Exam #1 - Muscle & Supporting Structures Flashcards
Only muscles can adapt to both immediate (acute) & repeated long- term (chronic) external forces that can destabilizes the body
- It is coupled to both the external environment & the internal control mechanisms of the nervous system
Skeletal muscle
Non-contractile elements of muscle
Connective tissue “harness” of muscle
The innermost layer that seperate individual muscle fibers & myofibrils
Endomysium
Encases fiber bundles
Perimysium
Enveloping fascial sheath around the entire muscle
Epimysium
The connective tissue framework is the ____ source of muscle’s resistance to ____ elongation
The connective tissue framework is the primary source of muscle’s resistance to passive elongation
What influences a muscles ultimate function?
Muscle shape
What muscle fibers run parallel to one another & to the central tendon
Fusiform muscle
What muscle fibers approach their central tendon obliquely
Pennate muscles
- Refers to the angle of orientation between the muscle fibers & tendon
- Produce greater maximal force than fusiform muscles of similar volume
Pennation Angle
a muscle produces a pulling force while maintaining a
constant length
Isometric
a muscle produces a pulling force as it shortens (contracts)
Concentric
muscle produces a pulling force as it is being elongated by another more dominant force
Eccentric
muscle or muscle group most directly involved in the initiation & execution of movement
Agonist
a muscle that opposes the action of another
Antagonist
muscles that work together to create a movement
Synergist
2 or more muscles on opposing sides of a joint work together to provide joint stability or create movement
Force-Couple
The distance a muscle can shorten after it has been elongated to its maximum
Functional Excursion
In some cases, the functional excursion, or range of a muscle, is ____ influenced by the joint or joints it ____
In some cases, the functional excursion, or range of a muscle, is **directly **influenced by the joint or joints it crosses
- A point in the range of motion where a muscle is shortened at each joint it crosses where it can no longer shorten
- This leads to decreased force production
Active Insufficiency
- A point in the range of motion where a muscle is lengthened at each joint it crosses where it can no longer lengthen
- Leads to decreased joint range of motion & decreased force production
Passive Insufficiency
Sternoclavicular Joint Stabalizer Tissues (5)
- Ant. SCJ ligament
- Post. SCJ ligament
- Interclavicular ligament
- Costoclavicular ligament
- Articular disc
Sternoclavicular joint stabalizer muscles (4)
- Sternocleidomastoid
- Sternothyroid
- Sternohyoid
- Subclavius muscles
Acromioclavicular joint stabalizer tissues (4)
- Superior ACJ capsular ligament
- Inferior ACJ capsular ligament
- Coracoclavicular ligament
- Articular disc (if present)
Acromioclavicular joint stabalizer muscles (2)
- Deltoid
- Upper trapezius
Glenohumeral joint stabalizer tissues (4)
- Joint capsule
- Glenohumeral ligament
- Coracohumeral ligament
- Glenoid labrum (increases depth also)
Glenohumeral joint stabalizer muscles (5)
- Rotator cuff muscles (subscapularis, supraspinatus, infraspinatus, & teres minor)
- Long head of the biceps brachii
What primary motion draws the superior glenohumeral ligament taut
adduction
What primary motion draws the middle glenohumeral ligament taut
abduction & external rotation
What primary motion draws the inferior glenohumeral ligament (axillary pouch) taut
90° ABD + anterior-posterior translation
What primary motion draws the inferior glenohumeral ligament (anterior band) taut
90° ABD + full ER
What primary motion draws the inferior glenohumeral ligament (posterior band) taut
90° ABD + full IR
What primary motion draws the coracohumeral ligament taut
ADD + ER
The fibrocartilage at articular surface of glenoid labrum is for ____ loading
The fibrocartilage at articular surface of glenoid labrum is for compressive loading
The outer rim of glenoid labrum is for ____ loading
The outer rim of glenoid labrum is for tensile loading
Coracoacromial arch is formed by
- Coracoacromial ligament
- Acromion process
Contents of the Subacromial Space
- Supraspinatus muscle & tendon
- Subacromial bursa
- Long head of the biceps
- Part of the superior capsule
What are the 4 causes of decreased subacromial space
- Hypertrophy
- Protraction
- Diabolo effect
- Architectural change
Origin & Insertion of proximal stabalizers of the shoulder
Origin: spine, ribs & cranium
Insertion: scapula & clavicle
Origin & Insertion for distal mobilizers of the shoulder
Origin: scapula & clavicle
Insertion: humerus or ulna
Elevator mm acting on scapulothoracic junction (3)
- Upper trapezius
- Levator scapulae
- Rhomboids
Upward rotator mm acting on scapulothoracic junction (2)
- Serratus anterior
- Upper & lower trapezius
Downward rotator mm acting on scapulothoracic junction (2)
- Rhomboids
- Pectoralis minor
Depressor mm acting on scapulothoracic junction (4)
- Lower trapezius
- Latissimus dorsi
- Pectoralis minor
- Subclavius
Retractor mm acting on scapulothoracic junction (3)
- Middle trapezius
- Rhomboids
- Lower trapezius
Protractor mm acting on scapulothoracic junction (1)
Serratus anterior
2 joints & 7mm that elevate arm
Glenohumeral joint: anterior/middle deltoid, supraspinatus, coracobrachialis, biceps (long head)
Scapulothoracic joint: serratus anterior, trapezius
5 primary mm that extend & adduct arm
- Posterior deltoid
- Latissimus dorsi
- Teres minor
- Triceps brachii (long head)
- Pectoralis major (sternocostal head)
Primary mm that internally & externally rotate arm
Internal rotators: subscapularis, ant deltoid, pectoralis major, latissiumus dorsi, teres major
External rotators: infraspinatus, teres minor, post deltoid
