Exam #1 Flashcards
skeletal system
- osteology/orthopedics
- consists of bones and cartilage
- provides support for the body and protects vital organs
- muscular system acts on the skeletal system to produce movements
articular system
- arthrology
- consists of joints and their associated ligaments
- connects the bony parts of the skeletal system and provides the sites at which movement occurs
muscular system
- myology
- consists of muscles that act (contract) to move or position parts of the body (ex: the bones that articulate at joints)
nervous system
- neurology
- consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves and ganglia), together with their motor and sensory endings
- controls and coordinates the functions of the organ systems
what is the anatomical position?
- head, eyes (gaze), and toes directed anteriorly (forward)
- upper limbs by the sides with the palms facing anteriorly
- lower limbs close together with the feet parallel and the toes directed anteriorly
median (median sagittal) plane
-is the vertical plane passing longitudinally through the center of the body, dividing it into right and left halves
vertical plane passing longitudinally through the center of the body, dividing it into right and left halves
median plane/median sagittal plane
sagittal plane
planes passing through the body parallel to the median plane
plane parallel to and near the median plane may be referred to as _______.
paramedian plane
frontal (coronal) plane
vertical planes passing through the body at right angles to the median plane, dividing in into anterior (front) and posterior (back) portions
planes passing through the body parallel to the median plane
sagittal plane
vertical planes passing through the body at right angles to the median plane, dividing in into anterior (front) and posterior (back) portions
frontal (coronal) plane
transverse plane
plane passing through the body at right angles to the median and frontal planes
-divides the body into superior (upper) and inferior (lower) parts
bilateral
paired structures having right and left members (ex: kidneys)
unilateral
structures occurring on one side only (ex: spleen)
ipsilateral
structures occurring on the same side of the body (ex: the right thumb and the right great toe are ipsilateral)
contralateral
structures occurring on the opposite side of the body (ex: the right hand is contralateral to the left hand
superficial
- nearer to the surface
ex: the muscles of the arm are superficial to its bone (humerous)
intermediate
- between a superficial and a deep structure
ex: the bicep muscle is intermediate between the skin and the humerous
deep
- farther from the surface
ex: the humerous is deep to the arm muscles
medial
- nearer to the median plane
ex: the 5th digit finger is on the medial side of the hand
lateral
- farther from the median plane
ex: the first digit (thumb) is on the lateral side of the hand
posterior
- nearer to back
ex: the heel is posterior to the toes
inferior
- nearer to feet
ex: the stomach is inferior to the heart
anterior
- nearer to front
ex: the toes are anterior to the ankle
distal
- father from trunk or point of origin (ex: of a limb)
ex: the wrist is distal to the elbow, and the distal part of the upper limb is the hand
proximal
- nearer to the trunk or point of origin (ex: of a limb)
ex: the elbow is proximal to the wrist, and the proximal part of an artery is its beginning
inferior foot surface
sole (plantar surface)
superior foot surface
dorsum (dorsal surface)
anterior hand
palm (palmar surface)
posterior hand
dorsum (dorsal surface)
superior
- nearer to the head
ex: the head is superior to the stomach
describe the flexion of the upper limb at the shoulder joint and the lower limb at the hip joint
pulling the upper/lower limb upwards on the anterior side of the body
describe the extension of the upper limb at the shoulder joint and the lower limb at the hip joint
pulling the upper/lower limb backwards towards the posterior side of the body
describe the flexion and extension of the forearm at the elbow joint and the leg at the knee joint
flexion: bending your knee and bending your elbow
extension: extending (straightening) your knee/elbow
describe the flexion and the extension of the vertebral column at inter vertebral joints
flexion: bending forward
extension: bending backwards
explain pronation and supination of the forearm at radio-ulnar joints
pronation: palm facing down
supination: palms facing up
explain flexion and extension of the hand at the wrist joint
flexion: bending your wrist towards the anterior part of your forearm
extension: bending your wrist towards the posterior side of your forearm
explain dorsiflexion and plantarflexion of the foot at the ankle joint
dorsiflextion: flexing your toes
plantarflexion: pointing your toes
explain inversion and eversion of the foot at subtalar and transverse tarsal joints
inversion: bending your foot inwards
eversion: bending your foot outwards
explain abduction and adduction of the 2nd, 4th, and 5th digits at metacarpophalangeal joints
abduction: separating your fingers
adduction: putting your fingers together
what is circumduction? use the lower limb to give an example
circular movement of the lower limb at the hip joint
explain what is protrusion and retrusion of the mandible at temporomandibular joints
retrusion: over-bite
protrusion: under-bite
explain what is the protraction and retraction of the scapula on the thoracic wall
protraction: extending your arms in front of you making your scapula separate from each other
retraction: extending your arms behind you making your scapula closer together
explain what is the opposition and reposition of the thumb and little finger at the carpometacarpal joint
opposition: touching your thumb to your pinky
reposition: pulling your thumb away from your pinky
what is the difference between abduction and extension of the thumb? what is the difference between adduction and flexion of the thumb?
abduction: lifting your thumb upwards rather than to the side (extension)
flexion: requires that you bend your thumb to reach the inner side of your palm, rather than just placing it to the side of the rest of your fingers (adduction)
axial skeleton
-bones of the head (cranium or skull), neck (cervical vertebrae) and trunk (ribs, sternum, vertebrae, and sacrum)
appendicular skeleton
-bones of the limbs, pectoral (shoulder), and pelvic girdles
what are the 5 functions of bones?
