SSN Anatomy #1 - KEY
Abby Pease (arp2002) & Matthew Maserati (mbm2004)
September 25, 2002
FEELING, BREATHING, PUMPING
1. ORGANIZATION OF THE SPINAL CORD AND ASSOCIATED STRUCTURES
On the following diagram, label and draw in pathways for somatic afferent, visceral afferent,
somatic efferent, parasympathetic, and sympathetic nervous systems. Be sure to label:
dorsal / lateral / ventral horns, dorsal / ventral roots, dorsal root ganglion, white / gray rami
communicantes, sympathetic chain, paravertebral ganglion, prevertebral ganglion,
splanchnic nerve, and spinal nerve.
2. MOTOR INNERVATION OF LUNGS AND HEART
Complete the following table:
Innervation /function Lungs
Heart
Sympathetic
THORACIC SPLANCHNIC BRANCHES
FROM SYMPATHETIC CHAIN.
CERVICAL SPLANCHNIC N.,
THORACIC SPLANCHNIC N.
Symp. Function
VASOCONSTRICTION, SECRETOMOTOR
ACTIVITY OF BRONCHIAL GLANDS
ACCELERATE HEART RATE,
INCREASE STROKE VOLUME
Parasympathetic
VAGUS N.
VAGUS N., RECURRENT LARYNGEAL
BRANCHES
Parasymp. Function
BRONCHIAL SM. MUSC, RESPIRATORY
REFLEX AFFERENTS
SLOW HEART RATE AND REDUCE
STROKE VOLUME
Finish the sentence. Sympathetic innervation is (adrenergic/cholinergic), and
parasympathetic innervation is (adrenergic/cholinergic)
Adrenergic (uses noradrenaline); cholinergic (uses acetylcholine)
3. What is REFERRED PAIN?
Pain felt at a specific dermatome that is of visceral origin. It is referred to the somatic
dermatome associated with the particular spinal level that received the visceral
afferent nerve.
Where is it possible to have referred pain as a result of pleurisy (inflammation of the lung
pleura)? [hint: what innervation does the diaphragm receive?]
C3-C5 dermatomes (neck & shoulder). Early in development, part of the diaphragm
forms in the neck region. Later, when it descends into the abdomen, it drags its
innervation (the phrenic nerve) with it. Intercostal nerves T6-T11 innervate the
diaphragm at the costal margin, and pain is referred to these dermatomes too.
4. What is the significance of LANGER’S LINES?
Connective tissue bundles in the dermis have a prevailing directionality. Cut parallel
to them ⇒ minimal scarring. Cut perpendicular to them ⇒ gaping wound.
5. LYMPHATICS
Complete the following tables:
Portion of breast
Lateral / inferior (75% of breast tissue)
Medial
Superior
Superficial
Organ
Bronchi, Trachea
Hilus of Lung
Esophagus
Posterior IC Spaces
Anterior IC Spaces
Lymphatic Drainage
AXILLARY NODES
PARASTERNAL NODES
SUPRACLAVICULAR NODES
CONTRALAT. BREAST / ANT. ABDOMINAL WALL
Nodal Drainage
Entrance into Systemic Venous Circulation
BRONCHOMEDIASTINAL
HILAR
PRE-AORTIC
PARA-AORTIC
PARASTERNAL
(R/L) BRACHIOCEPHALIC VEIN
(R/L) BRACHIOCEPHALIC VEIN
THORACIC DUCT → L BRACHIOCEPHALIC V.
THORACIC DUCT → L BRACHIOCEPHALIC V.
