MSK1 Head and Vertebral Column Flashcards
What is the area of junction of four bones within the temporal fossa?
The pterion is the area of junction of four sutures (frontal, temporal, sphenoid, parietal) within the temporal fossa.
Label the structure of the cranium in the anterior and lateral view
Label sutures of the cranium and the cranial base
Label the structures of the cranial base
What are the two major divisions of the cranium?
The two major divisions of the cranium are the neurocranium (cranial vault) and the viscerocranium (facial skeleton).
How many irregular bones form the cranial base?
Fifteen irregular bones form the cranial base.
How many paired bones form the calvaria (skullcap)?
Six paired bones occurring bilaterally form the calvaria.
What is the significance of the pterion?
The pterion is a critical area where four bones within the temporal fossa meet. It is important due to its proximity to the frontal (anterior) branches of the middle meningeal vessels making fractures in this area potentially life-threatening.
what contents of the optic canals?
Optic nerves (CN II) and opthalmic arteries
what contents in the superior orbital fissue?
opthalmic veins, opthalmic nerve (V1), CNs III, IV, VI and sympathetic
what contents are in the foramen ovale?
maxillary nerve (CN V3) and accessory menigeal artery
what contents are in the foramen rotundum?
maxillary nerve (CN V2)
what contents are in the jugular foramen?
CNs IX, X, XI, superior bulb of the internal jugular vein, inferior petrosal and sigmoid sinuses and meningeal branches of ascending pharyngeal and occipital arteries
Name the associated content of the cranial foramina/apeture
Why is the fracture of the pterion be life threatening?
The resulting epidural hematoma exerts pressure on the underlying cerebral cortex.
What is the result of untreated middle meningeal artery hemorrhage?
Untreated middle meningeal artery hemorrhage may cause death in a few hours.
Label the Radiograph of the cranium
What term is used for an indirect traumatic injury that displaces the orbital walls?
“blowout” fracture.
Which sinus may be involved in fractures of the inferior orbital wall?
- Fractures in the inferior orbital wall may involve the maxillary sinus.
- may entrap the inferior rectus muscle, limiting upward gaze.
Which sinus may be involved in fractures of the ** medial wall**?
Fractures of medial wall may involve ethmoidal and sphenoidal sinuses
What can happen if a sharp object penetrates the superior wall of the orbit?
If a sharp object penetrates the superior wall of the orbit it may pass into the frontal lobe of the brain.
What is the medical term for protrusion of the eyeball?
- exophthalmos
- often result of intra-orbital bleeding
What type of joint is the temporomandibular joint (TMJ)?
synovial joint.
Label the structure of the temporomandibular joint (TMJ
What can cause a dislocation of the temporomandibular joint (TMJ)?
- Yawning (excessive contraction of lateral pterygoids) OR taking a large bite ( heads of mandibles to dislocate anteriorly)
- a sideways blow to the chin when the mouth is open (dislocates the TMJ on the side that received the blow)
If a person has a dislocation of TMJ joint then what occurs?
mandible remains depressed and the person may not be able to close the mouth.
If a traumatic dislocation and rupture of the joint capsule and lateral ligament occur, then what happens?
- can lead to injury to auriculotemporal nerve supplying the TMJ and then leads to laxity and instability of the TMJ
what are the layers of scalp?
- Skin
- Connective dense tissue
- Aponeurosis
- Loose connective tissue
- Pericranium
If infection occurs in the loose connective layer, then what occurs?
- Danger area - pus or blood spreads easily through emissary veins/calvaria
can reach intracranial structures e.g. meninges
where can infection/fluid cannot pass in the scalp?
-
into the neck (occipital belly of the occipitofrontalis muscle attaches to the occipital bone and mastoid parts of the temporal bones)
* laterally beyond the zygomatic arches (epicranial aponeurosis continuous with the temporal fascia that attaches to these arches)
where can infection/fluid can pass in the scalp?
- enter eyelids and root of nose (frontal belly of the occipitofrontalis muscle inserts into the skin and subcutaneous tissue, not bone)
- **ecchymoses **(purple patches) develop as a result of blood in subcutaneous tissue and skin of eyelids and surrounding regions.
“black eyes” can result from injury to scalp or forehead
Label the cranial menginges
Label the meninges and venous sinuses in the medial aspect and cross section aspect
Label the dural sinuses
how do Basilar and occipital sinuses communicate through foramen magnum?
via internal vertebral venous plexuses
how does Metastasis of Tumor Cells occur in the Dural Sinuses?
