptom is pain posterior to and below the acromion in the vicinity of the greater tubercle, especially when attempting to abduct, flex, or adduct the humerus.
What are some special tests for shoulder impingement?
1) painful arc– abduct arm (pain present from 60 to 120 degrees abduction). 2) Can tests– to assess impingement or damage to the supraspinatus tendon. Full can is with abduction of arm to shoulder level and outwardly rotate humerus, press down on shoulder, if pain or difficulty then supraspinatus tendon is affected. Empty can test is abduction of arm to shoulder level and inwardly rotate humerus, press down on shoulder. If pain or difficulty then supraspinatus tendon is affected.
How does the anatomy of the can test positions differ and what does this mean?
Full can (outward rotation) moves the greater tubercle and attached supraspinatus tendon away from acromion. No irritation of this tendon and it can withstand pressing downward on the arm. Empty can (inward rotation) moves the greater tubercle and supraspinatus tendon directly under the acromion. In this position it is easy to have the supraspinatus tendon irritated by the acromion so it is a lot more difficult/painful for the patient to resist when you are pushing down on arm. Hence, impingement sign indicated by empty can.
What type of joint is the elbow joint?
synovial hinge joint betwen the distal humerus and proximal ulna and radius.
What are the joints of the elbow joint?
humeroradial joint– capitulum and head of radius
humeroulnar joint– trochlea and trochlear notch of ulna
Describe the capsule of the elbow joint
thin anteriorly and posteriorly, attaches anteriorly to the area proximal to coronoid and radial fossae and to the annular ligament. Attaches posteriorly to the olecranon fossa and trochlear notch. The synovial capsule is continuous with that of the proximal radioulnar joint.
What are the ligaments of the elbow joint?
1) radial or lateral collateral– fan shaped and attaches to the lateral epicondyle of the humerus and distally blends with the annular ligament of the radius.
2) ulnar or medial collateral– three bands. anterior from front of medial epicondyle of humerus to tubercle on medial margin of coronoid. Posterior from lower, back part of medial epicondyle to medial margin of the olecranon.
3) oblique connects to distal attachments of the other two
What are the bursa of the elbow joint?
1) 2 associate with olecranon– one subctaneous and one deep to the tendon of the triceps. 2) radioulnar bursa is between the extensor digitorum, supinator, and the radiohumeral joint. 3) interosseal bursa behind the supinator, lateral to the biceps 4) bicipitoradial bursa is between the biceps and tuberosity of the radius.
What innervates the elbow joint?
the musculocutaneous (terminal branch of the lateral cord), the radial nerve on the posterior cord, and some ulnar (funny bone), median, and anterior interosseous nerves (branch off of median nerve)
What supplies blood to the elbow joint?
The components of the anastomosis of the elbow– the brachial artery (2 ulnar collateral arteries off of brachial), the deep brachial, the ulnar (recurrant), and the radial.
What are the movements available at the elbow joint?
Flexion and extension. The axis for these movments is a horizontal line through the epicondyles of the humerus. Flexion involves bringing the radius and ulnar to approximate the humerus. Extension involves bringing the radius and ulna away from the humerus.
What is the proximal radioulnar joint?
Synovial pivot joint between the convex head of the radius and a concavity on the ulna. Formed by the head of the radius with the radial notch of the ulna. It contains a synovial cavity that communicates with the elbow joint.
What are the ligaments of the proximal radioulnar joint?
The annular ligament circles the head of the radius,forming 4/5 of the ring. Allowing for pronation and supination.
What does the synovial cavity of the proximal radioulnar joint do?
Communicates with the elbow joint
What innervates the proximal radioulnar joint?
the musculocutaneous, median, and radial nerves.
What is the blood supply to the proximal radioulnar joint?
the same as the elbow joint– brachial artery, the deep brachial artery, the ulnar, and the radial.
Describe the anastomosis of the elbow. What does it do?
Anastomosis of the elbow– brings brachial artery in anastomotic connection with the radial and ulnar arteries. It permits circulation to the forearm and wrist even with complete elbow flexion.
What is Nursemaid’s Elbow?
Happens in children often, when swinging or pulling on their arm the radius is pulled out of the annular ligament.
What are the movements of the proximal radioulnar joint?
pronation and supination. Pronation involves the radius moving on a fixed ulna. The radius rotates, bringing the hand and palm in a downward facing position. Supination involves the radius moving on a fixed ulna. The radius rotates, bringing the hand in a palm-up position.
