ANAT30007 - Summary Human Locomotor Systems PDF

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Week 1-7 Summary (MST1)...

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Movements - Simple pattern reflexes (knee jerk) - Complex postural/ reflex movements - Voluntary movements (walking) Motor neurons hierarchy - Upper motor neuron - Lower motor neuron Nerve organization - Nerve fibre < Endo < Fasciciels < Peri < Epi (neurium) < Nerve - Nervers (PNS axons) / Tracts(CNS) Spinal Cord/ Spinal nerves - 31 Pairs spinal nerves : 8 (7v),12,5,5,1 - C, T, L, S, C - Ventral/ Dorsal roots, ramus - Ganglia (cell bodies) Nerves plexus - Cervical, brachial, lumbar, sacral Cranial nerves 12 nerves - Olfactory , optic, (cerebral hemisphere) - oculomotor, trochlear (Mibrain) - Trigeminal, Abducens, Facial, Vestibulocochlear (pons) - Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal (Medulla) - Most not mixed/ no C1 dermatome Somatic v Autonomic (visceral) Sympathetic outflow (Thoracolumbar outflow) Origin lateral horn/ exits ventral horn/ pre/ post ganglionic neurons/ Myelinated: white communicating ramus (coming in) - Parasympathetic sacral nerve (Craniosacral) No sympathetic trunk, long preganglionic/ short postganglionic neuron ( postganglionic located near organ) 4 cranial parasympathetic nerves (oculomotor, Facial, Glossopharyngeal, Vagus) CNS - brain/ spinal cord (nucleus) PNS- 12 cranial, 31 spinal (ganglion) Brain - Gyuri (hills), Sulcus (valley) / Folia (cerebellum hills) - Frontal, Parietal, Occipital, Temporal lobe - Primary motor/ sensory cortex = at precentral gyrus/ postcentral gyrus - Corpus collusion- connects the two hemisphere/ major fiber tract (connection of neuron) - 4 ventricles (CSF) - 2 venticle/ 2 lateral Brodmann areas : based on cellular differences/ based on anatomy

Brainstem - b/w diencephalon(interbrain) and spinal cord - Midbrain(mesen)/ pons(the bridge)/ medulla obligator (myel) ncephalon - Extrapyramidal motor system: postural muscles controls Spinal cord - Grey matter: cell bodies (lateral surface on the brain, vise versa in the spinal cord) - White matter : myelinated tracts (funiculi in spinal cord ) - Cervical/ lumbar enlargement - Cauda equina (horse tail) : cord finish at L1/L2 Primary motor cortex - Internal capsule - Reach brainstem/ spinal cord - Left Hemisphere comm Right side of the body (cross at medulla pyramid) The motor homunculus - Size of motor cortical surface is proportional to the degree of motor control Motor cortices hierarchy - Prefrontal → SMC/ PMC → Primary motor cortex → Spinal cord→ somatic motor output Damage to Motor pathway lesions - Upper motor neuron: can't move in coordinated fashion (spastic paralysis),reflex pathway intact but triggered by sensory inputs, b/c loss of inhibitory drive - Lower motor neuron (spinal/ ventral roots/ nerves): paralysis( flaccid) - Lesion / damaged :premotor cortex / supplementary and other motor ares ( Apraxia- loss of learned movements) Corticospinal tract - Lateral corticospinal tract : 80% of fibers cross at medullary pyramids, distal limb control muscle, Travel in lateral column - Ventral corticospinal tract: cross at the level of the spinal cord, Travel in the ventral column, Innovate proximal muscles (trunk) - Decussation of the medulla pyramids ( where upper motor neurons cross) Pyramidal system - Voluntary movements - Direct pathways influencing lower MNs - Most originates from motor cortex and cross to contralateral side at the medullary P Extrapyramidal system - Involuntary movements - Indirect pathway influencing lower MNs - Tracts found within pons and medulla - Involvement of basal ganglia, midbrain nuclei and cerebellum - Coordination of movements/ posture control/ muscle tone - Motor pathways not part of pyramidal sys (inc basal ganglia) - Cortex influence through brainstem