(R)R LYMPHATIC DUCT, (L)THORACIC DUCT
6. MUSCLES OF RESPIRATION
Complete the following table:
Type of breathing
Muscles responsible
Relaxed Inspiration
EXTERNAL INTERCOSTALS, INTERCHONDRAL PORTION OF INTERNAL
INTERCOSTALS, DIAPHRAGM (Externals Elevate the ribs)
Relaxed Expiration
NONE (PASSIVE RECOIL OF RIB CAGE AND PULMONARY COMPLIANCE
OF LUNGS)
Forced Inspiration
ALL MUSCLES OF RELAXED INSPIRATION + PECTORALIS
MAJOR/MINOR, STERNOCLEIDOMASTOID, SCALENES
Forced Expiration
INTERNAL INTERCOSTALS, TRANSVERSUS THORACIS, QUADRATUS
LUMBORUM (stabilizes 12th rib), ABDOMINAL MUSCLES
MUSCLES OF RESPIRATION (Continued)
Fill in the blanks: (see diagram in April, p.247)
Synergist muscles act on the same side of the axis of rotation or are perpendicular to
each other on the opposite side of the axis of rotation. Antagonist muscles act on the
opposite side of the axis of rotation or are perpendicular to each other on the same
side of the axis of rotation.
7. MECHANICS OF INSPIRATION
Complete the following table:
Aspect of inspiration
Increase in which diameter (transverse or anteroposterior)?
“Bucket-handle” effect
TRANSVERSE THORACIC
“Pump-handle” effect
ANTERIOR-POSTERIOR
Rotation effect
TRANSVERSE THORACIC
The bucket-handle effect is due to elevation of the ribs as they rotate upwards in
inspiration. The pump-handle effect is due to elevation of the sternum as a result of
upward rotation of the crossed axes. The rotation effect is due to rotation of the ribs
(which are concave on their interior surface) on inspiration.
8. BREATHING DIFFICULTIES
Why is breathing more difficult for the elderly? How do they (and children) compensate for
this?
Calcification of costal cartilages ⇒ reduced thoracic compliance.
Both elderly and children tend to breathe diaphragmatically (vs. costal breathing).
What type of breathing do obese people favor and why?
Obese people, persons wearing girdles or corsets, and women in advanced
pregnancy cannot effectively contract the diaphragm and therefore favor costal
ventilation.
If a patient is bed ridden and having difficulties breathing, name one simple, non-invasive
procedure you could perform to help. Why is this procedure so successful?
Sit her up in bed. Gravity will pull down on abdominal organs, decreasing resistance
on diaphragm.
9. PLEURAL RECESSES
What are pleural recesses and name the two of them?
Potential spaces between the parietal and visceral pleura filled by a thin layer of fluid.
Costomediastinal and L&R costodiaphragmatic.
What might you find in them in a pathological situation?
Air (pneumothorax), Blood (hemothorax), Lymph (chylothorax), Pus (pylothorax)
Where do you tap a patient with hemothorax to sample the fluid and why?
Posterior to midaxillary line above ICS 9 (to avoid liver) but 1-2 ICS’s below fluid level
and just above superior surface of rib (to avoid neurovascular bundle).
Complete the following table:
Type of
Symptoms
pneumothorax
Consequences
Sucking
Mediastinal
flutter
Lung collapse b/c fluid monolayer gone ⇒ ↓ vent/perfusion of
lung in affected side ⇒ cyanosis
Tension
Mediastinal shift
Same as above but ↓ vent/perfusion of both lungs since air
that enters pleural space doesn’t leave ⇒ ↑ pressure ⇒
compression of unaffected lung
10. STRUCTURE OF THE LUNG AND CLINICAL CONSEQUENCES
Contrast the size and shape of the Right and Left Lung.
R: 3 lobes (vs. 2 on left), greater capacity, wider and shorter (b/c of liver, and more of
heart being on left side)
What are the differences in shape and position of the left and right main stem bronchi and
what clinical significance does this have?
The right main stem bronchus is shorter, wider, and MORE VERTICAL than the left. It
is the probable resting place for large aspirated objects. Specifically, the right lower
lobar bronchus is the most vertical division of the right main stem bronchus, and
small aspirated objects will likely rest here.
What section of the lung is most likely to be involved in aspiration pneumonia (Mendelson’s
syndrome)?
Superior segmental bronchi of both lobes because they face posteriorly when a
person is lying down.
