General anatomy of skeletal muscle

its innervation and blood supply

General anatomy of spinal nerve

Miloš Grim

Institute of Anatomy

First Faculty of Medicine,

Charles University

Winter semester 2017/2018

General Anatomy of Skeletal Muscle(final exam questions) Origin and development of muscles,

molecular mechanisms

General features of striated muscle, its auxiliary structures

(motor end plate, motor unit, muscle spindle, Golgi tendon organ),

motor and proprioceptive innervation

Attachments of skeletal muscles – origin, insertion

Muscle fibres, myofibrils, sarcomeres

Naming of muscles

Shape and fibre architecture, pennation

The endomysial and perimysial sheaths

The interface between muscle and connective tissue

Myofibrilar proteins

Sliding filament mechanism of contraction

Tendons, Aponeuroses

Synovial sheaths and bursae

Fascia, intermuscular septa, osteofibrous spaces

How to study skeletal muscles: identification, muscle groups,

innervation, function, origo, insertion,

position (scheme, tables), osteofascial

spaces (compartments),

transverse sections of limb segments,

dissection

R.S.Snell: Clinical Anatomy. Lippincott Williams Wilkins

Attachments of skeletal muscles – origin, insertion,

endomysial and perimysial sheaths, fascia

tendons, aponeuroses, neuro-vascular hilum (motor point)

Naming of Muscles

Shape:

deltoid (= triangular), quadratus (= square), rhomboid

(= diamond-shaped)

teres (= round), gracilis (= slender), rectus (= straight),

lumbrical (= worm-like)

Size : major, minor, longus (= long), brevis (= short),

latissimus (= broadest), longissimus (= longest)

Number of Heads or Bellies:

biceps (= 2 heads), triceps (= 3 heads), quadriceps (= 4 heads)

digastric (= 2 bellies), biventer (= 2 bellies),

Position:

anterior, posterior, interosseous (= between bones)

supraspinatus (= above spine of scapula),

infraspinatus (= below spine),

dorsi (= of the back), abdominis (= of the abdomen)

pectoralis (= of the chest), brachii (= of the arm)

femoris (= of the thigh), oris (= of the mouth)

Naming of Muscles

Depth:

superficialis (= superficial), profundus (= deep),

externus (or externi), internus (or interni)

Attachment:

sternocleidomastoid

(from sternum and clavicle to mastoid process)

coracobrachialis (from the coracoid process to the arm)

Action:

extensor, flexor, abductor, adductor,

levator (= lifter), depressor,

supinator, pronator, constrictor, dilator

Fascia, intermuscular septum, osteofibrous spaces

Osteofasciál

spaces of

the upper limb

Fibrous and synovial sheaths,

synovial bursa

Auxiliary structures of muscles

Retinaculum musculorum extensorum

m. extensor hallucis longus (Vesalius, 1555)

muscle fibre,

myofibril,

sarcomere

sarcoplasmic

reticulum,

T-tubules,

triads

mitochondria,

sarcolemma,

basal lamina

Satellite cell

http://fig.cox.miami.edu/~cmallery/150/neuro/muscle.htm

striated muscle fibres, sarkomere

Innervation of skeletal muscle

Neurovascular hilum

Blood supply

Motor innervation

Alfa motoneurons: slow and fast,

gamma motoneurons,

motor end-plate, ACh

motor unit, zone of motor end-plates,

polyneural innervation, segmental

innervation

Sensory (proprioceptive) innervation

muscle spindle, Golgi tendon organ,

proprioceptive reflexes

Innervation of skeletal muscle: motoneurons, motor units, motor

end- plates, acetylcholine, proprioceptive neurons,

muscle spindles, Golgi tendon organs

vizualization of motor end plates

visualization of motor end plates and axons,

acetylcholinesterase in subneural apparatus

synaptic vesicles containing acetylcholine

(neurotransmitter) in axon terminal of motor end-plate;

curare blocks the transmission

Muscle spindle

Golgi tendon organ

Elektromyography (EMG)

A young women with sensory neuropathy of unknown

origin who completely lost proprioceptive sensation:

She could not stand without watching her feet,

she could not held anything in her hands, and they

wandered around without her awareness…

„Something awful´s happened, I can´t feel my body.

I feel weird-disembodied“, she said, and „I may lose

my arms. I think they´re one place and I find they´re

another“.

After having proprioception explained, she said:

„This proprioception is like the eyes of the body,

the way the body sees itself. And if it goes, as it´s gone

with me, it´s like the body is blind…so I have

to watch it - be its eyes. Right?“ (Dr. O.Sacks, neurologist)

pennation of muscles

arrangement of parallel

running muscle fibres

myo-tendinous junction

Terms related to muscle functionIsotonic and isometric contraction, reciprocal

innervation, synergists, antagonists, resting tension,

postural muscles, electromyography,

denervation atrophy

Muscle activity controls motor systems of CNS

according to information from mechanoreceptors and

proprioceptors and according to motivation

processed by the limbic system

Posture, isometric contraction

Motion, isotonic contraction

Fibre Types of Skeletal Muscle• Type I fibres are slow-contracting and fatigue-resistant