Extrapyramidal system tracts Rubrospinal tract (Rubro)/red - Red nucleus from midbrain to cervical spinal cord - Travels in lateral funiculus - Postural and autonomous control of upper limb muscles Reticulo (interconnected nuclei in the brainstem) - Neurons collection from pons and medulla descending to the spinal cord - Travels in lateral and anterior column - Controls postural muscles Vestibulo (balance  control) - Originated from vestibular nuclei from the brain stem (medulla/ pons) - Travels in ventral column - Control posture and balance Tecto (midbrain) - Originated from the midbrain colliculi (4 at the back of brain stem) - Travels in ventral column - Vision and sound integration ( head orientation to visual and sound stimuli) Basal ganglia control system : Inhibitory/ excitatory fine tuning smoother movements/ basal, cerebral nuclei Corpus striatum : - Globus pallidus (old nucleus evolutionary than the other 2/ thus paleostriatum) - Patamen - Caudate nucleus (C shape structure) Midbrain nuclei - substantia nigra - subthalamic nucleus Feedback via cerebellum - Anatomically : Grey matter nuclei located within the white matter of the cerebellum - Functionally: several nuclei in diencephalon and brainstem (Close proximity providing similar function to control movement) Subthalamic nucleus (in green) - Ventral to thalamus, located in the diencephalon - Functionally part of basal ganglion not anatomically - Mostly glutamatergic(excitatory) neuron - Reciprocal connection with basal ganglia (globus pallidus) - Deep brain stimulation for parkinson Substantia Nigra (Black due to neuromelanin) - Located in midbrain/ functionally part of basal ganglia - Motor planning/ movement - Para compacta component Contain dopamine neurons (input to basal ganglia), degeneration for parkinson patients

Basal Ganglia loop (circuit anatomy) Direct pathway (excitatory signal to cortex) - Corticostriatal fibres → striatum → Gpi → Thalamus → t halamocortical fibres Indirect pathway: (inhibitory signal to the cortex) - Corticostriatal fibres → striatum → Gpe → Subthalamic nucleus → Gpi→ Thalamus → thalamocortical  fibres Substantia Nigra: regulation - Through nigrostriatal fibres → Striatum (dopamine enhance direct/ indirect pathway responses) to fine tune Basal ganglia regulation Cerebellum - Receive sensory input that sends to the motor thalamus - Fine movements/ coordination/ precision/ timing - Compare motor plan (cortex input) with motor action/ sensory feedback for refined movement Motor system summary - Pyramidal pathways : by corticospinal pathways (primary motor cortex telling muscle to contract by Lateral/ ventral motor pathways) - Extrapyramidal pathway : control postural muscles - Basal ganglia : for smooth/ refined movements - Cerebellum : feedback process (what we do is what we meant) Cerebellum damage - Unrefined movement (ataxia) Parkinson disease - Degeneration of globus pallidus and S niagara(dopamine reduction) - Imbalance b/w direct/ indirect pathway: increases in indirect (inhibition) pathway signalling - Hypokinetic disorder - stop for a time before start walking (greater indirect inhibition on motor circuit) - Deep Brain stimulation of the subthalamic nucleus: (high frequency impulses) inhibit the subthalamic outflow (allow Gpi to inhibit normally) restoring some indirect pathways Treatment: - Replacement of dopamine (L-dopa) - Surgical destruction of GP/ VL nu of Thalamus (dampened down too much inhibition) - Neurons containing dopamine striatal implants Spinal curvature “develops as we become more weatbearing” - Kyphotic (thoracic/ sacral): reversed C/ bend forward” curvature - Lordotic (cervical/ lumber) : “C/ bend back) curvature Vertebrae - Pedicle (bridge), lamina

