Anatomy 7-9 PDF - Upper Limb Anatomy

BMS Anatomy Asynchronous Lecture 7 Muscles of the Anterior Forearm Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 221...

BMS Anatomy Asynchronous Lecture 7 Muscles of the Anterior Forearm Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 221 – 227 Forearm Compartments Flexor – Pronator Median and/or Ulnar Ns. Extensor - Supinator Radial N. Retinacula Flexor-Pronator Muscles Pronator Teres (PT); Ori: -Humeral head: Medial epicondyle of humerus (via common flexor tendon) - Ulnar head: Coronoid process of ulna Ins: Middle of the lateral surface of radius Fun: N: 5 PT Note Impeachment of median nerve between two heads of PT; pronator syndrome 6 Flexor Carpi Radialis FCR); Ori: Medial epicondyle of humerus (via common flexor tendon) Ins: Base of the 2nd & 3rd. Metacarpals Fun: N: 7 FCR Notes Radial A. pulse 8 Palmaris Longus (PL); Ori: Medial epicondyle of humerus (via common flexor tendon) Ins: - Palmar aponeurosis - Flexor retinaculum Fun: N: 9 PL Notes Absent in 12-20% of population 10 Flexor Carpi Ulnaris (FCU); Ori: Humeral Head: Medial epicondyle of humerus (via common flexor tendon) Ulnar Head: 1. Olecranon process of ulna 2. Posterior border of ulna Ins: 1. Base of the 5th metacarpal 2. Hook of hamate 3. Pisiform Fun: N: 11 FCU Notes Only muscle which is innervated by ulnar N. Course of ulnar N. between its two heads 12 First four Flexors 13 Intermediate layer, has only one muscle Flexor Digitorum Superficialis (FDS); Ori: Humero-ulnar head: - Medial epicondyle of humerus (via common flexor tendon) - Coronoid process of ulna Radial head: - Proximal of anterior border of radius Ins: - Base of middle phalanges of fingers # 2-5 Fun: N: 14 FDS Notes Irritation of the tendon sheath in CT and pressing the median N. 15 ❑ Deep layer; Flexor Digitorum Profundus (FDP); Ori: - Proximal anterior & medial surface of ulna - Interosseous membrane Ins: Base of distal phalanges of fingers # 2-5 Fun: N: FDP Notes Dual innervation Role of medial and lateral halves of muscle in flexing the fingers 17 Flexor Pollicis Longus (FPL); Ori: - Anterior surface of the: - Radius - Interosseous membrane Ins: Base of distal phalanx of thumb Fun: N: FPL Notes One of the C. Tunnel muscles 19 Pronator Quadratus (PQ); Ori: Anterior surface of distal ¼ of ulna Ins: Anterior surface of distal ¼ of radius Fun: N: 20 BMS Anatomy Asynchronous Lecture 9 Upper Limb Vasculature and Transitional Areas Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 162 – 167, 189 – 194, 212 – 213, 233 – 237, 255 – 258 BLOOD SUPPLY OF THE UPPER EXTREMITY 2 BLOOD SUPPLY OF THE UPPER EXTREMITY 3 Axillary Artery 5 Axillary Artery 6 This artery is the continuation of subclavian artery, and lies between the first rib and the lower border of teres major muscle or pectoralis major muscle. Based on the position of the artery relative to the pectoralis minor muscle, axillary artery is divided into three different parts. The first part which lies before the muscle, has one branch which supplies the upper part of the thoracic cavity; hence the name Superior Thoracic artery. The second part of the artery that is covered by the muscle anteriorly, gives off two branches. The first branch is called thoracoacromial, and supplies some parts of pectoral and deltoid regions. The second branch is called lateral thoracic artery which mainly supplies the lateral thoracic wall including the serratus anterior muscle. The third part of the artery locating after the pectoralis minor gives off three branches. first branch is subscapular artery that supplies the muscles of the scapular region. The other two branches are anterior and posterior circumflex humeral arteries which turn around the surgical neck of the humerus anteriorly and posteriorly respectively. These arteries will supply those muscles attached to the proximal end of humerus. After passing the inferior border of teres major or pectoralis, the name of the artery will change to Brachial artery. 