Muscle Anatomy PDF

MUSCLE Dr Ruta Bapat Professor Department of Anatomy 1  Definition Types Structure Fascicular architecture Naming Actions Nerve supply Applied importance 2 MUSCLE (Latin: MUS-...

MUSCLE Dr Ruta Bapat Professor Department of Anatomy 1  Definition Types Structure Fascicular architecture Naming Actions Nerve supply Applied importance 2 MUSCLE (Latin: MUS- MOUSE) Muscle is a contractile tissue which brings about movement. Contractility, irritability, elasticity , extensibility. 3  Types Skeletal Cardiac Smooth 4 Gross structure of a typical skeletal muscle 5 6 Morphological classification (According to arrangement of fasciculi) A).Parallel fasciculi : a) Quadrilateral – Thyrohyoid b) Strap like – Sartorius d) Fusiform – Biceps, digastric c) Strap like with tendinous intersections – Rectus abdominis 7 B). Oblique fasciculi : 1. Convergent :- a) Triangular- Adductor longus b) Fan shaped – Temporalis 2. Pennate :- a) Unipennate – palmar interossei, flexor pollicis longus b) Bipennate – rectus femoris, dorsal interossiei c) Multipennate – Deltoid , Subscapularis d) Circumpennate (radial) – tibialis anterior 8 C). Sprial fasciculi – Pectoralis major, lattisimus dorsi D). Cruciate fasciculi – Sternocleidomastoid, masseter E). Sphincteric fasciculi – Sphincter ani, orbicularis oris, 9  SKELETAL MUSCLE FIBRES Red (Type I) fibres White (Type II) fibres 1. Red due to more Paler due to less myoglobin , myoglobin, rich, capellary poor capillary plexus plexus 2. Slow tonic contraction 2. fast, phasic contraction 3. Rich in mitochodria and 3. Poor mitochondria, rich in oxidative , enzymes glycolytic enzymes, glycogen 4. Less cross striations 4. More cross striations. 5. Aerobic metabolism, highly 5. Anaerobic metabolism, resistant to fatigue easily fatigued. Intermediate fibres 10  Contractions of muscle 1. Reflexive - Diaphragm 2. Phasic - a) Isotonic – tone remains same a) Concentric – length decreases b) Eccentric- length increases (less metabolic energy, higher tension levels 50%) b) Isometric – length remains same 11  Action is brought about by a group of muscles The group of muscles is classified according to functions – a) Prime movers b) Antagonists c) Fixators d) Synergists 12  Nomenclature of Muscle  According to location: Temporalis, pectoralis.  According to number of heads – biceps, triceps, quadriceps.  According to actions: flexor, extensor  According to position: Superficial, deep, supra infra  According to Shape: Trapezius, rhomboideus. 13  According to structure: Semimembranosus, gracilis,  According to attachment: Brachioradialis, sternocleidomastoid  According to Size : Maximus, Minimums , Magnus ,longus.  Direction of fibers : Rectus , tranversus, oblique, orbicularis 14 Nerve Supply of Skletal muscles Nerve - one or more motor points or neurovascular hila. Motor nerve - but it is a mixed nerve Motor fibers – 60%, Sensory fibers 40%, 15 Neuromuscuar Junction Between terminal end of axon (Motor end plate) and sarcolemma of muscle belly (sole plate) Motor unit: – Small motor unit: -5to 10 muscle fibers - extraocular muscles – Large motor unit – 100to 2000 muscle fibers - limb muscle 16 Composite (Hybrid) Muscle Muscles supplied two different motor nerves with different root values. – Adductor Magnus – obturator and sciatic nerve – Flexor digitorum profundus – Median and Ulnar nerve 17  KINESIOLOGY Three components- – Shunt – trans articular – power – Swing- cis articular ( trans axial)- speed – Spin – rotary along its axis Partition ratio P = c/q (c - cis articular , q - transarticular ) 18 Levers Bones & muscles as body levers – Class I, II , III levers 19  Applied Anatomy Paralysis 20  Muscular spasm 21  Muscle soreness or pulled muscle 22  Muscle testing – action against resistance Atrophy, hypertrophy, hyperplasia Electromyography (EMG) – electrical stimulation of muscle 23 24