Thoracic vertebra - Costal facets (one superior, inferior and transverse) - articulate with the ribes - Spinous process (elongate more inferiorly (coronal)) - prevent vertebral column tilting back - Articular facets : standing up tilted forward - prevent (flexion/ extension) One rib has 3 point of articulation with the spinal column (no movement) - Rib (7) head : articulate with T6 inferior/ superior T7 costal facet, rib body with T7 transverse costal facet - Joint with no movement: to dissipate force - Ribs are twisting and bending for subtle movements (somewhat flexible) Lumber vertebrate ( typical vertebrate) - Thicker/ bigger (vertebral bodies) going inferior - for weight bearing - Articular facets predominantly sagittal- flexion/ extension - Easy access to operate/ pathology- due to only soft tissue covering Sacrum/ coccyx (fused together vertebrate) Separate opening on both surfaces (anterior/ posterior sacral foramina) - Anterior - veins draining form pelvis structures - anterior/posterior - nerves pathways Promontory (vertebral body equivalent) - at S1 its more prominent anteriorly (thus name) Disc rupture and herniation (hole in the wall) - Posterior annular is thin- vulnerable to tear - Herniation will affect the nerve coming below the affected vertebrate (L1 vertebrae on L2 nerve). (When the vertebral column was developing, nerve was hooked at the superior part of the intervertebral foramen (ovular shape, due to 2 notches and disk space) Ligaments of vertebral column - Anterior/ posterior longitudinal ligaments - covering the vertebral body - Supraspinous ligaments - joining tips of the spinous process - Interspinous ligament - b/w the spinous processes - Ligamentum flavum (yellow)- b/w lamina to lamina Vertebral movements orientation by ARTICULAR FACETS

Zygapophyseal joints (posterior intervertebral joints) - Range of intervertebral motion - Degenerative joint disease risks Blood supply of the vertebral column Arterial system - Segmental supply (like the spinal cord) - Anteriorly - 1 spinal artery running down / 2 posteriorly Venus system - Segmental supply - Subarachnoid space - Spinal fluid - Epidural - fat/veins - Posterior/ anterior internal vertebral venous plexus - goes full length of the column (slow express highway to the brain where cancer can metastasis to the brain (ie from prostate) Power moves of the back Psoas major m - Merge distally with iliacus m - Both combined to give the most powerful flexor of the hip - Maintain posture of lumbar vertebrae Origin/ insertion - transverse processes T12-L4 / lesser trochanter of femur Nerve - lumbar plexus Function : flexes hip and lumbar intervertebral joints Quadratus lumborum (square muscle of lumbar region) - Origin: Iliolumbar ligaments and the iliac crest - Insertion: Inferior border of the 12th rib and the transverse processes of L1-4 vertebra - Function: Lateral flexion of the spine, elevation of the pelvis Erector spinae mm (group of muscles) - Keep spine erect (concentric contraction) - Control forced flexion (by gravity) of the vertebral column Intrinsic muscles  innervated by dorsal  primary rami each spinal nerve level - Erector spinae (iliocostalis, longissimus spinalis)mm - Horizontally (regions) : divided vertebral m into same regions as the bones (cervicis, throsis, lumborum) - Vertically (groups) : spinalis (against the spinous process), Longissimus (long and thicker to the spinous process), iliocostalis (parts goes from ileum to the ribs) Cervical vertebrae Cervical/ the neck (underneath the mandible/ base of the skull/ → shoulder and clavicle ) - Transverse foramen - transverse processes have holes - Anterior/ posterior tubercles (bumps) on transverse processes: for subtle muscle attachment - Bifid spinous processes: greater angle for subtle muscle attachment and power C7 vertebrae prominent (neck bulge/ not bidfid) Uncinate(hook shape) processes- only in cervical and occurs later in life( due to long term load bearing)

- Articular Facets are Oblique b/w transverse and coronal : permissive of any movements C1 and C2 atypical (joints at the base of the skull C1 - only 2 superior articular facets articles with the skull - Lacks spinous process and vertebral body - Have anterior/ posterior tubercles C2 - Make a vertebral body by connecting up anterior tubercle of C1 and C2 Dens : stable connection - Dens of C2 is held up against the anterior tubercle of C1 - Cruciform (cross like) ligament : a transverse/ longitudinal part - Alar (winglike) ligament

