Upper Limb Notes - Agam Notes - PDF

Preface Agam is a group of budding medicos, who are currently doing their under graduation in various Medical Colleges across Tamil Nadu and Pondicherry. The group was initiated on 18th November 2017, in the vision of uniting medicos for various social and professional causes. We f...

Preface Agam is a group of budding medicos, who are currently doing their under graduation in various Medical Colleges across Tamil Nadu and Pondicherry. The group was initiated on 18th November 2017, in the vision of uniting medicos for various social and professional causes. We feel delighted to present you Agam Anatomy notes prepared by Agam Divide and Rule 2020 Team to guide our fellow medicos to prepare for university examinations. This is a reference work of 2017 batch medical students from various colleges. The team took effort to refer many books and make them into simple notes. We are not the authors of the following work. The images used in the documents are not copyrighted by us and is obtained from various sources. Dear readers, we request you to use this material as a reference note, or revision note, or recall notes. Please do not learn the topics for the 1st time from this material, as this contain just the required points, for revision. Acknowledgement On behalf of the team, Agam would like to thank all the doctors who taught us Anatomy. Agam would like to whole heartedly appreciate and thank everyone who contributed towards the making of this material. A special thanks to Srivardhany Bhaskar and M. Snaha, who took the responsibility of leading the team. The following are the name list of the team who worked together, to bring out the material in good form. Karthika Devi S Ram Girythar VRS Lehak Agarwal Rifkhaa J Balamurugan Kiruthika P Gayathri Raveena Suvitha Isyalakshmi B Tharshna Priya B Prasanna Pandian S Kirthana Sri Kamali G Ashiq Ahamed Jawid Nazir Tanushree Kumaresan Varshni R Sanjana Singh Poorna Ajithvaas V C Sharupreethi S Harsha M Aathira Sunilkumar Yashi Awasthi Pranav. L. V Geethik Yallanti  1 INDEX – UPPERLIMB - ESSAYS: SR. NO. NAME OF THE QUESTION PAGE NO. 1. AXILLARY ARTERY 2 2. BRACHIAL PLEXUS 9 3. SHOULDER JOINT 15 4. ELBOW JOINT 22 5. BRACHIAL ARTERY 28 6. MEDIAN NERVE 31 7. RADIAL NERVE 33 8. ULNAR NERVE 38 9. MAMMARY GLAND 42 AGAM  2 1.. AXILLARY ARTERY COMMENCEMENT – upper border of first rib, continuation of subclavian artery COURSE – in axilla, runs along lateral wall nearer to anterior wall. In axilla – crossed superficially by pectoralis minor muscle PARTS OF AXILLARY ARTERY: Pectoralis minor divides it into 3 parts 1. FIRST PART – superior to muscle 2. SECOND PART- posterior to muscle 3. THIRD PART – inferior to muscle AGAM  3 RELATIONS OF AXILLARY ARTERY: PART ANTERIOR POSTERIOR MEDIAL LATERAL FIRST Skin, Superficial Medial cord of Axillary Brachial plexus fascia, Deep fascia PART Pectoralis major brachial plexus vein – lateral & (clavicular part) Serratus anterior posterior cords Clavicular fascia (1st & 2nd div.) Loop of communication Nerve to serratus b/w lateral & anterior medial pectoral nerves AGAM  4 PART ANTERIOR POSTERIOR MEDIAL LATERAL SECOND Skin, Brachial Brachial plexus Brachial plexus – PART superficial plexus – – medial cord lateral cord fascia, deep posterior cord Medial pectoral coracobrachialis fascia Subscapularis nerve Pectoralis Axillary vein major Pectoralis minor AGAM  5 PART ANTERIOR POSTERIOR MEDIAL LATERAL THIRD Skin, Radial nerve Axillary vein Coracobrachialis PART superficial Axillary nerve Medial Musculocutaneous fascia, deep (in upper part) cutaneous nerve (in upper part) fascia Subscapularis nerve of Lateral root of Pectoralis (in upper part) forearm & median nerve (in major (in Tendons of ulnar nerve upper part) upper part) Latissimus Medial Trunk of median Medial root dorsi & Teres cutaneous nerve (in lower part) of median major (in lower nerve of arm nerve (in part) upper part) AGAM  6 BRANCHES OF AXILLARY ARTERY: Six branches: one – from 1st part, two – from 2nd part, three – from 3rd part 1ST PART: 1.SUPERIOR THORACIC ARTERY (from first part) Arises near subclavius Passes b/w pectoral muscles Ends by supplying pectoral muscles AGAM  7 2ND PART: 2.THORACOACROMIAL ARTERY 3. LATERAL THORACIC ARTERY Arises & runs along pectoralis minor Arises near pectoralis minor (upper (lower border) border) Closely related to ant. group of axillary Pierces clavipectoral fascia lymph nodes Gives 4 terminal branches – In females, it gives lateral mammary pectoral br., deltoid br., acromial branches to breast. br., clavicular br. 3RD PART: 4.SUBSCAPULAR ARTERY 5. ANTERIOR CIRCUMFLEX 6. POSTERIOR CIRCUMFLEX HUMERAL ARTERY HUMERAL ARTERY Largest branch Runs along Arises at subscapularis Arise at subscapularis subscapularis (lower (lower border) (lower border) border) Anastomoses with Supplies – shoulder joint, Ends near inferior angle posterior circumflex deltoid, muscles bounding of scapula humeral quadrangular space Supplies – latissimus Gives an ascending Gives off descending dorsi & serratus branch supplying head branch (anastomose with anterior of humerus & shoulder ascending branch of Large branch- joint profunda brachii) circumflex scapular AGAM  8 ANASTOMOSES AND COLLATERAL CIRCULATION: Branches of axillary artery anastomose with branches from – internal thoracic, intercostal, subscapular, deep branch of transverse cervical, profunda brachii arteries. APPLIED ANATOMY: Axillary arterial pulsations Collateral circulation in blockage of proximal part of axillary artery. AGAM  9 2. BRACHIAL PLEXUS INTRODUCTION: This the plexus formed from cervical enlargement. To study the entire upper limb Nerve supply via it, the formation, its components and its nerve supply would help in understanding the nerves in an easy manner. FORMATION: i. Cervical Enlargement of spinal cord gives Brachial Plexus. ii. Root value-C5, C6, C7, C8; T1 from anterior primary Ramus Gives Brachial plexus. iii. Little Contribution also from C4, T2 spinal Nerves. iv. If Contribution from C4 is larger, T2 is absent it is called as Pre-fixed Brachial Plexus. v. If Contribution from T2 is larger and from C4 is absent it is called as Post-fixed Brachial Plexus. AGAM  10 COMPONENTS: 4 components of Brachial plexus a. Roots b. Trunks c. Divisions d. Cords Cords end up in forming terminal branches ROOTS: 5 Roots of Anterior Primary Ramus (C5-C8; T1)-Located in Neck deep to scalenus anterior muscle TRUNKS: Located in Neck- Occupying cleft between scalenus medius behind and Scalenus anterior in front Upper Trunk-Formed by C5, C6 Roots Middle Trunk-Root continues as Middle Trunk Lower Trunk-C8, T1 Roots joined to form lower trunk DIVISIONS: Each Trunk-Upper, Lower, Middle Trunk has anterior and Posterior Divisions located behind the clavicle. CORDS: Present in Axilla Formations a. Lateral - Anterior Divisions of Upper and Middle Trunk join to form the lateral cord b. Posterior-Posterior Division of Upper, Middle, Lower Trunk joins to form Posterior cord c. Medial-Anterior Division of Lower Trunk continues as Medial Cord (Ulnar Nerve) These Cords are named with respect to 2nd part of the Axillary artery. These Cords Continue in Axilla a. Lateral Cord-Musculocutaneous Nerve b. Posterior Cord-Radial Nerve c. Medial Cord-Ulnar Nerve Medial Nerve: Contributed by Lateral and Medial Cords in Midline AGAM  11 BRANCHES: FROM ROOTS: 1. LONG THORACIC NERVE (C5, C6, C7) Directed by roots in neck. Supplies Serratus Anterior. 2. DORSAL SCAPULAR NERVE(C5) Present in neck region. Supplies Scapular muscles in neck. Directly from C5 Root. Additionally, Contribution to phrenic Nerve (C5) supply diaphragm. Branches by roots to supply scalene muscles and Longus Colli (C5-C8). AGAM  12 FROM TRUNKS (ONLY FROM UPPER TRUNK): 1. SUPRASCAPULAR NERVE (C5, C6) Supplies Scapular muscles 2. NERVE TO SUBCLAVIUS (C5, C6) Branches from Roots and Trunks are Supraclavicular Branches of Brachial Plexus. There are no specific branches from the divisions. FROM CORDS: A. FROM LATERAL CORD 1. Lateral Pectoral Nerve(C5-C7) 2. Lateral root of Median Nerve (C5, C6, C7) 3. Musculocutaneous Nerve(C5-C7) B. FROM MEDIAL CORD 1. Medial Pectoral Nerve (C8, T1) 2. Medial Cutaneous nerve of Arm (C8, T1) 3. Medial Cutaneous Nerve of Forearm (C8, T1) 4. Medial Root of Median Nerve (C8, T1) 5. Ulnar Nerve (C8, T1) C. FROM POSTERIOR CORD 1. Upper Subscapular Nerve(C5-C6)-supply Subscapularis 2. Lower Subscapular Nerve (C5, C6)-Supply Subscapularis (Hybrid Muscle) 3. Thoracodorsal Nerve / Nerve to Latissimus Dorsi (C6-C8)- Supply Latissimus Dorsi 4. Axillary Nerve (C5, C6) - Supply Deltoid, Teres Minor 5. Radial Nerve (C5-C8; T1) - Nerve of Extension - Present in Radial Groove (Nerve of Posterior Compartment AGAM  13 AGAM  14 APPLIED ANATOMY: WINGING OF SCAPULA: Injury of Long Thoracic Nerve (Nerve to Serratus Anterior) ERB'S PALSY It is an Upper Trunk Injury. 