how many vertebrae are in the vertebral column?
how many individual vertebrae are there?
what is the organization of the vetebrae of the vertebral column?
7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral (sacrum), 4 fused coccygeal (coccyx)
what are pedicles?
processes that project dorsally to attach the body to the arch
what are laminae?
unite to form the spinous process
what fails to use in spina bifida?
laminae fail to fuse to form a spinous process
compare the following types of spina bifida:
1. spina bifida occulta
2. spina bifida cystica
a. with meningocele
b. with meningomyelocele
c. with myeloschisis or rachischisis
1. one or more spinous processes fail to form at lumbar or sacral levels; asymptomatic; marked by tuft of hair over defect usually
2. cyst protrudes through the defect
a. cyst lined by the dura and arachnoid and contains CSF
b. lumbosacral spinal cord is displaced into the cyst which stretches lumbosacral spinal nerves and may result in bladder, bowel, or lower limb weakness
c. caudal end of the neural tube fails to close in the dorsal midline and is exposed on the surface of the back
at what vertebral levels is spina bifida most commonly seen?
lumbar or sacral
what are costal processes?
usually form transverse processes that project laterally at the junction between each lamina and pedicle
label the components of the vertebrae
what are the primary curvatures of the vertebral column and how are they directed? secondary curvatures?
primary are the thoracic and sacral curvatures, convex directed posteriorly
secondary are the cervical and lumbar curvatures, convex directed anteriorly
what is kyphosis?
abnormal increase in the posterior curvature of the spine
thus, increased curvature in the thoracic or sacral regions
what are possible causes of kyphosis? which is the most common?
postural (most common)
anterior wedge-shaped thoracic vertebrae
resorption of the anterior parts of the thoracic vertebral bodies from osteoporosis
what is lordosis? what is a common cause?
abnormal increase in the anterior curvature of the spine
thus, increase in curvature in the lumbar or cervical regions
weakening of the anterior abdominal wall as a result of weight gain can cause
what is scoliosis? what is a common cause?
abnormal lateral curvature that may be caused by an absent half of a vertebra or a wedge-shaped vertebra or by an asymmetric weakness of back musculature
where are the zygapophyseal or facet joints located? what is their function?
between the facts of superior and inferior processes at the junction of each pedicle and lamina
permit gliding motion
acted on by intrinsic or deep back muscles
where are intervetebral disks located? what are their components? what is their function?
situated between bodies of most adjacent vertebrae
consist of a fibrocartilaginous annulus fibrosus surrounding a nucleus pulposus
functions to absorb shock and distribute weight over the entire surface of vertebral bodies durring compression and tension
what is the nucleus pulposis a remnant of?
where is the anterior longitudinal ligament found and what is its function?
covers the anterolateral parts of the vertebral boes and the disks to limit vertebral extension
where is the posterior longitudinal ligament found and what is its function?
covers the posterior part of the vertebral codies and the disks and functions to limit vertebral flexion
which is greater (thicker/stronger), the anterior or posterior longitudinal ligaments?
where are the elastic ligamentum flavum and what are their functions?
between the laminae of adjacent vertebrae
function to limit vertebral flexion and help maintain normal vertebral curvatures
where are the interspinous and supra spinous ligaments located?
interspinous ligaments a ligament connect the spinous processes of two adjacent vertebra
supraspinous ligaments a ligament connect the tips of the spinous processes of thoracic and lumbar vertebrae
where are the intervertebral foramina located? what are they bounded by? what do they transmit?
an opening between the pedicles of adjacent vertebrae, separating individual vertebrae
bounded by the pedicles of adjacent vertebrae, posteriorly by facet joints and anteriorly by the bodies/intervertebral disks
transmit dorsal and ventral roots of the spinal nerves
where/what is the vertebral canal? what does it contain?
the opening formed by the combination of the body and the vertebral arch as well as the ligaments/disks that interconnect them
contain the meninges, spinal cord, and roots of spinal nerves
where is the epidural space and what does it contain?
outside the dural layer of the meninges and contains fat and the internal vertebral venous plexus
what is the internal venous plexus? what is significant about it clinically in relation to cancer?
connects veins that drain the thorax, abdomen, and pelvis with dural venous sinuses of the cranial cavity
provides routes for metastasis of neoplasms of the prostate, uterus, and rectum to the cranial cavity
what is the dura mater and where is it located?
outermost covering of the spinal cord, it forms the dural sac containing the spinal cord within vertebral canal
continuous with the meningeal dura of the cranial cavity and ends at S2, with lateral extensions at the roots of spinal nerves
what is the subdural space?
potential space between the dura and the arachnoid mater
what is the arachnoid mater and where is it located?
intermediate one of the three layers of meninges
also extends to S2 and is pressed against the dura by the pressure of CSF
where is CSF contained in the spinal region?
the subarachnoid space (which has a spider web-like filaments)
what is the normal pressure of CSF?
100 mm H20
what is the function of CSF?
cushions the brain and spinal cord, absorbs waste products, transports hormones
has few cells, low protein content, and a lower glucose concentration than serum
what is the pia mater?
covers the spinal cord and roots of the spinal nerves
most delicate of the meningeal layers
what are the two specializations of pia mater and their functions?
denticulate ligaments: lateral extensions of the pia that anchor the spinal cord to the dura
filum terminale: consists of pia that extends from the inferior end of the cord at L2 and joins the dura and arachnoid to end in the sacral canal at S2
what is the spinal cord located in relation to the vertebral column?
occupies he superior 2/3 of the vertebral canal and ends inferiorly at L2
where/what is the conus medullaris?
tapered inferior end of the spinal cord that contains sacral and coccygeal cord segments and is located at L2
going down the vertebral canal, where do spinal nerves exit?
first 7 cervical nerves exit SUPERIOR to the cervical vertebra for which they are named
beginning with T1, all other spinal nerves exit INFERIOR to the vertebra for which they are named
the 8th cervical nerve exits through intervertebral formen between C7 and T1 (8 cervical nerves, but only 7 cervical vertebrae)
what forms the cauda equina and where is it located?