7 Brachial Artery This artery starts at the lower border of teres major or pectoralis major. Then it runs down in the arm. The main branches of the brachial artery are as follows: 1.Deep brachial (profonda brachii) artery, which moves posteriorly towards the radial groove to accompany the radial nerve. Here it supplies the posterior compartment of the arm. 2.Muscular branches (2-5) for the anterior compartment musculature. 8 Arteries of the Forearm ❑Brachial A. ends in the distal part of the cubital fossa by dividing into the ulnar and radial arteries.  Ulnar A. : The larger of the two terminal branches of the brachial artery. The ulnar artery lies under flexor carpi ulnaris and is accompanied by ulnar nerve on its way. Its branches in the forearm are more numerous than radial artery and supply the elbow, muscles of the anterior compartment on the medial side, the deep muscles of anterior compartment of forearm, the majority muscles of the posterior compartment and the wrist joint. It passes distally over the anterior aspect of the wrist to the palm and takes part in forming the palmar arterial arches.  Radial A.: Is smaller than the ulnar artery and supplies the lateral side of the forearm. The radial artery descends on the lateral side of the forearm under the cover of the brachioradialis muscle. The branches of this artery in forearm will supply elbow , muscles of the anterior compartment on the lateral side, the muscles on the lateral side of the posterior compartment, and the wrist joint. In the distal part of the forearm, it passes through the anatomical snuff box and, after passing through the first interosseous space in hand, enters the palm of the hand and takes part in forming the deep palmar arch. 9 Arteries of the Hand Radial artery is the major source of blood supply for the dorsal surface of the hand. The branches of this artery form a dorsal arterial arch at the level of carpal bones. The other branches of the radial artery will join with terminal branches of the ulnar artery to form a superficial and a deep palmar arterial arch. Arteries derived from these arches will supply the hand. 10 11 12 13 14 Surface Anatomy of Upper Limb 15 Surface Anatomy of Upper Limb 16 Surface Anatomy of Upper Limb 17 Locations of the Arterial Pulses of the Upper Limb Venous Return of the upper Extremity The venous system of the upper limb drains deoxygenated blood from the hand, forearm, and hand It can anatomically be divided into the superficial veins and the deep veins 19 20 21 22 Upper Limb Area of Transition 23 Cubital Fossa 24 Carpal Tunnel 25 Axilla ❑ Axilla or armpit is a four-sided pyramidal space situated between the upper part of the arm and the chest wall. This space is a transition region between the root of the neck and the upper limb and most of the structures that enter or leave the upper limb pass through this space. ❑ It has 4 walls: √ Anterior wall is formed by the pectoral region. √ Posterior wall is formed by the scapular region √ Medial wall is formed by the upper 4 ribs and the upper part of he serratus anterior muscle that attaches to these ribs. √ Lateral wall is narrow and is formed by the upper part of the humerus. Contents of Axilla Axillary artery and its branches Axillary vein and its tributaries Infraclavicular part of the brachial plexus Axillary Lymph nodes 27 BMS Anatomy Asynchronous