FA and BM of the Ribs, sternum, and diaphragm

Accessory muscles of respiration 13

subcostal pyramidalis QL serrates post S and I longissiumus iliocostalis Pec major and minor serrates anterior lat subclavius SCM These are muscles that we recruit when we need to get more air in (i.e. exercise) don't need to memorize exact muscles just know that there are some that we use when breathing nl and others that we pull in PRN

Sternal flex/ext

plane: sagittal axis: transverse

Components/attachments of the thoracoabdominal diaphragm

Components: -central tendon (lacks boney attachment) -cura (R and L) -arcuate ligaments (median, medial, and lateral) Attachments: -Internal surface of ribs 6-12 -Posterior aspect of typhoid process -lumbar vertebrae and IV disc of LV1-3 on L and LV1-4 on R via cura (longer on the R bc the liver is big and have to get around that)

Chondral structures of the thorax

Intervertebral discs Costal cartilages & subcostal margin

Terminology for an exhaled rib

"Prefers exhalation" "Freely moves into exhalation" "Is stuck in exhalation" "Is restricted in inhalation" "Is 'down in front' and 'up in back"' (depressed anteriorly) "Anterior narrowing of the intercostal space below the rib"

Terminology for an inhaled rib

"Prefers inhalation" "Freely moves into inhalation" "Is stuck in inhalation" "Is restricted in exhalation" "Is 'up in front' and 'down in back'" (depressed posteriorly) "Anterior narrowing of the intercostal space superior to the rib"

What sort of SDs can you have with the rib cage?

**Respiratory rib dysfunctions -Inhalation rib dysfunction (aka. Exhalation restriction) -Exhalation rib dysfunction (aka. Inhalation restriction) Can have these, but not focused on this for lab: Structural rib dysfunctions -Anterior and posterior subluxation -Superior subluxation of the first rib -Anteroposterior compression -Lateral compression

Clarification on rib motion

- in reality, each rib exhibits some degree of movement of each type of motion -orientation of the axis of the coupled costovertebral-costotransverse articulation determines the direction of movement for any given rib

What are some of the major structures within the thoracic cage?

-Dont need to memorize but understand that there are a lot of vital organs housed within this cage -heart, great vessels, lungs, trachea, GB, esophagus, stomach, spleen, kidneys, colonic flexures, thoracic duct, LNs, sympathetic trunk and ganglia

Thoracoabdomial diaphragm

-a domed shaped muscle that partially separates the thoracic cavity from the abdominal cavity -Apertures: IVC T8 Esophagus T10 Aorta T12 "I eight 10 eggs at noon" -"The dome shape of the diaphragm is created by a piston of viscera including the liver, stomach, and spleen, which is forced upward into the central tendon by the abdominal musculature, particularly the transversus abdominis."

Costotransverse articulation

-all ribs: Rib tubercle articulates with the transverse process of the thoracic vertebra of the corresponding level Allows for gliding costal motion with slight rotation

Costovertebral-costotransverse jt motion

-axis of movement of this coupled jt is formed by an imaginary line between the two articulations -the orientation of this axis is determined by the orientation of the vertebral TP -the orientation of the axis is what determines the direction of rib movement(s) (i.e. elevation/depression with breathing)

Xiphisternal jt

-between the xyphoid process and body of sternum

Thoracic inlet

-cephalic (superior) end of the thoracic cage -boundaries: body of TV1, medial margins of R and L first ribs, posterior aspect of manubrium, medial ends of R and L clavicle -Side note: has importnat clinical dysfunctions, clinical boundaries: manubrium to angle of Luis and ribs 1-2 on either side and TV1-4

Costovertebral-costotransverse jt

-complex jt formed by costovertebral and costotransverse articulations

Major structures passing through the thoracic inlet

-dont memorize, just appreciate Esophagus Trachea Apexes of the lungs Phrenic n., vagus n., recurrent laryngeal nn. Sympathetic trunk Stellate Ganglion Brachial Plexus Common Carotid Artery Vertebral Artery Thyrocervical Trunk Internal Thoracic Artery Internal Jugular Vein Subclavian a. and v. Anterior Cervical Nodes Thoracic Duct and Right Lymphatic Duct

Respiratory rib dysfunction

-inhalation rib dysfunction (AKA exhalation restriction) -exhalation rib dysfunction (AKA inhalation restriction) -may occur with a single rib or group of ribs -if in a group of ribs must identify key rib "BITE"

What happens to pressure during inhalation/exhalation?