- Because these venous channels are valveless, compression of the thorax, abdomen, or pelvis (e.g. heavy coughing and straining) may force venous blood into dural venous sinuses.
- the infection can move from inferior to superior, since NO restriction by valves and pressure in the body
- Thus, pus in abscesses and tumor cells in these regions may metastasize to the vertebrae and brain.
Why is an epidural hematoma over the pterion life-threatening?
An epidural hematoma over the pterion is life-threatening because it overlies the frontal (anterior) branches of the middle meningeal vessels which lie in grooves on the internal aspect of the lateral wall of the calvaria.
If Fractures of Cranial Base (Basilar) occur then what can happen after?
- Internal carotid artery may be torn, producing an arteriovenous fistula within the cavernous sinus.
- Arterial blood rushes into the cavernous sinus, enlarging it and forcing retrograde blood into its venous tributaries, especially the ophthalmic veins.
As a result, exophthalmos and chemosis) - Because CNs III, IV, V1, V2, and VI lie in or close to the lateral wall of the cavernous sinus, they may also be affected when the sinus is injured (Fig. 8.8).
what is the medical term for “eyeball protrudes”
exophthalmos
what is the medical term for “conjunctiva becomes engorged”
chemosis
what is the phenomenon known as “pulsating exophthalmos”?
The protruding eyeball pulsates in synchrony with the radial pulse
what could happen with a blow to the head?
- A blow to head can detach the periosteal layer of dura from the calvaria without fracturing the cranial bones.
- However, in the cranial base, the two dural layers are firmly attached and difficult to separate from the bones.
If a fracture of the cranial base and tears the dura ocurr then lead to?
results in leakage of CSF
Label the cranial base
Label the structures of ther brain
Label the structures of the coronal and sagittal MRI of brain
What is the CSF flow in the Ventricular system of brain?
- CSF flows from the lateral ventricles then
- to the third ventricle via the foramen of Monro then
- it flows across the cerebral aqueduct of Sylvius to the fourth ventricle then
- to the subarachnoid space through the apertures of Magendie and Luschka
What is the condition called when there is an excess of cerebrospinal fluid (CSF) in the ventricles?
hydrocephalus (water on the brain)
what are the causes of hydrocephalus?
- Overproduction of CSF, obstruction of its flow, or interference with its absorption results in an excess of CSF in the ventricles.
- Excess CSF dilates the ventricles; thinning the surrounding brain; and, in infants, separates the bones of the calvaria because the sutures and fontanelles are still open
- Can also occur in adults, without macrocephaly symptom.
In infants and young childen with hydrocephalus, why do head enlarges?
In infants, separates the bones of the calvaria because the sutures and fontanelles are still open, and the excess of the CSF leads to the enlargement of the head
What is the result of severe untreated hydrocephalus in infants and young children?
In severe cases of untreated hydrocephalus in infants and young children the head enlarges due to the accumulation of excess CSF and may result in nerve damage, vision loss and even death.
What is the term for the thinning of the surrounding brain due to excess CSF?
macrocephaly
what are types of Intracranial Hemorrhages?
- epidural hematoma
- subdural hematoma
- subarachnoid hematoma
what type of hemorrhage results from an arterial in origin and torn branches of the middle meningeal artery?
**Epidural hematoma **
* arterial in origin
* torn branches of middle meningeal artery
* brain compressed as blood mass increases, necessitating evacuation of blood and occlusion of bleeding vessels.
which type of hemorrhage results from usually venous origin and tearing of a superior cerebral vein?
Subdural hematoma
* typically venous in origin and commonly results from tearing of a superior cerebral vein bridging in as it enters the superior sagittal sinus.
* no naturally occurring space at the dura–arachnoid junction (thus correct term Dural border hemorrhage)
* extravasated (escaped) blood splits open dural border cell layer, creates a space at the dura–arachnoid junction
* usually follows a blow to the head that jerks and injures brain inside cranium
* hematoma may develop over many weeks from venous bleeding.
Which type of hemorrhage results from rupture of a saccular aneurysm or head trauma involving cranial fractures/cerebral lacerations/meningeal irritation?
Subarachnoid hemorrhage
* extravasation of blood, usually arterial, into subarachnoid space
* often result from rupture of a saccular aneurysm (sac-like dilation on an artery).
* some associated with head trauma involving cranial fractures and cerebral lacerations, or meningeal irritation
Identify what hemorrhage in the imagings
what muscles are involved with pulling the mouth
- Zygomaticus minor
- Zygomaticus major
what are the muscles involved with smiling?
