FULL SET

what are some key words for muscles of the trunk

unilateral - one side

bilateral - both sides

concentric - muscles shorten under tension

eccentric - muscles length under tension

isometric - muscles says the same length under tension

intrinsic - muscles contained within a region

extrinsic - muscles partially contained within a region

what is some information about intrinsic back muscles

• proximally attached to (originate from) back

• distal attachment on the arm/shoulder blade

what is the thoracolumbar fascia

a connective tissue that overlies intrinsic back muscles

• a common point of attachment for extrinsic back muscles

what is some information about intrinsic back muscles

span from one vertebrae to another, can also attach to:

• ileum, ribs, skull base

what are the functions of intrinsic back muscles

act upon vertebrae column:

• fine postural adjustments

• rotation

• forceful extension, lateral flexion

• arranged in 3 layers

what is the orientation of superficial layer of intrinsic back muscles

fiber orientation = inferomedial → superolateral

• bilaterally extend the spine

what are some muscles of the superficial layer

splenius:

• only in head & neck

• bilateral contraction = extends head & neck

• unilateral contraction = laterally flexes head & neck

erector spinae (3 muscles):

• spinalis - spinous process to spinous process

• longissimus - longest muscle in body

• iliocostalis - iliac crest to ribs

what is the movement pattern of the erector spinae

bilateral contraction = extension of the spine

unilateral contraction = lateral flexion

what is the orientation of transversospinales layer of intrinsic back muscles

fiber orientation = inferolateral → superomedial

• from transverse processes → spinous processes

• differing number of spanned segments

what are some muscles of the transversospinales layer

semispinalis:

• spans 4-6 vertebrae segments

• maintaining posterior

• extension/lateral flexion of the head & neck

Multifidis:

• spans 3-4 vertebrae segments

• important core stabilisator of thoracolumbar vertebrae

• allows erector spinae to act on VC as one unit

Rotatores:

• spans 1-2 vertebrae segments

• dynamic stabiliser of rotation movement

what are proprioceptors

sensory nerve endings that provide input on body movement and muscle tension

what is the fiber orientation of the deep layer

vertical, spans between adjacent vertebrae spinous processes (segmentals)

what are some muscles of the deep layer

interspinalis:

• muscles between adjacent spinous processes

intertransversarii:

• muscles between adjacent transverse processes

responsible for postural adjustments to the vertebrae

what are intercostal muscles

muscles that are located between the ribs

• arranged into 3 perpendicular layers (external, internal, innermost)

what are the external intercostals

fibers that run obliquely down towards midline

• superolateral to inferomedial

• act to elevate ribs during inhalation (expand the thorax)

what are the internal intercostals

fibers that run inferolateral to superomedial

• depresses rib during forced exhalation (compress/contract thorax)

what are the innermost intercostals

fibers that run inferolateral to superomedial

• depresses rib during forced exhalation (compress thorax)

• only spans 1 intercostal space

what are subcostal muscles

only present on posterior thoracic wall

• fibers can span 2-3 intercostal spaces

• depress ribs during forced exhalation

• superolateral to inferomedial

what are the transversus thoracis

fibers that project laterally from the internal aspect of the sternum

• breastplate

• depress ribs during forced exhalation

what is the intercostal neurovasculature

intercostal spaces are shared by:

• veins, arteries, nerves (superior to inferior

• runs along costal groove between internal & innermost intercostals

what are the intercostal nerves

11 intercostal nerves

• ventral rami of the thoracic nerves

12th nerves = subcostal nerve (beneath rib)

what are the intercostal arteries

2 sets of intercostal arteries:

• anterior intercostal arteries - arises from internal thoracic artery (lateral of sternum)

• posterior intercostal arteries - arises from the aorta

anterior & posterior intercostal arteries with anastomose (connect) with each other at the most lateral part of the trunk wall

what are the intercostal veins

2 sets of intercostal veins:

