MSK 2E03 - Midterm 2

Name the 4 superficial muscles of the anterior forearm

- Pronator teres
- Flexor Carpi Radialis
- Palmoris Longus
- Flexor Carpi Ulnaris

pronator teres insertion and actions.

- inserts on radius 1/3 down the shaft
- pronation of the wrist

flexor carpi insertion and actions

- inserts on 2nd and 3rd base of metacarpals on radial side of wrist
- flexion of the wrist and radial deviation of the wrist

palmoris longus insertion and actions

- blends into palmor aponeurosis
- very weak flexion of the wrist

flexor carpi ulnaris insertion and actions

- inserts on pisiform and has ligaments that extend into hook of hamate and base of MC5
- flexion of the wrist and ulnar deviation of the wrist

Name the 2 deep muscles of the anterior forearm

- flexor digitorum superficialis
- flexor digitorum profundus

flexor digitorum superficialis: origin and actions

- originates at medial epicondyle of humerus, little bit of ulna and middle of shaft of radius
- breaks into 4 tendons and lands on base of middle phalanx
-flexion of wrist, flexion of MCP joints, flexion of PIP joint

flexor digitorum profundus: origin and actions

- originates from ulna
- breaks into 4 tendons
- under FDS tendons and go longer to land at base of distal phalanx
- flexion of wrist. flexion of MCP joints, flexion of PIP joint, flexion of DIP joint

Motions in the hand/wrist

- flexion/extension,
- radial and ulnar deviation of the wrist/pronation and supination through radial-ulnar joint (proximal/distal),
- abduction/adduction of fingers
- opposition/re-position of the hand

Name the 3 muscles of the lateral forearm

- brachioradialis
- extensor carpi radialis longus
- extensor carpi radialis brevis

Brachioradialis: origin, insertion and actions

- originates on lateral supracondylor ridge
- inserts on distal end of radius
- crosses anterior aspect of elbow joint
- flexion of elbow joint

extensor carpi radialis longus: orgin, insertion and actions

- originates on lateral supracondylor ridge
- inserts on MC2
- extension of wrist, radial deviation of wrist

extensor carpi radialis brevis: origin, insertion and actions

- originates on lateral epicondyle
- inserts on MC3
- extension of wrist, radial deviation of wrist

Name the 4 muscles of the posterior forearm

- extensor carpi ulnaris (ECU)
- extensor digitorum (ED)
- extensor digiti minimi (EDM)
- supinator

extensor carpi ulnaris: origin, insertion and actions

- originates at epicondyle of humerus
- inserts on base of MC5 on ulnar side
- extension of wrist, ulnar deviation of wrist

extensor digitorum: origin, insertion and actions

- originates at lateral epicondyle of humerus
- inserts on distal and middle phalanges of MC 2, 3, 4 and 5
- extension of PIP/DIP joints, extension of wrist

extensor digiti minimi: origin, insertion and actions

- originates at lateral epicondyle of humerus
- inserts on distal and middle phalanges of MC5
- extension of PIP/DIP joints, extension of wrist

supinator: origin, insertion and actions

- originates from lateral epicondyle and supinator crest on ulna
- inserts wrapping around radius
- supination of radio-ulnar joint

Muscles in the hand

- muscles on the thumb side (thenar)
- muscles on pinky side (hypothenar)
- the interossei (between bones)

Thenar muscle actions

opposition and reposition

Hypothenar muscle actions

opposition and reposition

The interossei: origin, insertion and actions

- originates from metacarpals
- inserts on proximal phalanges
- abduction and adduction of fingers

Prehensile Gripping

manipulating very small objects with high level of dexterity

Power Gripping

high force but low precision activities (requires use of other joints)

The Shoulder Girdle

- the clavicle and scapula move to position the arm in space

Scapula landmarks

- 2 angles
- 2 borders
- glenoid fossa
- SOS and 2 fossae
- 2 processes

2 scapula angles

- superior
- inferior

2 Scapula borders

- medial
- lateral

SOS/2 fossae

- Spine of scapula
- supraspinatous fossa
- infraspinatous fossa

2 Scapula Processes

- acromion process
- coracoidon process (anterior side)

Shoulder Actions

- elevation/depression
- protraction/retraction

Joints of the Shoulder Girdle

- sternoclavicular joint
- acromioclavicular joint

Sternoclavicular Joint: location, jobs, etc.