1. Axillary Nerve-Total Injury. 2. Musculocutaneous Nerve-Partial Injury - coracobrachialis alone spared. 3. Radial Nerve-Partial Injury-Brachioradialis paralyzed. 4. Suprascapular Nerve also injured. CAUSES: Undue separation of head and Neck (Fall on shoulder, Birth Injury) FEATURES: Policeman tip hand deformity (Sensory Loss on lateral aspect of upper limb) POSITION: Shoulder-Abduction and Medial rotation Elbow-Extension Radioulnar Joint-Pronation KLUMPKEY'S PALSY It is a Lower Trunk Injury Median Nerve, Ulnar Nerve, T1-Sympathetic fibers - Involved CAUSES Hyperabduction of arm (Holding a branch while fall from tree) Birth Injury) CLINICAL FEATURES: Claw Hand Deformity (Metacarpophalangeal Extension, Interphalangeal Flexion) Horner Syndrome (Ptosis due to paralysis of Superior Tarsal Muscle) - Miosis due to paralysis of Dilator Pupillae AGAM  15 3. SHOULDER JOINT: TYPE OF JOINT: Ball and socket type of synovial joint. ARTICULAR SURFACES: 1. Head of humerus (1/3) - Rounded; Faces medially 2. Glenoid cavity of humerus: Shallow depression, faces laterally. AGAM  16 LIGAMENTS: 1. CAPSULAR LIGAMENT Encloses articular surfaces Extends between anatomical neck of humerus and glenoid cavity margins Encloses long head of biceps brachii tendon Joint cavity communicates with subscapular bursa and infraspinatus bursa 2. GLENOHUMERAL LIGAMENT Anterior thickening of fibrous capsule Defect causes anterior dislocation of shoulder joint. 3. CORACOHUMERAL LIGAMENT Extends between coracoid process of scapula and greater tubercle of humerus Degenerated part of pectoris minor 4. TRANSVERSE HUMERAL LIGAMENT Bridges bicipital groove Encloses biceps brachii tendon 5. CORACO ACROMIAL LIGAMENT Extends between coracoid process and acromial process of scapula Coracoid process + Coraco acromial ligament+ acromial process = Coraco acromial arch Prevents superior dislocation of shoulder joint 6. GLENOID LABRUM Fibrocartilage - Surrounds the margin of glenoid cavity Deepens glenoid cavity. AGAM  17 BURSAE: 1. SUBSCAPULAR BURSA: Lies below subscapular tendon. Communicates with joint cavity. 2. SUBACROMIAL BURSA: Lies between Coraco-acromial ligament above and supraspinatus below. Largest bursa and continues below deltoid as sub-deltoidal bursa. AGAM  18 3. INFRASPINATUS BURSA: Lies below infraspinatus tendon. Communicates with joint cavity. RELATIONS: 1. SUPERIOR: Coraco acromial arch Supraspinatus tendon Subacromial bursa Deltoid 2. INFERIOR: Long head of triceps brachii Axillary nerve Posterior circumflex humeral vessels 3. ANTERIOR: Subscapularis Coracobrachialis Short head of biceps brachii Deltoid 4. POSTERIOR: Infraspinatus Teres minor Deltoid AGAM  19 ROTATOR CUFF/ MUSCULOTENDINOUS CUFF: FORMATION: Formed by tendons of muscles surrounding shoulder joint a. Superior – Supraspinatus b. Posterior - Infraspinatus; Teres minor c. Interior - Subscapularis Most important factor providing support to shoulder joint. Deficient inferiorly (Inferior dislocation of joint is more common). AGAM  20 MOVEMENTS: Multiaxial joint Most Mobile and least stable joint More prone to dislocation MOVEMENTS MUSCLES INVOLVED Pectoralis Major FLEXION Deltoid (Anterior fibres) [Arm moves forwards; medially] Biceps brachii EXTENSION Latissimus dorsi [Arm moves backwards; laterally] Deltoid (Posterior fibres) Pectoralis major ADDUCTION Latissimus dorsi [arm moves backwards; medially] Teres major 0 - 15° Supraspinatus ABDUCTION 15 - 90° Deltoid (Lateral fibres) [arm moves forwards; laterally] 90 - 180° Serratus anterior, Trapezius MEDIAL ROTATION Subscapularis [arm moves medially in semi-flexed Deltoid (Anterior fibres) position] LATERAL ROTATION Infraspinatus [arm moves laterally in semi-flexed Teres minor position] Deltoid (Posterior fibres) AGAM  21 NOTE* Deltoid muscle forms all relations for shoulder joint except inferiorly Deltoid causes all movements at shoulder joint except adduction CIRCUMDUCTION - Combination of all movements of shoulder joint SCAPULOHUMERAL RHYTHM – Abduction of shoulder joint is accompanied by lateral rotation of scapula Scapula and humerus move in ratio 1:2 For every 15° abduction, scapular movement is 5° and humeral movement is 10° CLINICAL ANATOMY: DISLOCATION OF SHOULDER JOINT More common - Inferior dislocation Rotator cuff deficit inferiorly Causes injury of axillary nerve - Deltoid and teres minor palsy PAINFUL ARC SYNDROME / IMPINGEMENT SYNDROME Most common cause - Supraspinatus injury; Subacromial bursitis Painful abduction FROZEN SHOULDER Inflammation of rotator cuff tendons Painful movements AGAM  22 4. ELBOW JOINT: INTRODUCTION: It’s a hinge variety of synovial joint between the lower end of humerus and the upper end of ulna and radius bones. The elbow joint complex includes the humeroulnar, humeroradial and upper radioulnar joint. ARTICULATION: 1. UPPER: Formed by the capitulum and the trochlea of the humerus. Radial fossa lies above the capitulum which articulates with the radial head during extreme flexion. Coronoid fossa lies above the trochlea which articulates with the coronoid process of the ulna during extreme flexion. 2. LOWER: Upper surface of the head of the radius articulates with the capitulum. Trochlear notch of the ulna articulates with the trochlea of the humerus. LIGAMENTS: 1. CAPSULAR LIGAMENT: AGAM  23 Superiorly its attached to the lower end of humerus in such a way that the capitulum, trochlea, the radial fossa, the coronoid fossa and the olecranon fossa lies within it. lnferomedially, it is attached to the margin of the trochlear notch of the ulna except laterally Inferolaterally, it is attached to the annular ligament of the superior radioulnar joint. 2. THE ULNAR COLLATERAL LIGAMENT: It is triangular in shape. Its apex is attached to the medial epicondyle of the humerus, and its base to the ulna. The ligament has thick anterior and posterior bands. These are attached below to the coronoid process and the olecranon process respectively. Their lower ends are joined to each other by an oblique band which gives attachment to the thinner intermediate fibres of the ligament. The ligament is crossed by the ulnar nerve and it gives origin to the flexor digitorum. AGAM  24 3. THE RADIAL COLLATERAL LIGAMENT: It is a fan-shaped band extending from the lateral epicondyle to the annular ligament. It gives origin to the supinator and to the extensor carpi radialis brevis RELATIONS: 1. ANTERIORLY: Brachialis, median nerve, brachial artery and tendon of biceps brachii. (Contents of cubital fossa) 2. POSTERIORLY: Triceps brachii and anconeus. 3. MEDIALLY: Ulnar nerve, flexor carpi ulnaris and common flexors. 4. LATERALLY: Supinator, extensor carpi radialis brevis and other common extensors AGAM  25 BLOOD SUPPLY: From anastomoses around the elbow joint NERVE SUPPLY: The joint receives branches from the following nerves. a. Ulnar nerve. b. Median nerve. c. Radial nerve through branch to anconeus. d. Musculocutaneous nerve through its branch to the brachialis. MOVEMENTS: FLEXION: a. Brachialis. b. Biceps brachii. c. Brachioradialis. AGAM  26 EXTENSION: a. Triceps brachii. b. Anconeus. BURSAE OF ELBOW JOINT: 1. SUB TENDINOUS OLECRANON BURSA between the tendon of triceps and capsular ligament. 2. SUBCUTANEOUS OLECRANON BURSA behind the posterior attachment of the capsular ligament 3. A bursa between biceps brachii and the radial tuberosity. CARRYING ANGLE: Carrying angle is the angle between the long axis of arm and forearm when the arm is in fully extended position. The carrying angle prevents forearm hitting the hips while walking. Carrying angle is wider in females as compared to males due to wider pelvis of females. AGAM  27 CLINICAL ANATOMY: Distension of the elbow joint by an effusion occurs posteriorly because here the capsule is weak and the covering deep fascia is thin. ASPIRATION is done posteriorly on any side of the olecranon. Dislocation of the elbow is usually posterior, and is often associated with fracture of the coronoid process. The triangular relationship between the olecranon and the two humeral epicondyles is lost Subluxation of the head of the radius (pulled elbow) occurs in children when the forearm is suddenly pulled in pronation. The head of the radius slips out from the annular ligament. TENNIS ELBOW: Occurs in tennis players. Abrupt pronation with fully extended elbow may lead to pain and tenderness over the lateral epicondyle which gives attachment to common extensor origin. This is possibly due to: 1. Sprain of radial collateral ligament. 