Rib Biomechanics

Costotransverse Articulations and Ligaments

Costotransverse Articulation -joint between tubercle of rib and transverse process of corresponding vertebra -weak capsule is strengthened by costotransverse ligaments

Sternocostal Joints or Sternochondral Joints

-1st joint is primary cartilaginous joint (synchondrosis), articulate manubrium and costal cartilages -2nd-7th is synovial plane joint, articulate sternal body and costal cartilages -Anterior and posterior radiate sternocostal ligaments help stabilize joint -Store potential E with each inhalation

Pump Handle

-Anterior-posterior motion at costovertebral and costosternal joint -Describe Sagittal Plane motion -Prominent in upper ribs

Serratus Posterior Superior

-C7-T3 & 2nd-5th ribs -Elevates the ribs -Ventral rami of T2-5

Rib Articulations Anteriorly:

-Costo-Chondral Junction, transition between osseous rib & cartilage -Costal-Cartilaginous junction to Sternum

Rib Articulations Posteriorly:

-Costo-Vertebral -Costo-Transverse junctions Typical ribs articulates both

Rib Exhalation Dysfunction=Rib Inhalation Restriction

-Group rib dysfunction is restricted by key rib, usually the TOP one for exhalation dysfunction -A rib with exhalation dysfunction will stop short of full inhalation compared to the other side

Rib Inhalation Dysfunction=Rib Exhalation Restriction

-Group rib dysfunctions is restricted by key rib, usually the BOTTOM one for inhalation dysfunction. -A rib with inhalation dysfunction will stop short of full exhalation compared to the other side

Typical ribs(3-9) Head & neck connects to spinal column (posterior)

-Head: round, knob-like, has 2 facets -Neck and Tubercle: articulate of transverse processes and costotransverse ligament -Body/Shaft: thin, flat, curved -Distal concavity: cartilage attaches here

Costovertebral Articulations and Ligaments

-Heads of rib 2-9 articulate the corresponding vertebra, the intervertebral disc, and the vertebra ABOVE -Rib 1, 10, 11, 12 articulate with their own corresponding vertebral level -Synovial joint with joint capsule, strengthened by radiate ligament

Costotransverse Ligaments(3) Cont.

-Interosseous (Costotransverse), from TP to posterior surface of neck of corresponding rib -Posterior (Lateral Costotransverse), from tip of TP to lateral border of corresponding costal tubercle -Superior, from inferior border of TP to superior border of neck of the rib BELOW

Costovertebral Ligaments(2) Cont.

-Interosseous ligaments: between 2 demifacets to intervertebral disc -Radiate ligaments: 3 bands Superior->head of rib to vertebra above Intermediate-> head of rib to intervertebral disc Inferior->head of rib to corresponding vertebra

Caliper motion

-Most prominent in 11th and 12th ribs, no sternal attachment -Inhalation: ribs 11 & 12 move posteriorly & inferiorly Exhalation: ribs 11 & 12 move anteriorly & superiorly

Bucket handle

-Motion: up and down -Increase transverse diameter -Prominent in lower ribs During inspiration, lateral part of rib moves superiorly

Costochondral Joint

-Primary cartilaginous joint (hyaline) -articulate lateral end of costal cartilage and sternal end of rib -Bound by periosteum of rib and perichondrium of cartilage -Interlocking joints

-True ribs -False ribs

-Ribs 1-7; they attach directly to the sternum through their own costal cartilages -Ribs 8-12; their cartilages are joined to that of the rib superior, and this is an indirect connection to the sternum Ex: Vertebrochondral ribs: ribs 8-10 Floating ribs: ribs 11&12, lack cartilage and no connection to the sternum Ribs get progressively longer until rib 10

Diaphragm

-Sternal portion: posterior xiphoid -Costal portion: inner surfaces of cartilages -Lumbar portion: medial & lateral arcuate ligaments and right and left crura from anterolateral surfaces of bodies and discs of T12/L1-3 -Muscle of respiration -Phrenic nerve from cervical plexus C3-5

