Interval 1 Flashcards
where does clavicle articulate?
manubrium medially and acromion process of scapula laterally
location of suprasternal notch
superior margin of the manubrium of the sternum
what is the most frequently broken bone?
clavicla because it is the only bone that transmits forces directly from the upper limb to the thorax
significance of the sternal angle
1) ridge at junction of the manubrium and the body of the sternum
2) marks the level of articulation of the second rib with the sternum
3) transverse plane passing through the sternal angle will pass through the intervertebral disk between 4 and 5th thoracic vertebrae
4) marks position where: 1) trachea bifurcates into right and left bronchi w/in the thoracic cavity; 2) arch of aorta begins and ends; 3) SVC penetrates the pericardium to enter the heart
how many ribs do we have?
12
How do we classify the ribs?
7 true (articulate individually via their costal cartilages with the sternum) 8-10 are "false"--> costal cartilages that articulate with a more superior costal cartilage and contribute to the costal margin 11 and 12 are called "floating" because they do not articulate with the sternum or with the transverse process of thoracic vertebrae (they are embedded in musculature of the abdominal wall)
what rib articulates with the sternal angle?
2nd rib!
what are the spaces between the ribs and how are they named?
intercostal spaces and named for the rib above
3 parts of sternum
1) manubrium
2) body
3) xiphoid process
notes about manubrium:
contains the jugular notch, articulates with the medial end of each clavicle at the sternoclavicular joins, and articulates with costal cartilages of the first two ribs
notes about body of sternum:
body articulates with the manubrium at the sternal angle
costal cartilage of second rib articulates that the sternal angle
costal cartilages of ribs 3-7 articulate with the body inferior to the sternal angle
notes about xiphoid process:
articulates with the body and provides an attachment site for the diaphragm and the abdominal musculature
lowest of the anterior thoracic midline bony structures
thin, cartilaginous inferior end of the sternum
costal margin
lower boundary of thoracic cage and is formed by cartilages or ribs 7-10 as well as by the 11 and 12th rib laterally
iliac crest
superior margin of the pelvic bones
where does the iliac crest end anteriorly
Anterior superior iliac spine
highest point of iliac crest corresponds to what vertebrae
L4 (imp. for administering spinal anesthesia and performing a lumbar puncture)
where do costal margins end?
L3
skin is composed of which two layers?
epidermis (stratified squamous epithelium)
dermis (loose connective tissue and dense irregular connective tissue)
where is the superficial fascia?
aka hypodermis
immediately deep to the skin
composed of loosely packed, randomly oriented collagen fibers and fat cells and gives the skin mobility
what courses in superficial fascia?
superficial arteries, veins, lymphatics and nerves
what is below the superficial fascia?
deep fascia!
present as a series of membranous sheets of connective tissue of varying density that intimately invest muscle, bone, neurovascular structures, and/or surround organs
2 divisions of the nervous system
CNS and PNs
two divisions of PNS
1) somatic nervous system
2) autonomic nervous system
Do sensory nerves of the SNS and ANS have similar structures and courses?
yes
what actions do SNS and ANS control?
SNS- voluntary actions
ANS- involuntary actions
what do SNS and ANS innervate?
SNS innervates body wall structures- skeletal muscle
ANS innervates viscera (internal organs)- smooth and cardiac muscle
how many nerves does the somatic nervous system use?
one nerve system
how many nerves does the ANS use?
2 nerve system (nerve arises in the SC, but it must first synapse with a second autonomic nerve, outside the CNS, which then innervates the target organ)
first nerve: pre-ganglionic or pre-synaptic fiber
second nerve: post-ganglionic or postsynaptic fiber
NT of SNS and receptor?
SNS releases Acetylcholine to bind to N1 (nicotinic acetylcholine receptor)
NT and receptor of the ANS?
1st nerve: uses acetylcholine to bind to receptor on second neuron (N2 receptor- nicotinic acetylcholine receptor)
2nd nerve: uses acetylcholine (PNS) to bind to muscarinic receptors on target OR norepinephrine (Sympathetic) to bind to alpha and beta adrenergic recetpros on its target
how many spinal nerves? cranial?
31 pairs of spinal nerves
12 pairs of cranial nerves
spinal nerves vs. cranial nerves (motor and sensory)
spinal nerves and their branches contain both motor and sensory
cranial nerves contain different combinations of motor and sensory fibers and can be entirely motor or entirely sensory
nerve fibers in dorsal root vs. nerve fibers in ventral root
dorsal root: AFFERENT or sensory
derived from neural crest
dendrites of these dorsal root neurons arise in the periphery and their axons end in the spinal cord
their cell bodies are outside the spinal cord, clustered into a dorsal root ganglion
Ventral roots: EFFERENT or motor (cell bodies of motor axons are all derived from the neural tube; they are found in gray matter inside the spinal cord, mainly int he ventral horn and their axons extend to their target organs)
Branches of spinal nerve
cutaneous and muscular
what do cutaneous branches supply?
contain both sensory and motor fibers
supply a specific dermatome (area of skin supplied by all the branches of a single spinal nerve)
contain neuronal processes from a variety of sensory receptors in the epidermis and dermis
they also contain postganglionic sympathetic (motor) axons to smooth muscle and glands in the dermix
what do muscular branches supply?
a specific myotome- the muscle mass supplied by the branches of a single spinal nerve
mixed branches of spinal nerves (sensory and motor)
contain sensory neuronal processes from sensory receptors in skeletal muscle, and motor axons that make the skeletal muscles contract
3 important muscles of the chest
1) pectoralis major
2) pectoralis minor
3) serratus anterior
what nerve innervates the serratus anterior?
long thoracic nerve (unusual because it innervates it superficially; most muscles are innervated by nerves entering from the deep surface); exposed location of this nerve puts it at risk during axillary surgury
3 layers of intercostal muscles
1) external intercostals
2) internal intercostals
3) innermost intercostals
origin of external and internal innercostal muscles
inferior border of rib and insert on the superior border of the rib below
external is superficial to the internal
external and internal intercostals begin and end at different locations within the intercostal space so that they are off register relative to each other
where do external intercostals extend to?
external intercostals extend from tubercles of the ribs to the costo-chondral junction (where the bony portion of the rib meets the cartilaginous portion)- (thin membranes extend from muscle to fill out the deficiencies in the layers)
where do internal intercostals extend to?
extend from angles of the rubs to the sternum (thin membranes extend from muscle to fill out the deficiencies in the layers)
transverse thoracis?
found on the inner surface of the removed piece of thoracic cage originating from the sternum and inserting upon ribs 2-6
where do the intercostal vessels and nerves pass?
pass between the internal intercostal and the innermost layer in what is known as a neurovascular plane
which way do the fibers of the external intercostal muscles go?
inward
“hands in pockets”