-inhalation: decrease pressure in thoracic cavity and increase in abd cavity -exhale: decrease pressure in abd cavity and incraease in thoracic cavity this pressure change is what drives blood and lymphatics flow

Intrasternal articulations

-manubriosternal jt -xiphisternal jt

Thoracic outlet

-many important nervous and lymphatic structures pass through this -boundaries: clavicle (ant), scap (post), rib cage/1st rib (medially)

Torsional rib motion

-occurs with difficult ribs, motion of the thoracic vertebrae can affect ribs/sternum and vice versa -only occurs between a pari of typical ribs and two thoracic vertebrae to which the pair attaches -primary rotation of TV above in one direction can -> secondary rotation of the sternum in opposite direction via connection by a pair of typical ribs ex: When T5 rotates R on T6, the posterior aspect of the R 6th rib rotates externally while the posterior aspect of the L 6th rib rotates internally. This motion continues anteriorly, causing compensatory rotation of the sternum in the opposite direction as T5 (i.e. to the L).

Sternal SB

-plane of motion: coronal axis motion: A->P

Pump handle motion

-ribs 1-5 -axis movement: Transverse >AP plane movement: sagittal changing diameter: AP -during inhalation, these ribs rotate mostly around a transverse axis which increases the AP diameter of rib cage -motion best palpated anteriorly

Calpier motion

-ribs 11-12 -axis movement: vertical plan movement: TV changing diam: TV -during inhalation, these ribs rotate mostly around a vertical axis which increases the TV diameter of the rib cage -these ribs have no ant attachment to sternum so move post/lat during inhalation -motion is best palpated posteriorly

Bucket handle motion

-ribs 6-10 -axis movement: AP>TV plane movement: coronal changing diam: TV -during inhalation, these ribs rotate mostly around an AP axis which increases the TV diam of the rib cage -motion best palpated laterally

Classifications of rib motion

-ribs are classified by their predominate direction of movement during respiration

manubriosternal jt

-sternal angle of louis -between the manubrium and body of the sternum

What are the supporting osseous structures of the thorax?

-sternum -clavicle -thoracic vertebrae

Lymphatic drainage of the thorax

-the thoracic duct and R lymphatic duct drain lymphatic fluid from the entire body into the venous systems at the L and R venous angles -venous angles are located immediately posterior to the medial end of the clavicle and first rib -thoracic duct passes with the aorta through the aortic aperture of the diaphragm

Sympathetic trunk and ganglia

-the thoracic lateral chain ganglia of the sympathetic division of the ANS lie anterior to the capsule of the costovertebral articulations and are tightly bound down to the posterior thoracic wall by heavy dense fascia

Costovertebral articulation

-typical ribs: Rib head articulates with the superior costal facet of the thoracic vertebral body of the corresponding level, the annulus fibrosis of the intervening disk, and the inferior costal facet of the thoracic vertebral body above -atypical ribs: Rib head articulates with only the vertebral body at the corresponding level allows for gliding or sliding costal motion

Atypical ribs

1, 2, 10, 11, 12

Typical ribs and components

3-9 Head Two articular demifacets: Inferior articular facet Articulates with thoracic vertebral body at corresponding level Superior articular facet Articulates with body of thoracic vertebra above Neck Tubercle Articular facet Articulates with transverse process of thoracic vertebra at corresponding level Shaft Angle On posterior aspect of the rib shaft Attachment site for iliocostalis mm. Costal groove On internal inferior surface of rib Accommodates intercostal neurovascular bundle

What are the pre vertebral muscles of the thorax? 3

Anterior scalene m. Middle scalene m. Posterior scalene m.