• Type IIA fibres are fast-contracting and fatigue-resistant

• Type IIX (B) fibres are fast-contracting and susceptible

to fatigue

myosin ATPase, dehydrogenase, glycogen phosphorylase

Type I - SO Type IIa - FOG Type IIx - FG

Capillaries of skeletal muscle

FG IIx FOG IIa SO I

FG IIx FOG IIa SO I

A gene for speed? The evolution and function of a-actinin-3

Summary

The a-actinins are an ancient family of actin-binding proteins that play

structural and regulatory roles in cytoskeletal organisation and muscle

contraction. Alfa-actinin-3 is the most-highly specialised of the four

mammalian a-actinins, with its expression restricted largely to fast

glycolytic fibres in skeletal muscle. Intriguingly, a significant proportion (

18%) of the human population is totally deficient in a-actinin-3 due to

homozygosity for a premature stop codon polymorphism (R577X) in the

ACTN3 gene. Recent work in our laboratory has revealed a strong

association between R577X genotype and performance in a variety of

athletic endeavours. We are currently exploring the function and

evolutionary history of the ACTN3 gene and other a-actinin family

members. The a-actinin family provides a fascinating case study in

molecular evolution, illustrating phenomena such as functional redundancy

in duplicate genes, the evolution of protein function, and the action of

natural selection during recent h uman evolution. BioEssays 26:786–795,

2004. ß 2004 Wiley Periodicals, Inc.

DG MacArthur and KN North:

BioEssays 26:786–795, 2004

Only the R allele allows the synthesis of alpha actinin 3, a protein that is

predominantly present in FG (IIx) muscle fibers responsible for rapid and intense

muscle contraction

Development and Differentiation

of Skeletal MuscleMyogenesis,

Myogenic Determination Factors

Myf-5, myogenin, MyoD and Myf-6 (herculin)

Myostatin

Growth of Skeletal Muscle

Hypertrophy, not hyperplasia

Anabolic Steroids

Regeneration of Skeletal MuscleSatellite cells

Langman´s Medical Embryology

Paraxial mesoderm: somites, somatopleura, splanchnopleura

Histochem Cell Biol (2012) 138:187–199

Fate of somites

HH 25

MyoD

Epaxial and hypaxial musculature and its innervation

from dorsal and ventral branches of spinal nerves

Myogenese - diferenciace svalového vlákna

myoD

myf-5

mrf-4

Myogenin

myostatin

Mutation of myostatine gene resulting in overproduction of myogenic cells

Segmental

pattern

of muscle

innervation

The origin of the muscles of the limb

C DK HH 22

Migration of

myogenic cells into

limb primordium

Grim M: Z. Anat-EntwGesch 132:260-71,1970

Neural crest cells in embryonic chimeras

of Japanese quail and white Leghorn chicken

QCPN

Colonization

of the limb bud

(myogenic cells,

Schwann cells,

angioblasts,

ingrowing

Axons)

Ventral and dorsal muscle blastema in limb primordium

Desmin

Morfogenesis of limb muscles

Morfogenesis of limb muscles

Regeneration of skeletal muscle

Satellite cells are resident myogenic progenitors

in postnatal skeletal muscle involved in muscle

postnatal growth and adult regenerative capacity

Activation of satellite cells in muscle regeneration

Fate of the free muscle graft in the rat

1.day

3. day

5. day

7. day

30. day

60. day Intact muscle

General anatomy of spinal nerves

Regeneration of peripheral nerve

Spinal nerve

rootlets, anterior root - motor root,

posterior root - sensory root , spinal ganglion,

trunk of the spinal nerve (mixed nerve),

anterior ramus, posterior ramus

Spinal nerves: C 1-8, T 1-12, L 1-5, S 1-5, Co

Kandel et al:

Principles of neural

science,

2000 McGraw-Hill

Segmental innervation - areae radiculares (dermatomes)

Spinal cord and spinal

nerves of the newborn

Brachial plexus,

Lumbosacral plexus,

Development of segmental innervation of limbs

Neural tube- basal plate, alar plate, sulcus limitans,

somatomotoric zone, visceromotric zone,

viscerosensitive zone, somatosensitive zone,

Spinal ganglion, anterior root, posterior root

Development of the spinal nerve

Nerve graft bridging the partial defect, suture

of perineurium without tension, wavy course of axons

in the peripheral nerve can not be eliminated

peripheral nerve, endoneurium, perineurium,

perineural epithelium, epineurium, denervation atrophy

Regeneration of interrupted axon

General terms of angiology

Terms

of general angiology

Vascular development,

blood vessels,

structure of arteries, veins,

capillaries,

lymphatic vessel,

collateral circulation

collateral vessels,

arteriovenous anastomosis,

venous plexuses,

hepatic portal vein

Venous valves

Terms of general anatomy of lymphatic systemLymph, lymph node, lymph tissue in the organs, main

lymphatic trunks, lymphatic vessels and ducts

Literature and sources of illustrations used:

Mescher: Junqueira´s Basic Histology 12th Edit., 2010

Sadler: Langman´s Medical Embryology, 11th Edit. 2009

Gilroy, MacPherson, Schuenke, Schulte, Schumacher: Atlas of

Anatomy, Thieme 3 ed. 2016

Platzer: Color Atlas and Textbook of Human Anatomy –

Vol.1 Locomotor System, Thieme 2008

Kahle, Frotscher: Color Atlas and Textbook of Human Anatomy – Vol.

3 Nervous System and Sensory Organs, Thieme 2010

Stingl, Grim, Druga: Regional Anatomy, 2012

Netter: Atlas of Human Anatomy, Icon 2003

Sobotta: Atlas of Human Anatomy Vol.1+2, Williams and Wilkins 2000

Snell: Clinical Anatomy by systems, Lippincott Williams and Wilkins

Grim M, Naňka O, Helekal I: Atlas of Human Anatomy I, II , 2014,

2017

Beware of muscle atrophy from inactivity