• anterior intercostal veins - drains to internal thoracic veins (2)

• posterior intercostal veins - drains to azygous & hemiazygous veins

what is the azygous system

azygous:

• located on the right side of the midline

• receives right posterior intercostal veins

hemiazygous & accessory hemiazygous:

• receives left posterior intercostal veins

• this ultimately drains into the azygous

what is some information on the abdominal wall muscles

encloses the abdominal cavity

• anterolateral & posterior groups

• involved in actions that increased intraabdominal pressure (coughing, laughing, vomiting)

• retains abdominal viscera (protects from injury)

what is some information on the anterolateral abdominal wall muscles

attached anteriorly via aponeuroses

• tendon sheets

muscles may insert on Linea alba

• midline tendonous seam

what are the external oblique muscles

largest, most superficial muscles

• rotates torse towards contralateral (opposite) side

• laterally flex trunk

what are the internal oblique muscles

deep to external, smaller and thinner

• rotates torso to ipsilateral (same) side

• laterally flex trunk

what are the transverse abdominis

• deepest, transverse fiber orientation

• stabilizes lumbar spine & pelvis

• attaches posteriorly to lumbar vertebrae

what is the rectus abdominius

• flexes lumbar spine

• Linea semilunaris at lateral border

what is the rectus sheath

rectus abdominis enveloped by aponeuroses of:

• external & internal obliques

• transversus abdominis

these envelopes are the rectus sheath

• aponeurotic relationship changes at the arcuate line

what is some information about the section superior to the arcuate line

• Aponeuroses evenly distributed anterior and posterior to rectus abdominis

• Transversus abdominis aponeurosis courses posterior to rectus

what is some information about the section inferior to the arcuate line

• All aponeuroses course anterior to rectus abdominis

• Strengthens lower abdominal wall

what is diastasis recti

separation of the abdominis rectus

• caused by chronic increase intra-abdominal pressure

• can lead to umbilical hernia (part of small intestine pokes through belly button)

what are some structures of the posterior abdominal wall muscles

psoas major:

• attaches laterally to lumbar spine

• flexes hip

• important postural muscle

Quadratus lumborum:

• lateral to psoas major

• attaches to 12th rib & iliac crest

what is some information on the pelvic floor

• formed by 4 muscles

• retains pelvic & abdominal viscera within pelvis

• perforated (pierced) by 2-3 apertures

what are the main 2 apertures of the pelvic floor

• urogenital hiatus

• rectal hiatus

what is some information on the pelvic floor muscles

• support abdominopelvic viscera through tonic contraction (always contracting) important for expelling waste

• resists intra-abdominal pressure

what are the levator ani

3 of the 4 pelvic muscles that act to elevate the anus

• Puborectalis

• Pubococcygeus

• Iliococcygeus

what is the coccygeus

last pelvic floor muscle

• support pelvic viscera & weakly flexes coccyx

what is some information on the quadratus lumborum

• vertically arranged

• arises from lumber vertebrae

• arises from ribs (partly)

what is some information on the psoas major

• flexes the hip

• arises from lumber vertebrae

what are some Latin terms for the spine

foramen/foramina - ‘hole’

inter - ‘between’

intra - ‘within’

articulation - ‘joint’

vertebrae - ‘turning’

what is the difference between flexion & extension

flexion - ‘bending’ (front)

extension - ‘straightening’/’stretch out’

what are some of the components of the spinal cord

body - dense part that supports the weight of the body

pedicle - posterior projection

lamina/laminae - flat sheet

spinal/vertebral foramen - single unit of the spinal canal, encloses the spinal cord

spinous process - posterior projection (spinal palpate [can feel over skin])

transverse process - lateral projection

what is a neural arch

combination of the pedicle & lamina

what are key structures in this image

superior articular facet - forms synovial (fluid-filled) joint with vertebrae above

inferior articular facet - forms synovial (fluid-filled) joint with vertebrae below