1) protection for vital structures
2) support for the body and its vital cavities
3) the mechanical basis for movement
4) storage for salts (calcium)
5) a continuous supply of new blood cells produced by the marrow in the medullary cavity of many bones
cartilage
-a resilient, semi-rigid, avascular type of connective tissue that forms parts of the skeleton where more flexibility is necessary
articular cartilage
- the articulating surfaces of bones participating in synovial joints are capped with articular cartilage
- provides smooth, low friction gliding surfaces for movement
periosteum
the fibrous connective tissue covering that surrounds bones
perichondrium
the surrounding cartilage elements, excluding articular cartilage
what are the 2 types of bones?
compact (trabecular) and spongy (cancellous)
what is the difference between a compact and a spongy bone?
the difference depends on the relative amount of solid matter and the number and size of the spaces they contain
what are the 5 different classifications of bone?
1) long bone: tubular structures (ex: humerous, phalanges)
2) short bones: cuboidal and are found only in the ankle (tarsus) and wrist (carpus)
3) flat bones: usually serve protection functions (ex: cranium)
4) irregular bones: such as those in the face, have various shapes other than long, short, and flat
5) sesamoid bones: ex: patella, a bone that develops in certain tendons, these protect the tendons from excessive wear and often change the angle of the tendons as they pass to their attachments
condyle
a rounded articular area (ex: condyles of the femur)
crest
ridge of bone (ex: iliac crest, pubic crest)
epicondyle
eminence superior to a condyle (ex: epicondyle of the humerus)
facet
smooth flat area, usually covered with cartilage, where a bone articulates with another bone (ex: articular facet of vertebrae)
foramen
passage through a bone (ex: obturator foramen)
fossa
hollow or depressed area (ex: infraspinous fossa of the scapula)
line (linea)
linear elevation (ex: soleal line of the tibia)
malleolous
rounded prominence (ex: lateral malleolous of the fibula)
notch
indentation at the edge of a bone (ex: greater sciatic notch in the posterior border of the hip bone)
process
projecting spine-like part (ex: spinous process of a vertebrae)
protuberance
projection of a bone (ex: external occipital protuberance of the cranium)
spine
thorn-like process (ex: spine of the scapula)
trochanter
large, blunt eminence (ex: greater trochanter of the femur)
tubercle
small, raised eminence (ex: greater tubercle of the humerus)
tuberosity
large, rounded elevation (ex: ischial tuberosity of the hip bone)
where does growth in the long bone happen?
epiphesial plate
diaphysis
middle of bone
metaphysis
where the long bone starts to flare out
what are the 3 different types of joints?
1) fibrous joints
2) cartilaginous joints
3) synovial joints
fibrous joints
articulating bones that are joint my fibrous tissue
- ex: sutures of the cranium
- syndesmosis joint: bones are joined by an interosseous ligament or a sheet of fibrous tissue
- gomphosis joint: a peg-like process fits into a socket, fibrous tissue anchors the tooth
cartilaginous joints
articulating bones are united by fibrocartilage or hyaline cartilage
- synchondrosis: joined by an epiphysial plate
- symphysis: binding tissue is a fibrocartilaginous disc (ex: between 2 vertebrae)
synovial joint
2 bones are separated by the characteristic joint cavity (containing synovial fluid)
- most common and important type of joint
- provide free movement between the bones they join and are typical of nearly all the joints of the limbs
what are the 6 types of synovial joints?
1) pivot joint: (uniaxial) rounded process of bone fits into a bony ligamentous socket, permitting rotation (ex:atlanto-axial joint)
2) ball and socket joint: (multiaxial) rounded head fits into a concavity permitting movement on several axes (ex: hip joint)
3) plane joint: (usually uniaxial) permit gliding or sliding movements (ex: acromioclavicular joint)
4) hinge joint: (uniaxial) permit flexion and extension only (ex: elbow joint)
5) saddle joint: (biaxial) saddle shaped heads permit movement in two different planes (ex: carpometacarpal joint/thumb)
6) condyloid joint: (biaxial) permit flexion and extension, abduction adduction, and circumduction (ex: metacarpophalangeal joint)
what are the 3 types of muscle?