formed by dorsal and ventral roots of lumbar and sacral spinal nerves that extend inferior to the end of the spinal cord at L2
what is a lumbar puncture and where is it typically performed?
used to sample CSF or introduce anesthetic agents into the subarachnoid space
typically performed between L4 and L5 below the inferior end of the spinal cord
in a midline lumbar puncture, what layers will the needle transverse?
skin, superficial and deep fascia, supraspinous and interspinous ligaments, intralaminar space, epidural space, dura, arachnoid
in an off the midline lumbar puncture, what will the needle transverse?
ligamentum flavum instead of the supraspinous and interspinous ligaments and the intralaminar space
what are radiculopathies? what are typical symptoms?
compression of the roots of spinal nerves in the intervertebral foramina or in the vertebral canal
symptoms are pain and paresthesias in dermatomes supplied by affected sensory roots or weakness of skeletal muscles in myotomes supplied by compressed motor roots
what can radiculopathies be caused by?
osteoarthritis- inflammation that results in additional bone growth by osteophytes at the facet joints
spondylitis- inflammation that results in additional bone growth by osteophytes at the margins of the vertebral bodies; anterior longitudinal ligament and sacroiliac joint may undergo calcification; may exhibit ankylosis (joint stiffening) or bamboo spine (marie-strumpell disease)
spondylosis- degenerative changes in intervertebral disks, usually combined with osteoarthritis at the margins of the vertebral bodies
what are characteristics of the cervical vertebrae?
small bodies, short spinous processes (some with bifid tips), transverse processes that transmit vertebral arteries (have openings)
have facet joints of C3-C7 oriented at 45 degree angle relative to transverse plant-->permits flexion, extension, lateral bending, and rotation
uncinate processes on bodies of C3-C7 that form uncovertebral synovial joints with the vertebral bodies superior to them
describe the location and characteristics of the atlas vertebra?
has posterior arch and arnterior arch but no body or spinous process
no intervertebral disk in between C1 and C2
superior articular processes articulate with occipital condylesof the skull forming "yes" joints for flexion and extension
describe the location and chracteristics of the axis vertebra?
dens/odontoid process of the axis articulates with the anterior arch of the atlas and forms the "no" or pivotjoints to permit rotation of the atlas and skull
what holds the dens in place and what is the function of the dens/associated ligaments? what can happen clinically if damaged?
dens held in place by transverse ligament of the atlas (rupture can cause dislocation of the atlantoaxial joint and displacement of the dens posteriorly into the cervical spinal cord and if the cord is compressed quadriplegia can result)
dens is attached to margins of the foramen magnum by alar ligaments (reupture can cause excessive rotation of the skull)
describe the location and characteristics of vertebra prominens
long spinous process and small transverse formina that does not transmit the vertebral arteries
what is a herniated disk and which spinal nerves are they most likely to affect?
when a nucleus pulposis protrudes at the posterolateral part of an annulus fibrosus resulting in compression of roots of lower cervical or lower lumbar spinal nerves
the compressed roots are most commonly the more inferior spinal nerve (ex. at C5-6 disk, compresses C6 root)
where do herniated disks most often occur at the cervical level?
at cervical levels, most common herniations between C6-C7-->C7 spinal nerve compression: referred pain in neck and shoulder and index and middle fingers; diminished triceps reflex and weakness in extension of forearm at the elbow or wrist and fingers
less common is at C7-C8-->C8 spinal nerve compression: pain in neck and shoulder and ring and little fingers; weakness in hypothenar and interosseous muscles of the hand
what can occur with a cervical rib and what are the symptoms?
rib arising from costal process of C6
T1 spinal nerve and subclavian artery may be compressed as they course superior to cervical rib instead of first thoracic rib
diminished fadial pulse and pain and paresthesias in medial forearm
Horner's syndrome signs seen (drooping of the eyelid (ptosis) and constriction of the pupil (miosis), sometimes accompanied by decreased sweating (anhidrosis) of the face on the same side)
what are the characteristics of thoracic vertebrae?
"heart-shaped" or more rounded bodies ith ong obliquely oriented spinous processes
have costal facets on body and tranverse processes for articulation with ribs
also have facet joints oriented at a 60 degree angle relative to transverse plane which permits mainly lateral bending and rotation (flexion and extension limited by fixation by ribs)
what are the characteristics of lumbar vertebrae?
large kidney-shaped bodies, short flat horizontally oritented spinous processes; long transverse processes
facet joints oriented perpendicular to the transverse plane for flexion, extension, and lateral bending with limited rotation
superior and inferior articular processes interconnected by an observable isthmus or pars interarticularis
-->"Scottie dog" shape
what is spondylolysis?
defect or fracture of the isthmus with no anterior displacment of the vertebral body
what is spondylolisthesis? where does it most commonly occur?
unilateral or bilateral defect or fracture of the isthmus accompanied by anterior displacement of the vertebral body
most commonly occurs between L5 and sacrum streching roots of lumbosacral spinal nerves in cauda equina
where do herniated disks most often occur at the lumbar level?
between L4-L5-->compression of L5: results in sciatica (pain radiates from back into posterior thigh, anterolateral leg, and dorsum of the foot), weakness in extension of great toe and dorsiflexion (tibialis anterior)
between L5-S1-->compression of S1: pain and paresthesias in posterolateral leg, heel, and lateral side of foot; weakness in flexion of leg at knee (hamstring) and plantar flexion (gastrochemius and soleus), diminished Achilles tendon reflex
what do the median crest of the sacrum and the intermediate crests represent?
median crests= fused sacral spinous processes
intermediate crests= fused articular processes
what is the promontory?
forms ventral surface of the S1 vertebra (boundary of the pelvic inlet for obstretrics)
what trasmist the dorsal and ventral rami of S1-S4?