Thoracic vertebrae

Articular facets located on bodies and transverse processes which articulate with the ribs

Inhalation

Diaphragm contracts and descends, pushing inferiorly on the viscera. As the central tendon becomes fixed against the viscera, continued contraction of the diaphragm causes the lower 6 ribs ('bucket-handle' and 'caliper' ribs) to elevate and open, respectively, both increasing the transverse diameter of the thorax. Meanwhile, the External intercostal mm. (except anteromedial fibers), Internal intercostal mm. (parasternal/interchondral portion), and the Levatores costarum mm. contract to pull the ribs up and outward. Accessory muscles further aid this process of elevating and opening the ribs. Accessory muscles also help pull the sternum up and outward, helping to increase the AP diameter of the thorax. Overall effect: Increased volume of the thoracic cavity increase in negative intrathoracic pressure atmospheric air rushes into the lungs lungs expand. Meanwhile: Volume of the abdominal cavity decreases intraabdominal pressure increases pelvic diaphragm is pushed inferiorly. Diaphragmatic apertures: Esophageal - contracts Vena caval - dilates Aortic - unaffected (doesn't pierce diaphragm directly, runs posteriorly)

Exhalation

Diaphragm relaxes and moves superiorly by passive recoil of the viscera. Muscles of the abdominal wall contract, further forcing the viscera into the diaphragm causing it to move superiorly. Meanwhile, the External intercostal mm. (anteromedial fibers), Internal intercostal mm. (interosseous portion), and the Transversus thoracis mm. (aka. Sternocostalis mm.) contract to pull the ribs down and inward. Accessory muscles further aid this process of depressing and closing the ribs. Overall effect: Decreased volume of the thoracic cavity decrease in negative intrathoracic pressure air is forced out of the lungs lungs collapse. Meanwhile: Volume of the abdominal cavity increases intraabdominal pressure decreases pelvic diaphragm moves superiorly. Diaphragmatic apertures: Esophageal - dilates Vena caval - contracts Aortic - unaffected

Main muscles of inspiration

Don't need to memorize, just know big players Scalenes pull up and anchor ribs 1-2 so that they can be used as a stable attachment point from which the In and Ex intercostals can pull

Main muscles of expiration

Dont memorize, just know big players

What are the muscles of the thoracic wall of the thorax? 6

External intercostal m. Innermost intercostal m. Internal intercostal m. Levatores costarum mm. Subcostal m. Transversus thoracis m. (aka. Sternocostalis m.)

Principle muscles of respiration 13

External intercostal m. Innermost intercostal m. Internal intercostal m. Levatores costarum mm. Transversus thoracis m. (aka. Sternocostalis m.) EO IO Rectus abdominis transversus abdominis diaphragm scalene (A/M/P)

What are the muscles of the abdominal wall of the thorax? 5 (+ 2 posterior)

External oblique m. Internal oblique m. Pyramidalis m. Rectus abdominis m. Transversus abdominis m. Posterior: diaphragm and QL

What are the shoulder muscles of the thorax? 2

Latissimus dorsi m. Subclavius m.

What are the intermediate back muscles of the thorax? 2

Longissimus m. Iliocostalis m.

Sternum

Manubrium (head), gladiolus (body), xiphoid process (tail) Lateral edges are scalloped and articulate with costal cartilage of ribs

Costovertebral-costotransverse jt: upper vs lower ribs

Note that the orientation of the vertebral transverse processes affects the orientation of the axis of movement. Upper ribs: The transverse processes of the upper ribs extend more laterally. Axis of movement is orientated more in a transverse direction. Lower ribs: The transverse processes of the lower ribs extend more posteriorly. Axis of movement is oriented more in an anteroposterior direction

What are the pectoral/axillary region muscles of the thorax? 3

Pectoralis major m. Pectoralis minor m. Serratus anterior m.

Sternal rotation

Plane: transverse axis: superior -> inferior (vertical)

Clavicle as a supporting structure

Recall that the clavicle is considered 'Rib0'— this is because the clavicle must remain mobile for optimal motion of the rib cage, especially the first rib. The sternoclavicular joint is a true joint of the shoulder, meaning the position of the upper extremity can affect the sternum and thus the respiratory mechanics of the thoracic cage.