- Zygomaticus major
- Zygomaticus minor
- Levator labii superioris
- Risorius
what muscles are involved with mastication?
- Temporalis and masseter muscles.
- Temporalis muscle.
- Lateral and medial pterygoid muscles
What muscles put the lips together?
Orbicularis oris
What are the Innervation, branches of facial nerve (CN VII)?
- The facial nerve is associated with the derivatives of the second pharyngeal arch:
- Motor – muscles of facial expression, posterior belly of the digastric, stylohyoid and stapedius muscles.
- Sensory – a small area around the concha of the external ear.
- Special Sensory – provides special taste sensation to the anterior 2/3 of the tongue via the chorda tympani
- Parasympathetic – supplies many of the glands of the head and neck, including:
Submandibular and sublingual salivary glands.
Nasal, palatine and pharyngeal mucous glands.
Lacrimal glands.
what muscles are involved with the facial nerve (CNVII)?
- frontalis
- orbicularis oculi
- buccinator
- orbicularis oris
- platysma
- the posterior belly of the digastric
- stapedius muscle
What are Zygapophysial (facet) joints representative of?
They are representative of each region of the vertebral column
* cervical
* thoracic
* lumbar
* sacrum
* coccyx
Where can lordosis occur?
Cervical and lumbar spines
where can kyphosis occur?
thoracic and sacral spine
what is excessive thoracic kyphosis?
- abnormal increase in the thoracic curvature
- can result from erosion of anterior part of one or more vertebrae.
- progressive erosion and collapse of vertebrae results in an overall loss of height.
- widows hump colloquial kyphosis in older women from osteoporosis
- however, occurs in geriatric people of both sexes
what is excessive lumbar lordosis?
- abnormal increase in the lumbar curvature
- associated with weakened trunk musculature, especially of the anterolateral abdominal wall.
- women develop a temporary lordosis during late pregnancy.
what is scoliosis?
- abnormal lateral curvature accompanied by rotation of the vertebrae
- spinous processes turn toward the cavity of the abnormal curvature.
- common deformity of the vertebral column in pubertal girls
- causes include asymmetric weakness of the intrinsic back muscles (myopathic scoliosis), failure of half of a vertebra to develop (hemivertebra), and a difference in the length of the lower limbs are causes of scoliosis.
what is the function of the lamina?
the roof of the spinal canal that provides support and protection for the backside of the spinal cord
what is the pedicle?
Each vertebra has two cylinder-shaped projections (pedicles) of hard bone that stick out from the back part of the vertebral body, providing side protection for the spinal cord and nerves. The pedicles also serve as a bridge, joining the front and back parts of the vertebra
what is the function of the intervetbetral (IV) foramen?
the doorway between the spinal canal and periphery. It lies between the pedicles of neighboring vertebrae at all levels in the spine
Label the structures of the second lumbar vertebra
what is spinal stenosis?
- Stenotic (narrow) vertebral foramen in one or more lumbar vertebrae
- May cause compression of one or more spinal nerve roots occupying the vertebral canal.
- May be a hereditary anomaly that can make a person more vulnerable to age-related degenerative changes, such as IV disc protrusion, further compromising the size of the vertebral canal
- also note that lumbar spinal nerves increase in size as the vertebral column descends, but the IV foramina decrease in size.
what is treatment of spinal stenosis?
- Surgical treatment may consist of decompressive laminectomy
what is laminectomy?
- Surgical excision of one or more spinous processes and their supporting laminae (#1)
- Term also commonly used to denote removal of most of the vertebral arch by transecting the pedicles (pediculectomy) (#2)
- Provides access to vertebral canal to relieve pressure on spinal cord or nerve roots, commonly caused by a tumor, herniated IV disc, spinal stenosis, or bony hypertrophy
Label the structures of the cervical vertebrae and radiograph
what occurs in the Rupture of Transverse Ligament of Atlas?
When the transverse ligament of the atlas ruptures, the dens is set free, resulting in atlanto-axial subluxation or incomplete dislocation of the median atlanto-axial joint
if complete dislocation of the atlas occurs then what happens as a result?
- When complete dislocation occurs, the dens may be driven into the upper cervical region of the spinal cord
- pressure on the spinal nerves of the cauda equina or the medulla of the brainstem is called atlanto-axial subluxation.
- causing quadriplegia, or into the medulla of the brainstem, causing death.
what are can occur with fracture of atlas?
- Vertical forces (e.g. striking bottom of pool in diving accident) compresses the lateral masses between the occipital condyles and the axis drive them apart, fracturing one or both of the anterior or posterior arches (Fig. B2.4A).