What is Tommy John surgery?
Famous baseball pitcher who tore his ulnar collateral ligament. They drilled holes in his humerus and ulna and sewed the tendon through to sew his joint back together.
glenohumeral ligaments support in all directions except?
inferiorly
what is the key stabilizer of the anterior capsule?
inferior glenohumeral ligament
Which ligaments are especially involved with passive stability of the glenohumeral joint?
the coracohumeral ligament, the glenoid labrum, and the inferior glenohumeral ligament.
What happens regarding the glenohumeral joint if the SITS muscles are weak?
the humerus moves upward, pushing against the acromion, causing impingement of the supraspinatous tendon/muscle.
Describe humeral abduction and what muscles are involved.
Initiation of abduction is a function of the supraspinatus muscles. Bringing the arm to shoulder level is the action of the deltoid. Completing abduction to 180 degrees requires the synergistic action of the deltoid, trapezius, and serratus anterior muscles. The rotator cuff muscles (especially the infraspinatus, subscapularis, and teres minor) become very active during shoulder abduction. These muscles pull the head of the humerus downward and inward against the glenoid cavity. This action prevents the humerus from riding up and pressing the supraspinatus tendon between the acromion and greater tubercle of the humerus.
Which muscles are responsible for just abducting the humerus? Which are responsible for upward rotation of scapula?
1) Supraspinatus and deltoid.
2) Serratus anterior and trapezius.
Which muscle is the strongest flexor of the elbow joint when it is pronated? Supinated?
Pronated = brachialis. Supinated = biceps brachii
What must the biceps brachii first do before flexing the elbow joint?
supinate forearm. If the radioulnar joint is kept in a prone position, the biceps cannot act to flex the elbow.
Where is the brachialis in relation to the biceps brachii?
flat beneath
Where is the coracobrachialis in relation to the biceps?
beneath the short head
What is the main contributor to the musculocutaneous?
C6
Which cord is musculocutaneous nerve derived from?
lateral
Which nerve supplies motor innervation to the muscles in the anterior brachial compartment?
musculocutaneous
Which nerve supplies sensory information from the lateral portion of the forearm?
musculocutaneous
What supplies the blood to the anterior compartment of the arm?
brachial artery, a continuation of the axillary artery
What are the two compartments of the arm?
anterior/flexor– which contains muscles that flex the elbow joint and supinate the proximal radioulnar joint.
posterior/extensor– which contains muscles that extend the elbow joint
What are the two compartments of the forearm?
anterior/flexor – contains muscles that flex the wrist joint, pronate the radioulnar joint, and flex the digits.
posterior/extensor– contains muscles that extend the wrist joint, supinate the radioulnar joint, and extend and abduct the digits
What are transition zones?
Areas that connect one region to another in the compartments of the arm– in close proximity to moveable joints and therefore are subject to injuries.
What are the important transition zones in the arm and forearm?
Axilla (passageway for nerves and vessels that original in the neck to enter the axilla and upper limb), cubital fossa (anterior to elbow joint; provides passageway for nerves and vessels travelling from arm to forearm); wrist (connects and provides passageway for contents of forearm into hand)
What are the branches of the brachial artery?
1) muscular branches to the muscles in the anterior compartment of the arm, 2) collateral branches that participate in elbow anastomosis, 3) deep brachial artery that supplies the extensor compartment.
Which branches of the brachial artery participates in the elbow anastomosis?
collateral branches
Which branch of the brachial artery supplies the extensor compartment?
deep brachial artery branch
Which part of the triceps brachii forms the triangular space?
long head
What are the muscles in the posterior compartment of the arm primarily responsible for?
extending the elbow joint
What is the nerve of the posterior compartment of the arm?
the radial nerve (derived from the posterior cord of the brachial plexus)
What contributes the majority of the axons to the radial nerve?
C5-C7
The musculocutaneous nerve is part of which dermatome?
C6
Radial nerve is part of which dermatome?
C5
What is the cubital fossa?
region anterior to elbow joint. Region provides passageway for nerves and vessels travelling from the arm to the forearm.
where is venapuncture usually performed?
cubital fossa
What are the boundaries of the cubital fossa?
superior– imaginary line connecting epicondyles, medial– pronator teres, lateral – brachioradialis
What forms the roof and floor of cubital fossa?
roof– skin, fascia, biciptial aponerosis; floor – medial - brachialis, lateral- supinator
what are the contents of the cubital fossa from lateral to medial?