Lecture 8 Muscles of the Hand Presented By: Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 247 – 255 The Hand The hand is composed of three parts: the wrist (Carpus), the hand proper (Metacarpus) and the fingers (Digits). The latter are (from lateral to medial) thumb (L. Polex), index (L. Indicis), middle, ring and little (L. digitus minimus) fingers. ❖ The anterior surface of the hand is called the palm and the posterior surface is called the dorsum of the hand. Since the axis of the hand passes through the third metacarpal bone and middle finger, the ABD and ADD of the fingers are considered relative to the long axis of the middle finger. The long axis of the thumb (first metacarpal bone) has 90° medial rotation to the rest of the fingers; as a result, the movements of the thumb are defined at right angles to the movements of the other fingers of hand. ❖Carpal Arch: has been formed by the carpal bones. It is directed anteriorly and has been changed to a tunnel, the so called Carpal Tunnel, by the attachment of the flexor retinaculum to the sides of it. Nine tendons (FDS, FDP & FPL) and a nerve (median nerve) pass through the tunnel. Carpal Tunnel Intrinsic muscles of the hand 1. Thenar 2. Hypothenar 3. Central All these muscles are innervated either by median and/or ulnar nerves. Palmar aponeurosis 6 Thenar group; ❖ Abductor Pollicis Brevis (APB) Ori: - Flexor retinaculum - Tubercle of scaphoid - Tubercle of trapezium Ins: Lateral side of the base of proximal phalanx of thumb Fun: N: 7 ❖Flexor Pollicis Brevis (FPB) Ori: - Flexor retinaculum - Trapezium Ins: Lateral side of the base of proximal phalanx of thumb. Fun: N: 8 ❖Opponens Pollicis (OP) Ori: - Flexor retinaculum - Trapezium Ins: 1st metacarpal Fun: N: 9 ❑ Hypothenar group; All of the hypothenar muscles are innervated by the ulnar nerve Palmaris brevis (PB); Ori: palmar aponeurosis. Ins: skin of the medial side of the hand. Fun: 10 ❖Abductor Digiti Minimi (ADM) Ori: - Pisiform Ins: Medial side of base of proximal phalanx of little finger Fun: N: 11 ❖ Flexor Digiti Minimi Brevis (FDMB) Ori: - Flexor retinaculum - Hook of hamate Ins: Medial side of the base of proximal phalanx of 5th finger Fun: N: 12 ❖ Opponens Digiti Minimi Ori: - Flexor retinaculum - Hook of hamate Ins: 5th metacarpal bone Fun: N: 13 ❑ Central Group of intrinsic hand muscles ❖Adductor Pollicis (AP) Ori: Oblique head: - Base of 2nd & 3rd metacarpal bones - Capitate Transverse head: - Ant. surface of 3rd metacarpal bone Ins: Both heads: - Medial side of the base of proximal phalanx of thumb Fun: N: 14 ADD. Pollicis Note Most of the bulk of the 1st web is made by it 15 ❑ Central Group of intrinsic hand muscles ❖ Lumbrical Muscles; consists of four small and similar muscles. Ori: Tendon of the Flexor Digitorum Profundus (FDP) of each finger Ins: Dorsal digital expansion of four medial fingers - Lumbrical #1: into the dorsal digital expansion of the index finger (finger #2) - Lumbrical #2: into the dorsal digital expansion of the middle finger (finger #3) - Lumbrical #3: into the dorsal digital expansion of the ring finger (finger #4) - Lumbrical #4: into the dorsal digital expansion of the little finger (finger #5) Fun: N: 16 ❑ Central Group of intrinsic hand muscles ❖ Dorsal Interosseous Muscles Ori: Adjacent sides of metacarpals. Ins: Base of proximal phalanges and dorsal digital expansion of fingers (#2, #3,and #4) Dorsal interosseous #1 to the lateral side of the index finger Dorsal interosseous # 2 to the lateral side of the middle finger Dorsal interosseous # 3 to the medial side of the middle finger Dorsal interosseous # 4 to the medial side of the ring finger Fun: N: 17 ❑ Central