Anatomy of Musculoskeletal System 2 - Upper Limb - Muscles, Forearm, and Hand PDF

Anatomy of Musculoskeletal system 2- Upper Limb - Muscles and joints of arm, forearm and Hand Dr Suresh MBBS MD Objectives At the end of the lecture, students are able to, 1. Describe the proximal and distal attachments, innervation and actions of front and back of arm muscles 2. Describe...

Anatomy of Musculoskeletal system 2- Upper Limb - Muscles and joints of arm, forearm and Hand Dr Suresh MBBS MD Objectives At the end of the lecture, students are able to, 1. Describe the proximal and distal attachments, innervation and actions of front and back of arm muscles 2. Describe boundaries and clinical importance of cubital fossa. 3. Describe the proximal and distal attachments, innervation and actions of front and back of forearm muscles 4. Anatomy of elbow, wrist and radio ulnar joints 5. Describe intrinsic muscles of hand and thumb. Muscles of Scapula- Rotator cuff Greater Tubercle Lateral border Medial border  Muscles of Arm: Cross elbow, Move forearm Deep fascia separates the 2 muscle groups Leg has Biceps too Anterior Compartment Biceps brachii ceps mean head. Brachialis Brachiam means arm Coraco brachialis Coraco comes from Coracoid process Posterior Compartment (Extensors of forearm) Triceps brachii Osseous means bone Anconeus small muscle  Biceps brachii Origin: Intertubercular groove Long head-supraglenoid tubercle of scapula; Short head-apex of coracoid process Insertion: Radial tuberosity of radius Nerve supply: Musculocutaneous nerve Action: Flexor of the forearm at the elbow joint Supinator of the forearm Accessory flexor of the arm at shoulder joint Brachialis Origin: Anterior aspect of humerus Insertion: Tuberosity of the ulna Nerve supply: Musculocutaneous nerve Action: Flexor of the forearm at the elbow joint Coracobrachialis Origin: coracoid process of scapula Insertion: mid-shaft of humerus Nerve supply: Musculocutaneous nerve Action: Flexor of the arm at the shoulder joint Nerves – musculocutaneous nerve from Lateral cord of Brachial Plexus Branch of lateral cord of brachial plexus Pierces coracobarchialis muscle Supplies: (BBC) Biceps brachii, Brachialis Coraco brachialis  Triceps brachii Origin: Long head- Infraglenoid tubercle of scapula Medial head-posterior surface of humerus lateral head-posterior surface of humerus Insertion: Olecranon process of ulna Nerve supply: Radial nerve All back part of arm & forearm muscles are supplied by Radial nerve Action: Medial Lateral Extension of the forearm at the elbow joint. Long head - extend and adduct the arm at the shoulder joint Nerves – radial nerve Branch of posterior cord of brachial plexus Supplies muscles of back of arm and forearm Nerves Median nerve Ulnar nerve Medial epicondyle Arteries Axillary artery ▪ Commences at the outer border of the first rib ▪ Continuation of the subclavian artery ▪ Divided into three parts by pectoralis minor ▪ Continue as Brachial artery from the lower border of teres major Brachial. artery ▪ Commences at the lower border of teres major ▪ Divided into radial and ulnar artery below the elbow joint  Elbow joint- (Hing joint) uniaxial joint Radius Ulna Articular surfaces Capsule & ligaments Movements Arterial supply Nerve supply Brachial, - Musculocutaneous nerve. Profunda brachii, Brachial - Radial nerve. Radial, and ulnar arteries. - Ulnar nerve - Median nerve Cubital fossa Situated in anterior aspect of the elbow Boundaries: 1. Superiorly- an imaginary line connecting the medial and lateral epicondyles. 2. Medially- pronator teres & the mass of flexor muscles of the forearm 3. Laterally- brachioradialis ,mass of extensor muscles  Cubital fossa Contents (lateral to medial) tendon of the biceps brachii muscle brachial artery median nerve TAN Deep tendon reflex (Bicipital reflex) using knee hammer causes extension of forearm: BP taking: Blood taking: Muscles of forearm: Cross Wrist : flex, extend, abduct, adduct hand Cross Fingers : flex, extend fingers Front of forearm Anterior Flexor Compartment (Superficial + Deep layers) Most flexors have common tendon on medial epicondyle Contains 2 pronators Innervated by *Median, Ulnar nerves Back of forearm Posterior Extensor Compartment (Superficial + Deep layers) Innervated by Radial nerve Lateral epicondyle origin Radius Flexor & Extensor Retinaculam Ulna Collagenous bands keep tendons from bowing thick, deep fascia FOREARM Olecranon Olecranon Process (Triceps) Trochlear notch Coronoid process Proximal Head of radius Radial notch U shaped: Trochlea notch radio-ulnar Neck of joint radius Ulnar tuberosity Radial tuberosity Lateral Medial Medial Lateral Ulna Ulna Radius Ulna c Lateral view of ulna, showing Interosseous trochlear notch membrane Head of Ulna is the only one at the