Cervical ligaments - As Posterior longitudinal ligaments (getting wider towards c1 and goes through foramen magnum)→ called tectorial membrane - Supraspinous ligament (moving superiorly becomes a fan of fibrous tissue in the sagittal plane) → nuchal ligament Neck Vasculature Subclavian a (runs under clavicle) - Supplies inferior and posterior structures Main branchinces - Vertebral a (into the transverse foramen EXCEPT C7, runs to the base of the skull and in front of brainstem ) Two of them Each provide ⅓ of brain blood supply Vulnerable to “dissection” - a  tear within the blood vessel wall allowing blood to separate the wall layers - Internal thoracic a (drain into the thorax) - Thyrocervical trunk - (suprascapular, inferior thyroid, dorsal scapular artery*) - Costocervical trunk - ribs and neck branch Subclavian a → Axillary a (Past  the lateral margin of FIRST rib) L/R common carotid aa Bifurcate into - Internal carotid a Only suppliers internal structures Dont branch in the neck Two ICA supply the other ½ of brain blood supply - External carotid a Does branch in the neck To viscera and other soft tissues Muscles of the neck (Anterior)

Sternocleidomastoid m - Attaching near the midline to the sternal-clavicular → coming laterally-obliquely to the mastoid process - Principal muscle for subdivision region of neck Platysma: (thin sheet of neck muscle) - Gives facial texture - Same nerves innovating facial expression (Posterior) Both wraps around superior erectus spinale m group : - Splenius capitis m (bandage of the head)- Splenius cervicis m (bandage of the neck) Suboccipital triangle mm (Triangles like muscle group back of the neck, vertebral artery going through the middle) Superficial/ landmark mm Jugular v (external/ internal) - comes in relation to the sternocleidomastoid m/it protect it - Veins from either side drains all the blood from the brain's Infrahyoid muscles or strap muscles - Hyoid Bone/ thyroid cartilage / sternum : key landmarks for describing them (muscles protects the thyroid gland) - Sternohyoid m - Omohyoid m (hyoid crossing across Internal jugular vein → shoulder) - Thyrohyoid m - Sternothyroid m Carotid sheath (encloses up the neck) - Internal jugular v - Vagus (x) nerve - Common carotid a Muscles sitting anterior to the vertebral column - Prevertebral mm - Lateral vertebral mm Cervical ribs - Some people having a additional rib starting at C7 Shoulder and arm bones Pectoral girdle(circular brace) Structure Sternum, clavicle, scapular, Humerus - Incomplete girdle on posterior side - allow upper limb movements from midline Clavicle - (S shaped bone) Medial part anteriorly convex, and lateral part is concave dissipate forces

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Sternocleidomastoid muscle attachment Mobile - allow upper limbs to hang off the axial skeleton Lacks medullary cavity (partly endochondral and intramembranous ossification), but have bone marrow - Articulates with the manubrium ( Jugular (superternum), clavicular, costal cartilage of the 1st rib notch) Clavicular fracture - Fall on outstretched arm - Most common at the midpoint (deltoid/ SCM/ pectoralis major attachment) - Protects other structures being affected Scapular - Triangular in shape Borders and angles - medial/ vertebral - lateral/ axillary - Superior Suprascapular notch (along the medial border) (Anterior side) Glenoid cavity ( socket of the arm joint) - Shallow cavity ( mobile) Supraglenoid tubercle (long head of the bicep) Infraglenoid tubercle(long head of the tricep) (subscapular fossa) Body of the scapular Subscapularis muscle Coracoid process (coracoid process) bony outgrowth (Posterior side) - Scapular spine - Acromion (c hook) meet with acromion process of the clavicle Fossa (due to the spine) - Supraspinous (small region) - supraspinatus m - Infraspinous - infraspinatus m Humerus - Head - ⅓ of a spear (mobility) - Anatomical neck (constriction below the head) (Anterior surface) - Greater and lesser tubercle - Intertubercular groove (b/w the tubercle) (tendon of the long head of biceps) - Deltoid (deltoid m insert) Supracondylar region (where humorous widens, superior to condyle (Trochlea, Capitulum ) - Medial epicondyle (more prominent) → Trochlea → Ulna - Lateral epicondyle → Capitulum → Radial Humerus Fracture Surgical neck