four pairs of dorsal sacral foramina and four pairs of ventral sacral foramina
what is contained in the sacral canal? the sacral hiatus?
canal, which ends at the sacral hiatus in the dorsal midline, contains the roots of the S1-coccygeal spinal nerves
sacral hiatus transmits the S5 and coccygeal spinal nerves
where is an epidural or caudal block performed?
through sacral hiatus which diffuses through the meninges and anesthetizes the roots of the sacral and coccygeal spinal nerves in the cauda equina
what forms the sacroiliac joints?
lateral surfaces of superior sacrum and medial surface of each ilium
what is the coccyx attachment sites for?
anococcygeal ligaments which are attachment sites for muscles of pelvic diaphragm
what are the muscle groups of the back?
superficial, intermediate, deep or intrinsic
where do the superficial muscles of the back attach?
attached to pectoral girdle and act on the upper extremity
what muscles are included in the superficial muscles of the back?
trapezius, latissimus dorsi, rhomboid major, rhomboid minor, levator scapulae
what innervates the superificial muscles of the back?
ventral rami of spinal nerves through branches of the brachial plexus (except for trapezius which is supplied by CN XI/acessory nerve)
where do the intermediate muscles of the back attach to?
attach to the ribs and act as acessory muscle of respiration
what muscles are included in the intermediate muscles of the back?
serratus posterior superior, serratus posterior inferior, 12 pairs of levator costarum muscles
what innervates the intermediate muscles of the back?
ventral rami of spinal nerves
where do the deep/intrinsic muscles of the back attach?
attach mainly to transverse and spinous processes of vertebrae and act on the vertebral column at the intervertebral joints
what muscles are included in the deep/intrinsic muscles?
erector spinae (contain 3 parallel muscle groups, from lateral to medial: iliocostalis, longissimus, and spinalis)
splenius capitis and splnius cervicis
transversospinalis muscles (consist of 3 muscle groups, superifical to deep: semispinalis, multifiduc, rotatores)
muscles of the suboccipital triangle
what are the muscles of the erector spinae and what are their actions?
from lateral to medial: iliocostalis, longissimus, spinalis
acting bilaterally, extend the vertebral column at intervertebral joints
acting unilaterally, produce lateral bending of the vertebral column at intervertebral joints
where are the splenius capitis and splenius cervicis located and what are their actions?
supeficial to erector spinae in the neck
spleni capitis acts to extend the head; splenius cervicis acts to rotate the head
acting unilaterally, both will produce lateral bending of the cervical vertebrae
where are the transversospinalis muscles located? what are they and what are their actions?
deep to erector spinae
from superficial to deep: semispinalis, multifidus, rotatores
acting bilaterally, act to extend the vertebral column
acting unilaterally, produce rotation of the vertebral column
what are the actions of the suboccipital triangle muscles?
contribute to the extension at the atlantooccipital joints and rotation at the atlantoaxial joints
what innervates the deep muscles of the back?
dorsal rami of spinal nerves
A 45-year-old man complains of low back pain that radiates into both lower limbs and leg weakness. An MRI scan reveals the body of the L5 vertebra is displaced laterally. A diagnosis of the patient's condition would be:
E. spinal stenosis
D- spondylolisthesis- unilateral or bilateral defect or fracture of the isthmus accompanied by anterior displacement of the vertebral body-->bilateral lower back pain that radiates into both lower limbs and weakness in muscles of legs
spondylolysis-defect or fracture of the isthmus with no anterior displacement of the vertebral body
spondylosis- degenerative changes in intervertebral disks
spondylitis- inflammation that results in additional bone growth by steophytes at the margins of vertebral bodies; also calcification of anterior longitudinal ligament and sacroiliac joints-->anylosis (joint stiffening) and a bamboo spine (marie-srtumpell disease)
A spinal anesthesia is used for a patient undergoing surgery. A lumbar puncture is performed in the midline between L4 and L5. Which of the following will not be transvered?
A. interspinous ligament
B. posterior longitudinal ligament
C. epidural space
B. posterior longitudinal ligament- covers posterior parts of the vertebral bodies and intervening disks and is anterior to the dural sac
Which of the following structures in the vertebral canal will be anesthetized in a spinal procedure?
A. dorsal and ventral rami
B. lumbar spinal nerves
C. sacral spinal nerves
D. dorsal and ventral roots
E. lumbosacral plexus
D. dorsal and ventral roots are in the cauda equina found in the vertebral canal (others are found in intervertebral foramen or outside of the vertebral canal)
An MRI reveals a patient has a posterolateral herniation of the nucleus pulposus of the intervertebral disk between L5 and the sacrum. Which might you observe?
A. weakness in dorsiflexion
B. altered sensation on the dorsum of the foot
C. weakness in plantar flexion
D. altered sensation in the anterior thigh
E. weakness in extension of the leg at the knee
C. roots of S1 compressed which results in altered sensation in posterolateral leg, heel lateral side of the foot, weakness in flexion of the leg at the knee, weakness in plantar flexion
A 50-year-old man complains of bak pain and has difficulty walking. Diagnostic imaging reveals calcifications of the sacroiliac joints and anterior longitutinal ligament resulting from additional bone growth by osteophytes. This suggests the patient has:
D. spinal stenosis
A 64-year-old man presents with pain that radiates from the back, through the posterior thigh, and into the leg and foot. The diagnosis is a herniated nucleus pulposus of the intervertebral disk between the L4 and L5 vertebrae. What else might the patient experience?
A. altered sensation in the L3 dermatome
B. weakness of muscles innervated by the L5 spinal cord segment
C. inability to contract and empty the bladder
D. fecal incontinence
E. weakness in the ability to extend the leg at the knee
B. from compression of L5
A patient develops a peripheral neuropathy that results in the degeneration of nerve fibers in dorsal rami. All of the following may be evident EXCEPT:
A. sensation may be altered in skin covering the trapezius
B. iliocostalis muscle might be weak
C. axons firing through the dorsal sacral foramina may be affected
D. motor fibers in the dorsal scapular nerve may be affected
E. sensation from facet joints may be altered
C. dorsal scapular nerve is a ventral ramus of the C5 spinal nerve (few dorsal rami have names)
Your patient suffers from a herniated disk between the L5 vertebra and the sacrum. If the herniation is small, what neural structure might be subject to compression?
