Anatomy of the Upper Limb

Anatomy of the Upper Limb The Axilla Boundaries • • • • Medially: serratus anterior and thoracic wall Laterally: intertubercular sulcus Anteriorly: pectoralis muscles Posteriorly: latissimus dorsi, scapularis and teres major Contents of the axilla • • • • • Axillary artery Axillary vein Brachial plexus Biceps branchii and coracobrachialis Axillary lymph nodes Page 1 of 48 Clinical Significance • • • • First site of breast cancer metastasis - Axillary node involvement is the single most significant prognostic variable for breast cancer patients. Axillary region compression or stretching leading to damage can result in palsy (paralysis with tremors) of the radial nerve. The long thoracic nerve descends in the axillary region and compression, or damage of the nerve may give rise to winged scapula deformity. - Compression of the nerve may be a result from a tumour, an enlarged lymph node, or an aneurysm. If a patient has a pneumothorax, pleural effusion, or haemothorax (air, fluid, or blood in the intrapleural space, respectively), a chest tube is likely to be inserted. Local anaesthetic and skilful technique are required for the procedure to be safe. The safe region to insert this is in the triangle of safety. This is marked by the lateral border of pectoralis major anteriorly, the apex is just below the axilla, the horizontal line at the level of the nipple marks the base, and posteriorly by the anterior border of latissimus dorsi. Muscles of the shoulder girdle and glenohumeral joint Anterior thorax muscles Muscle Pectoralis major (Both heads) Origin Insertion Clavicular head – Intratubular groove medial half of clavicle Sternocostal head – ant. Surface of sternum, rib 1-6 costal cartilages Innervation Lat. + med. Pectoral nerves Function Horizonal Adduction + medial rotation (heads can function independently) Pectoralis minor Surface of ribs 3-5 Medial pectoral nerve (C8-T1) Protraction + rotation of scapula (Boxer/s muscle), accessory resp. muscle and abuduction Depress scapula Depress + stabilise clavicle Serratus Ribs 1-9 anterior Subclavius 1st rib Page 2 of 48 Coracoid process Medial boarder of the Long thoracic nerve scapula Inferior surface of Subclavian nerve (C5,6) clavicle Page 3 of 48 vvvvvvvvvvv Page 4 of 48 Scapulohumeral muscles Muscles from the scapula to the humerus including the rotator cuff muscles, Teres major and Deltoids. Muscle Supraspinatus Infraspinatus Teres minor Subscapularis Teres major Origin Insertion Medial 2/3 of Superior facet on supraspinous fossa greater tubercle (humerus) Medial 2/3 of Mid. Facet on greater infraspinous fossa tubercle (humerus) Upper 2/3 of post. Inf. facet on greater And lat. Aspect of tubercle (humerus) infraspinous fossa Subscapular fossa Lesser tubercle of humerus Innervation Suprascapular nerve (C5,6) Suprascapular Lat. Rotation + stabilise nerve (C5,6) Axillary nerve (C5,6) Lat. Rotation + stabilise Upper + lower subscapular nerves (C5,6) Dorsal surface of Medial lip of Lower subscapular scapula (towards intertubercular groove nerve (C5,6) inf. angle) Deltoids Function Initiate abduction + stabilise Medial rotation, adduction + stabilise Adduction rotation • • • Page 5 of 48 and medial Anterior: adduction and internal rotation of the arm at the shoulder joint Medial: abduction of the arm at the shoulder joint. Posterior: extension, abduction and external rotation. Posterior Thorax Muscles Refer to the back and the cervical spine notes. Page 6 of 48 Muscles of the Arm Anterior compartment Muscle Coracobrachialis Biceps brachii Brachialis Origin Tip of coracoid process Insertion Innervation Mid 1/3 of humerus Musculocutaneous (C5-7) Musculocutaneous • Long head: Radial tuberosity nerve (C5,6) supraglenoid tubercle • Short head: coracoid process (apex) Distal portion of ant. Tuberosity of ulna Musculocutaneous Humerus nerve (C5,6) + sometimes radial (C7) Page 7 of 48 Function Flex + adduct arm Secondary supination flexor + Primary forearm flexor (MVP!) Page 8 of 48 Page 9 of 48 Page 10 of 48 Posterior Compartment Muscle Triceps Brachii Origin Insertion • Long head: Olecranon infra-glenoid tubercle (scapula) • Medial + lateral heads: posterior surface of humerus Page 11 of 48 Innervation Radial nerve (C6-8) Function Elbow extension Page 12 of 48 Page 13 of 48 Page 14 of 48 Blood Vessels of the Upper Limb Arteries Axillary Artery Origin Subscapular Branch of third segment