- Below anatomical neck, more prone to damage - Damage to Axillary nerve and Humeral circumflex artery) Midshaft - Damage to radial nerve and brachial artery Supracondylar region - Median nerve and brachial artery Medial epicondyle (whole bit can break off) - Ulnar nerve Fascial compartments Deep fascia - Separate muscles into functional compartment (anterior flexor and posterior extensor) - For periosteum of the bone - Interosseous membrane (b/w radius and ulnar) -

Brachial fascia ( wraps superficial aspect) Antebrachial fascia (forearms) Flexor and extensor retinaculum Palmar aponeurosis

Upper limb muscles form the spine (Extrinsic back muscles) (Superficial) Trapezius - bass of the skull + spinous process C to T → spine of the scapular + the clavicle - elevate, depress and inward movement of scapular - Innovation by cranial accessory nerve Latissimus dorsi - crest of the ilium + lower of T/Lumbar vertebra Thoracolumbar fascia → intertubular groove - Extension (full limb backwards) - Adduction (inward) - Internal rotation of arm Deeper layer Levator scapulae - cervical at superior angle → scapula - Innervation: Anterior rami of Cervical and dorsal scapular nerve Rhomboid major and minor - vertebral column → medial scapular - Retract the scapular - Innervation: Dorsal scapular nerve (C5) (comes from medial margin of the scapular)

Triangle of auscultation (heart and lungs beat) - Medial border of scapula - inferior border of the trapezius - superior border of the latissimus dorsi Pectoral muscles Pectoralis major (convergent m) - Clavicle + sternum + costal cartilages of ribs → bicipital groove - Abduction , Internal rotation Pectoralis minor - 3 ribs → coracoid process of scapula - Elevate/ depress ribs (breathing aid) Serratus anterior - Lateral aspect of ribs → anterior medial scapular border - Adducted, protract scapula (pushing against the ribcage) - Nerve Supply is superficial to the muscle (injury prone) X-ray production - Image is formed by contrast - 3 main density - Bone, soft tissue and air - Bone, lead, Metal (white colour in image) vs Muscle/ Blood(grey) vs Fat/ Air (Black) X- ray summary - Good for bones and joint - Checking alignments - Need more than one view - Cheap , quick and safe Magnetic Resonance Imaging Pro - Good spatial and contrast resolution ( soft tissue and bone marrow) - Good inside joints/ cross sectional imaging - Multiple planes imaging Con - Expensive - Long scan time Main images (achieved by twerking RF) - T1 : Fluid is dark/ Great for bones - T2 : fluid is bright / great for muscular injury - PD: great for bones Ultrasound - Cross-sectional - multiplaner image (Porbe emit high frequency sound into the body) - Works like sona (needs to hits something) (reflexion, absorption and scatter) - Sound waves reflected back from tissue make up the images - Higher/ fine resolution on small area with less depth

Pro - No radiation, Operator dependent, Good soft tissue contrast res than MRI - Best for superficial structures, Dont see through bones, Cheap and practical Echotexture (density) - Echogenic/ hyperechoic (many reflectors) ie fat, tendon - white - Echopoor (few reflectors) Fluid - black CT (3 dimensional x ray) - X ray to form a cross sectional image - Don't use much in musculoskeletal (mainly for bones) - Radiation prone - Don't see individual fibers/ fine details - Visualise air, fat, water, soft tissue and bones - Excellent for cortical or trabecular bone structures, Complex joins as the pelvis Nuclear medicine Injecting a radioactive substance which bind to osteoblast asses vascularity and osteoblastic activity (can't give specific location) - Asses for metastases/ infection/ stress fractures/ osteonecrosis and arthritis Lumbar spine symptoms Pain - Localised - Referred to buttocks/ legs - Arise from disc, joins, bones or nerves Deformity - Scoliosis Loss of neurological function - Compressive effect Bones or disc Nerve roots (radiculopathy) Spinal cord (myelopathy) Imaging modalities - X ray and CT (most...