2. Tearing of fibres of the extensor carpi radialis brevis. STUDENT'S (MINER'S) ELBOW is characterized by effusion into the bursa over the subcutaneous posterior surface of the olecranon process. The bursa on the olecranon process gets inflamed GOLFER'S ELBOW is the microtrauma of medial epicondyle of humerus, occurs commonly in golf players, the common flexor origin undergoes repetitive strain and results in a painful condition on the medial side of the elbow. If carrying angle (normal is 13') is more, the condition is cubitus valgus, ulnar nerve may get stretched leading to weakness of intrinsic muscles of hand. If the angle is less it is called CUBITUS VARUS. AGAM  28 5. BRACHIAL ARTERY: INTRODUCTION: Main arterial supply of upper limb Present in the anterior compartment of the arm COURSE: Continuation of the axillary artery from the lower border of teres major Terminates at the level of neck of the radius by dividing into two terminal branches, radial and ulnar arteries The artery is superficial throughout its course, so it is easily accessible. RELATIONS: UPPER PART - Medial cutaneous nerve of forearm lies in front of it. ANTERIOR MIDDLE PART - Median nerve crosses it from lateral to medial side. LOWER PART - Bicipital aponeurosis crosses it. FROM ABOVE DOWN- long head of triceps, medial head of triceps, POSTERIOR coracobrachialis, brachialis. UPPER PART- Ulnar nerve and basilic vein. MEDIAL LOWER PART- Median nerve. UPPER PART- Median nerve, Coracobrachialis, Biceps. LATERAL LOWER PART- Tendon of biceps. AGAM  29 DISTRIBUTION/BRANCHES: 1. PROFUNDA BRACHII ARTERY: It is the largest and the first branch. After arising from the posteromedial aspect of the brachial artery, it descends along with the radial nerve  lower triangular intermuscular space spiral groove. 2. SUPERIOR ULNAR COLLATERAL ARTERY: It arises near the middle of the arm. It accompanies the ulnar nerve. 3. INFERIOR ULNAR COLLATERAL ARTERY: It arises near the lower end of the humerus. It will further divide into anterior and posterior branches. 4. MUSCULAR BRANCHES: To supply the muscles of the anterior compartment of the arm. 5. NUTRIENT ARTERY: It runs through the nutrient canal of the humerus. This is one of the events that occur at the level of insertion of the coracobrachialis. 6. TERMINAL BRANCHES: Ulnar artery and Radial artery. Of these, ulnar is larger and radial is smaller. **Diagram showing the extent and branches of the brachial artery AGAM  30 APPLIED ANATOMY: 1. BRACHIAL PULSE: Since the brachial artery is superficial for most of its course, its pulse can be felt. In the cubital fossa, its pulsations can be felt medial to the tendon of biceps. These pulsations are auscultated for Korotkoff sounds while recording blood pressure. 2. COMPRESSION OF BRACHIAL ARTERY: To stop hemorrhages in the upper limb, the brachial artery is compressed against the shaft of the humerus at the level of insertion of the coracobrachialis. 3. SUPRACONDYLAR FRACTURES OF THE HUMERAL SHAFT: These are common in children after a fall on the elbow or on an extended hand and may cause posterior displacement of the distal fragment. This proximal bone fragment may injure the brachial artery. This may lead to Volkmann’s ischemic contracture, where the flexors of the forearm are paralyzed due to ischemia. SURFACE ANATOMY: Abduct the arm at right angles Mark a point A on the lower end of the lateral wall of the axilla, in front of the posterior axillary fold (lower end of the axillary artery). Mark a point B in the anterior midline of the forearm at the level of neck of the radius, medial to the tendon of biceps brachii. Join all the points. This is the surface marking of the brachial artery. AGAM  31 6. MEDIAN NERVE LATERAL ROOT:C5 C6 C7 FORMATION MEDIAL ROOT:C8 T1 of brachial plexus Lies medial to brachial artery Enters cubital fossa Enters forearm Lie between flexor digitorium superficialis and flexor digitorum COURSE profundus Reaches the wrist Lies deep and lateral to palmaris longus tendon Passes deep to flexor retinaculum Enters palm CUBITAL FOSSA Medial-brachial artery Behind -bicipital aponeurosis Front - brachialis FOREARM between 2 head pronator teres Crosses ulnar artery RELATIONS Passes beneath fibrous arch of flexor digitorum superficialis Runs deep to this muscle on surface of flexor digitorium profundus Accompanied by medial artery Lies between tendons of flexor carpi radialis and flexor digitorum superficialis Overlapped by tendon of palmaris longus Passes through flexor retinaculum CARPEL TUNNEL = then enters the palm Muscular branches Anterior interosseous branch Palmar cutaneous branch BRANCHES Articular branch Vascular branch Communicating branch Carpel tunnel syndrome- positive Tinel and Phalen sign CLINICAL TINEL SIGN (percussion over the nerve elicits tingling sensations) ASPECTS PHALEN SIGN (flexing both wrists at 90 degree for 60 seconds) AGAM  32 AGAM  33 7. RADIAL NERVE: Continuation of posterior cord of brachial plexus in the axilla It is the largest nerve of the brachial plexus FORMATION/ROOT VALUE: C5, C6, C7, C8, and T1 of brachial plexus COURSE AND RELATIONS: A. IN THE AXILLA ANTERIOR: Third part of axillary artery POSTERIOR: Muscles forming posterior wall of axilla B. IN THE ARM It enters the arm at the lower border of the teres major. It passes between the long and medial heads of triceps to enter the lower triangular space, through which it reaches the spiral groove along with profunda brachii artery. C. IN THE SPIRAL GROOVE The radial nerve in the spiral groove lies in direct contact with the humerus. At the lower end of the spiral groove, the radial nerve pierces the lateral muscular septum of the arm and enters the anterior compartment of the arm. It first descends between the brachialis and brachioradialis, and then between brachialis and extensor carpi radialis longus. At the level of lateral epicondyle of humerus, it terminates by dividing into superficial and deep branches in the lateral part of the cubital fossa a. The deep branch; posterior interosseous nerve, in the cubital fossa b. The superficial branch (superficial radial nerve) is sensory. It runs downwards over the supinator, pronator teres, and flexor digitorum superficialis deep to brachioradialis. About one-third of the way down the forearm (at about 7 cm above wrist), it passes posteriorly, emerging from under the tendon of brachioradialis, proximal to the styloid process of radius and then passes over the tendons of anatomical snuff- box. AGAM  34 D. IN THE HAND It terminates as cutaneous branches in the anatomical snuff box which provide sensory innervation to skin over the lateral part of the dorsum of hand and dorsal surfaces of lateral 3½ digits proximal to the nail beds. AGAM  35 BRANCHES: A. IN THE AXILLA 1. Posterior cutaneous nerve of arm (which provides sensory innervation to skin on the back of the arm up to the elbow). 2. Nerve to the long head of triceps. 3. Nerve to the medial head of triceps. B. IN THE SPIRAL GROOVE 1. LOWER LATERAL CUTANEOUS NERVE OF THE ARM, which provides sensory innervation to the skin on the lateral surface of the arm up to the elbow. 2. POSTERIOR CUTANEOUS NERVE OF THE FOREARM, which provides sensory innervation to the skin down the middle of the back of the forearm up to the wrist. 3. NERVE TO LATERAL HEAD OF TRICEPS. 4. NERVE TO MEDIAL HEAD OF TRICEPS. 5. NERVE TO ANCONEUS; it runs through the substance of medial head of triceps to reach the anconeus. C. IN THE ANTERIOR COMPARTMENT OF ARM Above the lateral epicondyle, it gives off the following three branches: 1. NERVE TO BRACHIALIS (small lateral part). 2. NERVE TO BRACHIORADIALIS. 3. NERVE TO EXTENSOR CARPI RADIALIS LONGUS (ECRL) D. AT THE LEVEL OF LATERAL EPICONDYLE OF HUMERUS: Terminal superficial and deep branches in the lateral part of the cubital fossa. The DEEP BRANCH (posterior interosseous nerve) supplies 2 muscles in cubital fossa 1. Extensor carpi radialis brevis 2. Supinator After supplying these two muscles, it passes through the substance of supinator and enters the posterior compartment of the forearm and supplies all the extensor muscles of the forearm. Articular branches to the distal radio-ulnar, wrist, and carpal joints. The SUPERFICIAL BRANCH (superficial radial nerve) is sensory. Terminates as cutaneous branches in anatomical snuff box AGAM  36 Provide sensory innervation to skin over the lateral part of the dorsum of hand and dorsal surfaces of lateral 3½ digits proximal to the nail beds. INJURIES TO THE RADIAL NERVE: The radial nerve may be injured at three sites: A. In the axilla B. In the spiral groove C. At the elbow A. INJURY OF RADIAL NERVE IN THE AXILLA: In the axilla the radial nerve may be injured by the pressure of the upper end of crutch (crutch palsy) CHARACTERISTIC CLINICAL FEATURES: MOTOR LOSS: Loss of extension of elbow—due to paralysis of triceps. Loss of extension of wrist—due to paralysis of wrist extensors. This causes wrist drop due to unopposed action of flexor muscles of the forearm Loss of extension of digits—due to paralysis of extensor digitorum, extensor indicis, extensor digiti minimi, and extensor pollicis longus. Loss of supination in extended elbow because supinator and brachioradialis are paralyzed but supination becomes possible in flexed