of the axillary artery Anterior humeral circumflex artery (Smaller than the posterior one) Posterior humeral circumflex artery lateral side of the axillary artery Course Major Branches structures or regions supplied by this artery Thoracodorsal Deltoid muscle, • arises after the lateral thoracic artery at the level of artery, circumflex latissimus dorsi muscle, long head of triceps the inferior margin of the scapular artery brachii muscle, subscapularis muscle. subscapularis muscle, • runs inferolateral on the supraspinatus muscle, posterior axillary wall, infraspinatus muscle, following the lateral border serratus anterior of the subscapular muscle. muscle, adjacent skin Encircle surgical neck of humerus, Descending On reaching the anastomosing with each other branch intertubercular sulcus, it laterally, larger posterior branch gives off a branch which traverses’ quadrangular space ascends in the sulcus to supply the head of the humerus and the shoulder joint. Third part of Encircle surgical neck of humerus, Descending the axillary anastomosing with each other branch artery laterally, larger posterior branch traverses’ quadrangular space Page 15 of 48 Glenohumeral (shoulder) joint, deltoid muscle, teres major muscle, teres minor muscle, and long and lateral heads of the triceps muscle Page 16 of 48 Page 17 of 48 Brachial Artery Artery Origin Profunda Brachial brachii artery Page 18 of 48 Course Accompanies radial nerve along radial groove of humerus, supplying posterior compartment of arm and participating in periarticular arterial anastomosis around elbow joint Major Branches structures or regions supplied by this artery Page 19 of 48 Page 20 of 48 Page 21 of 48 Superficial veins Vein Origin Cephalic (Empties into the axillary vein) The cephalic vein forms over the anatomical snuffbox at the radial end of the dorsal venous network of hand Basilic Median cubital vein Intermediate antebrachial vein Page 22 of 48 Course • • Major Branches From its origin, it ascends up the lateral aspect of the radius Near the shoulder, the cephalic vein passes between the deltoid and pectoralis major muscles (deltopectoral groove) and through the clavipectoral triangle, where it empties into the axillary vein structures or regions drained by this vein Radial parts of the hand, forearm and arm Page 23 of 48 Page 24 of 48 Page 25 of 48 Deep Veins Vein Origin Radial Ulnar Brachial Axillary Page 26 of 48 Course Major Branches structures or regions drained by this vein Page 27 of 48 Nerves of the upper limb- Brachial Plexus Key Information The brachial plexus is the network of nerves supplying cutaneous, muscular, articular and vasomotor innervation to the upper limb. Identify the divisions of the brachial plexus including their peripheral branches. The divisions of the brachial plexus are divided into roots, trunks, divisions, cords and terminal branches. Page 28 of 48 Roots Formed by the ventral (anterior) rami of spinal nerves C5-T1. The following branches should be noted: Dorsal Scapular Nerve Long Thoracic Nerve Spinal Roots General Course Function Anterior/ventral • arises just above the clavicle, • provides motor innervation to the root of spinal nerve from the proximal part of the rhomboid major and rhomboid C5 anterior ramus of C5 spinal minor muscles. nerve. • supplies the levator scapulae • It pierces the scalenus medius muscle along with the branches muscle and descends between arising from spinal nerves C3 and C4 the levator scapulae on one side • aids in elevation and adduction of and serratus posterior the scapula toward the spinal superior and scalenus posterior column muscles on the other side. Lateral branch of • These nerve roots commence • a motor nerve that provides branchial plexus deep to the scalenus medius innervation to the serratus anterior and arises from muscle to form the trunk of the muscle spinal nerves C5, long thoracic nerve. • Since the long thoracic nerve is the C6, and C7 • Due to its relatively superficial only nerve to innervate the serratus location, almost the entire anterior muscle, its damage causes course of the nerve is easily the paralysis of this muscle, visible in cadavers. resulting in a winged scapula. • Upon arising, the trunk of the nerve descends posteriorly to the brachial plexus, axillary artery and axillary vein, and anteriorly to the scalenus posterior muscle. • The long thoracic nerve courses distally and laterally, deep