Group of intrinsic hand muscles ❖ Palmar Interosseous Muscles Ori: Anterior side of metacarpal of fingers #2, 4, and 5 Palmar interosseous #1: metacarpal #2 Palmar interosseous #2: metacarpal #4 Palmar interosseous #3: metacarpal #5 Ins: Base of proximal phalanges and dorsal digital expansion of fingers (#2, 4,and 5) Palmar interosseous # 1 to the index finger (finger #2) Palmar interosseous # 2 to the lateral ring finger (finger #4) Palmar interosseous # 3 to the little finger (finger #5) Fun: N: 18 BMS Anatomy Lecture 7 Introduction to Upper Limb Compartments Arm Muscles Introduction to Anterior Forearm Muscles (In-Person Class) Presented By: Dr. K. Lumsden; [email protected] (Toronto Campus) Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 207 – 211, 220 – 222 Arm Compartments Anterior Compartment: Flexion of the arm at shoulder Flexion of forearm at elbow Supination of the forearm (Musculocutaneous Nerve) Posterior Compartment Extension of the arm at shoulder Extension of forearm at elbow (Radial Nerve) ANTERIOR COMPARTMENT OF THE ARM: Biceps brachii: Ori: Short head: Coracoid process of scapula Long head: Supraglenoid tubercle of scapula Ins: Radial tuberosity and fascia of forearm via bicipital aponeurosis ACTIONS: 1. Flex. of the forearm 2. Supination of the forearm 3. Flex. of the arm INNERVATION: Musculocutaneous nerve Origin from C5,6,7 roots Terminal branch of lateral cord ANTERIOR COMPARTMENT OF THE ARM: Coracobrachialis: Ori: Coracoid process of scapula Ins: Middle third of the medial surface of humerus ACTIONS: 1. Flex. of the arm 2. Adduction of the arm (especially in horizontal adduction) INNERVATION: Musculocutaneous nerve Origin from C5,6,7 roots Terminal branch of lateral cord Coracobrachialis; ANTERIOR COMPARTMENT OF THE ARM: Brachialis: Ori: Distal half of the anterior surface of humerus Ins: - Ulnar tuberosity - Coronoid process of ulna ACTIONS: 1. Flex. of the forearm INNERVATION: Musculocutaneous nerve Origin from C5,6,7 roots Terminal branch of lateral cord POSTERIOR COMPARTMENT OF THE ARM: Triceps brachii: Ori: Long head: Infraglenoid tubercle Lateral head: Lateral, posterior humerus (superior to radial groove) Medial head: Posterior surface of humerus (inferior to radial groove) Ins: Olecranon process of ulna ACTIONS: 1. Extension of the forearm 2. Extension of the arm (long head only) INNERVATION: Radial nerve Origin from C5,6,7,8, T1 roots Terminal branch of posterior cord Forearm Compartments ANTERIOR COMPARTMENT: Main actions: Flexion and Pronation Innervation: Median & Ulnar Ns. POSTERIOR COMPARTMENT: Main actions: Extension and Supination Innervation: Radial N. ANTERIOR COMPARTMENT: ANTERIOR COMPARTMENT: Naming Convention: “First” name = gives an idea of main action “Middle and Last” names = gives an idea of where action is exerted ANTERIOR COMPARTMENT: Superficial Layer: Pronator Teres Flexor Carpi radialis Palmaris Longus Flexor Carpi ulnaris Intermediate Layer: Flexor Digitorum Superficialis SUPERFICIAL LAYER: PRIMARY ACTIONS: If the tendons cross the wrist = FLEX wrist If the tendons cross the phalangeal joints = FLEX digits Pronation of forearm Deep Layer: Flexor Pollicis longus Flexor Digitorum Profundus Pronator Quadratus DEEP LAYER: All of these muscles are innervated by the median nerve, except one and half muscles: FCU and medial half of the FDP, which are innervated by the ulnar nerve. Muscles and Nerves of the Upper Limb Summary of anterior forearm: Superficial Layer = median nerve Flexion of wrist Pronation of forearm Intermediate Layer = median nerve Flexion of digits 2-5 at MCP and PIP joints Deep Layer** Flexion of thumb joints (digit 1) = median nerve Flexion of