Upper Limb Muscles Flashcards
Facial Expression Muscles
Innervation - Facial Nerve (CN VII)
Mastication Muscles
- Temporalis
- Masseter
- Medial pterygoid
- Lateral pterygoid
Temporalis
Actions:
* Elevates mandible
* Retracts mandible
Origin - temporal fossa and temporal fascia
Insertion - coronoid process and ramus of mandible
Innervation - Mandibular nerve (CN V3)
Masseter
Action - elevates mandible
Origin - zygomatic arch
Insertion - angle of ramus of mandible
Innervation - Mandibular nerve (CN V3)
Medial Pterygoid
Actions:
* Elevates mandible
* Protracts side of mandible
* Side to side movement (contralateral/opposite excursion)
Origin - superficial head: tuberosity of maxilla and pyramidal process of palatine bone, deep head: medial surface of lateral pterygoid plate and pyramidal process of palatine bone
Insertion – medial surface of mandible
Innervation - Mandibular nerve (CN V3)
Lateral Pterygoid
Actions:
* Protracts mandible
* Side to side movement (contralateral/opposite excursion)
Origin - roof of infratemporal fossa and lateral surface of pterygoid process
Insertion – capsule of TMJ and pterygoid fossa of mandible
Innervation - Mandibular nerve (CN V3)
Deep Neck Flexor Muscles
- Rectus capitis anterior
- Rectus capitis lateralis
- Longus capitis
- Longus colli
Action - flexes head and neck
Innervation - Anterior rami of spinal nerves
Anterior Neck Triangle
Borders:
* Superior – inferior angle of mandible
* Lateral – anterior border of sternocleidomastoid
* Medial – midline of neck
Muscles:
* Suprahyoids
* Infrahyoids
Posterior Neck Triangle
Borders:
* Anterior – posterior border of sternocleidomastoid
* Posterior – anterior border of trapezius muscles
* Inferior – middle third of clavicle
Muscles:
* Sternocleidomastoid
* Splenius capitis
* Scalene muscles
* Trapezius muscles
Suprahyoid Muscles
- Stylohyoid (superficial) - facial nerve (CN VII)
- Digastric - mandibular nerve (CN V3)
- Mylohyoid - mandibular nerve (CN V3)
- Geniohyoid (deep) - C1 nerve roots
Action - elevates the hyoid (enables swallowing)
Located superior to hyoid bone
Infrahyoid Muscles
- Omohyoid
- Sternohyoid
- Sternothyroid
- Thyrohyoid
Actions: - Depresses the hyoid
- Depresses the thyroid cartilage
- Elevates the larynx (if hyoid is fixed - enables swallowing)
Located inferior to hyoid bone
Innervation - Anterior rami of C1-C3
Sternocleidomastoid
Actions:
* Bilateral - flexes neck
* Unilateral - lateral flexion and rotation of head to opposite side
Origin - manubrium, clavicle
Insertion – mastoid process
Innervation - Accessory nerve (CN XI)
Scalene Muscles
- Scalenus anterior (anterior scalene)
- Scalenus midius (middle scalene)
- Scalenus posterior (posterior scalene)
Scalenus Anterior (anterior scalene)
Actions:
* Lateral neck flexion
* Elevates 1st rib during forced inspiration
Innervation - Spinal nerves (C4 to C7)
Scalenus Midius (middle scalene)
Actions:
* Lateral neck flexion
* Elevates 1st rib during forced inspiration
Innervation - Spinal nerves (C3 to C7)
Scalenus Posterior (posterior scalene)
Actions:
* Lateral neck flexion
* Elevates 2nd rib during forced inspiration
Innervation - Spinal nerves (C5 to C7)
Suboccipital Muscles
- Obliquus capitis superior
- Obliquus capitis inferior
- Rectus capitis posterior minor
- Rectus capitis posterior major
Actions: - Postural support of head and neck
- Extend and rotate head
Innervation - Suboccipital nerve
Intrinsic Back Muscles
- Spinotransversales (superficial)
- Erector spinae (intermediate)
- Transversospinales (deep)
Spinotransversales
- Splenius capitis (superficial and larger)
- Splenius cervicis (deep)
Splenius Capitis
Actions:
* Bilateral - neck extension
* Unilateral - ipsilateral (same side) rotation of head
Innervation - Posterior rami of spinal nerves
Splenius Cervicis
Actions:
* Bilateral - upper cervical spine extension
* Unilateral - upper cervical spine rotation
Innervation - Posterior rami of spinal nerves