to the clavicle and superficial to the first and second ribs. • It continues along the anterior thoracic wall in the mid-axillary line and ends on the superficial surface of the serratus anterior muscle. Trunks Identify the spinal roots of the following trunks of the brachial plexus. • • • Superior - C5 and C6 Middle - C7 Inferior - C8 and T1 Page 29 of 48 Identify the following branches of the superior trunk. General Course of Passes laterally across lateral cervical region (po sterior triangle of neck), superior to brachial plexus, then through the scapular notch inferior to superior transverse scapular ligament Nerve to subclavius Superior trunk, receiving Descends posterior to clavicle fibres from C5, C6 and and anterior. often C4 to brachial plexus and subclavian artery ; often giving an accessory root to phrenic nerve Suprascapular nerve Spinal Roots Superior trunk brachial plexus Page 30 of 48 Function • Motor supply: supraspinatus muscle, infraspinatus muscle • Sensory supply: glenohumeral and acromioclavicular joints Subclavius and sternoclavicular joint (Accessory phrenic root innervates diaphragm) Divisions There are six divisions with an anterior and a posterior division coming off each trunk Cords and Terminal Branches Page 31 of 48 Clinical Question What is Erb’s Palsy? • • In Erb palsy, there’s an injury to the upper trunk of the brachial plexus, which is typically caused by an increase in the angle between the neck and the shoulder. This causes loss of sensation in the upper arm, in addition to paralysis to the deltoid, biceps, and brachialis muscles. The Forearm The cubital fossa Contents of the cubital fossa • • • • Radial nerve Biceps tendon Brachial artery Median nerve Clinical significance of the cubital fossa serves as a passageway for vascular and nervous structures passing between the upper arm and forearm. Page 32 of 48 Page 33 of 48 Forearm Muscles Anterior Compartment Superficial layer Muscle Pronator teres Flexor carpi radialis* Palmaris longus Flexor carpi ulnaris* Flexor digitorum superficialis* Origin Coronoid process of ulna for ulna head and Medial epicondyle of humerus (common flexor origin) for humeral head Medial epicondyle of humerus (common flexor origin) Medial epicondyle of humerus (common flexor origin) Medial epicondyle of humerus (common flexor origin) for humeral head and olecranon and posterior boarder of ulna via aponeurosis for ulna head Medial epicondyle (Common flexor origin and coronoid process) for humeral-ulnar head and superior half of anterior border of radial head Page 34 of 48 Insertion Innervation Function Midshaft of the radius Median nerve (C6, Pronates and flexes on its lateral surface C7) forearm (At elbow) Base of metacarpal 2nd Median nerve (C6, Flexes and abducts C7) hand (at wrist) Distal half of flexor retinaculum and apex of palmar aponeurosis Pisiform, hook of hamate, 5th metacarpal Median nerve (C7, Flexes hand (at wrist) C8) and tenses palmar aponeurosis Ulnar nerve (C7, Flexes and adducts C8) hand (at wrist) Shafts of middle Median nerve (C7, phalanges of medial C8, T1) four digits Flexes middle phalanges at proximal interphalangeal joints of middle four digits; acting more strongly, it. also, flexes proximal phalanges at metacarpophalangeal joints Page 35 of 48 Page 36 of 48 Page 37 of 48 Page 38 of 48 * Extrinsic muscles of the hand Note: Palmaris longus is absent in ~15% of the population Deep layer Muscle Pronator quadratus Origin Insertion Distal quarter of Distal quarter of anterior surface of ulna anterior surface of radius Flexor pollicis longus* Anterior surface of the Base of the distal radius and the phalanx of digit 1. interosseous membrane. Flexor profundus* digitorum Proximal three fourths of the anterior and medial surfaces of the ulna and the Page 39 of 48 Base of the palmar surface of the distal phalanges of digits 2-5. Innervation Anterior interosseous nerve, from median nerve (C8, T1) Anterior interosseous nerve, from median nerve (C8, T1) Anterior interosseous nerve, from median Function Pronates forearm; deep fibres bind radius and ulna together Flexes phalanges of 1st digit (thumb) • Lateral part: flexes distal phalanges 2 and 3 at distal interosseous membrane. nerve (C8, T1) for lateral part and ulnar nerve (C8 and T1) for medial head • interphalangeal joints Medial part: flexes distal phalanges 4 and 5 at distal interphalangeal joints Posterior Compartment