digits 2-5 all joints Digits 2 and 3 = Median Digits 4 and 5 = Ulnar POSTERIOR COMPARTMENT: POSTERIOR COMPARTMENT: Muscles of the Posterior forearm: All extensor muscles are innervated by the radial nerve. (The brachioradialis muscle in this group is also innervated by the radial nerve; however, it is a flexor of the forearm). SUPERFICIAL LAYER: DEEP LAYER: PRIMARY ACTIONS: Supination of forearm If the muscle crosses the wrist = EXTENSION of wrist If the muscle crosses the digits = EXTENSION of digits POSTERIOR COMPARTMENT: Muscles of the Posterior forearm: Superficial Layer: Brachioradialis Distal humerus to distal radius Anterolateral forearm muscle Functions: Flexion of elbow in “mid-pronation” Beer drinking muscle! Nerve innervation: Radial nerve Lateral Muscles and Nerves of the Upper Limb Muscles that perform Elbow Flexion: Flexion with Supination = Biceps = Musculocutaneous nerve Flexion with pronation = Brachialis = Musculocutaneous nerve Flexion in mid-pronation = Brachioradialis = Radial nerve ❑ Retinacula ❖ the extensor retinaculum, which retains the extensor tendons in position. ❖ the flexor retinaculum, which converts the anterior concavity of the carpus (wrist bones) into a carpal tunnel through which the flexor tendons and median nerve pass. BMS Anatomy Lecture 8 Posterior Forearm Muscles (In-Person Class) Presented By: Dr. K. Lumsden; [email protected] (Toronto Campus) Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 207 – 211, 220 – 222 POSTERIOR COMPARTMENT of Forearm: Remember! all posterior forearm compartment muscles are innervated by Muscles of the Posterior forearm: radial N. SUPERFICIAL LAYER: DEEP LAYER: PRIMARY ACTIONS: Supination of forearm If the muscle crosses the wrist = EXTENSION of wrist If the muscle crosses the digits = EXTENSION of digits ❖ Remember! all posterior forearm compartment muscles are innervated by radial N. Brachioradialis (BR); Ori: Proximal 2/3 of lateral supracondylar ridge of humerus Ins: Lateral surface of distal end of radius proximal to styloid process Fun: 3 N: Muscles and Nerves of the Upper Limb Muscles that perform Elbow Flexion: Flexion with Supination = Biceps = Musculocutaneous nerve Flexion with pronation = Brachialis = Musculocutaneous nerve Flexion in mid-pronation = Brachioradialis = Radial nerve ❖ Extensor Carpi Radialis Longus (ECRL) Ori: Distal 1/3 of lateral supracondylar ridge of humerus Ins: Base of 2nd metacarpal bone Fun: N: 5 ❖Extensor Carpi Radialis Brevis (ECRB) Ori: Lateral epicondyle of humerus (via common extensor tendon) Ins: Base of 3rd metacarpal bone Fun: N: 6 Mobile Wad of Three: BR,ECRL, ECRB ❖ Extensor Digitorum (ED) Ori: Lateral epicondyle of humerus (via common extensor tendon) Ins: Distal and middle phalanges of fingers #2 – 5 (via its dorsal digital expansion) Fun: N: 8 ❖ Extensor digiti minimi (Edm) Ori: Lateral epicondyle of humerus (via common extensor tendon) Ins: Middle and distal phalanges of little finger (via its dorsal digital expansion) Fun: N: 9 Dorsal Digital Expansion (Extensor Hood) ❑ The extensor tendons flatten to form “dorsal digital expansions” or “extensor hoods” on the dorsal aspect of the digits. These are triangular tendinous aponeurosis that wrap around the metacarpophalangeal joints and extend along the proximal and middle phalanges across two interphalangeal joints to attach to the distal phalanx. Interossei and lumbrical muscles attach to their sides. During flexion of the metacarpophalangeal joints by the lumbrical and interossei muscles, the proximal and distal interphalangeal joints are pulled by the extensor expansions into nearly complete extension (Ta-Ta Position). 