1) skeletal
2) cardiac
3) smooth
skeletal muscle
moves bones and other structures
cardiac (striated) muscle
forms most of the walls of the heart and adjacent parts of the great vessels
smooth muscle
forms part of the walls of most vessels and hollow organs, moves substances through viscera such as the intestine, and controls movement through blood vessels
most _____ are attached directly or indirectly through tendons and aponeuroses to bones, cartilages, ligaments, or fascia, however, some are attached to _____ and to _____
skeletal, organs, mucous membranes
muscles are named after what? (8 reasons)
1) function
2) attachment
3) shape
4) position
5) length
6) size
7) number of attachments
8) architecture
pennate muscle
feather-like in the arrangement of their fascicles (uni
fusiform muscles
spindle-shaped
parallel muscles
the fascicles lie parallel to the long axis of the muscle
convergent muscle
have a broad attachment from which fascicle converge to a single tendon
circular muscle
surround a body opening or orifice, constricting it when contracted
digastric muscle
feature 2 bellies in series sharing common intermediate tendon
what are the 3 types of contraction exhibited by a skeletal muscle?
1) reflexive contraction: automatic, ex: respiratory movements, or tapping a tendon with a reflex hammer
2) tonic contraction: slight contraction that does not produce movement or active resistance (muscle tone), maintenance of posture or stability of joints
3) phasic contraction (2 types = isometric and isotonic)
isometric: muscle length remains the same, no movement occurs, but muscle tension is increased
isotonic: the muscle changes length and there is movement
what are the 2 forms of isotonic muscle contraction?
1) concentric contraction: movement occurs during muscle shortening
2) eccentric contraction: there is a progressive relaxation of a contracted muscle
what is the structural unit of a muscle
muscle fiber
endomysium
connective tissue covering individual muscle fibers
a group of fibers is invested by ____
perimysium
the entire muscle is surrounded by ___
epimysium
the functional unit of a muscle consisting of a motor neuron and the muscle fibers it controls is a ______
motor unit
what is a prime mover/agonist muscle?
the main muscle responsible for producing a specific movement of the body
what are fixator muscles?
steady the proximal parts of a limb while movements are occurring in distal parts
what’s a synergist muscle?
complements the action of prime movers, ex: by preventing movement of the intervening joint when a prime mover passes over more than one joint
what is an antagonist muscle?
a muscle that opposes the actions of a prime mover, as a prime mover contracts, the antagonist progressively relaxes, producing a smooth movement
central nervous system
brain and spinal cord
peripheral nervous system
nerve fibers and cell bodies outside the CNS
somatic nervous system
voluntary nervous system, carries sensation from the skin and joints, and supplies skeletal muscle
autonomic nervous system
involuntary movement, supplies smooth muscle, glands, and viscera (internal organs) in the body cavities
structure and components of a typical spinal nerve:
what is the anterior (ventral) root?
consists of motor (efferent) fibers passing from nerve cell bodies in the anterior horn of the spinal cord gray matter to effector organs located peripherally
structure and components of a typical spinal nerve:
what is the posterior (dorsal) root?
consists of sensory (afferent) fibers that convey neural impulses to the CNS from sensory receptors in various parts of the body
visceral motor innervations of the autonomic nervous system:
the efferent nerve fibers and ganglia of the ANS are organized into two systems or divisions, what are these divisions?
sympathetic (thoracolumbar) division: the effects of sympathetic stimulation is catabolic (“fight or flight”)
parasympathetic (craniosacral) division: the effects of parasympathetic stimulation are anabolic (promoting normal function and conserving energy)
visceral motor innervations of the autonomic nervous system:
the efferent nerve fibers and ganglia of the ANS are organized into two systems or divisions, what are these divisions?
sympathetic (thoracolumbar) division: the effects of sympathetic stimulation is catabolic (“fight or flight”)
parasympathetic (craniosacral) division: the effects of parasympathetic stimulation are anabolic (promoting normal function and conserving energy)
true (vertebral) ribs
- 1st to 7th ribs
- attach directly to the sternum anteriorly through their costal cartilages
false (vertebrochondral) ribs
- 8th to 10th ribs
- have cartilages on their anterior ends that are joined to the cartilage of the rib just superior to them, thus indirectly connected to the sternum
floating (free) ribs
- 11th and 12th ribs (sometimes the 10th)
- do not connect, even indirectly, to the sternum, they end in the posterior abdominal musculature
what are the components of a ‘typical rib’?
- 3rd to 9th ribs
- head
- neck
- tubercle
- body
- angle
- costal groove
how does the 1st rib differ from the others?
- 1st rib is broad
- shortest and most sharply curved of the 7 true ribs
- contributes more to the ‘roof’ rather than the wall of the thoracic cavity
- has 2 shallow horizontal grooves crossing the superior surface for the subclavian (under clavicle) vessels separated by a scalene tubercle
- articulates with the T1 vertebrae
how does the 1st rib differ from the others?