Erector Spinae
- Spinalis (medial)
- Longissimus (intermediate and longest)
- Iliocostalis (lateral)
Spinalis
Actions:
* Maintains posture
* Bilateral - extends vertebral column
* Unilateral - lateral flexion of vertebral column
Innervation - Posterior rami of spinal nerves
Longissimus
Actions:
* Maintains posture
* Bilateral - extends vertebral column
* Unilateral - lateral flexion of vertebral column
Innervation - Posterior rami of spinal nerves
Iliocostalis
Actions:
* Maintains posture
* Bilateral - extends vertebral column
* Unilateral - lateral flexion of vertebral column
Innervation - Posterior rami of spinal nerves
Transversospinales
- Semispinalis (most developed in thoracic and cervical regions)
- Rotatores (most developed in thoracic region)
- Multifidus (most developed in lumbar region)
Semispinalis
Actions:
* Bilateral - extension of vertebral column
* Unilateral - contralateral (to opposite sides) rotation of vertebral column
Innervation - Posterior rami of spinal nerves
Rotatores
Actions:
* Bilateral - extension of vertebral column
* Unilateral - contralateral (to opposite sides) rotation of vertebral column
Innervation - Posterior rami of spinal nerves
Multifidus
Actions:
* Bilateral - extension of vertebral column
* Unilateral - contralateral (to opposite sides) rotation of vertebral column
Innervation - Posterior rami of spinal nerves
Segmental Back Muscles
- Levatores costarum
- Interspinales
- Intertransversarii
Levatores Costarum
Actions:
* Elevates ribs
* Facilitates inspiration
Innervation - Posterior rami of spinal nerves
Interspinales
Actions:
* Stabilises vertebral column
* Assist with extension of vertebral column
Innervation - Posterior rami of spinal nerves
Intertransversarii
Actions:
* Stabilises vertebral column
* Assist with extension of vertebral column
Innervation - Posterior rami of spinal nerves
Pectoralis Minor
Actions:
* Protraction of scapula
* Depression of scapula
* Medial/downward rotation of scapula
Origin - anterior surface of ribs 3 to 5
Insertion – coracoid process
Innervation - Medial pectoral nerve
Shoulder Complex Muscles
- Pectoralis minor
- Serratus anterior
- Trapezius (upper, middle and lower)
- Levator scapulae
- Rhomboid minor
- Rhomboid major
- Deltoid
- Pectoralis major
- Biceps brachii* (accessory muscle)
- Coracobrachialis
- Teres major
- Latissimus dorsi
- Triceps brachii (long head)* (accessory muscle)
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Serratus Anterior
Actions:
* Protraction of scapula
* Lateral/upward rotation of scapula
* Keeps scapula against thoracic wall
Origin - lateral surfaces of ribs 1 to 8
Insertion – costal surface of medial border of scapula
Innervation - Long thoracic nerve
Trapezius (upper, middle and lower)
Actions:
* Elevation of scapula (upper trapezius)
* Lateral/upward rotation of scapula
* Retraction of scapula
* Depression of scapula (lower trapezius)
Innervation - Accessory nerve (CN XI - motor) + anterior rami of C3 and C4 (sensory)
Levator Scapulae
Actions:
* Elevation of scapula
* Medial/downward rotation of scapula
Innervation - Dorsal scapula nerve (motor) + anterior rami of C3 and C4 (sensory)
Rhomboid Minor
Actions:
* Retraction of scapula
* Elevation of scapula
Innervation - Dorsal scapula nerve
Rhomboid Major
Actions:
* Retraction of scapula
* Elevation of scapula
Innervation - Dorsal scapula nerve
Deltoid
Actions:
* Abduction of GH joint
* Flexion of GH joint (anterior deltoid)
* Extension of GH joint (posterior deltoid)
Origin - scapular spine, acromion and lateral clavicle
Insertion – deltoid tuberosity of humerus
Innervation - Axillary
Pectoralis Major
Actions:
* Flexion of GH joint
* Adduction of GH joint
* Medial rotation of GH joint
Origin - medial clavicle, sternum and costal cartilages 1 to 7
Insertion – intertubercular sulcus of humerus
Innervation - Medial + lateral pectoral nerve
Biceps Brachii* (shoulder complex action)
Action - accessory flexor of GH joint
