Functional Anatomy of Upper Limb 10

Question 1

What is the general rule about range of motion of joints as they get more distal?

Answer 1

Movement becomes more restricted the further distal along the upper limb.

Question 2

Give the general movements exhibited at the joints of the upper limb.

Answer 2

Glenohumeral: elevation/depression, protraction/retraction, rotation
Radioulnar: flexion/extension, rotation
Radiocarpal: flexion/extension, radial/ulnar deviation (aBduction/aDduction)
Phalangeal: flexion/extension

Question 3

What 3 anatomical structures can be used to guide movement at any joint? Give an example of each type from the upper limb.

Answer 3

Bones, ligaments and muscles guide/control movements at articulations.
Bone-guided: ulnohumeral joint
ligament-guided: radiocarpal joint
muscle-guided: glenohumeral joint.

Question 4

How does insertion differ from origin with respect to muscle attachment?

Answer 4

The insertion of a muscle is the most moveable attachment; the origin its least moveable

Question 5

List three ways that muscles may be “attached”.

Answer 5

Fleshy, aponeurotic and tendinous muscle attachments.

Question 6

What is an aponeurosis? Give an example.

Answer 6

Thin, flat sheetlike tendon. Ex. Bicipital aponeurosis

Question 7

What fascial structure prevents bowstringing of tendinous muscle attachments as they cross the joint?

Answer 7

Retinaculum.

Question 8

How do muscles that are stabilizers differ from muscles that are mobilizers?

Answer 8

Muscles that stabilize are attached at a DISTANCE from the joint crossed (controlled).
Muscles that mobilize are attached CLOSE to the joint crossed (controlled).

Question 9

Be able to give an example of a muscle that can reverse its origin and insertion to provide differing functions.

Answer 9

By “chinning” the brachialis, once a mobilizer, becomes a stabilizer.
The brachioradialis, once a stabilizer, becomes a mobilizer. The attachments reverse when you make your hands the least freely moveable part of the upper limb instead of the most moveable.

Question 10

What constitutes a muscle sling?

Answer 10

All the mm. that cross at a given joint.

Question 11

Describe the term “tendon action of muscle”. What does it refer to?

Answer 11

Using the position of a joint to stretch/relax the tendon of a muscle crossing it - best illustrated in paralyzed muscles that have become fibrous. (Ulnar claw)

Question 12

List 3 types of ligaments associated with the scapulothoracic joint complex and give examples of each one.

Answer 12

Extracapsular: coracoclavicular, costoclavicular
Intracapsular: disc, meniscus
Capsular: coracoacromial, acromioclavicular sternoclavicular

Question 13

List the muscles involved in the scapulothoracic sling and their general actions.

Answer 13

Trapezius: retraction and superior rotation
Pectoralis minor: depression
Serratus anterior: protraction/aBduction and inferior/superior rotation
Levator scapula: elevation; rhomboids: retract (aDduct) and inferiorly rotate.

Question 14

List the mm. of the glenohumeral sling and their general actions.

Answer 14

Deltoid: aBduction
Subscapularis: internal; rotation
Supraspinatus, infraspinatus and teres minor: external rotation
Teres major: aDduction & internal rotation
Coracobrachialis: aDduction and flexion
Pectoralis major: internal rotator
Latissimus dorsi: internal rotator, aDductor & extension.

Question 15

List the mm of the ulno-humeral joint. Mobilize it?

Answer 15

Stabilizers are: brachioradialis

Mobilizers are: brachialis and long head of triceps

Question 16

List the mm. involved in the muscle sling for the wrist concerned with flexion.

Answer 16

Flexion of wrist: flexor carpi ulnaris, flexor carpi radialis (and palmaris longus).

Question 17

List the mm. involved in the muscle sling for the wrist concerned with extension.

Answer 17

Extension of the wrist: extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris.

Question 18

What is another term for ulnar deviation? Radial deviation?

Answer 18

Medial and lateral rotation.

Question 19

What is a general rule concerning the origin/insertion of forearm mm?

Answer 19

Deep muscles of the forearm insert more distally than superficial forearm muscles.

Question 20

Which retinaculum of the wrist must be severed to alleviate the clinical symptoms of carpal tunnel syndrome?

Answer 20

Flexor retinaculum.

Question 21

In general, what is the function of the retinaculae?

Answer 21

Prevent bowstringing of tendons during muscle contraction.

Question 22

List the phalangeal joints from proximal to distal.

Answer 22

MP - metacarpo-phalangeal
PIP - proximal interphalangeal
DIP - distal interphalangeal.

Question 23

What is the most stable position for these phalangeal joints?

Answer 23

Flexed as the ligaments acting on these joints are stretched taut in this position, strengthening the joints.

Question 24

Which muscle(s) of the digital sling flex the DIP joints of digits 2 thru 5?

Answer 24

The flexor digitorum profundus flexes DIP joints of digits 2-5.

Question 25

Which muscle(s) of the digital sling flex the DIP joints of the thumb?