Superficial layer Muscle Origin Brachioradialis (more Lateral prominent ant.) (humerus) Anconeus Posterior epicondyle Insertion Innervation condyle Lateral distal Radial Nerve radius lateral Posterior Radial Nerve proximal ulna Extensor carpi radialis Lateral condyle longus* humerus Extensor carpi radialis Lateral epicondyle brevis* humerus Extensor digitorum* Lateral epicondyle humerus Extensor digiti minimi* Lateral epicondyle humerus Lateral epicondyle humerus Extensor carpi ulnaris* Page 40 of 48 of Dorsal surface base of 2nd metacarpal of Dorsal surface base of 3rd metacarpal of Extensor hoods at base of middle + distal phalanges (index to little finger) of Extensor hood of little finger of Base of 5th metacarpal Radial Nerve Function Accessory forearm flexor Ulna abduction during pronation + accessory elbow extensor Wrist extension + abduction Radial Nerve Wrist extension + abduction Radial Nerve Digit extension Radial Nerve Extend little finger Radial Nerve Adduct + extend wrist Page 41 of 48 Page 42 of 48 Deep Layer Muscle Supinator Origin • Lateral epicondyle of humerus • Radial collateral ligament • Annular ligament • Supinator crest of ulnar pollicis Posterior surface of proximal half of radius, ulna, and interosseus membrane Abductor longus* Extensor brevis* pollicis Posterior surface of distal third of radius and interosseus membrane pollicis Posterior surface of middle third of ulna and interosseus membrane Extensor longus* Extensor indicis* Posterior surface of distal third of ulna and interosseous membrane Insertion Lateral, posterior and anterior surfaces of the proximal radius Base of Posterior metacarpal bone interosseous nerve 1 (trapezium (C7, C8) bone) Blood Vessels and Nerves Need to know origin, course and major branches • • Radial and ulnar - Superficial palmar arches - Dep palmar arches Veins - Cephalic - Basilic Page 43 of 48 • joint: Radiocarpal joint: hand extension • Carpometacarpal joint: thumb abduction and extension Posterior aspect Posterior Carpometacarpal and of base of interosseous nerve metacarpophalangeal joint 1: proximal phalanx (C7, C8) Thumb extension of thumb Posterior aspect Posterior • Wrist joints: weak of base of distal interosseous nerve hand extension phalanx of (C7, C8) • Metacarpophalangeal thumb and interphalangeal joint of the thumb” thumb extension Extensor Posterior • Wrist joints: weak expansion of interosseous nerve hand extension index finger (C7, C8) • Metacarpophalangeal and interphalangeal joints of index finger: Finger extension *Extrinsic muscles of the hand Arteries Innervation Function Posterior Proximal radioulnar interosseous nerve forearm supination (C7, C8) • Nerves - Radial - Median - Ulnar The wrist and the hand Important note: the carpal bones and arranged in rows of four. They articulate with the forearm and the metacarpals. Identify • • • • • • • • • Scaphoid Lunate Triquetrum Pisiform Trapezium Trapezoid Capitate Hamate Five metacarpals’ numbers medial to lateral (1-5) Carpal Tunnel • • Function: a passageway from the wrist to the hand. It is made from tendons, ligaments and bones. The median nerve passes through here, which provides sensation to the thumb, index finger, middle finger, and the thumb side of the ring finger. Borders: Flexor retinaculum • Attachments: - On the ulnar side, the flexor retinaculum attaches to the pisiform bone and the hook of the hamate bone. - On the radial side, it attaches to the tubercle of the scaphoid bone, and to the medial part of the palmar surface and the ridge of the trapezium bone. Page 44 of 48 Joints of the wrist Radiocarpal Joint Type Synovial ellipsoid joint Ligaments Articular surfaces Movements Palmar radiocarpal joint, dorsal • Proximal component - distal end of Flexion, extension, adduction radiocarpal ligament, ulnar and abduction radius, articular disc collateral ligament, radial • Distal component - scaphoid, lunate collateral ligament and triquetral of the proximal row of carpal bones (also includes triangular fibrocartilage complex) Major ligaments of the wrist • • • • Palmar radiocarpal Dorsal radiocarpal Ulnar collateral Radial collateral Features of the wrist joint • • Connects and serves as a transitional joint between the forearm and the hand It is a condyloid joint, which means it is a modified ball and socket joint that allows for flexion, extension, abduction, and adduction movements Joints of the hand Identify