elbow by the action of biceps brachii. SENSORY LOSS: Sensory loss on small area of skin over the posterior surface of the lower part of the arm. Sensory loss along narrow strip on the back of forearm. Sensory loss on the lateral part of dorsum of hand at the base of thumb and dorsal surface of lateral 3½ digits. (there is an isolated sensory loss on the dorsum of hand at the base of the thumb) AGAM  37 B. INJURY OF RADIAL NERVE IN THE RADIAL/SPIRAL GROOVE: In radial groove, the radial nerve may be injured due to: 1. midshaft fracture of humerus 2. inadvertently wrongly placed intramuscular injection 3. direct pressure on radial nerve by a drunkard falling asleep with his one arm over the back of the chair SATURDAY NIGHT PARALYSIS. Injury to radial nerve occurs most commonly in the distal part of the groove beyond the origin of nerve to triceps and cutaneous nerves. CLINICAL FEATURES: MOTOR LOSS: Loss of extension of the wrist and fingers. WRIST DROP. Loss of supination Extension of the elbow is possible but may have a little weakness because nerves to long and lateral heads of triceps arises in the axilla i.e., before the site of lesion. C. INJURY OF RADIAL NERVE AT ELBOW: RADIAL TUNNEL SYNDROME: Entrapment neuropathy of the deep branch of radial nerve at elbow. Caused by compression of radial nerve by: a. Fibrous bands, which can tether the radial nerve to the radio-humeral joint. b. Sharp tendinous margin of extensor carpi radialis brevis. c. Leash of vessels from the radial recurrent artery. d. Arcade of Frohse, a fibro-aponeurotic proximal edge of the superficial part of the supinator muscle. CHARACTERISTIC CLINICAL FEATURES: Loss of extension of the wrist and fingers but no wrist drop. Pain over the extensor aspect of the forearm. AGAM  38 8. ULNAR NERVE: FORMATION: Arises from medial cord of brachial plexus C8 and T1 at the level of axilla Receives a contribution from ventral ramus of C7 which supplies flexor carpi ulnaris. COURSE & RELATIONS: In axilla lies medial to 3rd part of axillary artery and lateral to axillary vein Enters arm as part of main neurovascular bundle & runs distally along medial side of brachial artery up to level of insertion of Coraco-brachialis Here pierces medial intermuscular septum and enters posterior compartment of arm and runs downwards to back of medial epicondyle, here it is lodged in a groove and easily palpated. NO BRANCHES IN AXILLA & ARM. Enters forearm by passing between two heads of (FCU) flexor carpi ulnaris, upper 1/ 3rd - vertically downwards under FCU, in lower 2/3rd superficial and lateral to FCU, here ulnar nerve and artery descend together where artery is in lateral side Enters palm by passing superficial to flexor retinaculum lying just lateral to pisiform, here it is covered by a fascial band (volar carpal ligament), the cavity formed by it is known as ulnar tunnel BRANCHES: IN FOREARM: In proximal forearm, muscular branches to: a. FCU b. Medial half of flexor digitorum profundus (FDP) In mid fore- arm gives palmar cutaneous branch which enters palm superficial to flexor retinaculum and provides sensory supply to skin above hypothenar eminence In distal forearm, gives dorsal cutaneous branch that provides sensory innervation to skin over medial half of dorsum of hand and digital branches to medial 1½ finger. IN PALM: Just distal to pisiform, ulnar nerve divides to form superficial and deep terminal branches: AGAM  39 AGAM  40 A. SUPERFICIAL TERMINAL BRANCH: Muscular branch to Palmaris brevis Digital branches to medial one and half digits including nail beds B. DEEP TERMINAL BRANCH: Muscular branch to muscles of hypothenar eminence, medial two lumbricals, eight interossei, terminates by supplying adductor pollicis and occasionally deep head of flexor pollicis brevis. EFFECTS OF INJURY: A. INJURY AT ELBOW: It may be due to: a. Fracture dislocation of medial epicondyle b. Thickening of fibrous root of cubital tunnel c. Compression between FCU muscle d. Valgus deformity of elbow (tardy or late ulnar nerve palsy) CLINICAL FEATURES: Atrophy and flattening of hypothenar eminence Claw hand deformity affecting ring and little fingers; first phalanges are extended and middle & distal phalanges are flexed NOT TRUE CLAW HAND Loss of abduction and adduction of fingers Depression of interosseous spaces on dorsum of hand due to atrophy of interosseous muscles Loss of abduction in thumb Foment's sign is positive (patient asked to grasp a card between thumb and index finger on affected side and when examining doctor pulls the card; flexion of distal phalanx of thumb occurs due to paralysis of adductor pollicis B. INJURY AT WRIST: It may be due to: a. Superficial position of ulnar nerve at this site makes its vulnerable to cuts and wounds b. Compression in GUYON'S CANAL/ PISOHAMTE’S TUNNEL AGAM  41 CHARACTERISTIC CLINICAL FEATURES: Claw hand deformity affecting ring and little fingers but here FDP is not paralyzed, therefore marked flexion of distal interphalangeal joints This is also known as ulnar paradox since FDP is not paralyzed Loss of abduction and adduction in fingers Atrophy and flattening of hypothenar eminence FOMENT'S SIGN IS POSITIVE AGAM  42 9.MAMMARY GLANDS Modified apocrine gland present in the superficial fascia of pectoral region. Found in both males and females, but rudimentary in males throughout their life. Develops in females in puberty On rare occasions the breasts in males become enlarged, this condition is called gynecomastia. In females, they are accessory sex organs and produce milk for new born. LOCATION: Breast lies in superficial fascia of the pectoral region. It is divided into four quadrants – a. Upper medial b. Upper lateral c. Lower medial d. Lower lateral Small extension from its upper lateral part called as AXILLARY TAIL OF SPENCE pierces deep fascia and extends into axilla. The aperture in the deep fascia throughout which axillary tail passes into axilla called the FORAMEN OF LANGER. The axillary tail is the site of high percentage of breast tumor. SHAPE: hemispherical bulge EXTENT: a. Vertically-2nd rib to 6th rib b. Horizontally- from lateral border of sternum to midaxillary line RELATIONS: Structures from superficial to deep: PECTORAL FASCIA- deep fascia covering the anterior part of pectoralis major – breast lies on it. THREE MUSCLES a. Pectoralis major b. Serratus anterior AGAM  43 c. External oblique muscle of abdomen Breast is separated from pectoral fascia by loose areolar tissue called as RETRO- MAMMARY SPACE – enables normal breast to move freely over the pectoralis major muscle. AGAM  44 Breast consists of three components: A. SKIN- covering the breast a. NIPPLE It is a conical projection below the center of breast. It has smooth & longitudinal muscles and is richly innervated by sensory nerves. It is Sensitive to tactile stimulation. b. AREOLA It is a circular area of pigmented skin around the base of nipple. It has modified sebaceous gland, produces oily secretion to lubricate the nipple and the areola. The sebaceous glands in the areola are enlarged during pregnancy and appear as nodular elevations called as MONTGOMERY’S TUBERCLES. B. STROMA It consists of connective tissue and fat. It forms supporting network of breast. The connective tissue condenses to form fibrous strand called SUSPENSORY LIGAMENTS OF COOPER. They connect dermis of overlying skin to the ducts of the breast & pectoral fascia. Fat forms main bulk of the gland C. PARENCHYMA It secretes milk to feed the new-born. Has 15-20 lobes in radial fashion, each lobe is further divided into lobules that consist of a cluster of acini, each lobe is drained by a lactiferous tubule. Near its termination at nipple, lactiferous duct expands to form lactiferous sinus – reservoir of milk during lactation. AGAM  45 ARTERIAL SUPPLY: Breast is highly vascularized. Arteries supplying breast are: 1. INTERNAL THORACIC ARTERY – branch of subclavian artery 2. LATERAL THORACIC ARTERY- branch of axillary artery  main blood supply of the breast. Also, superior thoracic and acromio-thoracic branches of axillary artery supply breast. 3. LATERAL BRANCHES OF POSTERIOR INTERCOSTAL ARTERY AGAM  46 VENOUS DRAINAGE: 1. AXILLARY VEIN 2. INTERNAL THORACIC VEIN 3. POSTERIOR INTERCOSTAL VEINS The superficial veins drain into internal thoracic vein and superficial veins of lower part of neck. Deep veins drain into internal thoracic, axillary and posterior intercostal vein. NERVE SUPPLY: Primarily somatosensory. Derived from 4th to 6th intercostal nerves through their anterior and lateral cutaneous branches. These nerves convey sensory fibres to skin and autonomic fibres to smooth muscle and blood vessels These nerves don’t control milk secretion. It is controlled by HORMONE PROLACTIN. LYMPHATIC DRAINAGE LYMPH NODES: 1. AXILLARY LYMPH NODES-in axilla – 4 groups: a. Anterior/pectoral b. Posterior c. Central d. Lateral 2. INTERNAL MAMMARY NODES -along internal thoracic vessels 3. SUPRACLAVICULAR NODES 4. POSTERIOR INTERCOSTAL NODES-lying in posterior parts of intercostal spaces in the front of the head of ribs. 5. CEPHALIC (deltopectoral) NODES- in deltopectoral groove. 