A. L4 spinal nerve
B. L5 spinal nerve
C. S1 spinal nerve
D. conus medullaris
E. lumbar splanchnic nerve
C- S1 spinal nerve
what does the pelvic girdle consist of? where do those parts fuse? what are its joints?
ilium, ishium, pubis
fushed together at the acetabulum
sacroiliac joints and hip joints
what is the function of the pelvic girdle?
it suspends lower limb away from the axial skeleton to increase range of motion
girdle itself has limited mobility
what type of joint is the sacroiliac joint?
what ligaments resist motion at the sacroiliac joints?
posterior sacroiliac ligaments
what type of joint is the hip joint?
ball and socket
what ligaments strengthen the articular capsule of the hip joint? what do they reinforce? what motions do they resist?
1. iliofemoral ligament- strongest in the hip joint; reinforces anterior part of capsule; resists extension
2. pubofemoral ligament- reinforces the anterior and inferior parts of the capsule; resists abduction
3. ischiofemoral ligament- reinforces the posterior part of the capsule; resists extension by screwing the femoral head into the acetabulum
what can happen as the result of a fracture of the femoral head?
avascular necrosis (from disruption of the medial circumflex femoral artery which is the main arterial blood source to head and neck)
patients will have thigh laterally rotated by short lateral rotators of the thigh at the hip and by the gluteus maximus
a dislocation of the head of the femur most commonly occurs in what direction?
what can occur as the result of dislocation of the head of the femur?
thigh is shortened and medically rotated by gluteus medius and minimus muscles
sciatic nerve may be compressed (resulting in weakness of muscles in the posterior thigh, leg, and foot and paresthesia over the posterior and lateral parts of the leg and the dorsal and plantar surfaces of the foot)
what makes up the knee joint and what type of joint is it?
medial and lateral condyles of the femur and tibeal plateau
what ligaments of the articular capsule and ligaments within the articular capsule strengthen the knee?
oblique popliteal ligament
fibular and tibial collarteral ligaments
anterior cruciate ligament
posterior cruciate ligament
(ACL and PCL are intracapsular)
what is the patellar tendon an extension of? what parts of the knee capsule does it strength?
extension of the quadriceps tendon
strengthens the anterior and lateral parts
what does the oblique popliteal ligament arise from and what part of the capsule does it strengthen?
part of the semimembranosus tendon
posterior part of the capsule
where do the fibular and tibial collateral ligaments originate and attach to? what parts of the joint to they support?
fibular: supports lateral part of joint; extends from the lateral epicondyle of the femur to attach to head of the fibula; same as lateral collateral ligament (LCL)
tibial: supports medial part of the joint: extends from the medial epicondyle of the femur to attach to the medial aspect of the tibia and deep fibers are attached to medial meniscus; same as medial collateral ligament (MCL)
what motions do the fibular and tibial collateral ligaments limit?
abduction and adduction of the knee when knee is flexed
where do the ACL and PCL originate and attach?
ACL= APEX ligament... attaches to Anterior aspect of the tibia and courses Posteriorly and EXternally/laterally to attach to lateral condyle of the femur
PCL= PAIN ligament... attaches to Posterior aspect of the tibia and courses Anteriorly and INternally/medially to attach to the medial condyle of the femur
what motions do the ACL and PCL resist? when is each most taut? which is weaker?
ACL is weaker than the PCL
ACL is most taut during knee extension; resists hyperextension by preventing antior displacement of the tibia on the femur
PCL is most taut when knee is flexed and resists excessive flexion by preventing posterior displacement of the tibia on the femur
*anterior drawer test vs. posterior drawer test
compare the medial and lateral menisci (where are they, their shape, mobility)
what is their main function?
both are intracapsular, fibrocartilages that attach to tibia and act as shock absorbers
medial meniscus: shape of C and is less mobile; attached to deep fibers of the tibial collateral ligament
lateral meniscus: shape of o; more mobile; separated from the fibular collatoeral ligament by the tenson of the popliteus
what are the three most common injuries at the knee? (terrible triad)
tibial collateral ligament (MCL), medial meniscus, ACL
when can a "terrible triad" injury of the knee occur? when is only the ACL torn not the other two? what signs will be exhibited with either of the situations?
blow to lateral aspect of the knee when foot is on the ground can sparin the tibial collateral ligament and tear the attached medial meniscus
patients with a medial meniscus tear will have pain when lef is medially rotated at the knee
ACL tears can occur when TCL and MM are injured or a blow to anterior aspect of flexed knee can tear only ACL
torn ACL will exhibit an anterior drawer sign- tibia may be displaced anteriorly form the femur in the flexed knee
does the fibula articulate with the knee joint?
no, not directly
it does articulate with the tibia and talus
what are the ankle joints?
talocrural, subtalar, and transver tarsal joints
what is the talocrural joint formed by and what type of joint is it?
formed by articulation between the trochlea of the talus and the lateral and medial malleoli of the fibula and tibia, respectively
hinge joint (permits dorsiflexion and plantarflexion)
is the foot more stable in dorsiflexed position or plantarflexed? why?
anterior part of the superior surface of the trochlea of the talus is wider than the posterior part of the talocrural joint
which tendons enter the sole of the foot after passing posterior and inferior to the medial malleolus?
tendons of the tibialis posterior, flexor digitorum longus, flexor hallucis longus muscles
what tendons enter the sole of the foot after passing posterior and inferior to the lateral malleolus?
tendons of the fibularis/peroneus longus and fibularis/peroneus brevis muscles
what ligaments strengthen the talocrural joint? which is the stronger of the two?
deltoid/medial ligaments and lateral ligaments
deltoid is stronger
the deltoid ligament has __ components... what are they?
