Functional Anatomy of Upper Limb 10 Flashcards
What is the general rule about range of motion of joints as they get more distal?
Movement becomes more restricted the further distal along the upper limb.
Give the general movements exhibited at the joints of the upper limb.
Glenohumeral: elevation/depression, protraction/retraction, rotation
Radioulnar: flexion/extension, rotation
Radiocarpal: flexion/extension, radial/ulnar deviation (aBduction/aDduction)
Phalangeal: flexion/extension
What 3 anatomical structures can be used to guide movement at any joint? Give an example of each type from the upper limb.
Bones, ligaments and muscles guide/control movements at articulations.
Bone-guided: ulnohumeral joint
ligament-guided: radiocarpal joint
muscle-guided: glenohumeral joint.
How does insertion differ from origin with respect to muscle attachment?
The insertion of a muscle is the most moveable attachment; the origin its least moveable
List three ways that muscles may be “attached”.
Fleshy, aponeurotic and tendinous muscle attachments.
What is an aponeurosis? Give an example.
Thin, flat sheetlike tendon. Ex. Bicipital aponeurosis
What fascial structure prevents bowstringing of tendinous muscle attachments as they cross the joint?
Retinaculum.
How do muscles that are stabilizers differ from muscles that are mobilizers?
Muscles that stabilize are attached at a DISTANCE from the joint crossed (controlled).
Muscles that mobilize are attached CLOSE to the joint crossed (controlled).
Be able to give an example of a muscle that can reverse its origin and insertion to provide differing functions.
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.
What constitutes a muscle sling?
All the mm. that cross at a given joint.
Describe the term “tendon action of muscle”. What does it refer to?
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)
List 3 types of ligaments associated with the scapulothoracic joint complex and give examples of each one.
Extracapsular: coracoclavicular, costoclavicular
Intracapsular: disc, meniscus
Capsular: coracoacromial, acromioclavicular sternoclavicular
List the muscles involved in the scapulothoracic sling and their general actions.
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.
List the mm. of the glenohumeral sling and their general actions.
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.
List the mm of the ulno-humeral joint. Mobilize it?
Stabilizers are: brachioradialis
Mobilizers are: brachialis and long head of triceps
List the mm. involved in the muscle sling for the wrist concerned with flexion.
Flexion of wrist: flexor carpi ulnaris, flexor carpi radialis (and palmaris longus).
List the mm. involved in the muscle sling for the wrist concerned with extension.
Extension of the wrist: extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris.
What is another term for ulnar deviation? Radial deviation?
Medial and lateral rotation.
What is a general rule concerning the origin/insertion of forearm mm?
Deep muscles of the forearm insert more distally than superficial forearm muscles.
Which retinaculum of the wrist must be severed to alleviate the clinical symptoms of carpal tunnel syndrome?
Flexor retinaculum.
In general, what is the function of the retinaculae?
Prevent bowstringing of tendons during muscle contraction.
List the phalangeal joints from proximal to distal.
MP - metacarpo-phalangeal
PIP - proximal interphalangeal
DIP - distal interphalangeal.
What is the most stable position for these phalangeal joints?
Flexed as the ligaments acting on these joints are stretched taut in this position, strengthening the joints.
Which muscle(s) of the digital sling flex the DIP joints of digits 2 thru 5?
The flexor digitorum profundus flexes DIP joints of digits 2-5.
Which muscle(s) of the digital sling flex the DIP joints of the thumb?
Flexor pollicis longus
Which muscle(s) of the digital sling flex the PIP joints of digits 2-5?
Flexor digitorum superficialis
Which muscle(s) of the digital sling flex the MP joints of the thumb?
The flexor pollicis brevis
Which muscle(s) of the digital sling flex the MP joints of digits 2-5?
The lumbricals and interossei
Which muscle(s) of the digital sling extend the MP joints for digits 2-5?
Extensor digitorum
Name the “additional” extensor mm. for this the MP joint on digit 5.
The extensor digiti minimi
List the muscle(s) that extend the DIP joint of the thumb.
Extensor pollicis longus
List the muscle(s) that extend the thumb MP.
Extensor pollicis brevis
Identify an additional extensor for the MP joint of digit 2.
Extensor indicis.
List the muscle(s) that extend the PIP and DIP of digits 2-5.
Lumbricals and interossei
Which interossei aBduct which digits?
Dorsal interossei 2-4 aBduct (“DAB”)
Which interossei aDduct which digits?
Palmar interossei 2-5 (“PAD”)
Describe Erb’s Palsy.
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”
Describe Klumpke’s Palsy.
Lower lesion of plexus (C8-T1)
- all instrinsic mm. of hand (ulnar and median nn)
- hyperextension of MP joints and flexion of IP joints
Describe a flail extremity.
Avulsion of all roots of the brachial plexus
-limb hangs at side, partial hemiparalysed diaphragm and partial Horner’s syndrome
Why is Horner’s syndrome a complication of lesions of the lower brachial plexus?
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.
Describe what would occur from a lesion of the long thoracic nerve.
winged scapula, can’t raise arm over head (serratus anterior)
Describe what would occur from a lesion of the axillary nerve.
loss of aBduction of limb (deltoid)
Describe what would occur from a lesion of the musculocutaneous nerve.
loss of forearm flexion (arm flexors)
Describe what would occur from a lesion of the radial nerve in the AXILLA.
loss of ability to extend elbow joint, wrist joint and fingers–“wrist drop” (extensors of arm/forearm).
Describe what would occur from a lesion of the radial nerve in the ARM.
- loss of forearm extensors + inability to extend MP joints = wrist drop
- loss of ability to extend, abduct the thumb
Describe what would occur from a lesion of the ulnar nerve above the elbow.
Loss of ALL intrinsic muscles of the hand (except thenar mm and lumbricals 1-2)–“ulnar claw”, you can’t extend digits 4-5.
Describe what would occur from a lesion of the median nerve at elbow
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”
Describe what would occur from a lesion of the median nerve at wrist
Thenar paralysis and impairment of digits 2-3. You have inability to oppose thumb–“ape hand”.
How can you use the thumb as a test for a test of integrity of the radial, median, and ulnar nerves?
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)
In general, what can be said about spinal nn. controlling upward and downward movement of joints of the upper limb moving proximal to distal?
- 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.
When the upper limb is fixed, what muscles can be accessory mm in respiration?
Any mm that are attached to the ribs: serratus anterior, pec major/minor, subclavius
What is the most powerful internal rotator of the upper limb?
Pec major
Phalangeal ligaments are ____________ in extension and __________ in flexion. Which one is more stable for the MP? Why?
Lax
Stretched
Flexion is more stable because the volar plate puts collateral ligaments in the flexed position