- between clavicles
- pivot point
- articular disc --> inside of joint
- reinforced by SC ligaments (anterior/posterior)
- prevents clavicle from 'popping up'
- anterior - retraction
- posterior - protraction
- costoclavicular ligament - attached to kostal cartalidge of rib
- depression/elevation

acromioclavicular joint: location, jobs, etc.

- where acromion process attaches to clavicle
- joint surface is small/shallow
- not much movement - mostly holds scapula/clavicle
- articular disc
- ligaments:
- coraco-clavicular ligaments - pair (conoid and trapezoid)
- suspensory
- prevent translation of lateral end of clavicle
- hold up scapula relative to clavicle
- coraco-acromial ligament - doesn't directly support joint

Muscles of the Shoulder Girdle

- trapezius (superficial)
- levator scapula
- rhomboid minor/major
- serratus anterior
- pectoralis minor

Trapezius: origin, ligament(s), etc.

- originates on occipital bone (external occipital protuberance
- superior nuchal line - attached to EOP
- nuchal ligament
- starts at EOP and tuns down spine touching each process in cervical spine (stops at C7)
- touches from T1-T12

Upper Fibers of Trapezius (UFT): origin, insertion, actions

- descending from skull down to SG
- inserts on lateral, superior clavicle
- stops around AC joint
- elevation

Middle Fibers of Trapezius (MFT): origin, insertion, actions

- T1-T3, horizontal to SG
- inserts on superior aspect of acromion process
- spine of scapula
- retraction

Lower Fibers of Trapezius (LFT): origin, insertion, actions

- T3-T12, ascending to SG
- insertion on SOS/medial border of scapula
- superior rotation of scapula, depression, posterior tilt of scapula

Levator Scapula: origin, insertion and actions

- originates from TPs of C1-C4
- descends to superior angle/medial border of scapula
- elevates superior angle/inferior scapular rotation

Serratus Anterior: origin, insertion and actions

- originates on lateral aspect of ribs 1-8
- one muscle belly that fills length of medial border of scapula
- sandwiched between scapula/rib cage
- protraction of sg (upper fibers), superior scapular rotation (lower fibers), control winging

Rhomboid Minor/Major: origin, insertion and actions

Minor
- originates from C7-T1
Major
- originates from T2-T5
Both
- land on medial border of scapula
- retraction of sg, inferior scapular rotation, control winging

Pectoralis Minor: origin, insertion and actions

- originates on ribs (anterior) 3, 4 and 5
- comes to medial side of coracoid process
- protraction/depression of sg
- anterior tilt of scapula (sometimes abnormally)

Glenohumeral Joint: Location, actions, etc.

- lateral and inferior to coracoid process
- head of humerus meets up with glenoid fossa on lateral side of scapula
- little bony congruency/bony stability
- lots of movement
- flexion/extension in sagital plane, abduction/adduction, flexion/extension in horizontal plane (cross-flexion/extension), external/internal rotation
- glenoid fossa is not a circle
- supraglenoid tubercle/infraglenoid tubercle - attachments for muscles

Humerus: Bony Landmarks

- 2 necks (anatomical/surgical)
- lesser/greater tuberosity
- between tubercles - bicipital groove
- deltoid tuberosity

Glenohumeral Joint: Joint structures (ligaments, etc.)

- Coraco-acromial ligament
- glenoid fossa
- glenohumeral ligaments

Coraco-acromial ligament

- doesn't limit joint motion
- completes coraco-acromial arch
- creates space for muscles (supraspinatous)

Glenoid Fossa

- glenoid labrum surrounds glenoid fossa

Glenohumeral Ligaments

- superior (1:00) (SGHL)
- middle (2:00) (MGHL)
- inferior glenohumeral complex (3:00-8:00)
- IGHL - 2 bands with in between space that is more relaxed

Superior glenohumeral ligament (SGHL): insertion and actions

- lesser tuberosity
- limit GH lateral rotation when down at side

Middle Glenohumeral Ligament (MGHL): insertion and actions

- anatomic neck
- limit GH lateral rotation when more abducted

Inferior Glenohumeral Complex (IGHC): insertion and actions

- anatomic neck
- limit lateral GH rotation when most abducted

Glenohumeral/Rotator Cuff Muscles

Rotator Cuff
- subscapularis
- supraspinatous
- infraspinatous
- teres minor
Glenohumeral
- deltoids