6. Subdiaphragmatic and Sub-Peritoneal Lymph Plexuses AGAM  47 LYMPHATICS: Lymphatics draining the breast into two groups: a. SUPERFICIAL- drains the skin of breast except nipple and areola b. DEEP- drains parenchyma of breast, skin of nipple and areola is drained by lymph vessels called as SUBAREOLAR PLEXUS OF SAPPEY. Deep lymphatics drain into anterior group of axillary lymph node. Superficial lymphatics on one side communicate with those of other side. Therefore, malignancy of one side can become bilateral. LYMPHATIC DRAINAGE OCCURS AS FOLLOWS: 1. AXILLARY and PECTORAL GROUP OF LYMPH NODE situated in deep and lower border of pectoralis minor drain the lateral quadrants. 2. INTERNAL MAMMARY LYMPH NODES situated along with internal mammary artery drains the medial quadrants. 3. Few other lymph nodes situated along with post. intercostal arteries drain into POSTERIOR INTERCOSTAL NODES. 4. The few lymph vessel from lower medial quadrant pierces the abdominal wall and communicate with SUB-PERITONEAL LYMPH PLEXUS From here, cancer cells migrate transcoelomically and get deposited on ovary producing secondary tumor called as KRUKENBERG'S TUMOR. 5. Lymph vessels from deep surface of breast pierce pectoralis major and clavipectoral fascia to drain into APICAL GROUP OF AXILLARY LYMPH NODES. **About 75% lymph nodes drain into axillary lymph nodes, **20% in internal mammary lymph nodes and **5% in posterior intercostal lymph nodes. AGAM  48 AGAM  49 CLINICAL CORRELATION 1. BREAST CANCER presents as Painless hard lump Breast becomes fixed and immobile due to infiltration of Suspensory Ligaments Retraction of nipple due to infiltration & fibrosis of lactiferous ducts PEAU’D ORANGE APPEARANCE of skin due to obstruction of superficial lymphatics. 2. LYMPHATIC DRAINAGE OH BREAST is important – metastasis of tumor cells of breast along lymph vessels to regional lymph nodes. AGAM  50 INDEX – UPPER LIMB - SHORT NOTES SR. PAGE QUESTION NAME NO. NO. 1. ARTERIAL ANASTOMOSIS AROUND SCAPULA 53 2. AXILLARY LYMPH NODES 54 3. MUSCULOTENDINOUS CUFF (ROTATOR CUFF) 56 4. MUSCULOCUTANEUS NERVE 58 5. ANASTOMOSIS AROUND ELBOW JOINT 60 6. CUBITAL FOSSA 61 7. JOINTS OF DIGITS 64 8. SEGMENTAL INNERVATION OF THE MUSCLES OF THE 68 UPPER LIMB 9. BOUNDARIES OF AXILLA 70 10. STERNOCLAVICULAR JOINT 72 11. ANATOMICAL EVENTS OCCURRING AT THE LEVEL OF 73 INSERTION OF CORACOBRACHIALIS 12. PROFUNDA BRACHII ARTERY- COURSE AND 74 BRANCHES AGAM  51 13. WRIST JOINT [RADIO CARPAL JOINT] 75 14. FLEXOR RETINACULUM [TRANSVERSE CARPAL 79 LIGAMENT] 15. EXTENSOR RETINACULUM (DORSAL CARPAL 81 LIGAMENT) 16. PALMAR ARCHES 83 17. WINGING OF SCAPULA 85 18. MEDIAL BORDER OF SCAPULA 86 19. SUPRACONDYLAR FRACTURE OF HUMERUS 88 20. CARRYING ANGLE 90 21. ULNAR CLAW HAND 91 22. ANATOMICAL SNUFF BOX 93 23. EXTENSOR RETINACULUM 94 24. DORSAL DIGITAL / EXTENSOR EXPANSION 96 25. POSTERIOR INTEROSSEOUS NERVE 98 26. POSTERIOR INTEROSSEOUS ARTERY 100 27. CEPHALIC VEIN 101 28. DELTOID 102 AGAM  52 29. MUSCLES CONTROLLING MOVEMENT OF THUMB 105 30. APPLIED ASPECTS OF HAND 108 31. CLINICAL ANATOMY OF PALMAR SPACES 110 32. SUPINATOR MUSCLE 112 33. EXTENSOR EXPANSION OF MIDDLE FINGER 114 34. MIDPALMAR SPACES 116 35. FINE MOVEMENTS OF FINGERS 117 36. ANTERIOR INTEROSSEOUS ARTERY 119 37. THENAR SPACE OF HAND 121 AGAM  53 1. ARTERIAL ANASTOMOSIS AROUND SCAPULA Principally formed between the branches of 1st part of the subclavian and the 3rd part of the axillary artery. AROUND THE BODY OF SCAPULA OVER THE ACROMION PROCESS SUPRASCAPULAR ARTERY, a ACROMIAL BRANCH OF THE branch of the thyrocervical trunk from THORACO-ACROMIAL ARTERY the 1st part of the subclavian artery. (2nd part of axillary artery) CIRCUMFLEX SCAPULAR ACROMIAL BRANCH OF THE ARTERY, a branch of subscapular SUPRASCAPULAR ARTERY (1st artery from 3rd part of axillary artery. part of subclavian artery) DEEP BRANCH OF TRANSVERSE ACROMIAL BRANCH OF THE CERVICAL ARTERY, a branch of the POSTERIOR CIRCUMFLEX thyrocervical trunk. HUMERAL ARTERY (3rd part of axillary artery) APPLIED ANATOMY: COLLATERAL CIRCULATION ensures ADEQUATE BLOOD SUPPLY TO THE UPPER LIMB in case of blockage between third part of axillary artery and first part of axillary artery. AGAM  54 2. AXILLARY LYMPH NODES: Scattered in fibrofatty tissue of axilla 20-30 nodes 5 groups of axillary lymph nodes I. ANTERIOR or PECTORAL GROUP II. POSTERIOR or SCAPULAR GROUP III. LATERAL GROUP IV. CENTRAL GROUP V. APICAL or INFRACLAVICULAR GROUP GROUP LOCATION DRAINAGE ANTERIOR Lies along lateral Receive lymph from OR thoracic vessels and a. Upper half of anterior wall of trunk PECTORAL lower border of b. Major part of breast. GROUP pectoralis minor POSTERIOR Lies along the Receive lymph from OR subscapular vessels on a. Upper half of posterior wall of trunk SCAPULAR the posterior fold of b. Axillary tail of breast GROUP axilla Lies along the upper Receive lymph from LATERAL part of humerus, a. Upper limb GROUP medial to axillary vein Receive lymph from CENTRAL Lies in the fat of upper a. Preceding groups GROUP axilla b. Floor of axilla Drain into Apical group Receive lymph from a. Central group(indirectly) APICAL b. Upper part of breast(directly) Lies deep to OR INFRA- c. Thumb and it’s web clavipectoral fascia, CLAVICULAR Drain into along axillary vessels GROUP a. Subclavian lymph trunk on right side b. Thoracic duct on left side c. Also, to supraclavicular lymph nodes AGAM  55 APPLIED ANATOMY: PALPATION OF AXILLARY LYMPH NODES: It is a part of clinical examination of the breast due to their involvement in breast cancer. The lymph node that first receive lymph from the area of the breast involved in cancer are termed as SENTINEL LYMPH NODES. These nodes are confirmed by injecting a radioactive substance into the affected area of the breast. DRAINAGE OF AXILLARY ABSCESS: incision in the floor of axilla – the most dependent part, Midway between anterior & posterior axillary folds nearer to medial wall to avoid injury to main vessels running along anterior, posterior & lateral walls of the axilla. AGAM  56 3. MUSCULOTENDINOUS CUFF (ROTATOR CUFF): Musculotendinous cuff of the shoulder is a fibrous sheath formed by four flattened tendons which blend with the capsule of the shoulder joint and strengthen it. The muscles which form the cuff arise from the scapula and are inserted into the lesser and greater tubercle of humerus. They are: a. Subscapularis b. Supraspinatus c. Infraspinatus d. Teres Major Their tendons while crossing the shoulder joint, become flattened and blend with each other and also with the capsule of the joint. AGAM  57 IMPORTANCE: The cuff gives strength to the capsule of the shoulder joint all around except inferiority. Therefore, dislocation of humerus is common in anteroinferior direction. ROTATOR CUFF DISORDERS: CALCIFIC SUPRASPINATUS TENDINITIS – Calcium deposits in supraspinatus tendon irritates overlying bursa leading to subacromial bursitis. Consequently, when the arm is abducted the inflamed bursa is caught between tendon & acromion impingement which causes severe pain. In most people, pain occurs during 60° - 120° of abduction known as painful arc syndrome. AGAM  58 4. MUSCULOCUTANEUS NERVE: Musculocutaneous nerve is named as it supplies muscle of front of forearm and skin of lateral side of the forearm. ROOT VALUE: Ventral rami of C5 -C7 segments of spinal cord. COURSE: A. AXILLA AND ARM: It is a branch of lateral cord of brachial plexus, lies lateral to axillary artery and upper part of brachial artery. It supplies coracobrachialis, pierces the muscle to lie in the intermuscular septum between biceps brachii and brachialis muscles. B. FOREARM: About 2.5 cm above the crease of elbow, it becomes cutaneous by piercing the deep fascia. The nerve is called the lateral cutaneous nerve of forearm which supplies the skin of forearm both on the front and back. BRANCHES: MUSCULAR – Coraco-brachialis, long head and short head of biceps brachii and brachialis CUTANEOUS- lateral side of fore arm ARTICULAR-elbow joint **MUSCULOCUTANEOUS NERVE innervations of arm are purely motor while that of forearm is purely sensory AGAM  59 CLINICAL ANATOMY: This nerve is well protected within the axilla. So, injury is uncommon. If injured during any penetrating trauma, it leads to: a. MOTOR LOSS: Paralysis of biceps brachii and brachialis & Coraco-brachialis b. SENSORY LOSS: It is on the lateral side of forearm AGAM  60 5. ANASTOMOSIS AROUND ELBOW JOINT: Anastomosis around the elbow joint links the brachial artery with radial and ulnar arteries. SITE OF ANATOMOSIS ARTERIES INVOLVED IN FRONT OF LATERAL Anterior descending\radial collateral with radial EPICONDYLE recurrent arteries BEHIND THE LATERAL Posterior descending\middle collateral with EPICONDYLE interosseous arteries IN FRONT OF MEDIAL Inferior ulnar collateral with anterior ulnar EPICONDYLE recurrent arteries BEHIND THE MEDIAL Superior ulnar collateral with posterior ulnar EPICONDYLE recurrent arteries CLINICAL ANATOMY: BRACHIAL PULSATIONS are felt in front of the elbow just medial to the tendon of biceps for recording the blood pressure. AGAM  61 6. CUBITAL FOSSA Cubital fossa is a triangular hollow situated on the front of the elbow. BOUNDARIES: A. LATERALLY: Medial border of brachioradialis B. MEDIALLY: Lateral border of pronator teres C. BASE: Imaginary line joining the front of the two epicondyles of the humerus. D. APEX: Meeting point of the lateral and medial boundaries. Here brachioradialis overlaps the pronator teres ROOF: 1. Skin 2. Superficial fascia containing median cubital vein 3. Deep fascia 4. Bicipital aponeurosis AGAM  62 FLOOR: 1. Brachialis (upper part) 2. Supinator (lower part) CONTENTS: 1. MEDIAN NERVE: It leaves the fossa by passing between the two heads of pronator teres. 