- radial nerve
- biceps tendon
- brachial artery and vein (v. is deep to a. with terminal branches of 1) radial artery and 2) ulnar artery)
- median nerve
Describe the venous contributions to the cubital fossa region and their clinical significance.
2 main cutaneous veins that drain the upper limb are derived from a venous arch on the dorsum of the hand. The basilic vein drains the skin on the ulnar portion of the forearm into the axillary vein in inferior axillary region. The cephalic vein drains skin on radial side of forearm and also drains into axillary vein (near apex, so more superior). The median cubital vein connects the basilic and cephalic veins in the cubital fossa and is the site for venapuncture.
What is the most common point of origin for the flexor muscles of the forearm?
medial epicondyle of humerus
pronation of forearm occurs by rotating which bone?
rotation of radius upon fixed ulna
which joints do the pronator teres and pronator quadratus act upon?
pronator teres = proximal radioulnar joint; pronator quadratus = distal radioulnar joint
What are the wrist flexors of the forearm?
flexor carpi radialis, palmaris longus, and flexor carpi ulnaris
where do the wrist flexors attach?
medial epicondyle of the humerus.
What is the main function of the palmaris longus?
keeping the palmar aponeurosis tight. It is a weak wrist flexor
which muscles of the forearm are considered extrinsic hand muscles and why?
flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus. These muscles have their bellies of origin in the forearm, but exert their actions on the wrist and hand.
Which is the only extrinsic hand muscle of the forearm that proximally attaches to the medial epicondyle of the humerus?
flexor digitorum superficialis
Do the tendons of the flexor digitorum superficialis and flexor digitorum profundus both pass through the carpal tunnel and deep to the flexor retinaculum?
yes
Which muscle is the prime flexor of the PIP?
flexor digitorum superficialis
Which muscle is the prime flexor of the DIP?
flexor digitorum profundus
Does the flexor pollicis longus tendon pass deep to the flexor retinaculum and go through the carpal tunnel?
yes
which muscles of the forearm does the median nerve supply?
pronator teres, pronator quadratus (anterior interosseous branch), flexor carpi radialis, palmaris longus, flexor digitorum superficialis, radial 1/2 of the flexor digitorum profundus (anterior interosseous branch), flexor pollicis longus (anterior interosseous branch)
Which muscles of the forearm does the ulnar nerve supply?
flexor carpi ulnaris, ulnar 1/2 of the flexor digitorum profundus
Which nerve supplies cutaneous innervation to the lateral side of the forearm?
lateral antebrachial cutaneous (C6), the cutaneous branch of the musculocutaneous nerve.
Which nerve supplies cutaneous innervation to the medial side of the forearm?
medial antebrachial cutaneous, a branch from the medial cord of the brachial plexus
Where do the radial and ulnar arteries branch from the brachial artery?
usually the cubital fossa, though it is not unusual for the radial artery to branch from the proximal portion of the brachial artery.
Which arteries supply the blood to the flexor compartment of the forearm?
radial and ulnar arteries
which artery branches into the common interosseus and then into the anterior and posterior interosseus arteries?
the ulnar artery.
what does the anterior interosseus artery supply? the posterior interosseus?
the anterior interosseus artery supplies blood to the deep lying muscle structures in the flexor compartment of the forearm. The posterior interosseus artery supplies blood to the muscles in the extensor compartment.
What is the common origin of the wrist and finger extensors?
lateral epicondyle of humerus
Where are anatomical snuff box tendons derived from?
3 muscles that arise from the lower portion of the shaft of the radius, ulna, and interosseous membrane
Where do the anatomical snuff box tendons form a depression?
base of 1st metacarpal.
which phalanges do the anatomical snuff box muscles act upon?
1st metacarpal and joints of the thumb
what are the muscles of the anatomical snuff box?
1) abductor pollicis longus, 2) extensor pollicis longus, 3) extensor pollicis brevis
What are the three muscles that extend the wrist?
extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris
why does wrist extension usually occur along with radial deviation?
because the extensor carpi radialis longus and brevis are stronger than the extensor carpi ulnaris
What are the finger extensor muscles?
the extensor digitorum, the extensor digiti minimi, extensor indicis
What is the primary function of the finger extensors?
extend the metacarpophalangeal joints of the four fingers. they can weakly extend the interphalangeal joints of the fingers
which muscle divides into 4 tendinous slips, with each slip participating in the formation of the dorsal digital expansion of each of the 4 fingers?
extensor digitorum
which is the drinking muscle?
brachioradialis
What are the 6 compartments of the wrist and which muscle tendons do they each contain?