Sternum - as supporting structure

Recall the manubriosternal and xiphisternal joints—these allow for hinge like movement within the sternum during respiration.

Functions of the diaphragm (9)

Respiration Micturition (urnation) Defecation Regurgitation Parturition Prevent gastric reflux (diaphragm contracts around esophageal hiatus w/ inhalation) Circulation (venous drainage) Lymphatic drainage Contraction (during inhalation) and relaxation (during exhalation) of the diaphragm results in alterations in intrathoracic and intraabdominal cavity pressures. These alternating pressures are responsible for many of the functions of the diaphragm.

Inhaled rib dysfunction

Rib prefers inhalation, Aka. Exhalation restriction The dysfunctional rib(s) will move superiorly during inhalation but fail to move inferiorly during exhalation, i.e. the rib(s) "prefers" or is (are) "stuck in" inhalation. Palpatory findings: 'Pump handle' ribs (1-5) will feel elevated anteriorly 'Bucket handle' ribs (6-10) will feel elevated laterally 'Caliper' ribs (11-12) will feel elevated posteriorly

True ribs

Ribs 1-7 -Aka. Vertebrosternal ribs The costal cartilages of the true ribs attach directly to the sternum at the sternochondral articulation

False ribs

Ribs 8-12 No direct attachment to sternum Vertebrochondral ribs (8-10) The costal cartilages of the vertebrochondral ribs attach indirectly to the sternum via the costal cartilage of rib 7 Vertebral ribs (11-12) Aka. floating ribs These two ribs lack costal cartilage and have no anterior attachment to the sternum

What is the main neck muscle of the thorax?

SCM

What are the superficial back muscles of the thorax? 2

Serratus posterior superior m. Serratus posterior inferior m.

Clavicle

Sometimes referred to as Rib0 Medial end articulates with manubrium and cartilage of rib 1 Only bony attachment of the UE to the trunk

Thoracic cage and actions of muscles of the thorax

The thoracic cage is a fibromuscular tube anchored superiorly by the scalene muscles via attachment to the first and second ribs, and inferiorly by the abdominal muscles via attachment to the subcostal margin. The layers of the intercostal muscles form incomplete helical sheets around the rib cage offering stability and flexibility to the thoracic cage. The muscles of thoracic area are required for many functions: Motion of ribs & vertebrae Breathing Posture & locomotion Head & neck control Upper extremity control Visceral function Lymphatic and venous drainage

Thoracic cage

The thoracic cage is an enclosed boney structure comprised of 12 thoracic vertebrae, 12 paired ribs, and the sternum. Note that the intervertebral discs and the costal margin also help create this "cage." Cartilaginous portion consists of IV discs, CC, subcostal margin

Rib 2

Two demifacet articulations on head (articulate with body of corresponding vertebra and vertebra above, just like the typical ribs) Tuberosity for serratus anterior muscle

Rib 11 and 12

Unifacet articulation on head (articulates with body corresponding vertebra only) Lack tubercles Tapered ends (no anterior attachment with sternum)

Rib 10

Unifacet articulation on head (articulates with body of corresponding vertebra only) Very similar to the typical ribs

Rib 1

Unifacet articulation on head (articulates with body of corresponding vertebra only) Lacks a rib angle Flatest, shortest, strongest, broadest, and most curved rib

sternochondral jt

between CC and triangular notches on sternum

Costochondral joint

between a rib and its costal cartilage

interchondral joint

between the CC of two ribs

SC jt

between the manubrium and the medial end of the clavicle -a true jt of the shoulder girdle

Exhaled rib dysfunction

rib prefers exhalation, AKA inhalation restriction The dysfunctional rib(s) will move inferiorly during exhalation but fails to move superiorly during inhalation, i.e. the rib(s) "prefers" or is (are) "stuck in" exhalation. Palpatory findings: 'Pump handle' ribs (1-5) will feel depressed anteriorly 'Bucket handle' ribs (6-10) will feel depressed laterally 'Caliper' ribs (11-12) will feel depressed posteriorly