- If the force is sufficient, rupture of the transverse ligament that links them will also occur
- The resulting Jefferson or burst fracture in itself does not necessarily result in spinal cord injury because the dimensions of the bony ring actually increase.
- Spinal cord injury is more likely, however, if the transverse ligament has also been ruptured
Label the structures in the radiograph
Lateral neck radiograph.
A: Spinous process of the C7 vertebra (vertebra prominens)
B: Spinous process of the C1 vertebra (atlas)
C: Anterior aspect of C2 vertebral body (axis)
D: Epiglottis
E: Hyoid bone
F: Thyroid cartilage
G: Trachea
Label the structures of the thoracic vetebrae
what is Vertebral body osteoporosis?
- Common metabolic bone disease
- Results from a net demineralization of the bones caused by a disruption of the normal balance of calcium deposition and resorption (covered in physiology).
- Affects the entire skeleton but most affected areas are the neck of the femur, the bodies of vertebrae, the metacarpals and the radius.
- These bones become weakened and brittle and are subject to fracture
- Demineralization - diminished radiodensity of the trabecular (spongy) bone of the vertebral bodies, causing the thinned cortical bone to appear relatively prominent
- Especially affects trabecular bone of the vertebral body (see Fig. B2.9A). Loss of the horizontal supporting trabeculae results in thickening of the vertical struts (Fig. B2.7A)
- Later stages x-rays reveal vertebral collapse (compression fractures) and increased thoracic kyphosis
- Vetebral body osteoporosis occurs in all vertebrae but is most common in thoracic vertebrae and is an especially common finding in postmenopausal females
what is ankylosing spondylitis?
- Inflammatory disease
- Over time can cause vertebrae to fuse, makes the spine less flexible and can result in a hunched posture.
- If ribs are affected, it can be difficult to breathe deeply.
- When condition is found on X-ray, it is called ankylosing spondylitis,
- When condition can’t be seen on X-ray but is found based on symptoms, blood tests and other imaging tests, it is called nonradiographic axial spondyloarthritis.
- Symptoms typically begin in early adulthood.
- There is no cure for ankylosing spondylitis, but treatments can lessen symptoms and possibly slow progression of the disease.
Label the lumbar vertebrae
What is the most common congenital anomaly of the vertebral column?
- spina bifida occulta
- Laminae (embryonic neural arches) of L5 and/or S1 fail to develop normally and fuse.
- Present in up to 24% of people, is concealed by skin, but its location is often indicated by a tuft of hair.
- Most people with spina bifida occulta have no back problems
What is the term for a herniation of the meninges (meningocele) and/or the spinal cord (meningomyelocele) through the vertebral arches?
- spina bifida cystica
- Usually, neurological symptoms are present in severe cases of meningomyelocele (e.g. paralysis of limbs and disturbances in bladder and bowel control).
What are the conditions known as when one or more vertebral arches almost completely fail to develop resulting in herniation of the meninges and/or spinal cord?
spina bifida cystica.
What condition can result from fractures of the interarticular parts of the vertebral laminae of L5?
Spondylolysis
What is the term for the forward displacement of the L5 vertebral body relative to the sacrum?
- spondylolisthesis
- Spondylolisthesis at the L5–S1 articulation may result in pressure on the spinal nerves of the cauda equina as they pass into the superior part of the sacrum, causing back and lower limb pain
- The intrusion of the L5 body into the pelvic inlet reduces the anteroposterior diameter of the pelvic inlet.
what is a commonality of Spondylolysis and spondylolisthesis?
both occur in the lumbar spine
What may spondylolisthesis at the L5–S1 articulation result in?
Spondylolisthesis at the L5–S1 articulation may result in pressure on the spinal nerves of the cauda equina causing back and lower limb pain.
what is the C3-C7 distinctive body characteristics?
Small, wider side to side
Sup.concave
Inf.convex
What is the thoracic distinctive body characteristics?
Heart shaped, costal facets
what is the lumbar distinctive body characteristics?
Massive, kidney-shaped when viewed superiorly
what is the C3-C7 distinctive transverse processes?
Transverse foramina for vertebral a. (not in C7); ant and post. tubercles
what is the thoracic distinctive transverse processes?
Long, strong, posterolateral; length diminishes from T1-T12
what is the lumbar distinctive transverse processes?
Long, slender; accessory process on post. surface of base
what is the thoracic distinctive spinous process?
Long and slender, slope posteroinf., extend to inferior body
what is the lumbar distinctive spinous process?
Short and sturdy; thick, broad, hatchet-shaped