what are some key structures in this image

intervertebral disc

facet/zygapophyseal joint - synovial

• orientation changes rotationally (impacts regional movement)

intervertebral foramen - conveys spinal nerves

what are intervertebral discs

fibrocartilage between adjacent vertebrae

• remains of the notochord

example of symphysis - type of cartilaginous joint

what are some structures of the intervertebral discs

annulus fibrosis - ring of fibrosis tissue

nucleus pulposus - core of gel-like substance

what are the different segments of the spine

cervical - 7

thoracic - 12

lumbar - 5

sacral - 5 (fused)

coccygeal - 3 (fused)

what are the different curves of the spine called

lordosis - convex anteriorly

• cervical, lumbar

kyphosis - concave anteriorly

• thoracic, sacral/coccygeal

what is a common pattern for the vertebrae as we move inferiorly

increase in the size of the vertebrae body, supports more body mass

what is scoliosis

exaggerated lateral curvature of the spinal cord

what is some information of the cervical region

obliquely transverse (slanted) facet joints, allows for:

• flexion/extension

• lateral flexion

• rotation

triangular spinal foramen - larger as spinal cord is thickest here

bifid spinous process

transverse foramen - houses the vertebral artery, supplies blood to brain stem

what is a vertebral artery dissection

damage of each form to the vertebral artery

• most cases are fatal

may result in locked-in syndrome

• lose of all voluntary movement except eye-control

what is a key structure on the occipital bone

occipital condyles, articulates with C1

what are the a-typical members of the cervical region

C1 (atlas)

C2 (axis) - important rotational joint

C7 (vertebra prominens) - uppermost palpable spinous process

what are some structures of the C1 vertebrae (atlas)

no spinal body

anterior/posterior tubercle

large lateral mass (each side) to support occipital condyles

what is the atlanto-occipital joint

C1 superior articular facets to occipital condyle

provides flexion/extension

what are some structures of the C2 vertebrae (axis)

dens/odontoid process - “stolen” body of C1

• forms the atlantoaxial joint that allows for rotation of the head

what is some information on the thoracic region

• facilitates rotation

• restricts flexion/extension

• facets join in coronal plane

what are some features of the thoracic vertebrae

Articulation with ribs:

• demifacets

• transverse facet

• elongated spinous processes

• small, heart-shaped bodies

what is some information about the lumbar region

• facets join in sagittal place

• facilitates flexion/extension

• limits rotation

what is the only a-typical member of the lumbar region

L5, due to articulation with the sacral region

what are some structures of the lumbar vertebrae

• large, cylindrical body

• small, triangular spinal foramen

• costal (transverse) process

• mamillary process

• thick, short spinous process

what is some information about the sacrum region

consists of 5 fused segments (may fuse with coccyx)

what are some anterior structures of the sacral region

auricular surface - articulates with pelvis

enlarged lateral part

• superior part = sacral ala

promontory - articulates and supports L5

anterior sacral foramina - convey ventral rami for sacral nerves

what are some posterior structures of the sacral region

posterior sacral foramina - conveys dorsal rami of sacral nerves

sacral canal - houses caudal nerves of spinal cord

medial sacral crest - similar to spinous process

what is transitional lumbosacral vertebrae are what are the 2 types

a spinal abnormality where L5 is not fully connected to the sacrum

• lumbarisation of S1 - S1 incorrectly incorporated into sacral block

• sacralisation of L5 - L5 incorrectly incorporated into sacral block

what is some information about the coccyx

consists of 3-5 fused segments

• represents vestigial tail

what are some root terms for the ribs

costal - '“rib”

chondral - “cartilage”

what are the 3 regions of the sternum

manubrium

body

xiphoid

what are some of the other features of the sternum

sternal angle - at manubriosternal joint

clavicular notches - sternoclavicular joint

jugular notch - palpable depression

7 costal facets - articulation with the ribs

what is some information on the ribs

• set of 12 (usually)