Answer 25

Flexor pollicis longus

Question 26

Which muscle(s) of the digital sling flex the PIP joints of digits 2-5?

Answer 26

Flexor digitorum superficialis

Question 27

Which muscle(s) of the digital sling flex the MP joints of the thumb?

Answer 27

The flexor pollicis brevis

Question 28

Which muscle(s) of the digital sling flex the MP joints of digits 2-5?

Answer 28

The lumbricals and interossei

Question 29

Which muscle(s) of the digital sling extend the MP joints for digits 2-5?

Answer 29

Extensor digitorum

Question 30

Name the "additional" extensor mm. for this the MP joint on digit 5.

Answer 30

The extensor digiti minimi

Question 31

List the muscle(s) that extend the DIP joint of the thumb.

Answer 31

Extensor pollicis longus

Question 32

List the muscle(s) that extend the thumb MP.

Answer 32

Extensor pollicis brevis

Question 33

Identify an additional extensor for the MP joint of digit 2.

Answer 33

Extensor indicis.

Question 34

List the muscle(s) that extend the PIP and DIP of digits 2-5.

Answer 34

Lumbricals and interossei

Question 35

Which interossei aBduct which digits?

Answer 35

Dorsal interossei 2-4 aBduct (“DAB”)

Question 36

Which interossei aDduct which digits?

Answer 36

Palmar interossei 2-5 ("PAD")

Question 37

Describe Erb's Palsy.

Answer 37

Upper lesion of plexus (C5-6) - aBductors & lateral rotators affected (suprascap., subcla., musculoc., ax. nerves - so limb hangs by side slightly medially rotated, inability to flex elbow, forearm is pronated and the wrist is flexed - "waiter's tip"

Question 38

Describe Klumpke's Palsy.

Answer 38

Lower lesion of plexus (C8-T1) - all instrinsic mm. of hand (ulnar and median nn) - hyperextension of MP joints and flexion of IP joints

Question 39

Describe a flail extremity.

Answer 39

Avulsion of all roots of the brachial plexus | -limb hangs at side, partial hemiparalysed diaphragm and partial Horner’s syndrome

Question 40

Why is Horner's syndrome a complication of lesions of the lower brachial plexus?

Answer 40

Due to the involvement of T1 from the brachial plexus. | - T1-T4 supply sympathetic innervation to the head and neck so there is some loss of this - Horner’s syndrome.

Question 41

Describe what would occur from a lesion of the long thoracic nerve.

Answer 41

winged scapula, can't raise arm over head (serratus anterior)

Question 42

Describe what would occur from a lesion of the axillary nerve.

Answer 42

loss of aBduction of limb (deltoid)

Question 43

Describe what would occur from a lesion of the musculocutaneous nerve.

Answer 43

loss of forearm flexion (arm flexors)

Question 44

Describe what would occur from a lesion of the radial nerve in the AXILLA.

Answer 44

loss of ability to extend elbow joint, wrist joint and fingers--"wrist drop" (extensors of arm/forearm).

Question 45

Describe what would occur from a lesion of the radial nerve in the ARM.

Answer 45

- loss of forearm extensors + inability to extend MP joints = wrist drop - loss of ability to extend, abduct the thumb

Question 46

Describe what would occur from a lesion of the ulnar nerve above the elbow.

Answer 46

Loss of ALL intrinsic muscles of the hand (except thenar mm and lumbricals 1-2)--"ulnar claw", you can't extend digits 4-5.

Question 47

Describe what would occur from a lesion of the median nerve at elbow

Answer 47

Loss of ability to pronate arm, so arm stays supinated, and you have weak wrist flexion + adduction. Also, you have difficulty flexing digits 1-3--"hand of benediction"

Question 48

Describe what would occur from a lesion of the median nerve at wrist

Answer 48

Thenar paralysis and impairment of digits 2-3. You have inability to oppose thumb--"ape hand".

Question 49

How can you use the thumb as a test for a test of integrity of the radial, median, and ulnar nerves?

Answer 49

radial nerve loss = inability to extend thumb median nerve loss = inability to flex DIP joint ulnar nerve loss = no aDduction of MP joint (with PIP and DIP joints extended)

Question 50

In general, what can be said about spinal nn. controlling upward and downward movement of joints of the upper limb moving proximal to distal?

Answer 50

- The most "cranial" nn. controlling a joint are responsible for its upward movement - The most "caudal" nn. for its downward movement. - The # of spinal nn. needed for movement at a joint decrease as you go distally along the limb.

Question 51

When the upper limb is fixed, what muscles can be accessory mm in respiration?

Answer 51

Any mm that are attached to the ribs: serratus anterior, pec major/minor, subclavius

Question 52

What is the most powerful internal rotator of the upper limb?

Answer 52

Pec major

Question 53

Phalangeal ligaments are ____________ in extension and __________ in flexion. Which one is more stable for the MP? Why?

Answer 53

Lax Stretched Flexion is more stable because the volar plate puts collateral ligaments in the flexed position