NUTR 367 Lab 1

Sternum: Manubrium

jugular notch

articular facets for clavicle and 1st rib

Sternum: Sternal angle

junction of manubrium and body

At T4 vertebral level

2nd rib articulate with both manbrium and body at sternal angle

Thoracic wall: Thoracic inlet (superior thoracic aperture)

T1 vertebrae posteriorly

Medial border of the 1st rib and its costal cartilage

superior border of manubrium anteriorly

Thoracic wall: thoracic outlet (inferior thoracic aperture)

Closed by the diaphragm

T12 vertebrae and 11 and 12 pair of ribs posteriorly (floating ribs)

Xiphoid process anteriorly

Thoracic wall: intercostal space

lies between ribs

Borders of T.C: Superior (thoracic inlet)

formed by manubrium, first ribs, and T1 vertebra

Borders of T.C: Inferior (thoracic outlet)

The diaphragm, a dome-shaped muscle separating the thoracic from the abdomen

Borders of T.C: anterior

sternum and anterior chest wall

Borders of T.C: posterior

thoracic vertebrae (T1-T12) and vertebral column

Borders of T.C: lateral

the ribs and intercostal muscles

External intercostal mm

Insertion:

passes inferomedially from rib to another

replaced anteriorly by anterior intercostal membrane at the costochondrial junction

Action: elevates ribs during inspiration

innervation: segmental innervation by the intercostal nn.

Internal intercostal muscle

Insertion:

passes inferomedially from one rib to another

replaced posteriorly by posterior intercostal membrane at angle of rib

Action: elevates ribs during inspiration and depresses rib during expiration

Innervation: segmental innervation by intercostal nn.

diaphragm

dome shaped skeletal muscle that serves as a physical boundary between the thoracic cavity and the abdominal cavity

Neurovascular bundle

intercostal nerves, arteries, and veins in between the internal and innermost intercostal m.

partially protected by the inferior border of rib running in the costal groove

Intercostal nerves: motor

innverates intercostal mm at each level (segmental)

intercostal nn. —> upper 11 thoracic spinal nerves

subcostal n. —> 12th thoracic spinal n

Intercostal nerves: sensory

carries general sensation from a strip of skin overlying each nerve

Intercostal nerves: dermatome

a strip of skin supplied by a single spinal nerve

Mediasternum

centrally located in btween two pulmonray cavities

contains all pulmonaary viscera except lungs

Superior medistinum

superior to the sternal angle anteriorly and inferior border of T4 posteriorly

Veins: left and right brachiocephalic vein

A: aortic arch and its branches

T: Trachea

E: Esophagus

Nerves: vagus, phrenic, and recurrent laryngeal

Inferior mediastinum

Middle: The pericardium & its contents

Middle contents: Heart and pericardium, roots of the great vessels (superior vena cava, ascending aorta, phrenic n, and pulmonray atery/ vein)

platysma muscle

o: base of mandible

i: clavicle and fascia of chest

a: depresses mandible and lower lip and tenses skin of neck

sternocleidomastoid muscle

o: manubrium and medial portion of clavicle

i: mastoid bone and superior nuchal line

a:

1. bilateral: flexes neck

2. unilateral (ipsilateral: rotates neck toward side being contracted and contralateral: rotates neck toward opposite side of contraction)

sternohyoid bone

o: manubrium of sternum

i: hyoid bone

a: depressed hyoid bone

sternothyroid bone

o: manubrium of sternum

i: thyroid cartilage

a: depresses hyoid and larynx

thyrohyoid m

o: manubrium of sternum

i: thyroid cartilage

a: depresses hyoid bone