1 - abductor pollicis longus and extensor pollicis brevis
2- extensor carpi radialis longus and brevis
3- extensor pollicis longus
4- extensor digitorum and extensor indicis
5- extensor digiti V
6- extensor carpi ulnaris
Which of the 6 extensor compartments is most clinically significant?
1 (with abductor pollicis longus and extensor pollicis brevis)
What is De Quervain’s disease?
Repetitive movements of the thumb and the wrist, which result in inflammation of the tendon sheath and narrowing of the space within the first compartment. Movements of the thumb and wrist, especially flexion of the thumb and ulnar deviation of the wrist, results in pain on the dorsal lateral aspect of the wrist.
What is the test for De Quervain’s disease?
curl thumb under fingers and adduct hand (ulnar deviation of wrist). pain on dorsal lateral aspect of wrist = positive test.
Describe how the radial nerve branches?
enters cubital fossa and divides into 1) muscular branches that supply extensor carpi radialis lonus and brevis and brachioradialis, 2) superficial branch conveying sensory from dorsum of hand and thumb. 3) deep branch that pierces the supinator muscle to innervate the musces in the posterior compartment of the forearm.
the dorsum of the hand and thumb are part of which dermatome?
C6
Which flexor muscle is supplied by the radial nerve?
brachioradialis
What are common sites of radial nerve damage?
compression within the axilla (Saturday night palsy), fracture of the humeral shaft, cubital fossa trauma, and entrapment within the supinator muscle
What are common sites of injury to the median nerve?
trauma to the cubital fossa, entrapment within the pronator teres muscle, and carpal tunnel sydrome
What are common sites of injury to the ulnar nerve?
cubital tunnel (funny bone), wrist injuries, entrapped within the hand (Tunnel of Guyon)
What is cubitis valgus?
when the forearm is abducted with respect to the long axis of the arm. This position is referred to as the “carry angle” of the forearm.
What are the carpal bones?
proximal row: scaphoid, lunate, triquetrium, pisiform
distal row: trapezium, trapezoid, capitate, hamate
What are the metacarpal bones?
thumb has proximal and distal phalanges, fingers each have proximal, middle, and distal phalanges.
What are the difference between the extrinsic and intrinsic hand muscles?
extrinsic muscles arise in forearm but insert onto digits, while intrinsic muscles arise and insert to the hand
Which nerve provides sensation to the radial portion of the dorsum of the hand?
radial
Which nerve provides innervation from the palmar surface of the hand and the first 3 1/2 digits?
median
which nerve provides sensation from the dorsal and palma surfaces of the ulnar side of the hand and the last 1 and 1/2 digits?
ulnar
Which nerves supply all the intrinsic muscles of the hand?
ulnar and median nerves
Which arteries supply blood to the hand and the digits?
radial and ulnar arteries
What bones articulate to form carpometacarpal joints that connect the wrist to the hand?
base of each metacarpal attaches with the distal row of carpal bones
What forms the metacarpophalangeal joints?
the distal portion of the metacarpal bones (metacarpal head) attaches with proximal phalanx of each digit to form metacarpophalangeal joints.
Where do movements of the digits occur?
at the metacarpophalangeal joints and the interphalangeal joints
What is the thenar eminence?
bulky fleshy area on lateral side of thumb
what forms thenar eminence?
Thenar muscles, intrinsic muscles that act on the thumb
what is the hypothenar eminence?
fleshy area on the medial side of 5th digit. Hypothenar muscles, intrinsic muscles that act on the pinky, form this eminence.
What does the distal crease of the wrist indicate?
the site of articulations between the distal row of carpal bones with the base of the metacarpal bones
What does the proximal crease of the thumb indicate?
the location of the metacarpophalangeal joint
What does the distal crease of the thumb indicate?
the location of the interphalangeal joint
what joints are at the proximal knuckles?
metacarpophalangeal
What is the purpose of the common synovial sheath and digital synovial sheath that surround the flexor digitorum superficialis and profundus muscle tendons?
provide lubrication to help the tendons move without resulting in inflammation and pain
which sheath forms the ulnar bursar?
the digital synovial sheath of the 5th digit, which is continuous with the common synovial sheath.
