UL Muscles.docx

Supraspinatus

Attached to supraspinous fossa and superior facet of greater tubercle
Action: Initiate and assist deltoid with abduction and stabilise GH joint
Nerve Supply: Suprascapular nerve
In use majority of time

Infraspinatus

Attached to infraspinous fossa and middle facet of greater tubercle
Action: Laterally rotate humerus and stabilise GH joint
Nerve Supply: Suprascapular Nerve

Teres Minor

Attached to lateral border of scapula and inferior facet of greater tubercle
Action: Laterally rotate humerus and stabilise GH joint
Nerve Supply: Axillary nerve (wraps around surgical neck of humerus)

Rotator Cuff Muscles – Inferior:

Subscapularis

Attached to subscapular fossa and lesser tubercle
Action: Medically rotate humerus (strongest rotator), stabilise GH joint, assist with adduction
Nerve Supply: Upper and Lower subscapular nerves

Upper Limb to Vertebral Column (Superficial)

Trapezius:

Attachments:
Skull (superior nuchal line and external occipital protuberance) and nuchal ligament
Vertebral column (Spinous processes C7-T12)
Clavicle (lateral 1/3)
Scapula (acromion and spine)
Actions (unilateral):
Superior/lateral rotates glenoid fossa (abduction)
Retracts scapula
Elevate scapula (upper part)
Depress scapula (lower part)
Laterally flex neck
Actions (bilateral):
Extend neck
Nerve Supply:
Spinal accessory nerve (motor)
C3-C4 (pain and proprioception)

Latissimus Dorsi:

Attachments:
Vertebral Column (spinous processes of T6-T12, thoracolumbar fascia, iliac crests)
Humerus (floor of intertubercular groove)
Actions:
Adducts arm
Medially rotates arm
Extends a flexed arm
Raises body towards arm
If humerus is fixed, can pull trunk forward and ‘hitch’ hips
Nerve Supply:
Thoracodorsal nerve

Upper Limb to Vertebral Column (Deep)

Levator scapulae:

Attachments:
Vertebral Column (transverse processes C1-C4)
Scapula (medial border, superior to root of spine)
Actions:
Elevate scapula
Medially rotate scapula
Nerve Supply:
Dorsal scapular nerve
Anterior rami C3-C4

Rhomboid Major:

Attachments:
Vertebral Column (nuchal ligament and spinous processes C7-T1)
Scapula (medial border adjacent to root of spine)
Actions:
Elevates scapula
Retracts scapula
Medially rotates glenoid fossa
Nerve Supply:
Dorsal scapular

Rhomboid Minor:

Attachments:
Vertebral Column (spinous processes T2-T5)
Scapula (medial border inferior to root of spine)
Actions:
Elevates scapula
Retracts scapula
Medially rotates glenoid fossa
Nerve Supply:
Dorsal scapular

Upper Limb to Scapula

Teres Major:

Attachments:
Scapula (lower 1/3 lateral border)
Humerus (medial lip of intertubercular groove)
Actions:
Adducts arm
Medially rotate arm
Nerve Supply:
Inferior subscapular nerve

Deltoid:

Attachments:
Clavicle (lateral 1/3)
Scapula (acromion and spine)
Humerus (deltoid tuberosity)
Actions:
Flexes and medially rotates arm (anterior fibres)
Abducts arm (middle fibres)
Extends and laterally rotates arm (posterior fibres)
Nerve Supply:
Axillary Nerve

Upper Limb to Scapula (Anterior)

Biceps Brachii:

Attachments:
Scapula – long head: supraglenoid tubercle and labrum
Short head – coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous nerve

Coracobrachialis:

Attachments:
Scapula (coracoid process)
Humerus (middle 1/3 of shaft medially)
Actions:
Assists in flexion of shoulder
Assist in adduction of shoulder
Nerve Supply:
Musculocutaneous nerve

Upper Limb to Scapula (Posterior)