10 Dorsal Digital Expansions (Extensor Hoods) ❖ Extensor Carpi Ulnaris (ECU) Ori: - Lateral epicondyle of humerus (via common extensor tendon) - Posterior border of ulna Ins: Base of 5th metacarpal bone. Fun: N: 12 ❖ Anconeus Ori: Lateral epicondyle of humerus Ins: - Olecranon process of ulna - Proximal of posterior surface of ulna Fun: N: 13 ❖ Supinator Ori: 1. Supinator crest of ulna 2.Lateral epicondyle of humerus Ins: Proximal 1/3 of lateral surface of radius Fun: N: 14 Supinator M. Notes Two heads, relationship with deep branch of radial N. Deep branch of radial nerve within heads of supinator 15 ❖ Abductor Pollicis Longus (APL) Ori: The middle of posterior surface of radius, ulna, and interosseous membrane Ins: Base of the 1st metacarpal Fun: N: 16 ❖ Extensor Pollicis Brevis (EPB) Ori: Distal 1/3 of posterior surface of radius and interosseous membrane Ins: Base of proximal phalanx of thumb Fun: N: 17 ❖ Extensor Pollicis Longus (EPL) Ori: Middle 1/3 of posterior surface of ulna and interosseous membrane Ins: Base of distal phalanx of thumb Fun: N: 18 ❖ Extensor Indicis (EI) Ori: Distal 1/3 of posterior surface of ulna and interosseous membrane Ins: Dorsal digital expansion of the 2nd finger Fun: N: 19 Anatomical Snuff Box  The tendons of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) bound the triangular anatomical snuff box laterally, and the tendon of the extensor pollicis longus (EPL) bounds it medially.  The “snuff box” is visible as a hollow on the posterolateral aspect of the wrist when the thumb is extended fully. This draws the APL, EPB, and EPL tendons up and produces a concavity between them.  The scaphoid and trapezium bones form the floor of the impression and can be palpated. The radial artery passes through the anatomical snuff box deep to the extensor tendons of the thumb. 20 Forearm Flexor and Extensor muscles clinical anatomy Medial Epicondylitis (Golf Elbow) Forceful and repeated bending of the wrist and fingers cause tiny ruptures of common flexor tendon. Golfing is only one of the causes of the pain at this bone. In the golf swing, the flexor muscles and tendons must tighten to hit the ball. Similar tasks that require repeated bending of the wrist, gripping, grasping, and turning the hand are common activities that cause medial epicondylitis. Small tears in the muscle begin to heal but when re-injured by continued use, become painful. Symptoms include tenderness and pain at the medial epicondyle, made worse by flexing the wrist. Forearm Flexor and Extensor muscles clinical anatomy Lateral Epicondylitis (Tennis Elbow) Tennis Elbow or Lateral Epicondylitis is a condition when the common extensor tendon becomes painful and tender, usually as a result of a specific strain, overuse, or a direct bang. Sometimes no specific cause is found. Symptoms include tenderness and pain of the outer part of the lateral epicondyle. CLINICAL CORRELATION: Radial Nerve Injury = Damage to the posterior cord of the brachial plexus What terminal branches would be affected? What muscle(s) would be affected? Deltoid, Teres Minor Distal Triceps, Anconeus, superficial and deep layers of forearm muscles Confirmed by testing strength of muscles and comparing bilaterally What movements would be affected? Weakness in abduction and external rotation of shoulder Loss of extension: elbow, wrist and fingers Weakness in supination What sensory deficits might be present? Loss of sensation to lateral aspect of shoulder, posterior forearm and lateral 3.5 digits (dorsal surface) What long term deficits might occur? “Wrist Drop” deformity and Deltoid atrophy BMS Anatomy Lecture 9 Upper Limb Nerves , Dermatomes & Myotomes (In-Person Class) Presented By: Dr. K. Lumsden; [email protected] (Toronto Campus) Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 165 – 174 RECALL: The Brachial Plexus Supraclavicular Branches: Branches that exit the brachial plexus “superior” to the clavicle Largely located in the cervical region Important branches: Long Thoracic Nerve Suprascapular Nerve Dorsal Scapular Nerve ANTERIOR, Right side Infraclavicular Branches (terminal Branches) Branches exit plexus inferior to clavicle Primarily located in axilla / armpit Musculocutaneous (C5,6,7) Axillary (C5/6) Radial (C5 – T1) Median (C5 – T1) Ulnar (C8/T1) 2 Musculocutaneous Nerve Origin: terminal branch of lateral cord Functions: Motor to anterior arm: Coracobrachialis Biceps Brachialis Sensory to : Skin of anterolateral forearm ANTERIOR, Right side Musculocutaneous Nerve - Terminal Branch of lateral cord within axilla - Travels through the coracobrachialis muscle belly *Most likely site of injury - Innervates muscles of the anterior compartment of the arm - Continues after passing the cubital fossa as the Lateral. Cutaneous N. of forearm 4 Axillary Nerve Origin: terminal branch of posterior cord Function: Motor to lateral shoulder: Deltoid Teres minor Sensory to: Skin of lateral shoulder ANTERIOR, Right side Axillary Nerve - Pathway: heads posteriorly in axilla - Travels through the quadrangular axillary space - Wraps around posterior aspect of humeral neck - Relationship with the surgical neck of humerus *Most likely site of injury - Innervates deltoid and Teres minor 6 Axillary Nerve Injury MOI: Fracture of Surgical neck of Humerus 7 Radial Nerve Radial nerve (C5, C6, C7, C8 and T1) Origin: terminal branch of posterior cord Function: Motor To: Extensor muscles of posterior arm Extensor muscles of posterior forearm Brachioradialis Supinator muscle Sensory to: Skin of posterior arm, forearm and hand Dorsal surface of digits 1, 2, 3 and lateral ½ of digit 4 (typically written as lateral 3.5 digits, dorsal surface) “Great extensor nerve” Posterior View Radial Nerve - Pathway: heads posteriorly in axilla - Travels posteriorly, inferior to the quadrangular axillary space - wraps around posterior aspect of humeral shaft - Relationship with the radial groove of humerus *Most likely site of injury - Innervates extensors of arm and forearm and supinator 9 Radial Nerve in Cubital Fossa 10 Radial Nerve - Sensory branches in posterior arm: - Post. Cutaneous Nerve of Forearm - Lower lateral cutaneous nerve of arm 11 Radial Nerve Terminal branches of radial N. Deep branch (motor) – innervates the muscles in the posterior compartment of the forearm. Superficial branch (sensory) – contributes to the cutaneous innervation of the dorsal hand and fingers. 12 Radial N. Palsy (Wrist Drop) MOI: Fracture of radial groove of Humerus 13 Median Nerve Median nerve (C5, C6, C7, C8 and T1) Origin: terminal branch of lateral and medial cords Function: Motor to Muscles of the anterior forearm and hand: Flexors of wrist Pronators of forearm Flexors of Digits 1, 2, 3 Lumbricals 1 and 2 Thenar muscles Sensory to: Palmer surface of digits 1, 2, 3 and lateral ½ of digit 4 (typically written as lateral 3.5 digits, palmer surface) Palmer View ANTERIOR, Right side Pathway: heads inferiorly from axilla, travelling down antero-medial arm (within layers of muscle) crosses anterior elbow within cubital fossa *likely site of injury travels down anterior forearm enters hand via carpal tunnel *likely site of injury Median Nerve injury Carpal Tunnel Syndrome: Compression of the median nerve as it passes through the carpal tunnel Typing Mechanics Pregnancy Obesity Will first impact function of median nerve in the hand (motor and sensory) Patient often complains of numbness and tingling in the first 3.5 digits and weakness of thumb movement As the condition progresses, sensory changes can radiate into the forearm, and even the axilla. To relieve symptoms, partial or complete surgical division of the flexor retinaculum may be necessary – this is known as ‘carpal tunnel release’. 