- anterior and posterior tibiotalar
the lateral ligaments has __ components... what are they?
- anterior and posterior talofibular
- calcaneofibular ligament
are inversion or eversion ankle sprains more common at the talocrural joint? what ligament and what part of the lateral ligament is most commonly torn during that?
inversion ankle sprains
the anterior talofibular part of the lateral ligament
what forms the subtalar joint and what type of joint is it?
articulation between the talus and calcaneus
ball and socket joint
what actions does the subtalar joint permit and what are they?
supination- combination of plantar flexion, inversion and adduction
pronation- combination of dorsiflexion, eversion, and abduction
what forms the transverse tarsal joints? what motions do the joint allow?
formed by the articulation of the talus with the navicular and the calcaneus with the cuboid
contribute to inversion and eversion with the subtalar joint
what muscles generally are contained in the sole of the foot?
short abductors and flexors of the great toe and little toe, respectively
(lacks the eminences and opponens muscles of the hand)
what is the action of the quadratus plantae muscle?
plantar muscle that acts to straighten out the oblique pull of the flexor digitorum longus tendons
(no counterpart in the hand)
what is the course of the femoral artery (origin, path, areas supplied)?
begins at the inguinal ligament from the extnal iliac artery
courses lateral to the femoral vein and medial to the femoral nerve through the femoral triangle in the anterior thigh
enters adductor canal to become the popliteal artery (after passing through the adductor hiatus)
profunda femoral artery gives rise to lateral and medial circumflex arteries-->thigh, head and neck of femur, hip joint (medial is main source for the head and neck of femur)
profunda artery also gives rise to 4 perforating arteries that supply the medial thigh and pass through the adductor magnus to supply the muscles in the posterior thigh
what is the cruciate anastomosis? what is its clinical importance?
medial and lateral circumflex femoral arteries, inferior gluteal atery, and first perforating artery contribute to cruciate anastomosis in the posterior thigh
can contribute to collateral circulation of lower limb is the femoral artery becomes occluded
what is the course of the popliteal artery?
beings at the adductor hiatus as a continuation of the femoral artery
courses through the popliteal fossa posterior to the knee with the tibial nerve
gives rise to 5 genicular arteries that supply the knee joint
ends when it divides into the anterior and posterior tibial arteries at the inferior border of the popliteus
what is the course of the anterior tibial artery and what does it supply?
enters the anterior compartment of the leg proximal to the interosseous membrane between the tibia and fibula
courses with the deep fibular/peroneal nerve and supplies the anterior compartment of the leg
continues as the dorsalis pedis
what is the course of the dorsalis pedis, what are its branches and what do they supply?
comes from the anterior tibial artery, on the dorsal aspect of the foot
branches into an arcuate artery, which gives rise to digital branches that supply the toes and a deep plantar artery, which contributes to a plantar arterial arch in the sole of the foot
where would one feel for the dorsalis pedis pulse?
compressing the dorsal artery of the foot against the tarsal bones lateral to the tendon of the extensor hallucis longus
what is the course of the posterior tibial artery? what are its branchs and what do they supply?
arises from the popliteal artery and courses through posterior compartment of leg with the tibial nerve
supplies the posterior compartment of the leg
gives rise to the fibular artery-->supplies the posterior leg and sends perforating branches into lateral compartment of the leg (fibularis longus and brevis muscles)
passes into foot (behind the medial malleolus) to divide into medial and lateral plantar arteries-->supply sole of the foot
what are the branches of the internal iliac artery?
superior gluteal artery
inferior gluteal artery
what is the course of the superior gluteal artery and what does it supply?
enters the gluteal region with superior gluteal nerve superior to the piriformis after passong through the greater sciatic foramen
supplies the gluteus medius and minimus, some of maximus
what is the course of the inferior gluteal artery and what does it supply?
enters the gluteal region with the inferior gluteal nerve inferior to the priformis muscle after passing through the greater sciatic foramen
supplies the gluteus maximus, short lateal rotators of the hip, promixal parts of the hamstrings
what is the course of the obturator artery and what does it supply?
enters the medial thigh with the obturator nerve, after passing through the obturator foramen
supplies the adductor muscles, obturator externus, pectineus, and gracilis muscles
which veins of the lower limb are superficial?
great saphenous and small saphenous veins
what is the course of the great saphenous vein?
arises from medial aspect of the dorsal venous arch of the foot
courses anterior to the medial malleolus, though medial aspect of the leg (with the saphenous nerve) and through the medial thigh
drains into the femoral vein after passing through the saphenous hiatus (fault in fascia lata)
what is the course of the small saphenous vein?
arises from the lateral aspect of the dorsal venous arch of the foot
courses posterior to the lateral malleolus and then through the posterior leg (with the sural nerve)
passes between the two heads of the gastrocnemius muscle and drains into the popliteal vein
in general, what are the deep veins of the lower limb and where do they course?
course with arteries of the same name (arteries from the iliac, femoral, politeal, posterior and anterior tibial arteries)
what nerve plexuses innervate the lower limb and where can they be found?
lumbar plexus: formed by ventral rami of L1-L4 (partly T12) and is found on posterior abdominal wall and greater plexus
lumosacral plexus: formed by ventral rami of L4-S3 and found in the lesser pelvis
what do the ventral rami of the lumbar plexus branch into (divisions and nerves)?
posterior division-->femoral nerve
anterior division-->obturator nerve
what do the ventral rami of the lumbosacral plexus divide into (divisons and nerves?)
posterior-->common fibular/peroneal (superior and inferior gluteal nerves also contain posterior division fibers)
During development, the lower limb undergoes a ______ rotation so that flexor muscles that were in the _____ embryo are then situated ______ and extensor muscles that were ____ in the embryo come to be situated ______. As a result the medial and posterior compartments of the thigh, the posterioer compartment of the leg, and the plantar muscles of the foot are innervated by the _____ or ____ nerves, which contain _____ division fibers. Muscles in the anterior compartment of the thigh and anterior and lateral compartments of the leg and the dorsum of the foot are innervated by the _____ or ______ nerves, which contain ______ division fibers.