Subscapularis: origin, insertion, actions

- originates from subscapular fossa
comes up across front of GH capsule to lesser tuberosity
- largest/most anterior
- rotation of GH joint (internal)

Supraspinatous: origin, insertion, actions

- originates from supraspinous fossa
- across to greater tuberosity (superior)
- abduction of GH

Infraspinatous: origin, insertion, actions

- originates from infraspinous fossa
- to posterior greater tuberosity
- external rotation

Teres Minor: origin, insertion, actions

- originates from lateral border of scapula
- into posterior, inferior greater tuberosity
- external rotation

Big Picture of Rotator Cuff

- ligaments compress head of humerus into glenoid fossa to enhance stability
- muscles hold head of humerus

Deltoids

- clavicular
- acromial
- spinal

Clavicular Deltoid: origin, insertion and actions

- originates from lateral 3rd of clavicle
- stops at AC joint
- GH abduction/flexion of GH/internal rotation

Acromial Deltoid: origin, insertion and actions

- originates from lateral edge of acromion process
- GH abduction

Spinal Deltoid: origin, insertion and actions

- originates from spine of scapula
- GH abduction, extension of GH

Axilla: Partnerships

- anterior
- posterior

Anterior Wall Muscles

- Pectoralis Major
- Coracobrachialis

Pectoralis Major: origin, insertion and actions

- originates from clavicle, sternum and ribs 1-6
- land at lateral lip of bicipital groove
- flexion of GH, internal GH rotation

Coracobrachialis: origin, insertion and actions

- originates from coracoid process
- attaches halfway down humerus shaft
- flexion of GH

Posterior Wall Muscles

- lattisimus dorsi
- teres major

Lattisimus Dorsi: origin, insertion and actions

- originates from T7-L5, iliac crest and lower ribs
- insetion in bicipital groove
- extension of GH

Teres Major: origin, insertion and actions

- originates from distal, lateral border of scapula
- inserts on medial lip of bicipital groove
- extension of GH

Elbow/Arm Bony Landmarks

Anterior
Radius (lateral)
- radial tuberosity
- rests against concave notch on ulna
Ulna (medial)
- coranoid process
- ulnar tuberosity
Posterior
Ulna
- olecranon process - top of ulna
- hooks into olecranon fossa (humerus)
Humerus
- medial epicondyle
- capitulum
- trochlea

Elbow/Arm Joints

- Superior Radial Ulnar Joint
- Humero-radial joint
- Humero-unlar joint

Superior radial ulnar joint: ligament(s), actions

- radius needs to be held against ulna
- annular ligament
- attaches to anterior/posterior margines of radial notch of ulna and loops around radial head but DOES NOT ATTACH

Humero-radial joint: ligament(s), actions

- head of radius meets capitulum of humerus
- lateral side of elbow: radial collateral ligament
- 2 bands start at lateral epicondyle of humerus and both blend into annular ligament
- posterior band blends into supinator crest (ulna)

Humero-Ulnar Joint: ligament(s), actions

- ulna scoops around trochlea
- ulnar collateral ligament (UCL)
- 3 bands all start at medial epicondyle of humerus
- anterior bands lands at coranoid process
- posterior band blends into olecranon process
- transverse band does not cross joint, connect from coranoid process to olecranon
- limits vagus

Elbow Muscles

- biceps brachii
- brachialis
- tripceps brachii

Biceps Brachii: origin, insertion and actions

- 2 heads
- short head originates from coracoid process
- long head originates from supraglenoid tubercle
- belly attaches to radial tuberosity and bicipital aponeurosis
- elbow flexion, supination of radio-ulnar joint

Brachialis: origin, insertion and actions

- under biceps brachii
- originates from distal half of anterior humerus
- one tendon that blends into ulnar tuberosity
- elbow flexion

Triceps Brachii: origin, insertion and actions

- 3 heads merge into 1 tendon that blends into olecranon process of ulna
- long head originates from scapula
- helps extension, adduction of GH joint
- lateral/medial originate from posterior surface of humerus shaft - land on either side of radial groove (where the radial nerve will travel)
- all three heads pull on olecranon process to lock into olecranon fossa which is extension.