Coracobrachialis
Actions:
* Flexion of GH joint
* Adduction of GH joint
Origin - coracoid process
Insertion – midshaft of humerus on medial side
Innervation - Musculocutaneous nerve
Teres Major
Actions:
* Extension of GH joint
* Medial rotation of GH joint
Origin - inferior angle of scapula
Insertion – intertubercular sulcus of humerus
Innervation - Inferior subscapular nerve
Supraspinatus
Actions:
* Rotator cuff muscle (GH joint stabiliser)
* Initiates abduction of GH joint (first 15°)
Origin - supraspinous fossa of posterior scapula
Insertion – greater tubercle of humerus
Innervation - Suprascapular nerve
Triceps Brachii (long head)* (shoulder complex action)
Action - Accessory adductor and extensor of GH joint
Latissimus Dorsi
Actions:
* Adduction of GH joint
* Extension of GH joint
* Medial rotation of GH joint
Innervation - Thoracodorsal nerve
Infraspinatus
Actions:
* Rotator cuff muscle (GH joint stabiliser)
* Lateral rotation of GH joint
Origin - infraspinous fossa of posterior scapula
Insertion – greater tubercle of humerus
Innervation - Suprascapular nerve
Biceps Brachii
Actions:
* Flexion of elbow joint
* Supinator of forearm (at radio-ulnar joints)
* Flexion of GH joint
Origin - long head: supraglenoid tubercle of scapula, short head: coracoid process
Insertion – biceps tendon: radial tuberosity, bicipital aponeurosis: blends with deep fascia of medial side of anterior compartment of forearm
Innervation - Musculocutaneous nerve
Teres Minor
Actions:
* Rotator cuff muscle (GH joint stabiliser)
* Lateral rotation of GH joint
Origin - inferior lateral border of posterior scapula
Insertion – greater tubercle of humerus
Innervation - Axillary nerve
Subscapularis
Actions:
* Rotator cuff muscle (GH joint stabiliser)
* Medial rotation of GH joint
Origin - subscapular fossa of anterior scapula
Insertion – lesser tubercle of humerus
Innervation - Superior + inferior subscapular nerve
Elbow Complex Muscles
- Biceps brachii
- Brachialis
- Brachioradialis
- Triceps brachii
- Anconeus
Anconeus
Actions - accessory extensor of elbow joint
Innervation - Radial nerve
Brachialis
Actions - flexion of elbow joint
Origin - anterior aspect of humerus
Insertion – ulnar tuberosity
Innervation - Musculocutaneous nerve
Brachioradialis
Action - accessory elbow flexor when forearm is mid pronated
Origin - lateral supracondylar ridge of humerus
Insertion – lateral aspect of distal radius
Innervation - Radial nerve
Triceps Brachii
Actions:
* Extension of elbow joint
* Accessory adductor and extensor of GH joint (long head)
Origin - infraglenoid tubercle of scapula
Insertion – common tendon of olecranon process of ulna
Innervation - Radial nerve
Anterior Forearm Muscles
- Pronator teres (superficial)
- Flexor carpi radialis (superficial)
- Palmaris longus (superficial)
- Flexor carpi ulnaris (superficial)
- Flexor digitorum superficialis (intermediate)
- Flexor digitorum profundus (deep)
- Flexor pollicis longus (deep)
- Pronator quadratus (deep)
Origin - medial epicondyle of humerus
Flexor Carpi Ulnaris
Actions:
* Flexion of wrist (with FCR)
* Radial deviation of wrist (with ECU)
Innervation - Ulnar nerve
Flexor Digitorum Profundus
Actions:
* Flexion of wrist
* Flexion of MCP joints (2-5)
* Flexion of DIP joints (2-5)
Innervation - Anterior interosseous nerve (median nerve – digits 2-3) + ulnar nerve (digits 4-5)
Pronator Teres
Action - pronation of forearm
Innervation - Median nerve
Flexor Carpi Radialis
Actions:
* Flexion of wrist (with FCU)
* Radial deviation of wrist (with ECRL/B)
Innervation - Median nerve
Palmaris Longus
Actions:
* Flexion of wrist
* Helps with gripping
Innervation - Median nerve
Flexor Digitorum Superficialis
Actions:
* Flexion of wrist
* Flexion of MCP joints (2-5)
* Flexion of PIP joints (2-5)
Innervation - Median nerve
Flexor Pollicis Longus
Actions:
* Flexion of IP joint of thumb (digit 1)
* Flexion of MCP joint of thumb (digit 1)