2. BRACHIAL ARTERY: It terminates in the fossa by dividing into radial and ulnar arteries. The radial artery is superficial and the ulnar artery is deep and passes deep to the pronator teres. 3. The tendon of BICEP BRACHII 4. RADIAL NERVE: It divides into superficial radial nerve and deep radial nerve (posterior interosseous nerve) at the level of lateral epicondyle. The latter disappears in supinator muscle. AGAM  63 CLINICAL ANATOMY: The median cubital vein is the vein of choice for the intravenous injections and to get blood samples. The blood pressure is universally recorded by auscultating the brachial artery in front of the elbow. The anatomy of cubital fossa is important for dealing with the fracture around the elbow like supracondylar fracture of humerus AGAM  64 7. JOINTS OF DIGITS: METACARPOPHALANGEAL JOINTS: TYPE: Synovial joints of ellipsoid/ condylar variety ARTICULAR SURFACES: 1. Proximal articular surface - Convex head of metacarpal 2. Distal articular surface - Shallow fossa on base of proximal phalanx LIGAMENTS: 1. CAPSULAR LIGAMENT - Thick in front & thin behind 2. PALMAR LIGAMENT - Fibro-cartilaginous plate (volar plate) - More firmly attached to phalanx than to metacarpal - Ligaments of 2nd, 3rd, 4th & 5th MP joints join together to form deep transverse metacarpal ligament 3. MEDIAL & LATERAL COLLATERAL LIGAMENTS - Cord-like, oblique fibrous bands present on each side of the joint - Extends from head of metacarpal to base of joint - Taut in flexion and relaxed in extension MOVEMENTS AT FIRST JOINT AND MUSCLES PRODUCING IT: MOVEMENT MUSCLES PRODUCING IT FLEXION Flexor Pollicis Longus, Flexor Pollicis Brevis EXTENSION Extensor Pollicis Longus, Extensor Pollicis Brevis ABDUCTION Abductor Pollicis Brevis ADDUCTION Adductor Pollicis AGAM  65 MOVEMENTS AT 2ND TO 5TH JOINT AND MUSCLES PRODUCING THEM: MOVEMENT MUSCLES PRODUCING IT FLEXION Interossei, Lumbricals EXTENSION Extensors of fingers ABDUCTION Dorsal interossei ADDUCTION Palmar interossei AGAM  66 INTERPHALANGEAL JOINTS (PROXIMAL & DISTAL): TYPE: Synovial joints of hinge variety ARTICULAR SURFACES: A. PROXIMAL INTERPHALANGEAL JOINT 1. Proximal articular surface - Head of proximal phalanx 2. Distal articular surface - Base of middle phalanx B. DISTAL INTERPHALANGEAL JOINT 1. Proximal articular surface - Head of middle phalanx 2. Distal articular surface - Base of distal phalanx LIGAMENTS: Similar to metacarpophalangeal joints One palmar fibrocartilaginous ligament, Two collateral bands running downwards and forwards MOVEMENTS AT INTERPHALANGEAL JOINT OF THUMB: MOVEMENT MUSCLES PRODUCING IT FLEXION Flexor pollicis longus EXTENSION Extensor pollicis longus MOVEMENTS AT SECOND TO FIFTH DIGITS: MOVEMENT MUSCLES PRODUCING IT Proximal IP joint – Flexor digitorum superficialis FLEXION Distal IP joint – Flexor digitorum profundus EXTENSION Interossei, Lumbricals AGAM  67 AGAM  68 8. SEGMENTAL INNERVATION OF THE MUSCLES OF THE UL: The knowledge of segmental values is of importance in the diagnosis of injuries to the nerve or to the spinal cord from which they arise. Proximal muscles of upper limb are supplied by proximal nerve roots forming brachial plexus and distal muscles by the distal or lower nerve roots. SEGMENTAL INNERVATION OF MOVEMENTS: 1. SHOULDER - ABDUCTION – Muscles supplied by C5 spinal segment - ADDUCTION – Muscles supplied by C6, C7 spinal segments 2. ELBOW - FLEXION - Muscles supplied by C5, C6 spinal segments - EXTENSION - Muscles supplied by C7 spinal segment 3. RADIO-ULNAR JOINT - SUPINATION - Muscles supplied by C6 spinal segment - PRONATION - Muscles supplied by C6 spinal segment 4. WRIST - EXTENSION - Muscles supplied by C6, C7 spinal segments - FLEXION - Muscles supplied by C6, C7 spinal segments 5. INTERPHALANGEAL JOINT - FLEXION - Muscles supplied by C7, C8 spinal segments - EXTENSION - Muscles supplied by C7, C8 spinal segments AGAM  69 SEGMENTAL INNERVATION OF MUSCLES: SEGMENT MUSCLES INNERVATED Deltoid Supraspinatus, infraspinatus, and teres minor C5 Rhomboideus major and minor Coracobrachialis, biceps brachii, and brachialis Brachioradialis and supinator Pectoralis major and minor Subscapularis, latissimus dorsi, and teres major C6 Serratus anterior Triceps Pronator teres and pronator quadratus C7 Extensors and flexors of wrist C8 Long flexors and extensors of fingers T1 Small muscles of hand AGAM  70 9. BOUNDARIES OF AXILLA: APEX or ANTERIOR: posterior surface of clavicle POSTERIOR: superior border of the scapula and medial CERVICOAXILLARY aspect of coracoid process CANAL MEDIAL: outer border of first rib BASE or FLOOR Skin, superficial fascia and axillary fascia Pectoralis major ANTERIOR WALL Clavipectoral fascia Pectoralis minor Subscapularis POSTERIOR WALL Teres major Latissimus dorsi Upper 4 ribs with their intercostal muscles MEDIAL WALL Upper part of serratus anterior Upper part of shaft of humerus in the region of bicipital groove LATERAL WALL Coracobrachialis Short head of biceps AGAM  71 CONTENTS OF AXILLA: 1. Axillary artery and its branches 2. Axillary vein and its tributaries 3. Infraclavicular part of brachial plexus 4. Axillary lymph nodes 5. Axillary fat 6. Long thoracic and intercostobrachial nerves AGAM  72 10. STERNOCLAVICULAR JOINT: TYPE Saddle type of synovial joint ARTICULAR Round head of clavicle SURFACE Shallow socket of superolateral angle of manubrium sterni Anterior and posterior sternoclavicular ligament Capsular ligament LIGAMENTS Interclavicular ligament Costoclavicular ligament Internal thoracic BLOODSUPPLY Suprascapular arteries NERVE Medial supraclavicular nerve SUPPLY Elevation Depression MOVEMENTS Protraction Retraction Anterior and posterior rotation ARTICULAR Present DISC CLINICAL Dislocation of joint ASPECTS Transmission of weight of upper limb AGAM  73 11. ANATOMICAL EVENTS OCCURRING AT THE LEVEL OF INSERTION OF CORACOBRACHIALIS: Circular shaft of Humerus becomes triangular below this level. Brachial artery moves from medial aspect of arm to anterior aspect. Basilic vein pierces deep fascia of arm. Median nerve crosses in front of brachial artery from lateral to medial side. Radial nerve pierces lateral intermuscular septum to pass from posterior compartment to anterior compartment. Ulnar nerve pierces medial intermuscular septum to go into posterior compartment. Medial cutaneous nerve of arm and forearm pierces deep fascia. Nutrient artery pierces humerus. AGAM  74 12. PROFUNDA BRACHII ARTERY- COURSE AND BRANCHES: Largest branch of brachial artery. ORIGIN: Posteromedial aspect of brachial artery just below Teres major. COURSE: Accompanies Radial nerve in the radial groove and terminates by dividing into anterior and posterior descending branches. BRANCHES: 1. DELTOID BRANCH = Ascends between the long and lateral heads of triceps and anastomoses with descending branch of posterior circumflex humeral artery. 2. NUTRIENT ARTERY = Enters shaft of Humerus in radial groove. 3. ANTERIOR DESCENDING ARTERY: (A.K.A- Radial collateral) Smaller terminal branch. It accompanies radial nerve and anastomoses with the radial recurrent artery in front of lateral epicondyle. 