CLINICAL CORRELATES Flashcards
How does a burst fracture of C1 typically occur? Why does it not necessarily result in spinal cord injury?
Happens when the lateral masses of C1/atlas are squeezed b/w the occipital condyles of the cranial base and C2, because of severe vertical forces
Burst fracture = break in anterior and posterior arches and potential rupture of transverse ligament holding the dens to the facet for dens
No spinal cord injury b/c breaking the arches widens the vertebral foramina
Why are the skin & edges of the platysma carefully sutured during repair of neck wounds?
If it’s not done, the platysma is distracted and stretches the skin in various directions, leaving ugly scars on the skin
Where can infections b/w the investing fascia & muscular part of the pretracheal fascia spread?
Up to the superior margin of the sternal manubrium
Where can infections b/w the investing fascia & visceral part of the pretracheal fascia spread?
Can go into the middle mediastinum anterior to the pericardium
What are symptoms of a retropharyngeal abscess?
Difficulty swallowing (dysphasia) & difficulty speaking (dysarthria) because it will press on the esophagus and the trachea which are located in the visceral part of the pretrachia fascia
What are the common causes & symptoms of congenital torticollis?
Causes: Lesion/fibrous tissue tumor in the SCM
Symptoms: Constant tilting of the head to the ipsilateral side and rotation of face to the contralateral side
What 4 diagnostic signs can be indicated by prominence of the EJV?
This means there is high venous pressure
- blocked SVC
- Heart failure
- Enlarged supraclavicular LN
- Increased intrathoracic pressure
How is backflow into the IJV prevented when intrathoracic pressure is increased or when standing on one’s head?
The inferior portion of the IJV has the INFERIOR BULB OF THE IVJ which contains a bicuspid valve that prevents backflow
Why do cervical sympathetic ganglia not receive white communicating rami?
This is only found from T1-L2 b/c those are the only locations that have a lateral horn
Also, these cervical sympathetics are all postsynaptic sympathetics while the thoracic and lumbars are presynaptic and thus have white communicating rami
How do postsynaptic sympathetic fivers from the cervical ganglia reach the cervical spinal nerves, the thoracic viscera, viscera of head & neck, and the intracranial cavity?
Cervical spinal nerves: Gray rami communicans
Thoracic viscera: cardiopulmonary splanchnic nerves
Viscera of head/neck + intracranial cavity: cephalic arterial branches
Why do ipsilateral vasodilation & anhydrosis in the face and neck occur after unilateral sympathetic trunk injury?
Sympathetics are needed for constriction of most things
w/ the damage you have unopposed parasympathetics and this means that you have vasodilation and excessive sweating (anhydrosis) from unregulated sweat glands
HORNER’S SYNDROME!
How do thyroglossal duct cysts develop? Where are they typically located?
Cysts form from remnants of the thyroglossal duct that has not been cleared away
Found all along the path of descent for the thyroid gland but specifically IN THE ANTERIOR PORTION OF THE NECK, CLOSE OR JUST INFERIOR TO THE BODY OF THE HYOID BONE
Where is aberrant thyroid glandular tissue typically located?
- Anywhere along the path of the thyroglossal duct
- Root of the tongue (posterior to the foramen cecum)
- Next to or just inferior to the body of the hyoid bone
Why are the inferior parathyroids susceptible to ectopic location in the thymus?
Both are derived embryonically from the endodermal 3rd pharyngeal pouch and they travel down together
What are lateral cervical cysts?
These are remnants of the cervical sinus that can be found below the angle of the jaw
How are lateral cervical cysts & thyroglossal cysts distinguished during physical examinations? How are the thryoglossal cysts & cancerous thyroid nodules distinguished?
Lateral cervical cysts = below the angle of the mandible
Thyroglossal cysts = often next to or inferior to the hyoid bone of anterior neck
Cancerous thyroid nodules = inferolateral to the thyroglossal cysts around the 2nd and 3rd laryngeal cartilage rings
What is goiter? Why does hypertrophy of follicular epithelium occur w/ graves disease?
Goiter is just an enlargement of the thyroid gland and can be due to many different diseases
Grave’s Disease = type of autoimmune where antibodies bind to the TSH receptors on follicular cells of the thyroid and chornically overstimulate —> LEADS TO HYPERTROPHY
What is the usual cause of primary hyperparathyroidism? Why do kidney stones result?
Primary cause = adenoma of one or more parathyroid glands
Kidney stones occur b/c the parathyroid secretes calcitonin to increase blood calcium levels by increasing osteoclastic activities…thus more calcium in blood = more calcium in filtrate and more calcium being reabsorbed —> FORMS kidney stones!
Why can thyroidectomy be fatal?
The parathyroid glands are found on the posterior end of the thyroid gland…if you undergo this procedure, then you can potentially remove the parathyroid hormone
Thus you’ll have low blood calcium = TETANY (a neurological syndrome where you have muscle spasms and twicthing)
Tetany of your respiratory and laryngeal muscles can be fatal
What are the functions of sutures & fontanelles? What is the value of postnatal palpation of the anterior fontanelle?
Function: help bones to overlap so that head can be squeezed through at birth and then after, allows the head to grow as big as needed
Postnatal palpation –> done to check if the cranial bones are ossifying correctly & to check for intracranial pressure
How is brain development affected by premature closing of the sutures and fontanelles and ensuing cranial malformations?
IT’S NOT AFFECTED!
Why do infants have large calvaria & rudimentary development of the face?
The calvaria or skull cap undergoes precocious development that makes it bigger than the face and also makes the face look smaller than it actually is
Why is the loose connective layer the “danger are of the scalp”?
The loose connective tissue allows for pus or bacteria or blood to spread easily
Via small emissary veins can spread into the cranial cavity and reach structures like the meninges
Which peripheral branch of the trigeminal ganglion is most commonly affected by neuralgia?
Maxillary nerve (CN V2), then mandibular (CN V3), and finally ophthalmic (CN V1)
When are infraorbital nerve blocks employed? What is the probable consequence of a careless injection?
These are used when you are treating wounds in the upper lip or cheek or repairing incisors of the maxilla
If you mess up, can enter the orbit and thus temporarily paralyze the extraocular muscles
What is an ophthalmic herpes zoster? Symptoms?
A viral infection that creates lesions along the ophthalmic nerve (CN V1) and leads to the formation of vesicles along the entire path of the nerve
Symptoms: Corneal ulceration &/or corneal scarring
Why is the facial nerve susceptible to injury during forceps delivery of a newborn?
In newborns the mastoid process of the temporal bone is yet to be fully developed. Thus the facial nerve isn’t protected and can be easily damaged by the location of the forceps around the skull if too close to the stylomastoid foramen
Why do patient’s with Bell’s Palsy frequently dab the affected eye & corner of the mouth & have difficulty chewing & speaking?
In Bell’s Palsy you have damage to the facial nerve (CN VII) and can lead to paralysis of the facial nerves
Dabbing corner of affected eye = orbicularis occuli…loss of tonus causes the inferior eyelid to evert and lacrimal fluid isn’t spread around evenly and can be drained improperly
Dabbing corner of mouth = orbicularis oris + buccinator can let food collect in oral vestibule
Difficulty chewing & speaking= weak muscles of the lips makes this difficult to do
What is the most common nontraumatic cause of facial nerve palsy? When is recovery from facial paralysis remote?
Inflammation of the facial nerve as it passes through the stylomastoid forament
Recovery is remote if the nerve is sectioned or severed
Why can scalp lacerations be fatal?
You have a lot of anastomoses here and thus the arteries and vessels can bleed from both ends