What are fibrous digital sheaths made up of?
dense anular and weaker cruciate ligaments that extend as far as the synovial digital sheaths extend, reaching the base of the distal phalanx of each finger. The anular and cruciate ligaments are attached at the MP and IP joints to a fibrocartilage palmar plate. This arragment allows for smooth movemen of the tendons within their sheaths.
how are tendon sheaths kept applied to the bones of the fingers?
fibrous digital sheaths
what causes mallet finger?
damage to the lateral bands of the extensor expansion. This makes the DIP joint in a position of flexion.
What is boutonniere deformity?
damage to the central band of the extensor expansion, resulting in the PIP joint being in a position of flexion and DIP in extension
Which tendon is surrounded by its own synovial digital sheath?
flexor pollicis longus. this sheath extends from the base of the distal phalanx of the thumb to just proximal to the flexor retinaculum. Sometimes is referred to as the radial bursa. Also kept applied to the bones of the thumb by a fibrous digital sheath.
What helps convey blood to the tendons within the synovial digital sheath?
long and short vincula
What are the four groups of intrinsic hand muscles?
1) thenar muscles that act on the thumb, 2) hypothenar muscles that act on the pinky, 3) lumbricals that act on all the fingers, 4) interossei that act primarily on the metacarpophalangeal joints of the fingers.
Which muscle is responsible for producing rotation of the first carpometacarpal joint?
opponens policis
what are the three steps to thumb opposition?
1) unlock metacarpophalangeal joint of the thumb when the abductor pollicis brevis abducts the joint. 2) flexor pollicis brevis brings the thumb across the palm by flexing the metacarpophalangeal joint of the thumb. 3) the opponens pollicis rotates the first metacarpal on the trapezium.
what innervates the thenar muscles?
recurrant (or thenar) branch of the median nerve
Where would you palpate the adductor pollicis?
fleshy prominence on the palmar surface of the hand between the 1st and 2nd digit.
what innervates adductor pollicis?
ulnar nerve
why can’t the opponens digiti minimi oppose the fifth digit?
the articulation between the fifth metacarpal bone and the hamate bone is not a saddle joint. Therefore, only minimal opposition.
What innervates the hypothenar muscles?
deep branch of ulnar nerve?
where do the muscles arise from?
tendons of the flexor digitorum profundus
what innervates lumbricals?
median (1 and 2) and ulnar (3 and 4) nerves
how many dorsal and how many palmar interossei are there?
4 dorsal and 3 palmar
do the dorsal or palmar inerossei abduct or adduct?
palmar interossei adduct, dorsal interossei abduct.
what do the palmar interossei do aside from adduction?
flexion at metacarpophalangeal joints
What is the dorsal digital expansion?
defines the way the extrinsic extensor tendons and lumbricals and interossei insert onto dorsum of fingers. extensor tendons form a moveable hood over the metacarpophalangeal joints of the fingers called the extensor hood.
Which muscles is primarily responsible for extension of MCP joint?
extensor digitorum (aided by extensor indicis and extensor digiti minimi)
The ulnar portion of the hand is part of which dermatome?
C8
The palmar surface of the first 3.5 digits is part of which dermatome?
C6
The dorsum of the hand and thumb is part of which dermatome?
C6
What is the extensor hood?
covers the metacarpophalangeal joint of each finger, formed by tissue connecting the tendons of the extensor digitorum, the interossei, and the lumbricals of each finger. extensor indicis tendon joins hood of the 2nd finger. extensor digiti minimi joins hood of the fifth digit.
what are the components of the dorsal digital expansion?
extensor hood and bands, interossei and lumbricals
where do the central and lateral bands of the dorsal digital expension go?
central extends to the base of the middle phalanx, while lateral bandsextend to the distal phalanx.
what is the function of the dorsal digital expansion?
enables the extrinsic extensor tendons to strongly extend the metacarpophalangeal joints.
when can dorsal digital expansion (lumbricals) extend the interphalangeal joints?
only when the metacarpophalangeal joints are flexed
where does the blood supply to the hand come from?
radial and ulnar arteries, which both divide into superficial and deep branches. the superficial of the ulnar is large, usually joining the smaller branch of the radial artery to form the superficial palmar arch. superficial arch supplies the skin and superficial structures of the hand. the deep branch of the radial artery is larger than its counterpart from the ulnar artery. crosses the palm to join the deep branch of the ulnar artery, forming deep palmar arch. the deep arch supplies most of the intrinsic muscles of the hand.
what forms the superficial palmar arch and what does it supply?
joining of the superficial ulnar branch and the smaller branch of radial artery. Supplies the skin and superficial structures of the hand
what forms the deep palmar arch and what does it do?
the deep branch of the radial artery is larger than its counterpart from the ulnar artery. crosses the palm to join the deep branch of the ulnar artery, forming deep palmar arch. the deep arch supplies most of the intrinsic muscles of the hand.
when can the lumbricals flex the MCP joints?
only when they simultaneously extend the IPJ joints of the fingers.