4. POSTERIOR DESCENDING ARTERY: (A.K.A-Middle Collateral) Larger terminal branch. It descends behind shaft of Humerus and anastomoses with the interosseous recurrent artery behind the lateral epicondyle of Humerus. AGAM  75 13. WRIST JOINT [RADIO CARPAL JOINT]: TYPE: Ellipsoid Joint ARTICULAR SURFACES: PROXIMAL SURFACE DISTAL SURFACE Inferior surface of lower end of radius Proximal surfaces of scaphoid, Inferior surface of articular radio-ulnar lunate & triquetral joint disc of inferior LIGAMENTS: There are 6 ligaments around wrist joint. AGAM  76 CAPSULAR LIGAMENT: Fibrous covering of joint ATTACHMENT: a. ABOVE- to the distal ends of radius, ulna b. BELOW- to the proximal row of carpal bones Synovial membrane lines the inner surface of capsule PALMAR RADIO-CARPAL LIGAMENT: It is formed by thickening of lateral part of fibrous capsule It extends from anterior margin of lower end of radius to anterior surface of scaphoid, lunate, triquetral PALMAR ULNO-CARPAL LIGAMENT: It is formed by thickening of medial part of fibrous capsule. It extends from styloid process of ulna and adjoining articular disc to anterior surface os lunate and triquetral. DORSAL RADIO CARPAL LIGAMENT: It extends from posterior margin of lower end of radius to dorsal surface of scaphoid, lunate, triquetral. RADIAL COLLATERAL LIGAMENT: It extends from styloid process of radius to lateral aspect of scaphoid &trapezium ULNAR COLLATERAL LIGAMENT: It extends from styloid process of radius to lateral aspect of scaphoid &trapezium ULNAR COLLATERAL LIGAMENT: It extends from styloid process of ulna to medial aspect of triquetral & pisiform bones AGAM  77 RELATIONS: ANTERIOR: Tendon of flexor digitorum superficialis [FDS] and tendon of flexor digitorum profundus [FDP] associated with ulnar bursa. Tendon of flexor pollicis longus [FPL] Tendon of flexor carpi radialis Median nerve Ulnar nerve & vessels. POSTERIOR: Extensor tendon of wrist and fingers Anterior interosseous artery Posterior interosseous nerve AGAM  78 LATERAL: Tendon of abductor pollicis longus [APL] Tendon of extensor pollicis brevis [EPB] Radial artery MEDIAL: Dorsal cutaneous branch of ulnar nerve MOVEMENTS: It is a biaxial joint It permits the following movements a. FLEXION b. EXTENSION c. ABDUCTION d. ADDUCTION e. CIRCUMDUCTION. CLINICAL ANATOMY: GANGLION: It is a non-tender cystic swelling due to mucoid degeneration of synovial sheath around the tendon. ASPIRATION OF THE WRIST: It is done by introducing needle posteriorly below the styloid process of radius. AGAM  79 14. FLEXOR RETINACULUM [TRANSVERSE CARPAL LIGAMENT] SHAPE: Rectangular FORMED BY: Thickening of deep fascia Bridges the carpal bones and forms an Osseo-fibrous tunnel called CARPAL TUNNEL. On either side it gives a slip. SUPERFICIAL SLIP DEEP SLIP On medial side On lateral side Ulnar nerve & vessels passes Tendon of flexor carpi through it radialis passes through it ATTACHMENT: MEDIALLY: attached to pisiform & hook of hamate LATERALLY: attached to scaphoid & crest of trapezium. RELATIONS: STRUCTURES PASSING SUPERFICIALLY: a. Ulnar nerve b. Ulnar artery c. Palmar cutaneous branch of ulnar nerve d. Palmar cutaneous branch of median nerve e. Superficial palmar branch of radial artery f. Tendon of palmaris longus AGAM  80 STRUCTURES PASSING DEEPLY [THROUGH CARPAL TUNNEL]: a. Tendon of flexor digitorum superficialis [FDS] b. Tendon of flexor digitorum profundus [FDP] c. Tendon of flexor pollicis longus [FPL] d. Median nerve CLINICAL ANATOMY: CARPAL TUNNEL SYNDROME: Compression of median nerve in carpal tunnel. Compression may due to wrist fracture, swelling or inflammation due to arthritis. AGAM  81 15.EXTENSOR RETINACULUM (DORSAL CARPAL LIGAMENT): Thickening of deep fascia to form strong fibrous band to retain tendon of long muscles in position. Prevents bow stringing during their action. Directed obliquely, medially and downwards. ATTACHMENTS: a. LATERALLY - Anterior border of radius b. MEDIALLY- Triquetral, pisiform and styloid process of ulna COMPARTMENTS OF EXTENSOR RETINACULUM: From lateral to medial numbered as 1 to 6. Tendons enclosed within synovial sheaths traverse in their compartments accordingly. AGAM  82 TRANSVERSE SECTION OF WRIST: 1. ABDUCTOR POLLICIS LONGUS (APL) Thumb abduction 1 EXTENSOR POLLICIS BREVIS (EPB) Radial border of anatomical snuff box 2. EXTENSOR CARPI RADIALIS LONGUS Extension of wrist EXTENSOR CARPI RADIALIS BREVIS 3. EXTENSOR POLLICIS LONGUS(EPL) ULNAR border of anatomical snuff box 4. EXTENSOR DIGITORUM (ED) Extension of medial 4 digits 3 EXTENSOR INDICIS (EI) POSTERIOR INTEROSSEOUS NERVE ANTERIOR INTEROSSEOUS ARTERY 5. EXTENSOR DIGITI MINIMI (EDM) Extension of little finger 6. EXTENSOR CARPI ULNARIS (ECU) Extension and adduction of wrist 5 6 IMPORTANT SPOTTER: ATTACHMENTS & COMPARTMENTS MAYBE SUB QUESTIONS. AGAM  83 16. PALMAR ARCHES: SUPERFICIAL PALMAR ARCH DEEP PALMAR ARCH Direct continuation of ULNAR artery Direct continuation of RADIAL artery (superficial palmar branch of ulnar artery) COURSE: COURSE: Enters palm, curves laterally behind Enters palm from dorsal aspect passing palmar aponeurosis and in front of between 2 heads of first dorsal long flexor tendons. interosseous Gives 2 branches : Radialis indicis, princeps pollicis Then, passes between 2 heads of adductor pollicis. Completed laterally by Completed medially by anastomosing anastomosing with any of these with deep palmar branch of ULNAR branches of RADIAL artery: artery 1. Superficial palmar branch of radial artery 2. Radialis indicis 3. Princeps pollicis BRANCHES: BRANCHES: 1. 3 common palmar digital arteries 1. 3 palmar metacarpal arteries 2. 1 proper digital artery 2. 3 perforating arteries 3. Cutaneous branches to palm 3. Recurrent branch RELATIONS: RELATIONS: Superficial: Palmar aponeurosis Superficial: Long flexor tendons, Deep: Long flexor tendons of lumbricals FDS,FDP Deep: Proximal parts of shafts of Lumbricals metacarpal, interosseous muscles Digital branches of median and ulnar nerves SURFACE ANATOMY: SURFACE ANATOMY: Lies across center of palm at the Lies 1 cm proximal to superficial palmar level of distal border of fully arch extended thumb AGAM  84 APPLIED ANATOMY: LACERATION OF PALMAR ARTERIAL ARCH: Causes profuse and uncontrollable bleeding. MOST EFFECTIVE METHOD TO CONTROL BLEEDING: Compression of BRACHIAL artery against AGAM  85 17. WINGING OF SCAPULA: Paralysis of serratus anterior produce winging of scapula (Wings of Heaven). Inferior angle and medial border of scapula more prominent. Paralysis of this muscle −serratus anterior due to injury to long thoracic nerve. (C5, C6, C7). This leads to protraction of scapula becomes weaken, arm cannot abduct beyond 90 degree. CAUSES: A. Axillary node dissection after mastectomy B. Stab wounds SERRATUS ANTERIOR NERVE ORIGIN INSERTION CLINICALS SUPPLY Muscle insert into costal surface of scapula Paralysis of 8 digitations Superior angle of scapula Long this muscle from upper 8 medial border of scapula Thoracic lead to ribs (Ribs 1-9) Nerve winging of Inferior border of scapula scapula AGAM  86 18. MEDIAL BORDER OF SCAPULA: Muscle attachment to medial border of scapula, A. Levator scapula B. Rhomboid major C. Rhomboid minor LEVATOR SCAPULAE: ORIGIN INSERTION NERVE SUPPLY ACTION Transverse Dorsal scapular Medial border of processes of nerve (C5) Elevation of scapula between C1−C4 scapula and the superior angle C3 and C4 spinal Vertebrae medial rotation. and root of spine nerve RHOMBOIDUS MAJOR: NERVE ORIGIN INSERTION ACTION SUPPLY Spine of T2-T5 Inferior part of Dorsal Retraction, vertebrae. medial border scapular medial of scapula. nerve (C5) rotation, elevation AGAM  87 RHOMBOIDUS MINOR: ORIGIN INSERTION NERVE ACTION Lower part of SUPPLY ligmentum Base of triangular Retraction, nuchae Dorsal scapular elevation of area at root of spine nerve (C5) scapula Spine T2 −T5 of scapula vertebrae AGAM  88 19. SUPRACONDYLAR FRACTURE OF HUMERUS: Also called MALGAIGNE’S FRACTURE. It is a fracture of the distal humerus just above the elbow joint. The fracture is usually transverse or oblique and above the medial and lateral condyles and epicondyles. MECHANISM OF INJURY: EXTENSION TYPE: Fall on outstretched hand Elbow hyperextended Forearm-pronated or supinated FLEXION TYPE: Fall directly on the elbow rather than out stretched hand POSTEROLATERAL POSTEROMEDIAL DISPLACEMENT DISPLACEMENT Fall with a forearm pronated, Fall onto an outstretched displaces the fragment poster supinated forearm, displaces the medially. fragment poster laterally. Medial displacement places the radial Lateral displacement places the median nerve at risk. nerve and brachial artery at risk. AGAM  89 CLINICAL SIGNS AND SYMPTOMS: 1. Pain and swelling 2. Tenderness in both condyles 3. Limited extension 4. S shaped deformity 5. Anterior pucker sign positive CLINICAL CORRELATION: Rupture of brachial artery due to supracondylar fracture of humerus leads to Volkmann’s ischemic contracture. AGAM  90 20. CARRYING ANGLE: It is an angle between the longitudinal axes of the arm and forearm Average angle: a. For FEMALES:20 (The wider carrying angle in females avoids rubbing of forearms with the wider female pelvis while carrying loads., for example buckets filled with water from one place to another.) b. For MALES :15 degrees. IMPORTANCE: It increases progressively from childhood until 16 years. Epicondylar disease Surgical planning for elbow reconstruction. For Carrying objects. FACTORS INFLUENCING CARRYING ANGLE: Elbow musculature/ligaments Forearm rotation Elbow flexion Anatomical Factors Superior articular surface of the coronoid