- 1st rib is broad
- shortest and most sharply curved of the 7 true ribs
- contributes more to the ‘roof’ rather than the wall of the thoracic cavity
- has 2 shallow horizontal grooves crossing the superior surface for the subclavian (under clavicle) vessels separated by a scalene tubercle
- articulates with the T1 vertebrae
how does the 2nd rib differ from the others?
- thinner and more typical than the 1st
- formations for attachments of serratus anterior and posterior scalene muscles
- almost twice the length of the 1st rib
how do the 10th through 12th ribs differ from the others?
-like the 1st rib, have only one facet on their heads
how do the 11th and 12th ribs differ from the others?
-short and have no necks or tubercles
what are 3 characteristics of thoracic vertebrae?
1) bilateral superior and inferior costal facets (demifacets) for articulation with the heads of ribs
2) costal facets on their transverse processes for articulation with the tubercles of the ribs
3) long inferiorly slanting spinous processes that overlap the IV disc and vertebrae below
thoracic vertebrae are typical vertebrae in that they are ______ and have _____, _____, and ___ processes for muscular and articular connection
independent, bodies, vertebral arches, 7
what are the 3 parts of the sternum?
manubrium, sternal body, xiphoid process
what level of the spine does the manubrium sit at?
T3 and T4 vertebrae
the manubrium and the sternal body lie in slightly different planes, forming a projecting ______
sternal angle
what are the superior (origin) and the inferior (insertion) attachments of the external oblique muscles?
origin: inferior border of the ribs
insertion: superior border of ribs below
what is the innervation and main action of the external oblique muscles?
intercostal nerve
-during forced respiration, elevates ribs
what is the origin and insertion of the external, internal, and innermost intercostal muscles?
origin: inferior border of ribs
insertion: superior border of ribs below
what is the innervation of th external, internal, and innermost intercostal muscles?
intercostal nerve
what is the main action of the internal intercostal muscle and the innermost intercostal muscle?
during forced respiration: interosseus part depresses ribs, interchondral part elevates ribs
what is the origin and insertion of the subcostal muscles?
origin: internal surface of lower ribs near their angles
insertion: superior borders of 2nd or 3rd ribs below
what is the innervation of the subcostal muscles?
intercostal nerve
what is the main action of the subcostal muscle
probably act in same manner as internal intercostal muscle: depress and elevate ribs
what is the origin and insertion of the levatores costarum muscle?
origin: transverse processes of the C7-T11 vertebrae
insertion: subjacent ribs between tubercle and angle
what is the innervation of the levatores costarum muscle?
posterior rami of C8- T11 nerves
what is the main action of the levatores costarum muscles?
elevate ribs
what is the origin and insertion of the serratus posterior superior
origin: nuchal logament, spinous prosess of the C7-T3 vertebrae
insertion: superior borders of the 2nd - 4th ribs
what is the innervation of the serratus posterior superior?
2nd-5th intercostal nerves
what is the main action of the serratus posterior superior?
elevate ribs
what is the origin and insertion of the serratus posterior inferior
origin: inferior borders of the 8th - 12th ribs near their angles
insertion: spinous processes of T11 - L2 vertebrae
what is the innervation of the serratus posterior inferior?
9th - 11th intercostal nerves, subcostal (T12) nerve
what is the main action of the serratus posterior inferior?
depress ribs
what is the mediastinum
the central compartment of the thoracic cavity
- superior part is from the 1st rib to the T4 vertebrae (or sternal angle)
- inferior starts at the T4 vertebrae and ends at the T12 vertebrae (inferior border is the sternum)
abdominal cavity
the space bounded by the abdominal walls, diaphragm, and pelvis
the diaphragm makes up the superior border of what?
the abdominal cavity
what are the 4 quadrants of the abdominal cavity?
1) RUQ: right upper quadrant
2) RLQ: right lower quadrant
3) LUQ: left upper quadrant
4) LLQ: left lower quadrant
-these are separated by the transumbilical plane (plane passing through the umbilicus at the L3 and L4 vertebrae) and the median plane
name the layers of the skin, going from most superficial, to deepest
- skin
- superficial fatty layer of subcutaneous tissue (camper fascia)
- deep membranous layer of subcutaneous tissue (scarpa fascia)
- external oblique
- internal oblique
- transversus abdominis
what is the origin and insertion of the external oblique muscle?
origin: external surfaces of 5th - 12th ribs
insertion: linea alba, pubic tubercle, and anterior half of iliac crest
what is the innervation and the main action of the external oblique muscle?
thoraco-abdominal nerves (anterior rami of T7 - T11) and subcostal nerve
-compress and support abdominal viscera; flex and rotate trunk
what is the origin and insertion of the internal oblique muscle?
origin: thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament
insertion: inferior borders of 10th - 12th ribs, linea alba, and pubis via conjoint tendon
what is the innervation and main action of the internal oblique muscle?
thoraco-abdominal nerves (anterior rami of T7 - T11 subcostal and first lumbar nerve)
-compress and support abdominal viscera; flex and rotate trunk
what is the origin and insertion of the transversus abdominis muscle?