bottom (elbow side) https://aclandanatomy- com.singaporetech.rem Ulnar notch Distal radio-ulnar joint of radius otexs.co/MultimediaPla Head of ulna Dorsal Tubercle aka Lister's Tubercle yer.aspx?multimediaId= Head of ulna Ulnar styloid process Radial styloid 10528065 process a Posterior view b Anterior © 2018 Pearson Education, Ltd. view  HAND SLTP: SLT Program TTCH: Too Tough Can't Help She – Scaphoid Looks– Lunate Too – Triquetral Pretty – Pisiform Try – Trapezium To – Trapezoid Catch – Capitate Her – Hamate P T L has a hook S looks like figure of 8 https://aclandanatomy- com.singaporetech.remotexs.co/MultimediaPlayer.aspx?multimediaId=10528093  Innervation of Anterior Compartment- Forearm Muscles Muscle Nerve Superficial Muscles Pronator teres Median Flexor carpi radialis passes in radial side Median exception in naming Palmaris longus Median Flexor carpi ulnaris attaches in carpal bone Ulnar bcos name implies ulnar (Intermediate layer) Flexor digitorum superficialis Median Deep Muscles Pronator quadratus Median Pollex means thumb Flexor pollicis longus Median Profound means deep Flexor digitorum profundus Ulnar (med 1/2) Median (lat 1/2) middle & index finger Anterior Compartment Forearm- Superficial layer Medial Epicondyle Common Flexor Origin Pronator Teres Flexor Carpi Radialis Palmaris longus Flexor Carpi Ulnaris PFPF: Pass Fail Pass Fail If you perform in exams: Pass If you don't perform in exams: Fail Flexor Digitorum Superficialis is deep to other flexors goes all the way up to 4 digits & splits into 2 slips (except thumb) Anterior Compartment Forearm-Deep layer Flexor dig. profundus goes all the way to the end digits (just 1 slip) Flexor pollicis pass between the two slips of the Superficialis longus goes to thumb Pronator quadratus Pronator teres Origin: medial epicondyle of humerus Ulnar head-coronoid process Insertion: mid-shaft, of radius Nerve supply: median nerve Action: Pronate and flexes forearm Flexor carpi radialis Origin: medial epicondyle of humerus Insertion: Base of metacarpals II and III Nerve supply: median nerve Action: Flexion and abduction of wrist  Palmaris longus Origin: Medial epicondyle of humerus Insertion: Palmar aponeurosis of hand Nerve supply: median nerve Action: Flexion of wrist joint  Flexor carpi ulnaris Origin: medial epicondyle of humerus Ulnar head: olecranon and posterior border of ulna Insertion: Pisiform bone, hamate and base of metacarpal V(5) Nerve supply: Ulnar nerve Action: Flexion and adduction of wrist  Flexor Digitorum Superficialis is deep to other flexors Flexor digitorum superficialis middle phalanges goes all the way up to 4 digits & splits into 2 slips (except thumb) Origin: Medial epicondyle of humerus, coronoid process of ulna head of radius Insertion: Four tendons, which attach to the palmar surfaces of the middle phalanges of the index, middle, ring, and little fingers Nerve supply: median nerve Action: Flexes proximal interphalangeal joints of the index, middle, ring, and little fingers; can also flex metacarpophalangeal joints of the same fingers and the wrist joint  Flexor digitorum profundus Distal phalanges Origin: Ulna and interosseous membrane Insertion: Four tendons, which attach to the palmar surfaces of the distal phalanges of the index, middle, ring, and little fingers Nerve supply: Median Ulnar Lateral half by median nerve , medial half by ulnar nerve Action: Flexes distal interphalangeal joints of the index, middle, ring, and little fingers; flex metacarpophalangeal joints of the same fingers and the wrist joint Flexor pollicis longus thumb Origin: Anterior surfaces of radius and interosseous membrane Insertion: base of distal phalanx of thumb Nerve supply: median nerve Action: Flexes interphalangeal and metacarpo- phalangeal joint of the thumb Pronator quadratus deepest muscle Origin: Distal anterior surface of ulna Insertion: Distal anterior surface of radius Nerve supply: median nerve Action: pronation Posterior Compartment of Forearm  Forearm Muscles- Posterior Compartment Superficial These 3 don't cross the wrist joint Brachioradialis elbow joint Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor carpi ulnaris Extensor digiti minimi little finger Radial nerve Anconeus for extension of elbow joint Deep Supinator forearm bones Abductor pollicis longus Extensor pollicis longus + brevis Extensor indicis index finger Brachioradialis Humerus -> Radias Origin: supracondylar ridge of humerus Insertion: Distal end of radius Nerve supply: radial nerve Action: flexor of elbow joint  Muscle Origin Insertion Action Extensor carpi radialis supracondylar ridge of humerus Dorsal surface of base of Extends and abducts longus metacarpal II the wrist Extensor carpi radialis Lateral epicondyle of humerus Dorsal surface of base of