Function of infraspinatus, teres minor & subscapularis during elevation
exert a depression force on the humeral head
Function of infraspinatus & teres minor during elevation
externall rotate the humerus
Rotator cuff muscles (4)
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Function of supraspinatus during elevation
- Compresses humeral head against glenoid
- Restricts excessive superior humeral translation
Strengthens the articular capsule providing stability of the elbow joint
Collateral ligaments
Motions that increase tension of medial collateral ligament (anterior fibers)
- valgus
- extension & flexion
Primary valgus stabalizer of elbow
Medial collateral ligament (anterior fibers)
Primary varus stabalizer of elbow
Lateral (ulnar) collateral ligament
External rotation of elbow A.K.A
supination
Motions that increase tension of medial collateral ligament (posterior fibers)
- valgus
- flexion
Motions that increase tension of radial collateral ligament
- varus
- external rotation (supination)
Motions that increase tension of lateral (ulnar) collateral ligament
- Varus
- External rotation & flexion
Motions that increase tension of annular ligament
- distraction of radius
- external rotation (supination)
The tight fit between the trochlea & the trochlear notch provides most of the ____ of the elbow
The tight fit between the trochlea & the trochlear notch provides most of the stability of the elbow
- Binds the radius to the ulna
- Attachment for extrinsic hand mm
- Transmits forces proximally
Function of interosseous membrane
When weight is transmitted across interosseous membrane via central band to the ulna it promotes…
a sharing of the load to the elbow
Load at the radiocarpal joint during compression ____% of load crosses on the radial side & ____% crosses on the ulnar side
Load at the radiocarpal joint during compression 80% of load crosses on the radial side & 20% crosses on the ulnar side
The radius is held to the ulna via a ____ ring
The radius is helf to the unla via a fibro-osseous ring
Stability of the DRUJ is achieved via muscle ____ & local ____ ____
Stability of the DRUJ is achieved via muscle activation & local connective tissues
DRUJ tissue stabalizers (2)
- Triangular fibrocartliage complex (TFCC)
- Distal fibers of interosseous membrane
Capsular ligaments of the DRUJ (2)
- Capsular ligaments of DRUJ
- Ulnar collateral ligament
DRUJ muscle stabalizers (2)
- pronator quadratus
- tendon of externsor carpi ulnaris
2 mm & 1 structure that limits supination
- pronator teres
- pronator quadratus
- TFCC
2 mm & 1 structure that limits pronation
- Biceps
- Supinator mm
- TFCC
Flexor mm of Elbow (4)
- Biceps brachii
- Brachialis
- Brachioradialis
- Pronator teres
Extensor mm of Elbow (2)
- Triceps brachii
- Anconeous
Primary & secondary pronator mm of elbow (5)
Primary pronators: pronator teres, pronator quadratus
Secondary pronators: flexor carpi radialis, palmaris longus, brachioradialis
Triangular Fibrocartilage Complex
- The ____ stabalizer of DRUJ
- ____ ulnar side of wrist
- Forms part of the ____ of radiocarpal joint
- Helps ____ part of compression forces that naturally cross wirst/hand into forearm (~20%)
- The primary stabalizer of DRUJ
- Reinforces ulnar side of wrist
- Forms part of the concavity of radiocarpal joint
- Helps transfer part of compression forces that naturally cross wirst/hand into forearm (~20%)
Extrinsic ligaments of wrist (4)
- Dorsal radiocarpal
- Radial collateral
- Palmar radiocarpal
- TFCC
Connects carpal bones & forearm (stiff, not as elastic)
Extrinsic ligaments
Capable of greater elongation before permanent deformation (interconnect carpal bones)
Intrinsic ligaments
Intrinsic ligaments of wrist (3)
- Short (distal row)
- Intermediate lig
- Long (“inverted V”)
Long (“inverted V”) ligaments (2)
- Palmar intercarpal
- Dorsal intercarpal
Carpometacarpal Joint ligaments help to
- ____ the extent & direction of joint motion
- ____ joint alignment
- ____ ____ produced by activated muscle
- Control the extent & direction of joint motion
- Maintain joint alignment
- Dissipate forces produced by activated muscle
What position is the anterior oblique ligament the most taut
Full extension (hitch hiker position)
What position is the ulnar collateral ligament the most taut
ABD + Ext
What position is the first intermetacarpal ligament the most taut
Flexion
What position is the posterior oblique ligament the most taut
Flexion
What position is the radial collateral ligament the most taut
All movements to varying degrees except extension
Primary wrist extensor mm act on the wrist ONLY (3)
- ECR longus
- ECR brevis
- ECU
Secondary wrist extensor mm act of wrist & hand (4)
- Extensor digitorum
- Extensor indicis
- Extensor digiti minimi
- Extensor pollicis longus
Primary wrist flexor mm act on wrist only (3)
- FCR
- FCU
- Palmaris longus
Secondary wrist flexor mm act on wrist & hand (5)
- Flexor digitorum profundus
- Flexor digitorum superficialis
- Flexor pollicis longus
- Abductor pollicis longus
- Extensor pollicis brevis
Main function of wrist extensors is to ____ & ____ wrist during active flexion of fingers (making a fist)
Main function of wrist extensors is to position & stabalize wrist during active flexion of fingers
When making a fist this position optimizes ____-____ relationship of ____ finger flexors = maximal grip strength
When making a fist this position optimizes length-tension relationship of extrinsic finger flexors = maximal grip strength
7 mm responsible for Radial Deviation
- ECR longus
- ECR brevis
- Extensor pollicis longus
- Extensor pollicis brevis
- FCR
- Abductor pollicis longus
- Flexor pollicis
5 mm responsible for Ulnar Deviation
- ECU
- FCU
- Flexor digitorum profundus
- Flexor digitorum superficialis
- Extensor digitorum