origin: internal surfaces of the 7th - 12th costal cartilages, thoraco-lumbar fascia, iliac crest, and connective tissue deep to inguinal ligament
insertion: linea alba with aponeurosis of internal oblique, pubic crest, and pubis via conjoint tendon
what is the innervation and action of the transversus abdominis muscle?
thoraco-abdominal nerves (anterior rami of T7 - T11), subcostal and first lumbar nerve
-compresses and supports abdominal viscera
what is the origin and insertion of the rectus abdominis muscle?
origin: pubic symphysis and pubic crest
insertion: xiphoid process and 5th - 7th costal cartilages
what is the innervation and action of the rectus abdominis muscle?
thoraco-abdominis and subcostal nerves (anterior rami of the T7 - T12 spinal nerves)
-flexes trunk (lumbar vertebrae) and compresses abdominal viscera, stabilizes and controls tilt of pelvis (antilordosis)
what are the functions and the actions of the anterolateral abdominal muscles?
- form a strong expandable support for this region
- protect abdominal viscera
- compress abdominal viscera
- produce the force required for defecation (pooping), micturition (peeing), vomitting, and parturition (childbirth)
- produce anterior and lateral flexion and rotation of the trunk and help maintain posture
diaphragm
- a dome shaped musculotendinous partition separating the thoracic and abdominal cavities
- chief muscle of inspiration (descends during inspiration)
what is the name of the 2 muscular slips that attach to the posterior aspect of the xiphoid process of the sternum, this part is not always present
the sternal part
what are the 3 parts of the diaphragm?
- sternal part
- costal part
- lumbar part
what part of the diaphragm forms the domes?
costal part
what part of the diaphragm forms the right and the left muscular crura that ascends to the central tendon?
lumbar part
what is the posterior abdominal wall composed of? (6 things)
1) 5 lumbar vertebrae associated with IV discs
2) posterior abdominal wall muscles - psoas, quadratus lumborum, iliacus, transversus abdominis, and internal and external oblique
3) lumbar plexus, composed of the anterior rami of lumbar spinal nerves
4) fascia, including thoracolumbar fascia
5) diaphragm, contributing to the superior part of the posterior wall
6) fat, nerves, vessels, and lymph nodes
what are the muscles of the posterior abdominal wall?
- psoas major
- iliacus
- quadratus lumborum
what are the superior and inferior attachments of the psoas major?
superior: transvers processes of lumbar vertebrae, sides of bodies of T12 - S1 vertebrae and intervening IV discs
inferior: by a strong tendon to lesser trochanter of femur
what is the innervation and action of the psoas major?
lumbar plexus via anterior branches of nerves L2-L4
-acting inferiorly with iliacus, flexes thigh; acting superiorly, flexes vertebral column laterally to balance the trunk; when sitting, acts inferiorly with iliacus to flex trunk
what are the posterior and inferior attachments of the iliacus?
superior: superior 2/3 of the iliac fossa. ala of sacrum, and anteror sacro-iliac ligaments
inferior: lesser trochanter of femur and shaft inferior to it and to psoas major tendon
what is the innervation and action of the iliacus?
femoral nerve (L2-L4) -flexes thigh and stabilizes hip joint; acts with psoas major
what are the posterior and inferior attachments of the quadratus lumborum?
posterior: medial half of inferior border of 12th rib and tips of lumbar transverse processes
inferior: iliolumbar ligament and internal lip of iliac crest
what is the innervation and the action of the quadratus lumborum?
anterior branches of T12 and L1 - L4 nerves
-extends and laterally flexes vertebral column; fixes 12th rib during inspiration
obturator nerve
-emerges from the medial border of the psoas major and passes through the pelvis to the medial thigh, supplying the adductor muscles
femoral nerve
-emerges from the lateral border of the psoas major and innervates the iliacus and passes deep to the inguinal ligament to the anterior thigh, supplying the flexors of the hip and extensors of the knee
lumbosacral trunk
-passes over the ala (wing) of the sacrum and descends into the pelvis to participate in the formation of the sacral plexus along with the anterior rami of the S1-S4 nerves
greater pelvis
false pelvis
lesser pelvis
true pelvis
the pelvic inlet is bound by the what? (6 things)
1) superior margin of the pubic symphysis anteriorly
2) posterior border of the pubic crest
3) pecten pubis, the continuation of the superior ramus of the pubis, which forms a sharp ridge
4) arcuate line of the ilium
5) anterior border of the ala of the sacrum
6) sacral promontory
the pelvic outlet in bounded by what? (4 things)
1) inferior margin of the pubis symphysis anteriorly
2) inferior rami of the pubis and ischial tuberosities anterolaterally
3) sacrotuberous ligaments posterolaterally
4) tip of the coccyx posteriorly
what are the 3 main functions of the pelvic girdle?