the hand joints, determine their movements, and describe the articular surfaces and ligaments • • • • • • • • Intercarpals Subtalar Carpometacarpals Intermetacarpals Metacarpophalangeal (M.P.) Interphalangeal (I.P.) Thumb Fingers Muscles of the hand • • Extrinsic muscles of the hand arise in the foreman (described above) * Intrinsic muscles of the hand are organised into five compartments. Interosseous compartment • Located between the metacarpals. Page 45 of 48 Name Dorsal interossei Palmar interossei Origin Insertion Adjacent sides of • 1 & 2: Radial bases of metacarpal bones proximal 1-5 phalanges/extensor expansions of digits 2 & 3 • 3 & 4: Ulnar bases of proximal phalanges/extensor expansions of digits 3 and 4 Ulnar side of • 1: Ulnar base of proximal metacarpal bone 2, phalanx/extensor Radial side of expansion of digit 2 metacarpal bones 4 • 2 & 3: Radial base of and 5 proximal phalanges/extensor expansions of digits 4 and 5 Innervation Function Deep branch of • Metacarpophalangeal ulnar nerve (C8 – joints 2-4: Finger T1) abduction, finger flexion. • Interphalangeal joints 2-4: Finger extension Deep branch of ulnar nerve (C8T1) • • Metacarpophalangeal joints 2,4 & 5: Finger adduction, Finger flexion. Interphalangeal joints 2,4 & 5: Finger extension Central compartment • With long flexor tendons Name Origin Insertion Innervation Function Lumbricals Tendons of flexor Extensor expansion • Lumbricals 1-2: • Metacarpophalangeal digitorum profundus of hand Median nerve (C8joints 2-5: Finger muscle T1) flexion • Lumbricals 3-4: Ulnar • Interphalangeal joints nerve (C8-T1) 2-5: Finger extension • Mnemonic: '1 2 me, 3 4 u' (One to me, three for you) Thenar Compartment • Name Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis Located at the base of the thumb for the thumb movement Origin Tubercle of trapezium bone, flexor retinaculum Tubercles of scaphoid and trapezium bones, Flexor retinaculum • • Insertion Radial border of metacarpal bone 1 Lateral aspect of base of proximal phalanx 1 (via radial sesamoid bone) Lateral aspect of Superficial head: Flexor base of proximal phalanx 1 (via radial retinaculum, tubercle of sesamoid bone) trapezium bone Deep head: Trapezoid and capitate bones Page 46 of 48 Innervation Function Recurrent branch of median Carpometacarpal joint nerve (C8, T1) Thumb opposition Recurrent branch of median Carpometacarpal joint nerve (C8, T1) Thumb abduction • • 1: 1: and Superficial head: Carpometacarpal Recurrent branch of metacarpophalangeal joint 1: Thumb flexion median nerve Deep head: Deep branch of ulnar nerve (C8, T1) Hypothenar Compartment • Name Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis Located at the base of the cute little fingers. Origin Insertion Innervation Function Hook of hamate bone, Ulnar aspect of Deep branch of ulnar nerve Carpometacarpal joint 5: flexor retinaculum metacarpal bone 5 (C8, T1) Finger flexion, finger lateral rotation/opposition Pisiform bone Ulnar side of base • Metacarpophalangeal Deep branch of ulnar nerve (Pisohamate ligament, of proximal phalanx joint 5: Finger (C8, T1) Tendon of flexor carpi of digit 5, Extensor abduction and ulnaris) expansion of digit 5 flexion. • Interphalangeal joints: Finger extension Hook of hamate, flexor Base of proximal Deep branch of ulnar nerve Metacarpophalangeal joint retinaculum phalanx of digit 5 (C8, T1) 5: Finger flexion (+ finger lateral rotation/opposition) Adductor Compartment Name Adductor pollicis Origin • Transverse head: Palmar base of metacarpal bone 3 • Oblique head: Capitate bone, palmar bases of metacarpal bones 2 & 3 Insertion Innervation Function Medial base of Deep branch of ulnar nerve Carpometacarpal joint proximal phalanx 1 (C8, T1) Thumb adduction (via ulnar sesamoid bone) 1: Not Compartmentalised Muscles Name Origin Insertion Innervation Function Palmaris brevis Palmar aponeurosis, Dermis of skin of Superficial branch of ulnar Tightens palmar flexor retinaculum hypothenar region nerve (C8, T1) aponeurosis, tightens grip Blood Vessels For the following blood vessels and nerves, identify the origin, course, and major branches. Arteries • Radial - Deep palmer arch Page 47 of 48 • - Princeps pollicis Ulnar - Superficial palmer arch - Common palmer digital Veins • • Cephalic - Dorsal venous arch Basilic - Dorsal venous arch Nerves • • • Median - Recurrent - Palmer digital Ulnar - Superficial - Deep Radial - Superficial Page 48 of 48