process of the ulna is placed obliquely to the long axis of the ulna. AGAM  91 21. ULNAR CLAW HAND: Injury of Ulnar nerve at wrist causes Ulnar Claw Hand. The ulnar nerve supplies all the interossei, the 3rd and 4th lumbrical muscles, the hypothenar muscles, and the adductor pollicis. Atrophy of the interossei in chronic ulnar nerve palsy causes guttering of the intermetacarpal spaces and the 1st webbed space. The 4th and 5th joints are hyperextended at the MCP and flexed at the IP joints, resulting in an ulnar claw hand, which is caused by a paralysis of the 3rd and 4th lumbricals. CAUSES: Ulnar nerve at wrist is superficial which makes it vulnerable to cuts and wounds. Compression in Guyon's canal. CLINICAL FEATURES OF ULNAR CLAW HAND: Hyperextension at metacarpophalangeal joints, flexion at the interphalangeal joints, involving ring and little finger more than middle and index finger. Claw hand deformity is more obvious in wrist lesions as Flexor Digitorum Profundus is not paralyzed, hence there is marked flexion at terminal phalanges. Atrophy and flattening of hypothenar eminence. Loss of adduction (2, 4, 5 digits). Loss of abduction (2, 3, 4 digits). Gutters seen in palm. Forment's sign positive. AGAM  92 Sensory loss over medial 1 ½ digits in both palmar and dorsal aspect. [Injury of both ulnar and median nerve causes complete or true ulnar claw hand AGAM  93 22. ANATOMICAL SNUFF BOX: Triangular depression at the base of thumb. Best seen in extended thumb. BOUNDARIES: ANTEROLATERALLY: Tendon of Abductor pollicis longus. Tendon of Extensor pollicis brevis. POSTEROMEDIALLY: Tendon of Extensor pollicis longus. STRUCTURES CROSSING THE ROOF: Cephalic vein (medial to lateral) Terminal branch of superficial radial nerve (lateral to medial) CONTENT: Radial Artery. APPLIED ASPECTS: Cephalic vein at roof of Anatomical snuffbox often used for giving intravenous fluids. Tenderness in anatomical snuff box indicates fracture of Scaphoid bone. Pulsations of radial artery can be felt in the anatomical snuff box. AGAM  94 23. EXTENSOR RETINACULUM: It is the thickened deep fascia on the back of the wrist. It is an oblique band - directed downwards medially. It holds the tendons of extensor muscles in place. ATTACHMENTS: LATERALLY - lower part of sharp anterior border of radius MEDIALLY a. Styloid process of ulna b. Triquetral c. Pisiform COMPARTMENTS: The retinaculum sends down septa which are attached to the posterior surface of lower end of radius. Thus 6 osseo-fascial compartments are formed. Each compartment is lined by synovial sheath which is reflected onto the contained tendons AGAM  95 COMPARTMENTS: STRUCTURES PRESENT IN THE COMPARTMENTS COMPARTMENTS Abductor pollicis Longus I Extensor pollicis brevis Extensor carpi radialis Longus II Extensor carpi radialis brevis III Extensor pollicis longus Extensor digitorum Extensor indicis IV Posterior interosseous nerve Anterior interosseous artery V Extensor digiti minimi VI Extensor carpi ulnaris AGAM  96 24. DORSAL DIGITAL / EXTENSOR EXPANSION: It is a small triangular aponeurosis covering the dorsum of proximal phalanx. This aponeurosis is related to the tendons of extensor digitorum. Its base is proximal and covers the metacarpophalangeal (MP) joint. Main tendon of extensor digitorum occupies the central part and is separated from the MP joint by a bursa. Tendons of interossei and lumbrical muscles join at posterolateral corners of extensor expansion. Corners are attached to deep transverse metacarpal ligament. Wing tendons - The point of attachment of interossei and lumbrical is often called wing tendon Near the proximal interphalangeal joint extensor tendon divides into a central slip and 2 collateral slips. Central slip is inserted into the dorsum of the base of the middle phalanx. Collateral slips along with thick margin of extensor expansion are inserted into the dorsum of base of distal phalanx. Extensor expansion forms the dorsal part of fibrous capsule of metacarpophalangeal and interphalangeal joints. MUSCLES INSERTED INTO DORSAL DIGITAL EXPANSION: INDEX FINGER: 1stdorsal interosseous,2ndpalmar interosseous, 1stlumbrical, extensor digitorum slip and extensor indicis. MIDDLE FINGER :2nd and 3rd dorsal interossei, 2ndlumbrical, extensor digitorum slip. RING FINGER: 4th dorsal interosseous, 3rd palmar interosseous, 3rd lumbrical and extensor digitorum slip. LITTLE FINGER: 4th palmar interosseous, 4th lumbrical, extensor digitorum slip and extensor digiti minimi. AGAM  97 AGAM  98 25. POSTERIOR INTEROSSEOUS NERVE: Posterior interosseous nerve is motor and chief nerve of the back of the forearm. ORIGIN: It begins in the cubital fossa as one of the two terminal branches of radial nerve at the level of lateral epicondyle of humerus. COURSE: PIN leaves cubital fossa by winding around lateral side of neck of radius in the substance of supinator. After emerging from supinator, it runs in fascial plane between superficial and deep extensor muscles. At the lower border of extensor pollicis brevis, it passes deep to extensor pollicis BRANCHES: I. MUSCULAR BRANCHES: Before piercing supinator- extensor carpi radialis brevis and supinator While passing through supinator – supinator After emerging from supinator- extensor digitorum, extensor digiti minimi, extensor carpi ulnaris and all deep extensors. II. ARTICULAR BRANCHES TO Wrist Distal radio-ulnar Carpal joints AGAM  99 CLINICAL ANATOMY: LESION OF POSTERIOR INTEROSSEOUS NERVE: CAUSE: Damaged during surgical exposure of head of radius in fracture of proximal end of radius. Wrist drop does not occur as extensor carpi radialis longus is spared which is supplied by radial nerve directly AGAM  100 26. POSTERIOR INTEROSSEOUS ARTERY Posterior interosseous artery is smaller terminal branch of the common interosseous artery from ulnar artery. ORIGIN: It begins in cubital fossa, enters back of forearm by passing through the gap between oblique cord and upper margin of interosseous membrane. COURSE: Posterior interosseous artery passes between supinator and abductor pollicis longus accompanying the posterior interosseous nerve. In lower part of forearm, it ends by anastomosing with anterior interosseous artery BRANCHES: 1. INTEROSSEOUS RECURRENT ARTERY - Takes part in formation of anastomosis around elbow joint. 2. MUSCULAR BRANCHES to supinator, abductor pollicis Lingus, extensor muscles of forearm. AGAM  101 27. CEPHALIC VEIN: Cephalic vein is the preaxial limb of upper limb FORMATION: Lateral end of dorsal venous arch COURSE: It runs upwards through the roof of anatomical snuff box. Winds around the lateral border of distal part of forearm It continues upwards in front of the elbow and along the lateral border of biceps brachii. Pierces the deep fascia at the lower border of pectoralis major. Runs in the deltopectoral groove up to the infraclavicular fossa. It pierces the clavipectoral fascia and joins the axillary vein AREA OF DRAINAGE: At the elbow, the greater part of blood is drained into basilic vein through median cubital vein and partly into deep veins through perforator vein. RELATION: It is accompanied by Lateral cutaneous nerve of forearm & Terminal part of radial nerve. TERMINATION: Drains into the axillary vein. AGAM  102 28. DELTOID: ORIGIN: 1. Anterior border and adjoining surface of lateral one third of clavicle. 2. Lateral border of acromion where four septa of origin are attached. 3. Lower lip of the crest of the spine of the scapula. INSERTION: Deltoid tuberosity of the humerus where three septa of insertion are attached. NERVE SUPPLY: Axillary nerve (C5, C6) ACTIONS: Powerful abductors of arm at the shoulder joint from beginning to 90 degree. Anterior fibres are flexors and medial rotators of arm. Posterior fibres are extensors and lateral rotators of arm. AGAM  103 STRUCTURES UNDER COVER OF DELTOID: BONES: Upper end of the humerus. Coracoid process. MUSCLES INSERTION: Pectoralis minor on coracoid process. Supraspinatus, infraspinatus and teres minor on greater tubercle of the humerus. Subscapularis on lesser tubercle of humerus. Pectoralis major, teres major and latissimus dorsi on the Long head of triceps brachii from infraglenoid tubercle. Lateral head of triceps brachii from the upper part of posterior surface of humerus. intertubercular sulcus of humerus. MUSCLES ORIGIN: Coracobrachialis and short head of biceps brachii from coracoid process Long head of biceps brachii from the supraglenoid tubercle. VESSELS: Anterior circumflex humeral. Posterior circumflex humeral. NERVE: Axillary nerve JOINTS AND LIGAMENTS: Musculotendinous cuff of shoulder. Coracoacromial ligament. BURSAE: Subacromial bursa and subdeltoid bursa. AGAM  104 CLINICAL ANATOMY: Intramuscular injection is often given in the deltoid. It should be given in the middle of the muscle to avoid injury to the axillary nerve. Axillary nerve may be damaged by dislocation of shoulder o