GAS Lectures

fibrous joints (synarthroses)

immovable joints such as sutures, gompohoses, synchondroses

cartilaginous joints (amphiarthroses)

slightly movable joints such as syndesmoses and symphyses (intervertebral)

synovial joints (diarthorses)

freely movable joints

uniaxial synovial joints

planar, pivot, hinge

biaxial synovial joints

ellipsoid, condyloid, saddle

multiaxial synovial joints

ball and socket

6 types of synovial joints

hinge, ball and socket, condyloid, pivot, planar, saddle

hinge joints

joints that open and close in one direction (knees and elbows)

ball and socket

rounded end of one bone fits into an indentation in another bone, can rotate and turn in almost any direction (shoulders and hips)

condyloid joints

made of two oval shaped bones that fit together, similar to ball and socket joints, except they can't rotate in a full 360 degrees (wrist joints and joints where toes meet the rest of your foot)

pivot joints

rotate in place without moving out of their original position (these joints in neck let the head move from one side to another)

planar joints

formed when 2 mostly flat bones come together, move by one piece of bone sliding over the other without rotating (carpal bones that join your wrist to your forearm and the joints between the vertebrae in your spine)

saddle joints

formed when two curved bones meet; can move in any direction, but can't twist or rotate (joint where your thumb joins your hand)

hyaline cartilage

smooth. most common. matrix closely packed with collage. tough but slightly flexible. chondrocytes arranged in small groups with solid and smooth matrix. allows tissues to slide/glide more easily (between ribs and sternum, nasal cartilage, articular cartilage)

fibrocartilage

toughest and durable. dense masses of white collagen fibers. provide support and rigidity (intervertebral discs, callus, public symphysis, junction where tendons insert to bone

elastic cartilage

flexible and provides support. chondrocytes located between a network of threadlike elastic fibers. provides support and maintains shape of earlobe, epiglottis and blood vessel walls

process of making cartilage

chondrogenesis

components of ECM that are important for cartilage formation

aggrecan and type 2 collagen

germ layer cartilage is formed from

mesoderm

zygapophyseal joint

joint between superior and inferior articular processes (symphyseal joints)

role of zygapophyseal joint

stabilizes and limits spinal rotation

anterior longitudinal ligament

stabilizes vertebral bodies and annulus fibrosus. limits spinal extension. (throat side)

posterior longitudinal ligament

stabilizes bodies and annulus fibrosus. limits spinal flexion

ligamentum flavum

stabilizes laminae. limits spinal flexion

interspinous ligament

stabilizes spinal process. limits spinal flexion

Supraspinous ligament

continuous with nuchal ligament above C7 (THICK) (posterior and back side)

Longitudinal vessels of spinal cord

1 anterior spinal artery & 2 posterior spinal arteries

Segmental spinal arteries (neck)

from vertebral and deep cervical arteries

Segmental spinal arteries (thorax)

from posterior intercostal arteries

Segmental spinal arteries (abdomen)

lumbar arteries

nerve plexus

network of nerves

what forms the nerve plexus

only ventral rami of spinal nerves

cervical plexus nerves

formed by ventral rami of C1-C4 nerves

cervical plexus innervation

skin (via cutaneous branches) & muscles of neck and shoulder (via ansa cervicalis)

Phrenic Nerve nerves (cervical plexus)

C3-5 (C3,4,5 Keeps you alive)

Phrenic nerve innervation (cervical plexus)

diaphragm, vital for respiration

Brachial plexus nerves

ventral rami of C5-T1

Brachial plexus innervation

innervates the upper limbs. lies in neck and armpit (axilla)

Musculocutaneous nerve of brachial plexus

flexor of arm (biceps etc)

Median nerve of brachial plexus

all flexors of forearm except 1.5 muscles

Ulnar nerve of brachial plexus

1.5 flexors of forearm (flexor carpi ulnas and medial 1/2 of flexor digitorum profundus)

Axillary nerve of brachial plexus

deltoid & teres minor

Radial nerve of brachial plexus

all extensors of arm and forearm

Lumbar Plexus nerves

ventral rami of L1-L4 nerves (lies in posterior abdominal wall)

2 main nerves of lumbar plexus

femoral nerve & obturator nerve

Femoral Nerve of lumbar plexus

innervates anterior muscles of thigh (quadriceps)

Obturator Nerve of lumbar plexus

innervates medial muscles of thigh (adductors)

Sacral Plexus nerves

ventral rami of L4-S4 (immediately caudal to lumbar plexus)