Extends and abducts brevis metacarpals II and III the wrist Extensor digitorum Lateral epicondyle of humerus bases of the middle and Extends the index, distal phalanges of the middle, ring, and index, middle, ring, and little fingers; can little fingers also extend the ‘Extensor Hoods' wrist at back of fingers ie. Dorsal Digital Extension Extensor digiti minimi Lateral epicondyle of humerus Dorsal hood of the little Extends the little finger finger Extensor carpi ulnaris Lateral epicondyle of humerus base of metacarpal V Extends and adducts and ulna the wrist end of second finger end of third finger  Deep muscles of Posterior Compartment Muscle Origin Insertion Action Supinator Superficial part-lateral Lateral surface of supination epicondyle of humerus, radius ulna Extensor indicis Ulna Extensor hood of Extends index index finger finger  Deep muscles of Posterior Compartment Muscle Origin Insertion Action Abductor pollicis Posterior surfaces of ulna Lateral side of base of Abducts carpometacarpal longus and radius metacarpal I joint of thumb Extensor pollicis brevis Posterior surface of base of proximal phalanx of Extends radius the thumb metacarpophalangeal and carpometacarpal joint of the thumb Extensor pollicis longus Posterior surface of ulna Dorsal surface of base of Extends interphalangeal distal phalanx of thumb joint of the thumb; can also extend carpometacarpal and metacarpophalangeal joints of the thumb goes to thumb Hand Interosseus muscle On Palm of hand: Palmar Interossei If back of hand: Dorsal Interossei  Intrinsic Muscles of Hand Muscle Nerve little finger Thenar muscles All digiti minimi Opposition Ulnar Hypothenar muscles (Flexor, Abductor, Opponens) Thumb Abductor pollicis brevis Median Flexor pollicis brevis Median Opponens pollicis Median Adductor pollicis Ulnar Other Intrinsic Muscles Palmar + Dorsal Interossei Ulnar Lumbricals Median, Ulnar  Muscles of Hand Muscle Origin Insertion Nerve supply Action Thenar muscles Opponens Tubercle of Lateral margin and median nerve Medially rotates thumb pollicis trapezium and adjacent palmar flexor surface of retinaculum metacarpal I Abductor Tubercles of Proximal phalanx median nerve Abducts thumb at pollicis brevis scaphoid and and extensor metacarpophalangeal joint trapezium and hood of thumb adjacent flexor Flexor pollicis Tubercle of the Proximal phalanx median nerve flexes the metacarpophalangeal joint brevis trapezium and of the thumb of the thumb flexor retinaculum  Muscles of Hand Muscle Origin Insertion Nerve supply Action Hypothenar muscles Opponens digiti Hook of hamate Medial aspect of Deep branch of ulnar Laterally rotates minimi and flexor metacarpal V nerve [C8,T1] metacarpal V retinaculum Abductor digiti Pisiform, the Proximal phalanx of Deep branch of ulnar Abducts little finger at minimi pisohamate little finger nerve [C8,T1] metacarpophalangeal ligament, and joint tendon of flexor carpi ulnaris Flexor digiti minimi Hook of the Proximal phalanx of Deep branch of ulnar Flexes little finger at brevis hamate and flexor little finger nerve [C8,T1] metacarpophalangeal retinaculum joint Lumbricals 1ST Dorsal interossei Adductor pollicis Flexor pollicis brevis Opponens pollicis Abductor pollicis brevis Palmar interosseus Abductor digiti minimi Flexor digiti minimi brevis Opponens digiti minimi Intrinsic Muscles of Hand PAD (Palmar: Adduction) DAB (Dorsal: Abduction) Lumbricals for the snake action Palmar Dorsal Interossei Interossei 3rd ADDuction ABduction 2nd 4th 1st Interossei help the lumbricals to extend IP joints and flex MC-P joints BLOOD SUPPLY Wrist joint synovial joint ARTICULAR SURFACES: SLT bone Distal end of radius & scaphoid, lunate, triquetral LIGAMENTS: Fibrous capsule with synovial membrane Dorsal & palmar radio-carpal ligaments Radial & ulnar collateral ligaments Movements: adduction- abduction flexion – extension Radio-ulnar joints APPLIED ANATOMY Subluxation or pulled elbow. Preschool children. eg., lifting a child into bus. Nerves Median nerve 3.5 fingers Ulnar nerve 1.5 finger Radial nerve 3.5 fingers  Carpal tunnel syndrome Median nerve compressed Retinaculum holds all the tendons in place at the wrist References Richard Drake A. Wayne Vogl Adam 2011. Gray's Anatomy for Students, 3rd edition Churchill Livingstone Standring, 2020 Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 42nd Edition,, Churchill Livingstone Moore, K.L., Dalle,A.F. & Agur, A.M. 2017. Clinically Oriented Anatomy. 8th edition. Philadelphia: Lippincott Williams & Wilkins. Snell, R.S. 2018. Clinical Anatomy by Regions. 10th edition. Philadelphia: Lippincott Williams & Wilkins. Frederic H. Martini. Fundamentals of Anatomy & Physiology, Global Edition, 11th Edition: Pearson (instructor resources) http://anatomediaonline.com/amedia/index.html