1) transfer the weight of the upper body from the axial to the lower appendicualr skeleton
2) withstand compression and other forces resulting from its support of body weight
3) house and protect the pelvic viscera
what are the 2 parts of the ischium?
body: forms the posterior part of the acetabulum
ramus: forms the posterior part of the inferior boundary of the obturator foramen
the bony pelvis is separated into greater (false) and lesser (true) pelvis by the oblique plane of the _____
pelvic inlet
what are the 3 main differences in a male and female pelvis?
1) male pelvis has a narrow pubic arch and subpubic angle (70 degrees), female is wide (80 degrees)
2) the obturator foramen of a male pelvis is round, while a females is oval
3) the acetabulum of a male pelvis is large, while a females is small
sacro-iliac joints
-stron, weight bearing, compound joints consisting of an anterior synovial joint and a posterior syndesmosis
how do the sacro-iliac joints differ from most synovial joints?
-they have limited mobility because they have to bear the weight of most of the upper body on the hip bones
lumbosacral joints
- the L5 and sacrum articulate anteriorly at the anterior intervertebral joint, formed by the L5/S1 intervertebral disc between their bodies posteriorly, and at 2 zygapophysial joints (facet joints) between the articular process of these bones
- the superior articular facets on the sacrum face posteromedially, interlocking with the anterolaterally facing inferior articular facets of the L5 vertebra, preventing L5 from sliding anteriorly
what is the role of the sacrotuberous and the sacrospinous ligaments?
prevents the pelvis joint from rotating too far
sacrococcygeal joint
- secondary cartilagenous joint with an IV disc
- join the apex of the sacrum to the base of the coccyx
what are the proximal and distal attachments of the coccygeus muscle?
proximal: ischial spine
distal: inferior end of sacrum and coccyx
what is the innervation and action of teh coccygeus muscle?
branches of S4 and S5 nerves
-forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx
what are the proximal and distal attachments of the obturator internus muscle?
proximal: pelvic surface of ilium and ischium; obturator membrane
distal: greater trochanter of femur
what is the innervation and action of the obturator internus muscle?
nerve to obturator internus
-laterally rotates hip joint; assists in holding head of femur in acetabulum
what are the proximal and distal attachements of the piriformis muscle?
proximal: pelvic surface of 2nd to 4th sacral segments, superior margin of greater sciatic notch and sacrotuberous ligament
distal: greater trochanter of the femur
what is the innervation and action of the piriformis muscle?
anterior rami of S1 and S2
-laterally rotates hip joint; abducts hip joint; assists in holding head of femur in acetabulum
what is innervated by the sciatic nerve?
-articular branches to hip joint and muscular branches to flexors of knee (hamstring muscles) and all muscles in leg and foot
what is innervated by the superior gluteal nerve?
gluteus medius, gluteus minimus, and tensor fasciae latae muscles
what is innervated by the inferior gluteal nerve?
gluteus maximus
what is innervated by the nerve to piriformis?
piriformis
what is innervated by the nerve to quadratus femoris and inferior gemelius?
quadratus femoris and inferior gemelius muscles
what is innervated by the nerve to obturator internus and superior gemelius?
obturator internus and superior gemelius muscles
what does the back consist of? (9 things)
1) skin
2) subcutaneous tissue
3) deep fascia
4) muscles
5) ligaments
6) vertebral column
7) ribs
8) spinal cord and meninges
9) various segmented nerves and vessels
the adult vertebral column typically consists of:
-33 vertebrae arranged in 5 regions: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal
the 25 cervical, thoracic, lumbar, and first sacral vertebrae articulate at what type of joint?
synovial zygapophysial joints
the sacral (pelvic) curvatures of the back (also known as kyphoses) are concave ______, while the cervical and lumbar curvatures (lordoses) are concave _____
anteriorly, posteriorly
a typical vertebrae consists of what?
- vertebral body
- vertebral arch
- 7 processes
what is the role of the vertebral body?
- gives strength to the vertebral column
- support body weight
what are the distinctive characteristics of the body of a cervical vertebrae?
- small and wider
- superior surface is concave
- uncinate (hook shaped) processes
what are the distinctive characteristics of the vertebral foramen of a cervical vertebrae?
-large and triangular
what are the distinctive characteristics of the transverse processes of a cervical vertebrae?
- foramen transversum small or absent in C7
- arteries pass through foramina
- anterior and posterior tubercles
what are the distinctive characteristics of the articular processes of the cervical vertebrae?
-superior facets directed posteriorly, inferior facets directed anteriorly
what are the distinctive characteristics of the spinous process of the cervical vertebrae?
- short and bifid (C3-C5)
- C6 is long but C7 is longer
what are the distinctive characteristics of the atlas? (C1)
- ring like, kidney shaped
- no spinous process or body
- consists of 2 lateral masses
- concave superior articular facets form antlo-occipital joints with occipital condyles
what are the distinctive characteristics of the axis? (C2)
- strongest cervical vertebrae
- dens
- provides a pivot
what are the distinctive characteristics of the body of a thoracic vertebrae?