Sternum

-Sternum angle of Louis: at level of 2nd pair of costal cartilages, 4th disc space -at level of T5-9 vertebrae -4 parts/ossification centers "sternabrae" -Manubriosternal joint, articulates manubrium and sternum, a secondary cartilaginous joint (symphysis) -Xiphisternal joint, articulates xiphoid and sternum, A primary cartilaginous joint (Synchondrosis) These two joints often fuse and become synostosis in older people

Serratus Posterior Superior

-T11-L3 and 9th-12th ribs -Involve directly in thoracic, lumbar and respiratory movement -Exhalation: draw ribs posterior and inferior -Ventral rami of T9-12

Sternoclavicular Joint

-Triaxial joint: saddle joint or ball and socket joint -Enclosed by synovial capsule, strengthened by surround ligaments: 1. Anterior/posterior sternoclavicular ligaments, interclavicular ligament 2. Intra-articular disc attaches to superior part of first costal cartilage and to medial/superior part of clavicle (2 synovial cavities)

Xiphoid Process

-at level 10th vertebrae -Ossified by age 40 -Inferior border of thoracic cavity, marker of upper liver border, central tendon of diaphragm, inferior border of heart

1. Serratus Anterior 2. Scalenes 3. Sternocleidomastoid 4. Latissimus Dorsi

1. Ribs 1-8, scapula 2. -Anterior, Middle scalenes attach from cervical transverse processes to first rib Lifting first rib by scalene contraction can change the angulation of manubrium-> change upper part of thoracic cage -Posterior Scalenes 3. Sternum, clavicle, mastoid process 4. SP 6-12 vertebrae, iliac crest, lower 3-4 ribs, thoracolumbar fascia

Quadratus Lumborum

Iliolumbar ligaments, posterior part of iliac crest to inferior border of 12th rib and transverse processes of upper 4 lumbar vertebra -lateral flexion of lumbar vertebral column; helps action of diaphragm in inspiration -Lumbar plexus, T12-L3

Rib 11 & 12 Inhalation Dysfunction

In Rib 11/12 inhalation dysfunction, Freedom-> Posteriorly & Inferiorly Restriction-> Anterior & Superiorly

Manubrium

Level T3-T4 bodies Jugular notch, Clavicular notch Attachment for costal cartilage of 1st rib and clavicles

Levatores Costarum(deep layer back muscle)

Longi: TP of T7-10 and 2nd rib below its origin, between tubercle and the angle Breves: TP of C7-T11 and rib below, between tubercle and the angle

Iliocostalis Longissimus

Longissimus: -unilaterally, laterally flexes the vertebral column; bilaterally extends vertebral column; draw ribs down -Dorsal rami of spinal nerves

Muscles of Expiration Passive-> use potential E stored in costal cartilage

Primary: Internal Intercostals(interosseus part) Accessory(active breathing): Rectus abdominus, Ext/Int oblique, Transversus abdominus

Muscles of Inspiration

Primary: Diaphagm, External intercostals, Internal intercostal(intercondral part) Accessory: Sternocleidomastoid, Scalenes, Pectoralis Majoy/minor, Inferior fibers of Serratus Anterior, Latissimus Dorsi, Serratus Posterior Superior, Superior fibers of Iliocostalis

Atypical ribs(1, 2, 10-12)

Rib 1: -Flat, shortest length, greatest curvature, no angle groove, single facet (head articulates only) -Thoracic INLET is key area. Major Lymphatic Drainage, Brachial Plexus & arterial supply passes near, near apex of lung & mediastinum Rib 2: -Its costal cartilage has 2 demifacets to join with manubrium and sternum -Articulate posteriorly with T1 & T2 -Attach to the sternal angle Rib 10-12: -Only one facet -10th attaches to diaphragm -11th & 12th has no necks or tubercles