• protect the thorax

• articulate posteriorly with thoracic vertebrae

• terminate anteriorly as costal cartilage

how are the ribs classified

2 different classifications:

• true, false, floating

• typical, atypical

what ribs are classified as what

True: 1-7 (cartilage directly attach to sternum)

False: 8-10 (cartilage attaches indirectly via 7th rib cartilage)

Floating: 11-12 (don’t attach to sternum)

how do ribs connect to the sternum

attach to sternum via cartilaginous intervals, thus there exists 2 joint types:

• costochondral (rib-cartilage)

• sternochondral (sternum-cartilage)

what are interchondral joints

joints between cartilage of ribs, the connection between ribs 8-10 and the 7th rib

what are some anatomical features of a rib

head

articular facets

• attaches to vertebral bodies

neck

tubercle

• attaches to transverse process

• distal to neck

what are some typical features of the ribs

body (shaft)

costal groove - conduit for intercostal neurovascular structures (nerves, arteries, veins)

angle

flat laterally & anteriorly

what are some atypical structures of the ribs

ribs 1&2:

• shorter/wider than most ribs

• head of rib 1 only attaches to body of 1 vertebrae (T1)

marked by grooves:

• subclavian vessels (rib 1)

• scalenes (rib 1&2)

how are ribs 10, 11 & 12 atypical

• rib 10 only attaches to 1 vertebral body

• rib 11 & 12 are floating (don’t attach to transverse process)

why is vertebrae 9 atypical

ribs normally articulate with the body of 2 ribs

in the case of rib 10, it only articulate with the body of vertebrae 10, thus making both rib 10 and vertebrae 9 atypical

in summary, what are the atypical ribs & vertebrae

ribs: 1, 2, 10, 11, 12

vertebrae: 1, 9, 10, 11, 12

what is some information about the costovertebral joint

• articulation between rib & vertebrae

• spans 2 thoracic vertebrae & intervertebral disc

• demifacets facilitate this joint

what is the costotransverse joint

articulation between the costal tubercle & transverse facet

what do the costovertebral & costotransverse joint allow for

function together to facilitate rotation

how do the ribs move during breathing

• increases width of thorax

• increase anteroposterior depth of thorax

why can ribs grow in other vertebrae regions abnormally

there is a costal (rib) derivative region in each spinal region which can lead to the development of a rib under abnormal circumstances.

what are the three main bones of the pelvis

ileum, pubis, ischium

• all meet at acetabulum (hip socket)

what are some other features of the pelvis

iliac crest

• bony ridge

• felt as hips/waist

ischial tuberosity

• ‘sit'‘ bone

what are some other features of the pelvis

pubic symphysis

• fibrocartilage joint (medial caudal part of pelvis)

inguinal ligament

• connective tissue band from ileum to pubis

• attachment of abdominal wall muscles

what rib meets the the sternum at the manubriosternal joint

rib 2

what are some common greek terms for embryotic anatomy

epi - upon

hypo - below

blast - build

clast - broken (in pieces)

what is the bilaminar embryonic disc

The bilaminar embryonic disc is a flat structure formed during early embryonic development, consisting of two layers: the epiblast and the hypoblast. It gives rise to the three germ layers.

describe some of the labelled structures

primitive streak: thick layer of epiblast cells that migrate caudal to cranial

primitive groove: indentation caused by the primitive streaks, forms as cells migrate during gastrulation

primitive node: cranial from primitive streak, indented by primitive pit

what is the process of ingression

process by which dorsal epiblast cells migrate into the primitive pit and groove to form the mesoderm

what are the new names of the blast cells are ingression (primary germ layers)

hypoblast becomes endoderm

migrating epiblasts becomes mesoderm

remaining epiblasts becomes ectoderm

what do ectoderm cells form

• brain & spinal cord

• nerves

• nails, hair & skin