You are most likely to fracture which carpal bone if you fall on your outstretched hand?
scaphoid bone
What is the dinner fork deformity?
If the broken end of the radius is displaced posteriorly. Caused by falling on outstretched hand.
what causes gamekeeper’s thumb?
overabduction of the thumb leads to tearing the ulnar collateral ligament
What causes carpal tunnel syndrome?
compressing the median nerve in the carpal tunnel. sensory = pain/loss of sensation over palmar 3.5 digits. Motor = loss of function of LLOAF muscles, leading to “ape hand.” Can’t oppose thumb. Can lead to wasting away of thenar eminence.
What causes pronator teres syndome?
compressed median nerve as it passes through pronator teres, which leads to loss of forearm flexors and LLOAF muscles. Causes “papal hand” because can’t flex digits 2 and 3 when told to make a fist, also ulnar deviation.
Guyon’s Tunnel Syndrome?
compression of the ulnar nerve as it passes through hook of hamate and pisiform bone. loss of sensation ulnar 1.5 digits. loss of hand muscles except LLOAF. Can’t hold paper between fingers or make a tight fist.
What is Fromet’s sign and what does it test for?
Can’t hold paper between fingers. Means Guyon’s Tunnel Syndrome
What is swan neck deformity?
MP joint is in flexion, PIP is extended, and DIP is flexed. Usually caused by rheumatoid arthritis. The MCP and DIP are in flexion while PIP is hyperextended. Inflammation of the long flexor tendon sheath causes the MCP joint to be in a position of flexion. Inflammatory disease of the PIP/inflammation of long flexor tendon can disrupt palmar place reinforcing PIP on flexor side. Leads to increased tension on extensor tendons. Flexed MCP lads to increased tension on central and lateral bands of the extensor mechanism, resulting in the PIP being in a position of hyper extension. This causes tension on flexor digitorum profundus tendon placing the DIP joint into a position of flexion.
What is Trigger finger?
inflammation of the synovial sheath. affected digit is in flexed position. affected digit is in pain. can be passively extended often with sudden popping into place.
What is Tinel Sign?
tap entrapped nerve. positive test = parasthesia produced by the tapping.
Phalen’s test?
Flex hands with arms prone. press dorsum of hands together for 30 seconds. positive test = tingling along palmar surface of thumb and fingers 1 and 2
Fromet’s sign?
ulnar nerve damage. thumb cannot adduct. patient uses flexor pollicis longus to hold paper with fingers, rather than adducting thumb.
What is Cubital Tunnel Syndrome?
proximal ulnar nerve lesion– compression of ulnar as it passes into the forearm. Will have all the symptoms of distal ulnar nerve lesion in addition to movements of flexion and ulnar deviation of the wrist are very weak due to weakness of flexor carpi ulnaris.
Radial Nerve entrapment?
compression of the deep branch of the radial nerve within the sbstance of the supinator muscle will not affect the wrist but will make it difficult to extend the digits because of weakness to the posterior forearm muscles that extend the digits. Cutaneous branch of the radial nerve is not affected.
what happens if nerve entrapment is not corrected?
permanent nerve damage and paralysis
The joints of the digits are what type of joints?
synovial
what type of joint are the MCP joints?
condyloid between head of the metacarpal with phalanx of proximal phalanx.
what movements can take place at the MCP joints?
flexion/extension, ab/aduction
what type of joints are the IP joints?
hinge type joints. flex/extension
what ligament reinforces the MCP and IP joints?
thick palmar carpal ligament (plate) made of fibrocartilage. ulnar and radial collateral ligaments are thickenings of the capsule of each joint that strengthens each joint on the medial and lateral side. Also attach to the palmar carpal plates. the palmar plates of the MCP joints of digits 2-5 are united to form the deep transverse metacarpal ligament, which keeps the heads of the metacarpals from being mobile.
Which ligament keeps the heads of the metacarpals from being mobile?
deep transverse metacarpal ligament
What is the most visible symptom indicating radial nerve damage?
drop-wrist (injury in axilla, arm, or cubital fossa). will also result in loss of sensation from the radial side of dorsum of hand.
how do you feel the radial artery pulse?
compressing radial artery against distal portion of radius.