16 Ape hand deformity (Median nerve lesion) 17 Ulnar Nerve ANTERIOR, Right side Ulnar nerve (C8 and T1) Origin: terminal branch of medial cord Function: Motor to medial forearm and hand: Medial ½ of flexor digitorum profundus Hand intrinsics Lumbricals 3&4 Hypothenar group Palmer and Dorsal Interossei Sensory to: Palmer and Dorsal surface of medial ½ of digit 4 And all if digit 5 (typically written as medial 1.5 digits) Dorsal Palmer Pathway: heads inferiorly from axilla, travelling down antero-medial arm (protected by muscle) passes posterior to medial epicondyle, *Most likely site of injury travels down medial forearm enters hand external to carpal tunnel 19 Ulnar Claw Hand MOI: Fracture of medial epicondyle of Humerus 20 Axillary C5-C6 Cutaneous Supply from Brachial Plexus: Radial C5, C6, C7, C8, T1 Medial Brachial Cutaneous Medial Antebrachial Cutaneous Musculocutaneous C5, 6, 7 Radial C5, C6, C7, C8, T1 Median C5, C6, C7, C8, T1 Ulnar C8 - T1 Cutaneous Supply from Brachial Plexus: Median Palmer surface of lateral 3.5 digits Ulnar Palmer and dorsal surface of medial 1.5 digits Radial Dorsal surface of lateral 3.5 digits RECALL: Anatomy of the Spinal Nerves There are 31 pairs of spinal nerves exiting off spinal cord Nerves are WHITE matter pathways that provide a route for motor and sensory signals to travel between PNS and CNS Spinal nerves are IPSILATERAL and will carry signals to and from targets/receptors on the same side of the body Posterior/Dorsal root carries sensory/afferent information into CNS so it can ascend in the cord to reach the cortex Ventral/Anterior root carries motor/efferent information out of CNS that has descended from the cortex to the cord Swelling/bulb contains the soma/cell bodies of incoming sensory cells Ventral & Dorsal roots come together to form a spinal nerve in the intervertebral foramen 23 Dermatomes and Myotomes Dermatome is a specific area on the skin innervated by a specific spinal root Myotome is a specific group of muscles innervated by a particular spinal root. Testing both dermatome and myotomes can provide important clinical feedback about the function of spinal nerves 24 25 Dermatomes of the Upper Limb Dermatomes of the Upper Limb 27 Nerve Root Myotome Function C5 Deltoid muscle Abduction of the arm at the shoulder C6 Biceps Flexion of the arm at the elbow C7 Triceps Extension of the arm at the elbow C8 Small muscles of the hand Finger flexion T1 Small muscles of the hand Finger Abduction 28 Myotomes of the Upper Limb https://www.youtube.com/watch?v=8UcSvosgKWA 29 Clinical Test: C5 Dermatome = sensation of skin of anterior/lateral arm (skin over deltoid) Myotome = muscle strength of deltoid (arm abduction) 30 Clinical Test: C6 Dermatome = sensation of anterior skin of thumb Myotome = muscle strength of biceps (elbow flexion) 31 Clinical Test: C7 Dermatome = sensation of anterior skin of digits 2 and 3 Myotome = muscle strength of triceps (elbow extension) 32 Clinical Test: C8 Dermatome = sensation of skin of digits 4 and 5 Myotome = muscle strength of finger flexors 33 C8 Motor Nerve 34 Clinical Test: T1 Dermatome = sensation of skin of antero/medial elbow Myotome = muscle strength of finger abductors 35 The Reflex Arc. Simplest of all neural responses Automatic Predictable Acquired Summary of Deep Tendon Reflexes of Upper Limb 37