Muscle And Fascia Compartments Trans

BONY LANDMARKS Muscle and Fascia Compartments of the Upper (parts that can be palpated- all areas in green) Limb Anterior Dr. Adelia Matanguihan- Quijano M.D.

FASCIA (divisions) – Superficial (Hypodermis, Subcutaneous Tissue) – Deep ○ Derivatives 1. intermuscular septa 2. ligaments 3. tendons 4. aponeurosis 5. muscular and nervous investments ○ Receives different names according to region 1. Pectoral Fascia – encloses pectoralis major. 2. Clavipectoral Fascia – encloses subclavius and pectoralis minor. 3. Axillary Fascia 4. Brachial Fascia – arm 5. Antebrachial Fascia – forearm 6. Palmar Fascia 7. Dorsal Fascia 8. Flexor and Extensor Retinacula 9. Digital Fibrous Flexor Sheaths UPPER LIMB (divisions) – Joints divide the superior appendicular skeleton – Limb is divided into 4 main regions (bold) ○ Shoulder (pectoral) ○ Arm (brachium) ○ Elbow (cubitum) ○ Forearm (antebrachium) ○ Wrist (carpus) ○ Hand BONES OF UPPER LIMB

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Fyi- clavicle is the first long bone to ossify in fetus

Posterior

1 July 2009

Legend: C- Scaphoid, D- Lunate, E- Triquetrum, F-Psiform, G- Trapezium, HTrapezoid, I-Capitate, J-Hamate, L- Radius, L1-Styloid process of the Radius, M- Ulna, M1- Styloid process of the Ulna

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3. Teres major (+ Teres minor)- minor is more superiorly located; both help in lateral rotation SCAPULOHUMERAL DISSECTION *teres minor- above, major- below

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MUSCLES OF THE PECTORAL REGION 1- Trunk to scapula or clavicle a. Trapezius- assists in suspending the pectoral girdle and elevates, retracts and rotates the scapula b. Levator scapulae- pulls up the scapula c. Rhomboideus major/minor- adducts scapula towards the midline d. Pectoralis minor- stabilizes the scapula, for flexion e. Subclavius- stabilizes (anchors and depresses) the clavicle f. Serratus anterior- (serrated appearance); keeps scapula close to trunk and rotates it 2- Trunk to humerus a. Latissimus dorsi- widest back muscle b. Pectoralis major **extends, adducts and rotates the humerus medially

Winging of the scapula - paralysis of serratus anterior / injury to long thoracic nerve - when the medial border of the scapula moves laterally and posteriorly away from the thoracic wall

Quadrangular space ○ Teres minor, teres major, triceps brachii (medial), humerus(lateral)  Enervated by Axillary nerve  Post humeral circumflex artery runs through it – Triangular space ○ Teres minor, teres major and triceps brachii  Circumflex scapular artery from subscapular artery runs through it ARM: MUSCULAR COMPARTMENTS – Anterior- flexors (3) ○ Enervated by musculocutaneous nerve ○ Bloody supply from brachial artery ○ Supinator ○ Biceps brachii coracobrachialis (passes only shoulder joint) and brachialis muscles ○ Covered by superficial Antibrachial fascia ○ Presence of bicipetal aponeurosis which forms a roof over cubital fossa and protects underlying structures – Posterior- extensors (2) ○ Enervated by radial nerve ○ Blood supply c/o brachial artery ○ Triceps brachii- long, lateral and medial heads + Anconeus (muscle that assists the triceps in extending the elbow joint) FOREARM: MUSCULAR COMPARTMENTS – Anterior- flexors (+pronators) ○ Enervated by Median nerve and/or ulnar nerve (only 1 and a ½ exceptions are supplied by latter) ○ 3 layers/groups  1 superficial group- common flexor tendon; origin- medial epicondyle of humerus; made up of 4 muscles • Pronator teres • Wrist flexors (3)- flexor carpi radialis, Palmaris longus, and flexor carpi ulnaris

AXILLA – The pyramidal space inferior to the glenohumeral joint and is superior to the axillary fascia at the junction of the arm and thorax MUSCLES OF PECTORAL REGION  Scapula to humerus 1. Deltoid- triangular muscle that forms the rounded contour of the shoulder; middle area is multipennate; functions as the principle abductor of the arm (flexion of shoulder joint) 2. Rotator Cuff muscles (scapulohumeral muscles- SITS) a. Supraspinatus b. Infraspinatus- lateral rotator c. Teres minor d. Subscapularis- medial rotator • Initiate abduction for first 150 degrees; deltoid does the rest; grasps and pulls the humerus head against the glenoid cavity (reinforces anteriorly, superiorly and posteriorly)