What is Finkelstein’s Test?
Flexion of the thymb at MCP along with ulnar deviation of the wrist.
where does the greatest amount of flexion at the wrist occur?
radiocarpal joint
where does extension of the wrist occur?
midcarpal joint
the presence of the triangular fibrocartilagenous disc between the ulna and the triquetrium allows for greater range of…?
adduction than abduction
describe the ligaments of the wrist.
1) ulnar collateral ligament = binds styloid process of ulna to proximal row of carpal bones. Very strong ligament.
2) radial collateral ligament attaches radial styloid process to carpal bones. limits adduction of wrist.
3) palmar radiocarpal ligament binds carpal bones on palmar surface of the wrist and helps limit wrist extension.
4) dorsal radiocarpal ligament binds carpal bones on dorsal surface to limit wrist flexion
what is flexor retinaculum?
continuation of deep fascia of forearm that attaches to scaphoid, trapezium, pisiform, and hamate. Also called transverse carpal ligament. The attachment of this ligament to the scaphoid, trapezium, pisiform, and hamate converts this space between the ligament and bones into the carpal tunnel. Median nerve passes through this tunnel as well as flexor tendons to all of the digits. compression here adversely affects median nerve and results in carpal tunnel syndrome.
where is pain noticed with scaphoid fracture?
anatomical snuffbox
Trace the pathway of the lateral cord branches of the brachial plexus?
1) lateral pectoral branch goes to the pectoral major. 2) Musculocutaneous branch goes through the coracobrachialis (potential site of entrapment) to innervate the anterior compartment. Then it goes to innervate the skin of the lateral forearm with the lateral antebrachial cutaneous. 3) The median nerve branches into the anterior interosseous at the pronator teres (potential entrapment). It goes through the anterior compartment as the median nerve and through the carpal tunnel. Then it innervates the palmar muscles of the first two lumbricals, the opponens policis, the abductor pollicis brevis, and the flexor pollicis brevis. Also innervates the anterior skin of
Trace the pathway of the medial cord
1) medial pectoral goes to pec major and minor. 2) Medial brachial cutaneous innervates the skin of the medial side of the arm. 3) Medial antebrachial cutaneous nerve runs with the basilic vein to innervate the skin of the medial forearm. 4) ulnar nerve goes through the cubital tunnel (potential site of entrapment) by the funny bone. It innervates the ulnar half of the flexor digitorum profundus and the flexor carpi ulnaris. Then it goes through the unnel of gunyon (annother site of entrapment) and divides into the superficial and deep branches. The superficial branches innervates the palmar and dorsal sensory to the first 1 1/2 digits. The deep branches innervate the hypothenars, adductor pollicis, lumbercals, and the 3rd and 4th interossei. Then it gives off median nerve contributions.
Trace the pathway of the posterior cord
The posterior cord gives off the 1) upper subscapular nerve, which innervates the subscapularis, and 2) the thoracodorsal nerve, which innervates the latissimus dorsi. It also gives off the 3) lower subscapular nerve, which innervates the subscapularis and the teres major. It also gives off the 4) axillary nerve, which innervates the deltoid and teres minor. The axillary nerve passes through the quadangrular space (site of entrapment) and innervates the skin on the lateral side of the shoulder. 5) Radial nerve runs alongs the posterior aspect of the humerus, going through the medial and lateral heads of the triceps (potential site of entrapment or lesion if humerus is fractured). It emerges from the brachialis and brachioradialis, passes beneath the brachioradialis, passes under the extensor carpi radialis, splitting into deep and superficial branches. The superficial innervates the radial dorsal side of the hands. The deep branch innervates the supinator and extensor carpi radialis brevis. It passes underneath the supinator (potential site of entrapment). It ceomes the posterior interosseous and innervates all the stuff in the extensor compartment.
Where is the axillary artery in relation to the posterior, lateral, and medial cords of the brachial plexus?
The axillary artery lies anterior to the posterior cord, between the lateral and medial cords.
Which part of the brachial plexus lies under the clavicle?
divisions
Where do the roots and the trunks of the brachial plexus pass through?
the posterior triangle of the neck.
What nerves come off of the posterior cord?
upper subscapular, lower subscapular, thoracodorsal, radial nerve, and axillary nerve (ULTRA)
What forms the M of the brachial plexus?
lateral and medial cords join to form the median nerve in the center of the M, musculocutaneous off the anterior lateral cord forms the first stroke, ulnar forms the final stroke off the anterior medial cord.