Innervation - Anterior interosseous nerve (median nerve)
Pronator Quadratus
Action - pronation of forearm
Innervation - Anterior interosseous nerve (median nerve)
Posterior Forearm Muscles
- Brachioradialis (superficial)
- Extensor carpi radialis longus (superficial)
- Extensor carpi radialis brevis (superficial)
- Extensor digitorum (superficial)
- Extensor digiti minimi (superficial)
- Extensor carpi ulnaris (superficial)
- Supinator (deep)
- Abductor pollicis longus (deep)
- Extensor pollicis longus (deep)
- Extensor pollicis brevis (deep)
- Extensor indicis (deep)
Origin - lateral epicondyle of humerus
Brachioradialis
Action - accessory elbow flexor when forearm is mid pronated
Origin - lateral supracondylar ridge of humerus
Insertion – lateral aspect of distal radius
Innervation - Radial nerve
Extensor Carpi Radialis Longus
Actions:
* Extension of wrist (with ECRB and ECU)
* Radial deviation of wrist (with ECRB and FCR)
Innervation - Radial nerve
Extensor Carpi Radialis Brevis
Actions:
* Extension of wrist (with ECRL and ECU)
* Radial deviation of wrist (with ECRL and FCR)
Innervation - Deep branch of radial nerve
Extensor Digiti Minimi
Action - extension of digit 5
Innervation - Posterior interosseous nerve (radial nerve)
Extensor Digitorum
Actions:
* Extension of digits 2-5
* Extension of wrist
Innervation - Posterior interosseous nerve (radial nerve)
Extensor Carpi Ulnaris
Actions:
* Extension of wrist (with ECRB/L)
* Ulnar deviation of wrist (with FCU)
Innervation - Posterior interosseous nerve (radial nerve)
Supinator
Action - supination of forearm
Innervation - Posterior interosseous nerve (radial nerve)
Abductor Pollicis Longus
Action - abduction of CMC joint of thumb (digit 1)
Innervation - Posterior interosseous nerve (radial nerve)
Extensor Pollicis Longus
Actions:
* Extension of IP joint of thumb (digit 1)
* Extension of CMC joint of thumb (digit 1)
* Extension of MCP joint of thumb (digit 1)
Innervation - Posterior interosseous nerve (radial nerve)
Extensor Pollicis Brevis
Actions:
* Extension of MCP joint of thumb (digit 1)
* Extension of CMC joint of thumb (digit 1)
Innervation - Posterior interosseous nerve (radial nerve)
Intrinsic Hand Muscles
- Abductor pollicis brevis (thenar group)
- Flexor pollicis brevis (thenar group)
- Opponens pollicis (thenar group)
- Abductor digiti minimi (hypothenar group)
- Flexor digiti minimi brevis (hypothenar group)
- Opponens digiti minimi (hypothenar group)
- Adductor pollicis
- Lumbrical muscles (1-4)
- Dorsal interossei muscles (1-4)
- Palmar interossei muscles (2-4)
Extensor Indicis
Action - extension of digit 2
Innervation - Posterior interosseous nerve (radial nerve)
Abductor Pollicis Brevis
Action - abduction of thumb (digit 1)
Innervation - Recurrent branch of median nerve
Flexor Pollicis Brevis
Action - flexion of MCP joint of thumb (digit 1)
Innervation - Recurrent branch of median nerve
Opponens Pollicis
Action - medial rotation of MCP joint of metacarpal 1
Innervation - Recurrent branch of median nerve
Abductor Digiti Minimi Brevis
Action - abduction of MCP joint of digit 5
Innervation - Deep branch of ulnar nerve
Opponens Digiti Minimi
Action - lateral rotation of CMC joint of metacarpal 5
Innervation - Deep branch of ulnar nerve
Adductor Pollicis
Action - adduction of CMC joint of thumb (digit 1)
Innervation - Deep branch of ulnar nerve
Lumbrical Muscles
(Lumbricals 1-2: unipennate, lumbricals 3-4: bipennate)
Actions:
* Flexion of MCP of individual digit
* Extension of IP joints of individual digit
Innervation - Digital branch of median nerve (lumbricals 1-2) + deep branch of ulnar nerve (lumbricals 3-4)
Dorsal Interossei Muscles
Actions:
* Abduction of MCP joint of individual digit
* Flexion of MCP joint of individual digit
* Extension of IP joint of individual digit
Innervation - Deep branch of ulnar nerve
Palmar Interossei Muscles
Action - adduction of MCP joint of individual digit
Innervation - Deep branch of ulnar nerve