Triceps Brachii:

Attachments:
Scapula – long head: infraglenoid tubercle
Humerus (posterior): lateral head – superior to radial groove, medial head – inferior to radial groove
Ulna – proximal end of olecranon (elbow lump – blend together) and deep fasica
Actions:
Extends shoulder (weakly as it crosses the shoulder joint)
Extends forearm
Nerve Supply:
Radial nerve

Upper Limb to Thoracic wall

Serratus Anterior:

Attachments:
Ribs (lateral aspects of ribs 1-8)
Scapula (anterior surface of medial border) SCAPULOTHORACIC ‘JOINT’
Actions:
Protract scapula
Superior/lateral rotation of scapula
Nerve Supply:
Long thoracic nerve

Pectoralis Major:

Attachments:
Clavicle (medial ½ anterior surface)
Sternum (anterior manubrium and body)
Costal cartilages 1-6
Humerus (lateral lip of intertubercular groove)
Actions:
Adducts arm
Medially rotates arm
Clavicular head flexes arm
Sternocostal head extends arm (when flexed)
Assists latissimus dorsi to raise trunk towards arms
Nerve Supply:
Medial and lateral pectoral nerves

Pectoralis Minor (deep to Major):

Attachments:
Ribs 3-5
Scapula (coracoid process)
Actions:
Stabilises scapula (holds against thorax)
Nerve Supply:
Medial pectoral nerve

Accessory Muscle

Subclavius:

Attachments:
Junction of rib 1 and its costal cartilage
Clavicle (subclavian groove)
Actions:
Depress clavicle
Nerve Supply:
Nerve to subclavius
Anterior: Supplied by musculocutaneous nerve
Posterior: Supplied by radial nerve

Anterior Group:

Coracobrachialis:

Attachments:
Scapula (coracoid process)
Humerus (middle 1/3 of shaft medially)
Actions:
Assists in shoulder flexion
Assists in shoulder adduction
Nerve Supply:
Musculocutaneous Nerve

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachialis:

Attachments:
Humerus (anterior distal ½)
Ulna (coronoid process and ulnar tuberosity)
Actions:
Prime flexor of elbow joint
Nerve Supply:
Musculocutaneous Nerve

Posterior Group:

Triceps Brachii:

Attachments:
Scapula: Long head – infraglenoid tubercle
Humerus (posterior):
Lateral head: superior to radial groove
Medial head: inferior to radial groove
Ulna: (lateral and medial heads blend) proximal end of olecranon and deep fascia
Actions:
Extend shoulder (weak)
Extend forearm
Nerve Supply:
Radial Nerve

Anconeus:

Attachments:
Humerus (lateral epicondyle)
Actions:
Extend forearm
Nerve Supply:

Radial Nerve

Muscles of Elbow Joint:

Arranged into 2 compartments: anterior and posterior

Anterior:

Shoulder flexors
Elbow flexors
Biceps brachii, coracobrachialis and brachialis
Supplied by musculocutaneous

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachialis:

Attachments:
Humerus (anterior distal ½)
Ulna (coronoid process and ulnar tuberosity)
Actions:
Prime flexor of elbow joint
Nerve Supply:
Musculocutaneous Nerve

Brachioradialis (forearm):

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (distal, lateral to styloid process)
Actions:
Flexes forearm (especially in mid-pronation)
Pronation (return to mid-pronation)
Supination (return to mid-pronation)
Nerve Supply:
Radial Nerve

Flexion:

Brachialis: recruited first
Biceps Brachii: stronger when flexed and supinates simultaneously (used when resistance applied)
Brachioradialis (forearm): assists with flexion, places hand into mid-pronation

Posterior:

Shoulder extensors
Elbow extensors
Triceps brachii and anconeus
Supplied by radial

Triceps Brachii:

Attachments:
Scapula: Long head – infraglenoid tubercle
Humerus (posterior):
Lateral head: superior to radial groove
Medial head: inferior to radial groove
Ulna: (lateral and medial heads blend) proximal end of olecranon and deep fascia
Actions:
Extend shoulder (weak)
Extend forearm
Nerve Supply:
Radial Nerve

Anconeus:

Attachments:
Humerus (lateral epicondyle)
Actions:
Extend forearm
Nerve Supply:
Radial Nerve

Extension:

Anconeus: recruited first
Triceps Brachii (main extensor): medial head = workhorse, lateral head = recruited next, long head = recruited last (back-up)

Muscles of Radioulnar Joints:

Supination

Supinator – recruited first
Biceps brachii – when supinating against resistance
Brachioradialis – when in pronated position

Supinator:

Attachments:
Humerus (lateral epicondyle)
Ulna (supinator crest and supinator fossa)
Radius (proximal 1/3 of anterior, lateral and posterior surface)
Actions:
Supinate forearm
Nerve Supply:
Radial nerve (deep branch)

Biceps Brachii:

Attachments:
Scapula:
Long Head: supraglenoid tubercle and labrum
Short Head: coracoid process
Radius (radial tuberosity and deep forearm fascia)
Actions:
Weak flexor of shoulder
Short head resists shoulder dislocation
Supinates forearm
Flexes forearm
Nerve Supply:
Musculocutaneous Nerve

Brachioradialis:

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (distal, lateral to styloid process)
Actions:
Flexes forearm (especially in mid-pronation)
Pronation (return to mid-pronation)
Supination (return to mid-pronation)
Nerve Supply:
Radial Nerve
Pronation

Pronator quadratus – (smaller) recruited first
Pronator teres - when pronating against resistance
Brachioradialis – when in supinated position

Pronator Quadratus:

Attachments:
Ulna (distal ¼ of anterior surface)
Radius (distal ¼ of anterior surface)
Actions:
Pronate forearm
Nerve Supply:
Median Nerve

Pronator Teres:

Attachments:
Ulna (coronoid process)
Humerus (medial epicondyle)
Radius (lateral surface of radial shaft)
Actions:
Pronate forearm
Flexes forearm (weakly)
Nerve Supply:
Median Nerve

Muscles of the Forearm:

Arranged into 2 compartments – anterior and posterior
Anterior: wrist flexors, forearm pronators, pronantor teres, FCR, palmaris longus, FCU, FDS, FDP, FPL, pronator quadratus
Supplied by median or ulnar nerve
Posterior: wrist extensors, forearm supinators, brachioradialis, ECRL, ECRB, ED, EDM, ECU, supinator, APL, EPB, EPL, EI
Supplied by radial nerve (deep branches)

Anterior Compartment:

4 layers
Superficial to deep, 4:1:2:1 muscle arrangement
1^st and 2^nd layer muscles have attachment to medial epicondyle (common flexor origin)
ALL supplied by MEDIAN NERVE
EXCEPT flexor carpi ulnaris and medial ½ of flexor digitorum profundus (ulnar)

Anterior Layer 1:

Pronator Teres:

Attachments:
Ulna (coronoid process)
Humerus (medial epicondyle)
Radius (lateral surface of radial shaft)
Actions:
Pronate forearm
Flexes forearm (weakly)
Nerve Supply:
Median Nerve

Palmaris longus (NOT ALWAYS PRESENT):

Attachments:
Humerus (medial epicondyle)
Flexor retinaculum (distal ½)
Palmar aponeurosis (apex)
Actions:
Flex wrist
Tenses palmar aponeurosis
Nerve Supply:
Median Nerve

Flexor Carpi Radialis (FCR):

Attachments:
Humerus (medial epicondyle)
Metacarpals (base of 2^nd)
Actions:
Flexes wrist
Abducts hand
Nerve Supply:
Median Nerve

Flexor Carpi Ulnaris (FCU):