Which of the following does not give passive stability to the glenohumeral joint? A) deltoid, B) trapezius, C) labrum, D) supraspinatus
D) Supraspinatus– active stability
What is tennis elbow also known as?
lateral epicondylitis
What separates the median cubital vein from underlying neurovascular structures?
bicipital aponeurosis– it is the roof of the cubital fossa.
The loss of opposition of the thumb is a symptom associated with lesion of which nerve?
median
What nerve would be damaged if there were a fracture of the medial epicondyle of the humerus?
ulnar
What nerve would be damaged if there were a fracture to the humeral shaft in the middle?
radial
What nerve would be damaged if there were a fracture at the surgical neck of the humerus?
axillary
What nerve would be damaged if there were an anterior dislocation of the lunate?
median
What are common sites of radial nerve damage?
compression within axilla (Saturday night palsy), fracture of the humeral shaft, cubital fossa trauma, and entrapment within the supinator
What is the Allen Test?
Test for occlusion of the radial or ulnar arteries. Patient makes a tight fist, while you compress both radial and ulnar arteries at wrist. Instruct patient to unclench fist and relieve pressure off arteries. If color returns to hand in less than 10 seconds then the test is negative and the patient has good blood supply to hand.
What are common sites of injury to the ulnar nerve?
cubital tunnel (funny bone), wrist injuries, entrapped within the hand (tunnel of guyon)
Which nerve runs with the brachial artery?
median nerve
The radial nerve passes through what muscle in forearm?
supinator
Ulnar nerve passes through what muscle in forearm?
flexor carpi ulnaris?
Median nerve passes through what muscle in forearm?
pronator teres
Which nerve passes beneath the retinaculum of the wrist?
median
The corocobrachialis arises from the corocoid process along with which head of the biceps brachii?
short head
Which nerve goes through the coracobrachialis?
musculocutaneous
What are the medial and lateral boundaries of the cubital fossa?
medial = pronator teres. lateral = brachioradialis.
What are the two tunnels/canals that the ulnar nerve travels through?
guyon’s canal = enters hand. cubital tunnel = at elbow.
when the radial nerve splits, what are the two branches?
posterior interosseous and superficial branch
which branch of the radial nerve passes through the supinator?
posterior interosseous
Which branch of the radial nerve supplies innervation to the extensor compartment, and which supplies sensory innervation to the dorsum of the hand?
posterior interosseous = innervation to extensor muscles. superficial branch = sensory to back of hand.
What’s the one weird nerve sticking out of the skin on two of the bodies?
Intercostobrachial nerve
where does the vertebral artery run?
up through the transverse foramen of the vertebrae.
where does the subclavian artery run?
underneath the clavicle.
When does the subclavian artery become the axillary artery?
after 1st rib
What runs with the deep brachial artery?
radial nerve
what runs with the posterior humeral circumflex artery?
axillary nerve
What is with the suprascapular artery?
suprascapular nerve
Which artery pokes out by itself of the triangular space?
circumflex scapular
where do the supraorbital an supratrochlear branches of the frontal branch of V1 (opthalmic) of the trigeminal nerve exit?
supraorbital foramen
What does cornea sensation?
nasociliary branch of opthalmic branch of trigeminal
where does maxillary (v2) exit?
infraorbital foramen, then it turns into the infraorbital nerve.
where does mandibular (v3) inferior alveolar branch exit?
inferior alveolar branch goes through the mandibular forament to provide sensation for the lower teeth, then exits mental foramen, turning into the mental nerve, supplying sensation to the skin of the lower jaw/face
What goes through the triangular interval?
deep brachial artery and radial nerve
what are the boundaries of the triangular space?
teres major inferiorly, long head of triceps laterally, and teres minor superiorly
what goes through the triangular space?
scapular circumflex artery
What are the borders of the quadrangular space?
long head of triceps, humerus, teres minor, and teres major
what passes through the quadrangular space?
posterior humeral circumflex artery and axillary nerve
what are the borders of the triangular interval?
teres major superiorly, long head of triceps medial, humerus/lateral head of triceps lateral border.
Where does the suboccipital nerve run? Greater occipitial nerve?
Suboccipital nerve runs through the suboccipital triangle, while the greater occipital nerve runs over the suboccipital triangle.
where would you find the spinal portion of the accessory nerve?
under the sternocleidomastoid