Main nerve in sacral plexus

sciatic nerve

Sciatic Nerve of sacral plexus

innervates muscles and skin of posterior thigh and most of the leg

thickest and longest nerve in the body

sciatic nerve

Herpes Zoster

virus that produces chickenpox. Sits dormant in cells of dorsal root ganglia. Once activated travels along neuronal bundles to areas supplied by the nerve (dermatome)

epaxial muscles

true back muscles (innervated by dorsal rami)

hypaxial muscles

superficial & intermediate back muscles & limb (innervated by ventral rami)

crossbar of H in gray matter

gray commissure (bundles of axons that cross from one side of CNS to another)

Where are ventral horns the largest?

in cervical and lumbar segments of the spinal cord due to innervation of upper and lower limbs

3 types of fibers in white matter

ascending, descending, commissural

Asending fibers

carry sensory information from sensory neurons of body up to the brain

Descending fibers

carry motor instructions form brain to spinal cord

Commissural fibers

carry information from one side of spinal cord to other

2 enlargements of spinal cord

cervical (C5-T1) & lumbosacral (L1-S3)

How many cervical spinal nerves are there?

8 (different than the 7 vertebrae in the cervical region)

How many coccygeal nerves are there?

1 (different than the 4 fused vertebrae in coccyx)

Where do spinal nerves lay?

in the intervertebral foramina

Where is CSF formed

choroid plexus

3 layers of meninges (superficial to deep)

Dura mater, arachnoid mater, pia mater

3 functions of the spinal cord

sensory and motor innervation, two way conduction pathways for signals between the brain and body, major center of reflexes

4 stages of development of spinal cord

neural plate --> neural fold --> neural tube --> spinal cord

What condenses into the neural plate?

neuroectoderm (derived from ectoderm)

Sulcus limitans

longitudinal groove formed by the neural tube that divides spinal cord into dorsal and ventral portions

Altar Plates

dorsal portions. location of sensory somatic and visceral input

Basal Plates

ventral portions. location of motor function output

Conus Medullaris definition & location

tapered end of spinal cord. L2

filum terminale

made of Pia mater. tapered end of conus medullaris. attaches to coccyx and anchors spinal cord

Cauda Equina

collection of descending nerve roots

Nucleus pulposus

pulpy interior of intervertebral discs. shock absorption. remnant of notochord. 80% water and loses water content with age

Annulus Fibrosus

fibrous outer ring. helps contain nucleus pulpous

Secondary curvatures

lordotic (cervical and lumbar)

Primary curvature

kyphotic (thoracic and sacral)

When does secondary curvature arise in babies

1 year

What kind of curvature do chimps have?

secondary curvature only in cervical region

hyperkyposis

hunchback. Cobb angle > 30. more common with age especially after 40

hyperlordosis

swayback. lordosis exceeding normal range. common in pregnant women

scoliosis

lateral curvature and rotation of vertebrae

types of scoliosis

congenital, degeneration, adolescent idiopathic (most common), neuromuscular

bones of shoulder and arm

clavicle, scapula, humerus

joints of shoulder and arm (3)

sternoclavicular, acromioclavicular, glenohumeral

sternoclavicular joint

saddle joint. medial clavicle articulates with manubrium of sternum

acromioclavicular joint

gliding joint. lateral clavicle articulates with acromion of scapular

glenohumeral joint (shoulder)

ball and socket joint. glenoid cavity of scapula articulates with head of humerus

acromion process of scapula

continuous with spine of scapula. articulates with clavicle

glenoid process of scapula

articulates with head of humerus of glenohumeral joint. splits into supraglenoid tubercle (origin of long head of bicep) & infraglenoid tubercle (origin of long head of tricep)

coracoid process of scapula

origins of coracobrachialis, short head of biceps brachii. insertion of pectoralis minor

4 ligaments supporting sternoclavicular joint

anterior sternoclavicular ligament, posterior sternoclavicular ligament, interclavicular ligament, costoclavicular ligament

acromioclavicular joint

plane gliding synovial joint with capsule

ligaments supporting acromioclavicular joints (2)

acromioclavicular ligament (reinforces joint capsule), coracoclavicular ligament (stabilizes distal clavicle and coracoid process), coracoclavicular ligament (conoid ligament -- medial and trapezoid ligament -- lateral)

glenohumeral joint

ball and socket synovial joint

functions of glenohumeral joint

abduction, adduction, flexion, extension, medial rotation, lateral rotation, circumduction

glenoid labrum

a fibrocartilaginous collar that deepens the glenoid cavity. continuous with tendon of long head of bicep brachii

transverse humeral ligament

within the intertubercular sulcus, stabilizes glenohumeral joint