Attachments:
Humerus (medial epicondyle)
Ulnar (olecranon and posterior border of ulna)
Pisiform
Hook of hamate
5^th metacarpal
Actions:
Flexes wrist
Adducts hand
Nerve Supply:
ULNAR Nerve

Anterior Layer 2:

Flexor Digitorum Superficialis (FDS):

Attachments:
Radius (superior ½ of anterior border)
Humerus (medial epicondyle)
Ulna (coronoid process)
Hand (shaft of middle phalanx of digits 2-5)
Actions:
Flexes PIP joints of digits 2-5
Nerve Supply:
Median Nerve

Anterior Layer 3:

Flexor Digitorum Profundus (FDP):

Attachments:
Ulna (proximal ¾ of medial and anterior surfaces)
Interosseous membrane
Base of distal phalanges digits 2-5
Actions:
Flexes DIP joints of digits 2-5
Nerve Supply:
Medial ½ = ULNAR nerve
Lateral ½ = median nerve

Flexor Pollicis Longus (FPL):

Attachments:
Radius (anterior surface)
Interosseous membrane
Base of distal phalanx of 1^st digit (thumb)
Actions:
Flexes PIP and DIP joint of 1^st digit
Nerve Supply:
Median Nerve (anterior interosseous nerve)

Anterior Layer 4:

Pronator Quadratus:

Attachments:
Ulna (distal ¼ of anterior surface)
Radius (distal ¼ of anterior surface)
Actions:
Pronate forearm
Nerve Supply:
Median Nerve

Posterior Compartment:

Superficial (6 muscles) and deep (5 muscles)
ECRB, ED, EDM, ECU and supinator: attach to lateral epicondyle (common extensor origin)
ALL muscles supplied by radial nerve (deep branches)

Posterior Superficial:

Brachioradialis:

Attachments:
Humerus (proximal 2/3 of supracondylar ridge)
Radius (lateral surface of distal end, proximal to styloid process)
Actions:
Weak flexion of forearm (especially in mid-pronation)
DOES NOT CROSS WRIST JOINT
Nerve Supply:
Radial Nerve

Extensor Carpi Radialis Longus:

Attachments:
Humerus (lateral supracondylar ridge
2^nd metacarpal (base of dorsal aspect)
Radius (lateral surface of radial shaft)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Extensor Carpi Radialis Brevis:

Attachments:
Humerus (lateral epicondyle)
3rd metacarpal (base of dorsal aspect)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Extensor Digitorum:

Attachments:
Humerus (lateral epicondyle)
Extensor expansion (of digits 2-5)
Actions:
Extend digits 2-5 at MCP and IP joints
Nerve Supply:
Radial Nerve

Extensor Digiti Minimi:

Attachments:
Humerus (lateral epicondyle)
Extensor expansion of digit 5 (pinky)
Actions:
Extend digit 5 at MCP and IP joints
Nerve Supply:
Radial Nerve

Extensor Carpi Ulnaris:

Attachments:
Humerus (lateral epicondyle)
Ulna (posterior border)
5^th metacarpal (base of dorsal aspect)
Actions:
Extend wrist
Abduct wrist
Nerve Supply:
Radial Nerve

Posterior Deep:

Supinator:

Attachments:
Humerus (lateral epicondyle)
Ulna (supinator crest and supinator fossa)
Radius (proximal 1/3 of anterior, lateral and posterior surface)
Actions:
Supinate forearm
Nerve Supply:
Radial nerve (deep branch)

Abductor Pollicis Longus:

Attachments:
Ulna (posterior surface, proximal ½)
Radius (posterior surface, proximal ½)
Interosseous membrane
1^st metacarpal (base of dorsal aspect)
Actions:
Abducts 1^st digit
Extends CMC joint of 1^st digit
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Pollicis Brevis:

Attachments:
Radius (posterior surface of distal 1/3)
Interosseous membrane
Proximal phalanx of 1^st digit (base of dorsal aspect)
Actions:
Extends CMC and MCP joints of 1^st digit
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Pollicis Longus:

Attachments:
Ulna (posterior surface of middle 1/3)
Interosseous membrane
Proximal phalanx of 1^st digit (base of dorsal aspect)
Actions:
Extends 1^st digit at MCP and IP joints
Nerve Supply:
Radial nerve (posterior interosseous branch)

Extensor Indicis:

Attachments:
Ulna (posterior surface of distal 1/3)
Interosseous membrane
Extensor expansion (of digit 2)
Actions:
Extends digit 2
Nerve Supply:
Radial nerve (posterior interosseous branch)

Thenar Muscles:

Abductor Pollicis Brevis:

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
Base of proximal phalanx of thumb (lateral side)
Action:
Abduct thumb
Assists with opposition
Nerve Supply:
Median Nerve

Flexor Pollicis Brevis:

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
Base of proximal phalanx of thumb (lateral side)
Action:
Flexes thumb
Nerve Supply:
Median Nerve

Opponens Pollicis (deep):

Attachments:
Flexor retinaculum
Scaphoid
Trapezium
1^st metacarpal (lateral side)
Action:
Opposes thumb (medially rotate and draws 1^st metacarpal to centre of palm)
Nerve Supply:
Median Nerve

Central Muscles:

Lumbricals 1 and 2:

Attachments:
Lateral 2 tendons of FDP (unipennate)
Extensor expansion of digits 2-5 (lateral side)
Action:
Flexes MCP joints digits 2-5
Extend IP joints digits 2-5
Nerve Supply:
Median Nerve

Lumbricals 3 and 4:

Attachments:
Medial 3 tendons of FDP (bipennate)
Extensor expansion of digits 2-5 (lateral side)
Action:
Flexes MCP joints digits 2-5
Extends IP joints of digits 2-5
Nerve Supply:
Ulnar Nerve

Hypothenar Muscles:

*may see palmaris brevis covering hypothenar muscles (supplied by Ulnar)

Abductor Digiti Minimi:

Attachments:
Pisiform
Base of proximal phalanx of digit 5 (medial side)
Action:
Abduct digit 5
Assists with flexion
Nerve Supply:
Ulnar Nerve

Flexor Digit Minimi Brevis:

Attachments:
Flexor retinaculum
Hook of hamate
Base of proximal phalanx of digit 5 (medial side)
Action:
Flexes proximal phalanx of digit 5 (medial side)
Nerve Supply:
Ulnar Nerve

Opponens Digiti Minimi (Deep):

Attachments:
Flexor retinaculum
Hook of hamate
5^th metacarpal (medial side)
Action:
Draw 5^th metacarpal anteriorly and rotate towards centre of palm
Nerve Supply:
Ulnar Nerve

Adductor Pollicis:

Attachments:
Transverse head: shaft of 3^rd metacarpal (anteriorly)
Oblique head: base of 2^nd and 3^rd metacarpals, capitate and adjacent carpals
Base of proximal phalanx of thumb (medial side)
Action:
Adduct thumb
Nerve Supply:
Ulnar Nerve

Interossei Muscles (deep and between bones):

Dorsal Interossei (4):

Attachments:
Adjacent sides of 2 metacarpals (bipennate)
Bases of proximal phalanges
Extensor expansion of digits 2-4
Action:
Abduct digits 2-4
Assist with flexion of MCP joints
Assist with extension of IP joints
Nerve Supply:
Ulnar Nerve

**DAB – Dorsal abduct

Palmar Interossei (3):

Attachments:
Palmar surface of 2^nd, 4^th and 5^th metacarpals (unipennate)
Bases of proximal phalanges
Extensor expansion of digits 2, 4, 5
Action:
Adduct digits 2, 4, 5
Assist with flexion of MCP joints
Assist with extension of IP joints
Nerve Supply:
Ulnar Nerve

**PAD – Palmar adduct