STRUCTURE OF THE LUNG AND CLINICAL CONSEQUENCES CONTINUED
What is a Pancoast tumor and what are its clinical sequelae?
A lesion of the upper lobe of either lung. It may compress:
a) Subclavian or brachiocephalic vein ⇒ ipsilateral venous engorgement / edema
of face/arm
b) Subclavian artery ⇒ diminished pulse in ipsilateral arm
c) Phrenic nerve ⇒ compression results in paralysis of a hemidiaphragm
d) Recurrent laryngeal nerve ⇒ compression results in vocal horseness
e) Sympathetic chain ⇒ compression results in Horner’s syndrome (miosis,
pseudoptosis, anhydrosis)
What structures would be found at the hilus of the lung?
Main stem bronchus, pulmonary artery, pulmonary veins, bronchial lymphatics,
bronchial arteries, hilar lymph nodes.
What are the main components of a bronchopulmonary segment?.
Segmental bronchus, segmental artery, intersegmental veins.
11. JOINTS
Joint Type
Movement (Y/N)
Examples
Synarthrosis
No
Sagittal suture, tibiofibular joint
Amphiarthrosis
Yes (limited)
Pubic symphisis, intervertebral discs
Diarthrosis
Yes (free)
Shoulder, elbow, wrist joints
12. DIAPHRAGMATIC HIATUS
Complete the following table:
Hiatus
Structures transmitted
Location
Aortic
Aorta
Thoracic duct
Azygos vein
Midline, between crura (T12)
Esophageal
Esophagus
Left & right vagus nerves
Slightly left of midline (T10)
Caval
Inferior vena cava
Branches of right phrenic nerve
On right, in tendinous portion (T8)
13.
CARDIAC CYCLE
14. FETAL CIRCULATION
Complete the following table:
Prenatal
Shunts blood
Circulatory
from:
Anatomy
Shunts blood
to:
Umbilical Veins
MOTHER VIA
UMBILICUS
Ductus Venosus
Foramen Ovale
Ductus
Arteriosus
Umbilical
Arteries
UMBILICAL VEIN
R. ATRIUM
PORTAL V./
DUCTUS
VENOSUS
INF. VENA CAVA
L. ATRIUM
L. PULMONARY
ARTERY
AORTA
L/R INTERNAL
ILIAC ARTERIES
MOTHER VIA
UMBILICAL
ARTERIES
13. CARDIAC MALFORMATIONS
Complete the following table:
Defect
R Auricular
Appendage
L Auricular
Appendage
Cardiac
Homologous adult structure
LIGAMENTUM TERES
LIGAMENTUM VENOSUM
FOSSA OVALIS (PULMONARY SHUNT)
LIGAMENTUM ARTERIOSUM (PULMONARY
SHUNT)
PROXIMAL: SUPERIOR VESICULAR
ARTERIES (TOP OF BLADDER)
DISTAL: MEDIAL UMBILICAL LIGAMENTS
Vascular Pathology
Sequelae
POTENTIAL SITE OF THROMBI
FORMATION
PULMONARY EMBOLISM
POTENTIAL SITE OF THROMBI
FORMATION
SYSTEMIC, CEREBRAL
EMBOLISM
Atrial Septal Defect
PATENT FOSSA OVALIS
Small VSD
INCOMPLETE INTERVENTRICULAR
SEPTUM
INCOMPLETE INTERVENTRICULAR
SEPTUM AND PULMONARY
ARTERY STENOSIS
A. VSD ALLOWS
INTERVENTRICULAR
COMMUNICATION
B. ↑ PRESSURE IN LV
TRANSMITTED TO RV CAUSING
RV HYPERTROPHY
C. HYPERTROPHY OF
SUPRAVENTRICULAR CREST
CAUSES PULM. STENOSIS AND
FORCES BLOOD THROUGH TO
THE LV
VSD w/ pulmonary
artery stenosis
Ventricular
Septal
Tetralogy of Fallot
ASYMPTOMATIC: L→R
SHUNT B/C L ATRIAL
PRESSURE > R ATRIAL
PRESSURE
ASYMPTOMATIC L→R
SHUNT
R→L SHUNT LEADING TO
CYANOSIS
THE FUNCTIONAL
OCCLUSION OF THE
PULMONARY OUTFLOW
TRACT FORCES A R→L
SHUNT SENDING
DEOXYGENATED BLOOD
TO THE LV AND THEN
INTO THE AORTA.