During development, the lower limb undergoes a MEDIAL rotation so that flexor muscles that were in the ANTERIOR embryo are then situated POSTEROMEDIALLY and extensor muscles that were POSTERIOR in the embryo come to be situated ANTEROLATERALLY. As a result the medial and posterior compartments of the thigh, the posterioer compartment of the leg, and the plantar muscles of the foot are innervated by the OBTURATOR or TIBIAL nerves, which contain ANTERIOR division fibers. Muscles in the anterior compartment of the thigh and anterior and lateral compartments of the leg and the dorsum of the foot are innervated by the FEMORAL or COMMON FIBULAR nerves, which contain POSTERIOR division fibers.
what forms the lumbosacral trunk and what is its course?
fibers of L4 and L5 form the lumbosacral trunk
lumbosacral trunk emerges from medial aspect of the psoas major, corsses the pelvic brim, joins with the ventral rami of S1-S3 to form the lumbosacral plexus
where do the terminal and collateral nerves of the lumbosacral plexus exit the pelvis?
greater sciatic foramen
The nerves from the superior rami of the lumbar and lumosacral plexus (L2-L4) innervate muscles where? and thus at on what joints?
anterior and medial thigh
acting on hip and knee joints
The nerves that contain fibers from the inferior rami of the lubar and lumbosacral plexus (#1-S3) innervate what muscles? and thus act on what joints?
joints of the ankle and foot
the femoral nerve contains posterior division fibers from which ventral rami?
what is the course of the femoral nerve? what does it innervate?
emerges from lateral border of the psoas major in the iliac fossa and passes into the anterior thigh, posterior to the inguinal ligament and lateral to the femoral artery
innervates muscles in the anterior compartment of the thigh: 4 heads of quadriceps femoris, iliopsoas, sartorius, pectineus (which all act to flex thigh at hip and extend leg at knee)
innervates skin of the anterior and medial thigh (medial and intermediate cutaneous nerves)
also gives rise to the saphenous nerve
what is the longest branch of the femoral nerve and the only branch of the lumbar plexus to cross the knee joint?
what is the course of the saphenous vein and what does it innervate?
branch from femoral
enters adductor canal but leaves without passing through the adductor hiatus
courses with the great saphenous vein and innervates the skin of the medial side of the leg and foot
what is a common way the femoral nerve can be damaged? what symptoms are associated?
damaged in the abdomen by an abscess of the psoas major or pelvic neoplam
patients experience weakness in flexion of thigh, abiliy to extend leg at knee, and diminish patellar tendon reflex
what are examples of common ways the saphenous nerve can be damaged? what are associated symptoms?
during surgical procedure of the leg to remove varicose veins or great saphenous vein or lacerated as it pierces wall of adductor canal
patients experience pain and parethesia in the skin of the medial aspect of the leg and foot
what fibers from what rami are contained in the obturator nerve?
contains anterior division fibers from the L2-L4 ventral rami
what is the course of the obturator nerve and what does it innervate?
emerges from medial side of psoas major, crosses pelvic brim, courses anteriorly and inferiorly in the lesser pelvis to the obturator foramen then through the obturator externus into medial thigh
divides into anterior branch (passes theough adductor longus and brevis) and posterior branch (passes between adductor brevis and adductor magnus)
innervates muscles in the medial thigh (adductor longus, brevis, and magnus, gacilis, and obturator externus)... which act to adduct the thigh and assist in hip flexion
innervtes skin in the small region of the medial thigh
where is the obturator nerve most commonly lesioned? what are the symptoms associated?
in the pelvis (pelvic neoplasm or pregnancy)
patients unable to adduct the thigh at hip and may have paresthesia in skin of the medial thigh
what are the five collateral nerves of the lumbar plexus? what are their spinal nerve origins?
subcostal nerve (T12)
iliohypogastric nerve (T12-L1)
ilioinguinal nerve (L1)
genitofemoral nerve (L1, L2)
lateral femoral cutaneous nerve (L2, L3)
what is the path of the subcostal nerve and what does it innervate?
passes between the psoas major and quadratus lumborum muscles inferior to the 12th rib
innervates abdominal muscles and overlying skin of the lateral and anterior abdominal wall
what is the path of the iliohypogastric nerve and what does it innervate?
emerges between the psoas and quadratus lumborum muscles inferior to the subcostal nerve
innervates abdominal mucles and skin of the inguinal and hypogastric regions of the lateral and anterior abdominal wall
what is the path of the ilioinguinal nerve and what does it innervate?
courses inferior to the iliohypogastric nerve
pierces the inguinal canal and passes trhough the superficial inguinal ring to innervate the skin of the medial thigh, and labium majus or anterior aspect of the scrotum
above the superificlal inguinal ring it will innervate the abdominal muscles and skin of the inguinal and hypogastric regions of the lateral and anterior abdominal wall
what is the path of the genitofemoral nerve and what does it innervate?
courses through and then anterior to the psosas major muscle
divides into a femoral branch: passes posterior to the inguinal ligament and innervates skin of the medial thigh, and a genital branch: enters inguinal canal through the deep inguinal ring and innervates the cremasteric muscle
what is the path of the lateral femoral cutaneous nerve and what does it innervate?
emerges lateral to the psoas major muscle then crosses the iliacus to reach the ASIS then descends into the lateral thigh after passing posterior to the inguinal ligament
innervates anterolateral thigh
what is a common site/cause of lateral femoral cutaneous nerve lesions and what are the associated symptoms?
may be compressed as it passes posterior to the lateral part of the inguinal ligament just medial to the ASIS (meralgia paresthetica)
pain and paresthesia in the anterolateral thigh
What are the terminal nerves of the lumbosacral plexus and what are their spinal cord origins?
superior gluteal nerve (posteror division fibers from L4, L5, S1)
inferior gluteal nerve (posterior division fibers from L5, S1, S2)
tibial nerve (anterior division fibers from L4, L5, S1-S3)
common fibular/peroneal nerve (posterior division fibers from L4, L5, S1, S2)
superficial fibular nerve (L4, L5, S1)
deep fibular nerve (L5, S1, S2)
what is the course of the superior gluteal nerve and what does it innervate?
enters gluteal region with the superior gluteal artery by passing through the greater sciatic foramen superior to the piriformis muscle
innervates the gluteus medius, gluteus minimus, and tensor fasciae latae muscles
what are symptoms associated with a superior gluteal nerve lesion?