-heart shaped
what are the distinctive characteristics of the vertebral foramen of a thoracic vertebrae?
-circular and smaller than cervical and lumbar regions
what are the distinctive characteristics of the transverse process of a thoracic vertebrae?
- long and strong
- attach to rib via tubercle
what are the distinctive characteristics of the articular processes of a thoracic vertebrae?
-superior articular facets directed posteriorly and slightly laterally
what are the distinctive characteristics of a spinous process of the thoracic vertebrae?
-long
what are the distinctive characteristics of the body of a lumbar vertebrae?
-massive, kidney shaped. larger and heavier than other regions
what are the distinctive characteristics of the vertebral foramen of a lumbar vertebrae?
- triangular
- larger than in thoracic, small than cervical
what are the distinctive characteristics of the transverse processes of a lumbar vertebrae?
-long and slender
what are the distinctive characteristics of the articular processes of a lumbar vertebrae?
-superior articular facets directed medially
what are the distinctive characteristics of a spinous process of a lumbar vertebrae?
- short and sturdy
- hatchet shaped
the joints of the vertebral column include what kind of joints?
1) joints of vertebral bodies
2) joints of vertebral arches
3) craniovertebral joints
4) costovertebral joints
5) sacro-iliac joints
the joints of vertebral bodies are designed for what function?
weight bearing and strength
the ______ is a ring consisting of concentric lamellae of fibrocartilage forming the circumference of the IV disc
anulus fibrosus
the _____ is the central core of the IV disc
nucleus pulposus
the _______ ligament is a strong, broad, fibrous band that covers and connects the anterolateral aspects of the vertebral bodies and IV discs
anterior longitudinal
the ______ ligament is a much narrower, somewhat weaker band compared to the anterior longitudinal ligament that runs within the vertebral canal along posterior aspects of the vertebral bodies
posterior longitudinal
the joints of the vertebral arches are the ______ joints
zygapophysial (facet joints)
zygapohpysial joint
- synovial joint
- between vertebrae
- surrounded by a loose joint (articular) capsule
the laminae of adjacent vertebral arches are joined by broad, pale, yellow elastic fibrous tissue called the _____
ligamenta flava
the supraspinous ligament merges superiorly with the ____ ligament
nuchal
adjacent spinous processes are united by weak, almost membranous _______ ligaments
interspinous
what is the nuchal ligament
the strong ligament of the neck
atlanto-occipital joints
- between the lateral masses of C1 (atlas) and the occipital condyles
- permit nodding of the head (flexion and extension of the neck)
- synovial condyloid joint
atlanto-axial joints
- 3 atlanto-axial articulations
- 2 between the lateral masses of C1 and the superior facets of C2
- 1 median atlanto-axial joint between the dens of C2 and the anterior arch and the transverse ligament of the atlas
- makes it possible to shake your head
name the vertebrae that have the least range of motion to the most range of motion
- thoracic spine (limited by the rib cage)
- lumbar spine
- cervical spine (most range of motion)
the range of movement of the vertebral column is limited by what 6 things?
1) thickness, elasticity and compressibility of the IV discs
2) shape and orientation of the articular facets
3) tension of the joint capsules of the above joints
4) resistance of the back muscles and ligaments
5) attachment to the thoracic cage
6) bulk of the surrounding tissues
the flexion, extension, lateral flexion, and rotation of the neck are especially free because of what?
- IV discs, although thin relative to most other discs, are thick relative to the small size of the vertebral bodies
- articular surfaces of the zygapophysial joints are relatively large and the joint planes are almost horizontal
- joint capsules of the zygapophysial joints are loose
- neck is relatively slender (with less surrounding tissue/bulk)
the spinal cord begins as a continuation of the _____ and ends at the _______
medulla oblongata, conus medullaris (high as T12 or low as L3)
the cervical enlargement
- extends from the C4 through the T1
- brachial plexus of nerves, which innervates teh upper limbs
the lumbosacral (lumbar) enlargement
- extends from the L1 through S3
- contribute to the lumbar and sacral plexus of nerves (innervate the lower limbs)
___ pairs of spinal nerves are attached to the spinal cord; ___ cervical, ___ thoracic, ___ lumbar, ___ sacral, and ___ coccygeal
31, 8, 12, 5, 5, 1
spinal meninges
- dura mater, arachnoid mater, pia mater
- these membranes and CSF surround, support, and protect the spinal cord and the spinal nerve roots, including those in the cauda equina
spinal dura mater
- tough, fibrous, and some elastic tissue
- outermost covering of the meninges
- separated from the vertebrae by the extradural (epidural) space
spinal arachnoid mater
- delicate, avascular membrane composed of fibrous and elastic tissue
- lines the dural sac and the dural root sheaths
spinal pia mater
- innermost membrane of the spinal cord
- directly covers the roots of the spinal nerve
- inferior to the cornus medullaris
- continues as the filum terminale
subarachnoid space
- lies between the arachnoid mater and the pia mater and is filled with CSF
- the enlargement of the subarachnoid space containing CSF in the cauda equina is the lumbar cistern
extrinsic back muslces
- superficial extrinsic back muscles: contribute to upper limb movements
- connect the upper limbs to the trunk
- although these are in the back, they receive their nerve supply from the anterior rami of the cervical nerves
-intermediate extrinsic back muscles: serratus posterior superior and inferior
intrinsic back muscles
- innervated by the posterior rami of spinal nerves
- act to maintain posture and control movements of the vertebral column
- extend from pelvis to cranium
- enclosed by deep fascia
- deep back muscles
superficial layers of intrinsic back muscles
- splenius muscles: thick and flat, lie on the lateral and posterior aspects of the neck
- splenius cervicis and splenius capitits: cover the deep neck muscles
intermediate layer of intrinsic back muscles
- errector spinae mucles (sacrospinalis)
- iliocostalis
- longissimus
- spinalis
what is the origin of the splenius muscles? (splenius capitits and splenius cervicis)
arise form the nuchal ligament and spinous processes of C7-T6 vertebrae
what is the insertion of the splenius capitis muscle?