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2 intermediate group • Flexor digitorum superficialis muscleflexes in fast action 3 deep group- flexors of digits and pronator (made up of 3 muscles) • Flexor digitorum profundus- flexes fingers in slow action • Flexor pollicis longus – extends the thumb, extrinsic muscle

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Pronator quadratesbetween the radius and ulna

** FYI- biceps brachii serves supinator function

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Cubital Fossa- triangular area in elbow which serves as an imaginary border; found by the brachialis muscle; filled with a variable amount of fat ○ 3 boundaries  Superiorly: imaginary line connecting the medial and lateral epicondyle  Medially- mass of forearm flexor muscles (pronator teres) arising from a common flexor attachment on the medial epicondyle  Laterally- mass of extensor muscles (brachioradialis) ○ Contents of fossa  Terminal end of the brachial arteryand divisions of radial and ulnar arteries  Deep accompanying veins of the arteries  Biceps brachii tendon  Median nerve  Radial nerve Posterior- Extensors (+supinator and forearm flexor) ○ Enervated by the radial nerve ○ Divided into 3 functional groups  Extensor muscles of the wrist joint  Extensor muscles of the fingers  Thumb abductor and extensors ○ Blood supply is from both radial and ulnar arteries  Flexor of the elbow joint (forearm)brachioradialis which is slanted and found in the humerus to the radius • Exception to the rule that radial nerve supplies only extensory muscles and that all flexors are found anteriorly (flexor compartment)  Extensors • E. carpi radialis longus and E. carpi radialis brevis- extends and abducts hand at wrist joint; for clenching • E. digitorum (communis)extends 4 medial fingers • E. digiti minimi – extends 5th finger • E. carpi ulnaris- extends and adducts hand at wrist joint; for clenching  Supinator, Abductor and Extensor • Abd, pol. Longus • E. pol. Brevis • E. pol. Longus ** extends and abducts the thumb • E. indicis – extends 2nd finger (for independent extension) Anatomical Snuffbox ○ (triangular hollow) depression between ext. pol. Longus and brevis tendons

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Formed by scaphoid and trapezium bones

FASCIA: WRIST AND HAND – Deep fascia continues from antebrachial fascia I. Retinacula (At wrist region) a. Extensor retinaculum b. Flexor retinaculum- forms carpal tunnel as it bridges carpal bones concavity; for passage of flexor digitorum profundus and superficialis and flexor pollicis longus ** in the carpal tunnel runs the median nerve

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Palmar carpal ligament- fund superficial to flexor retinaculum II. Palmar Fascia a. Thenar Fascia b. Hypothenar Fascia c. Palmar Aponeurosis III. Dorsal fascia IV. Fibrous Flexor Sheaths of Digits (covering of Flexor Digitorum Tendons) V. Vincula – attach superficial fascial and deep flexor tendons to middle and distal phalanges respectively; provide route for blood supply to tendons. FASCIAL SPACES (4) – Carpal Tunnel – Thenar Compartment – Hypothenar Compartment – Central compartment ○ Palmar Space  Thenar Space  Midpalmar Space ○ Synovial Flexor Sheaths (for support)  Ulnar Bursa – Contains tendons of Flexor Digitorum Superficialis and Profundus  Radial Bursa – Contains tendon of Flexor Pollicis Longus  Synovial Sheaths for second to Fourth Digits INTRINSIC MUSCLES OF THE HAND – Nerve supply c/o ulnar nerve EXCEPT thenar muscles and the 1st 2 lumbricals which are supplied by the median nerve – Thenar compartment (act on thumb) ○ Abductor Pollicis brevis ○ Flexor Pollicis brevis ○ Opponens Pollicis – Hypothenar compartment (act on little finger) ○ Abductor digiti minimi ○ Flexor digiti minimi ○ Opponens digiti minimi – 12 short muscles ○ Lumbricals – in central compartment; arise from flexor digitorum profundus; flexes metacarpophalangeal (MP) joint and extends dorsal and palmar interphalangeal (DIP and PIP) joints  1 and 2 = unipennate  3 and 4 = bipennate

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Muscles in Interossei- adductor compartment  3 palmar (adducts) and 4 dorsal (abducts)  1 Adductor pollicis (adducts the thumb)

1 July 2009

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