- weakness in ability to abduct the thigh at the hip
- waddling or Trendelendburg gait in which pelvis sags on side opposite the nerve lesion during unsupported stage of walk
what is the course of the inferior gluteal nerve and what does it innervate?
enters gluteal region by passin through the greater sciatic foramen inferior to the piriformis muscle
innervates the gluteus maximus
what symptoms are associated with an inferior gluteal nerve lesion?
- weakness in ability to laterally rotate and extend the thigh at the hip
- difficulty climbing stairs or rising from a chair due to difficulty extending thigh from a flexed position
- gluteus maximus gait- thrust their torso posteriorly in an attempt to coutract the weakness of the gluteus maximus
what is the course of the tibial nerve? what does it branch into and where?
enters gluteal region with common fibular nerve in the sciatic nerve by passing through the greater sciatic foramen inferior to the piriformis
courses through posterior thigh deep to hamstring and separates from common fibular at superior border of the popliteal fossa
then courses in the posterior part of the leg with the posterior artery and then passes thorugh the tarsal tunnel and into th sole of the foot after coursing behind the medial malleolus
divides into the medial and lateral plantar nerves distal to the tarsal tunnel
what does the tibial nerve innervate in general?
muscles in the posterior thigh, posterior leg and plantar foot
what does the medial plantar nerve innervate?
medial plantar nerve (L5, S1, S2) innervates 4 muscles in the sole of the foot: flexor digitorum brevis, flexor hallucis brevis, abductor hallucis, first lumbrical; common and digital plantar branches innervate skin of the medial side of the sole of the foot and medial 3 1/2 digits
- similar to median nerve in hand
what does the lateral plantar nerve innervate?
lateral plantar nerve (L5, S1, S2) innervates the rest of the intrinsic foot muscles (quadratus plantae, flexor digiti minimi brevis for toe 5, lumbricals II-IV, interrossei, dorsal interossi, abductor digiti minimi, adductor halluscis, plantar interossi); common and digital plantar branches innervate the skin of the alteral side of the sole of the foot and lateral 1 1/2 digits
- similar to ulnar nerve of the hand
what are common causes of sciatic nerve lesions?
- susceptible to damage from an intramuscular injection in the lower medial quadrant of the gluteus maximus muscle
- compressed from posterior dislocation of the femur
- L5 and S1 roots of the sciatic nerve compressed by intervertebral disk herniations
where are common sites for tibial nerve lesions and what are symptoms associated?
- in the gluteal region-->weakness in ability to flex leg at the knee and plantar flex at the ankle
- compressed at the ankle as it courses through the tarsal tunnel adjacent to the medial malleolus (tarsal tunnel syndrome)-->pain and parethesia in the sole of the foot
what is the course of the fibular nerve and what does it innervate?
emerges from the pelvis with the tibial nerve inferior to the piriformis muscle in sciatic nerve into the posterior thigh
innervates the short head of the biceps femoris in posterior thigh then separates from the tibial at the superior border of the popliteal fossa
courses laterall along the tendon of the biceps femoris and spiral around the neck of the fibula into the lateral leg
enters the fibularis longus muscle and divides into the superficial and deep fibular nerves
where/how is the common fibular nerve commonly lesioned and what are associated symptoms?
frequently lesioned in the lower leg such as when it passes around the neck of the fibula
- footdrop from loss of dorsiflexion at the ankle and loss of eversion
- pain and parethesi in the lateral leg and dorsum of the foot
- with footdrop, may also have steppage gait- raise affected leg high off the ground and foot slaps ground when walking
piriformis syndrome: nerve compressed by piriformis when it passes through it rather than anterior to it with the tibial nerve
what is the course of the superficial fibular nerve and what does it innervate?
innervates the fibularis longus and brevis muscles in the lateral leg
emerges from distal third of lateral leg to innervate skin of the lateral leg and dorsum of the foot (except for the first dorsal webbed space between the great toe and second toe)
where is a common site of supericial fibular nerve lesion and what are associated symptoms?
lesioned as the nerve emerges from the lateral compartment of the leg
pain and parethesia in the dorsal aspect of the foot
what is the course of the deep fibular nerve and what does it innervate?
courses through the fibularis longus muscle and anterior compartment of the leg with the anterior tibial artery
innervates muscles in the anterior compartment of the leg (tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus teritius muscles)
innervates muscles in dorsum of the foot (extensor digitorum brevis and extensor hallucis brevis muscles)
skin of the webbed space between the great toe and second toe
where is a common site of deep fibular nerve lesion and what are associated symptoms?
compressed in the anterior compartment of the leg
footdrop and paresthesia in the skin of the webbed space between the great toe and second toe
what are the collateral nerves of the lumbosacral plexus and their origins?
sural nerve (contributons from tibial and common fibular nerves), nerve to quadratus femoris muscle (L4, L5, S1), nerve to obturator internus muscle (L5, S1, S2), posterior femoral cutaneous nerve (anterior and posterior division fibers from S1-S3), nerve to piriformis muscle (S1-S2), perforating cutaneous nerve (S2-S3)
what is the course of the sural nerve and what does it innervate?
innervates the skin of the posterior leg and lateral foot
courses with the small saphenous vein in the posterior leg
what is the course of the nerve to the quadratus femoris muscle and what does it innervate?