what is the insertion of the splenius cervicis muscle?
splenius capitis: superolaterally to mastoid process of temporal bone and lateral third of superior nuchal line of occipital bone
splenius cervicis: tubercles of transverse processes of C1-C3 or C4 vertebrae
what is the nerve supply of the splenius muscles?
posterior rami of spinal nerves
what are the main actions of the splenius muscles?
acting alone: laterally flex the neck and rotate head to side of active muscles
acting together: extend head and neck
what is the origin of the iliocostalis, longissimus, and spinalis muscles?
arises by broad tendon from posterior part of iliac crest, posterior surface of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament
what is the insertion od the iliocostalis muscle?
-fibers run superiorly to angles of lower ribs and cervical transverse processes
what is the insertion of the longissimus muslce?
-fibers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions and to mastoid process of temporal bone
what is the insertion of the spinalis muscle?
-fibers run superiorly to spinous processes in upper thoracic region and to cranium
what is the innervation of the iliocostalis, longissimus, and spinalis muscles?
posterior rami of spinal nerves
what are the actions of the iliocostalis, longissimus, and spinalis muscles?
- acting bilaterally: extend vertebral column and head: as back is flexed, control movement by gradually lengthening their fibers
- acting unilaterally: laterally flex vertebral column
deep to the erector spinae muscles is an obliquely disposed group of muscles called the ______
transversospinales muscle group
what is the origin and insertion of the semispinalis muslce?
origin: arises from transverse processes of C4-T10 vertebrae
insertion: superiorly to occipital bone and spinous processes in upper thoracic and cervical regions
what is the innervation and the action of the semispinalis muscle?
posterior rami of spinal nerves
-extends head and thoracic and cervical regions of vertebral column and rotates them contralaterally
what is the origin and insertion of the multifidus muscle?
origin: posterior sacrum, posterior iliac spine, sacro-iliac ligaments, mammilary process of lumbar vertebrae
insertion: thickest in lumbar region, attach superiorly/ medially to entire length of spinous processes of vertebrae located 2-4 segments superior to origin
what is the innervation and action of the multifidus muscle?
posterior rami of spinal nerve
-unilateral contraction rotates to contralateral side; stabilizes vertebrae during bilateral contraction
what is the origin and insertion of the rotatores muscle?
origin: arises from transverse processes of vertebrae, are best developed in thoracic region
insertion: pass superomedially to attach to junction of lamina and transverse processes or spinous processes of vertebrae immediately (brevis) or two segments (longus) superior to vertebrae of origin
what is the innervation and the action of the rotatores muscle?
posterior rami of spinal nerves
-possibly stabilize vertebrae and assist with local extension and rotary movements of vertebral column
what is the origin and insertion of the interspinales muscles?
origin: superior surfaces of spinous processes of cervical and lumbar vertebrae
insertion: inferior surfaces of spinous processes of vertebrae superior to vertebrae of origin
what is the innervation and action of the interspinales muscles?
posterior rami of spinal nerves
-aid in extension and rotation of vertebral column
what is the origin and insertion of the intertransversarii muscles?
origin: transverse process of cervical and lumbar vertebrae
insertion: transverse processes of adjacent vertebrae
what is the innervation and action of the intertransversarii muscles?
posterior and anterior rami of spinal nerves
-aid in lateral flexion of vertebral column; acting bilaterally, stabilize vertebral column
what is the origin and insertion of the levatores costarum muscles?
origin: tips of transverse processes of C7 and T1-T11 vertebrae
insertion: pass inferolaterally and insert on rib between its tubercle and angle
what is the innervation and the action of the levatores costarum muscles?
posterior rami of spinal nerves
-elevate ribs, assisting respiration; assist with lateral flexion of vertebral column