14. VALVE DEFECTS
Complete the following table:
Type of Valve Pathology
Atypical Sounds
Pitch
Atrioventricular
INSUFFICIENCY
SYSTOLIC MURMUR
LOW PITCHED
Atrioventricular
STENOSIS
DIASTOLIC MURMUR
LOW PITCHED BEFORE 1ST HEART SOUND
Semilunar
INSUFFICIENCY
DIASTOLIC MURMUR
Semilunar
STENOSIS
SYSTOLIC MURMUR
HIGH PITCHED
15. CORONARY CIRCULATION
Complete the following table.
Variation
Balanced (60-65% of the population)
Left Preponderant (10-15%)
Right Preponderant (20-25%)
Arterial Supply
RCA gives off posterior descending
branch, supplying the septum but not
significantly supplying the left ventricle.
Circumflex artery gives rise to the posterior
descending branch, so that both arteries
supplying the septum arise from the same
stem Æ lower chance of survial w/infarct
RCA reaches into typical distribution of the
circumflex artery, supplying a substantial
portion of the left ventricle.
15. CLINICAL QUICKIES AND OTHER QUICKIES
What spinal nerve innervates the nipple?
T4
The umbilicus? T10 .
How can you diagnose a breast tumor by observation only?
Breast will dimple due to compression of suspensory ligaments of Cooper, which
connect skin to Scarpa’s fascia and separate lobes.
What happens to the costal groove with coarcation with the aorta?
Narrowing of descending aorta leads to decreased blood flow through aorta and
posterior intercostals arteries, which must be compensated for by increased blood
flow through the internal thoracic artery and anterior intercostals arteries. Therefore,
scalloping of ribs occurs due to expansion of intercostals arteries.
What are the two routes used to perform pericardiocentesis?
Subcostal: needle into sternocostal angle (rib/xiphoid), angle up at 45° and L. (avoid
marginal br. of RCA and avoids pleural cavities.
Parasternal: into L 4th or 5th ICS adjacent to sternum, avoiding Int. Thoracic Artery,
Ant. Interventricular Artery, and pulmonary pleura (cardiac notch).
What are the first arteries off the aorta, and when does blood flow through them?
R/L Coronary arteries. Only during diastole.
What veins of the heart DO NOT drain into the coronary sinus?
Anterior Cardiac Veins (directly into RA), Thebesian (least cardiac) Veins (into closest
chamber of heart.)
What is the function of the papillary muscles?
Tighten chordae tendinae to prevent eversion of valve cusps (NOT to close valves.)
What is the Bundle of Kent and what is its clinical significance?
Abnormal muscle bridge (modified cardiac tissue) electrically connecting the atria
and the ventricles. Excitatory impulses bypass the A-V node disrupting the normal
synchonry of the heart.
The Left brachiocephalic artery…
Does not exist.
Esophageal varices are often associated with what condition?
Portal hypertension caused by diseased liver.
Finish the sentence. Cervical spinal nerves exit just (above/below) the corresponding
vertebrae; thoracic spinal nerves exit just (above/below) the corresponding vertebrae.
Cervical spinal nerves exit just above the corresponding vertebrae, i.e. 3rd cervical
spinal nerve emerges through the intervertebral foramen between cervical vertebrae 2
& 3. One exception is the 8th cervical spinal nerve, which exits between the 7th
cervical vertebra and the 1st thoracic vertebra. Thoracic spinal nerves exit just below
the corresponding vertebrae, i.e. 3rd thoracic spinal nerve emerges through the
intervertebral foramen between thoracic vertebrae 3 & 4.