enters the gluteal region after passing through the greater sciatic foramen
innervates the quadratus femoris (duh) and inferior gemellus
what is the course of the nerve to the obturator internus muscle and what does it innervate?
enters the gluteal region after passing through the greater sciatic foramen and innervates the superior gemellus
crosses the ischial spine and through the lesser sciatic foramen to innervate the obturator internus (duh)
what does the posterior femoral cutaneous nerve innervate?
skin of the posterior thigh and upper calf
where does the nerve to the piriformis muscle arise from and what does it innervate?
ventral rami of S1 and S2
innervates the piriformis muscle (duh)
where does the perforating cutaneous nerve arise form and what does it innervate?
ventral rami of S2 and S3
innervates skin covering the ischioanal fossa and gluteal region near the anal canal
what is the only branch of the lumbosacral plexus to contain both anterior division (S2, S3) and posterior division (S1, S2) fibers?
posterior femoral cutaneous nerve
weakness in ability to dorsiflex the foot and altered sensation in skin between the great toe and second toe is caused by lesion in what nerve?
deep fibular/peroneal nerve
altered sensation in skin covering the great saphenous vein in the leg is caused by a lesion in what nerve?
weakness in ability to abduct thigh at the hip is caused by lesion in what nerve?
superior gluteal nerve
a lesion in what nerve would cause weakness of muscles in ability to evert foot and altered sensation in the skin of the dorsal aspect of the foot, but leave ability to extend toes intact?
superficial fibular/peroneal nerve
a lesion in what nerve would cause weakness in ability to extend thigh at the hip when arising from a chair and difficulty walking up stairs, but leaves cutaneous sensation intact?
inferior gluteal nerve
if a patient develops tarsal tunnel syndrome and has weakness in the ability to flex the great toe, what nerve may be lesioned?
when a limb is off the ground during gait, and a patient experiences lateral pelvic tilt toward the unsupported side, what nerve is most likely lesioned?
superior gluteal nerve (gluteus minimus and medius)
a ballet dancer can no longer stand on her "tip toes." what nerve may be lesioned?
*TIP TOES: Tibial Inverts and Plantarflexes allowing one to stand on TOES
weakness in ability to adduct the thigh at the hip is most likely caused by a lesion in what nerve?
obturator nerve (adductors, gracilis)
a lesion in what nerve would be most likely to cause an inability to flex the thigh at the hip and extend the leg at the knee?
femoral nerve (flexion of femur: rectus femoris, sartorius, pectineus; extension of tibia and fibula: quadriceps femoris)
A football player suffers trauma to the lateral part of the leg just distal to the head of the fibula and a nerve is lesioned. What might the patient experience?
A. weakness in ability to plantar flex the foot
B. loss of ability to invert the foot
C. altered sensation in the skin of the medial aspect of the leg
D. altered sensation in the skin of the dorsal aspect of the foot
E. weakened ability to flex the toes
Lesion to the common fibular nerve-->
result in footdrop and altered sensation in the skin of the dorsal aspect of the foot: D
An elderly woman who suffers from osteoporosis falls and "breaks her hip." The orthopedic surgeon recommends that the proximal part of the femur be replaced with a prosthesis because of the likelihood of avascular necrosis of the head of the femur.
What artery supplying the neck and head of the femur might have been lacerated by the fracture?
A. inferior gluteal artery
B. medial circumflex femoral artery
C. pudendal artery
D. profunda femoral artery
E. obturator artery
B. this is the main source of arterial blood supply to the head and neck of the femur
the profunda femoral artery (a branch of the femoral artery which is a branch of the external iliac artery) will give rise to the lateral and medial circumflex arteries that supply the thigh, head and neck of femur, and the hip joint
A traumatic injury to the lateral aspect of a patient's knee tears several structures at the knee joint. An examination reveals a positive anterior drawer sign and a clicking sound when the patient attends to extend the leg at the knee.
Of the following structures, which one was most likely spared from being stretched or torn in this knee injury?
A. medial meniscus
B. tibial collateral ligament
C. fibular collateral ligament
D. anterior cruciate ligament
E. tendon of the sartorius muscle
A lateral blow to the knee will usually injure the terrible triad: ACL, MCL/tibial collateral ligament, medial meniscus
will also tear tendons that cross the medial aspectr of the joint such as the sartorius
least likely, is C which is on the lateral side of the joint
A health care worker inadvertently administers an injection to the gluteal region that results in a lesion to a nerve. The patient begins to walk with an altered gait. Upon raising the left foot off the ground during gait, the patient leans to the right, and when standing on the right foot without leaning, the left buttock seems to sag.
what muscle might have been weakened by the nerve lesion?
A. gluteus maximus
B. gluteus medius
E. quadratus femoris
lesion would be the to superior gluteal nerve
- weakness in ability to abduct thigh at hip and keep pelvis level during gait
- waddling/Trendelenburg gait - pelvis sags on side of unsupported limb because of weakness of gluteus medius muscle
A cross-country runner begins to experience leg and foot pain during and after training for an upcoming season. The pain radiates from the anterolateral leg into the dorsal aspect of the foot. Dorsiflexion and extension of the toes are performed only with pain. The leg appears to be swollen in the area of the pain.
Which of the following arteries may have been compressed by the swelling?
A. popliteal artery
B. anterior tibial artery
C. posterior tibial artery
D. peroneal artery
E. medial plantar artery
courses through the anterior comparment of the leg
A 56-year-old man develops numbness and tingling in the lower limb followed by progressive muscle weakness. You suspect the main's peripheral neuropathy may be a side effect of a drug he is taking. You order a biopsy of a cutaneous nerve in the posterior leg that accompanies the small saphenous vein. Which of the following nerves was biopsied?
B. superficial fibular
E. deep fibular
sural nerve is a cutaneous nerve that innervates the posterior leg
the saphenous nerve supplies the medial leg
superficial fibular supplies the lateral leg
tibial and deep fibular nerves do not have cutaneous branches in the leg