Thoracic Osteology, Arthrology and Myology Flashcards
Contents/boundaries of superior thoracic aperture (thoracic inlet)
Trachea/esophagus
Nerves and vessels supplying neck and UE
Boundaries: T1 vertebrae, 1st ribs and superior manubrium
Contents and boundaries of inferior thoracic aperture
Esophagus, inferior vena cava, aorta
Boundaries: T12, 11th/12th ribs, 7-10th costal cartilages and xiphisternal joint
Divisions of thoracic cavity
Two pulmonary cavities laterally, which contain lungs and pleurae
Mediastinum, contains heart, thoracic great vessels, trachea, thoracic esophagus and thymus
Manubrium costal notches articulate with
1st rib and half of the 2nd rib
Costal notches of the sternal body articulate with
half of 2nd, 3rd-6th and half of 7th ribs
Xiphoid process articulates with
Half of 7th rib
Types of ribs
True ribs (vertebrocostal): 1-7th, attach directly from vertebral segments to sternum via their own costal cartilage False ribs (vertebrochondral): 8-10th attach from vertebral segments to join the costal cartilage immediately superior to that segment Floating (vertebral) ribs: 11-12th- do not attach to sternum at all
Typical ribs
3-9th
Superior articular facet articulates with inferior costal demifacet on thoracic vertebral body one segment superiorly
Inferior articular facet articulates with superior costal demifacet on thoracic vertebral body of the same numeral segment
Tubercle- contains nonarticular part that is attachment point for lateral costotransverse ligament
Atypical ribs
1, 2, 10-12th
1st rib
Scalene tubercle- attachment for anterior scalene M.
Groove for subclavian artery
Groove for subclavian vein
Second rib
Tuberosity of serratus anterior M.
10-12th ribs
Nothing special, only have head, no tubercle or neck
Most commonly fractured ribs
Middle ribs, at their weakest locus, just anterior to the costal angle
Can damage internal organs and produce severe pain
Supernumerary ribs
Extra ribs either in the cervical region or lumbar region. Cervical ribs typically produce no symptoms, however, can produce neural and circulatory problems based on their proximity to the brachial plexus and subclavian A.
Lumbar ribs also often produce no symptoms, however, can result in confusion when reading radiographs and such
Types of synovial joints
Planar- flat/gliding Ginglymus- hinge Trochoid- pivot Condylar- concave Sellar- saddle Spheroidal- ball and socket Compound synovial - combination of above
Fibrous joints
Sutures
Schindylesis- tongue in groove
Gomphosis- peg in socket
Syndesmosis- bone-ligament-bone
Cartilagenous joints
Synchondrosis- hyaline cartilage - temporary/growth plates
Symphysis- secondary cartilage joints- fibrocartilage
Manubriosternal joint
Symphysis
Sternal angle of louis
2nd costal notch
Xiphisternal joint
Synchondrosis
Inferior limit of the thorax
7th costal notch
Sternocostal joints
Rib 1- synchondrosis
Ribs 2-7: synovial planar - anterior/posterior radiate sternocostal ligaments
Costovertebral joints
Synovial planar
Radiate ligament- head of rib to vertebral body
Intraarticular ligament- head of rib to intervertebral disc
Articular capsule- strongest anteriorly as the radiate ligament
Head of rib - vertebral articulations
Head of rib articulates with inferior costal facet of superior numeric thoracic vertebral segment and superior costal facet of the same numeric thoracic vertebral segment
The articulating facet of the costal tubercle articulates with the same numeric thoracic vertebral segment
Costotransverse joint
Synovial planar
Lateral costotransverse ligament- tubercle of rib to transverse process
Superior costotransverse ligament- neck of rib to transverse process one vertebral segment superiorly
Costovertebral joint movement
Two types of movement, both increase thoracic volume and decrease thoracic pressure during inspiration
- Bucket handle movement- elevation of the lateral most portion of the rib, increasing transverse diameter of thorax
- Pump handle movement: elevation of sternal end of rib, increasing anterior-posterior diameter of thorax
Dislocation vs separation
Dislocation refers to dislocation at a sternocostal joint
Separation of ribs refers to a separation at the costochondral joint
External intercostal muscle
11 pair; anteriorly, muscle fibers are replaced by the external intercostal membrane which overlies the internal intercostal muscles
Inferiorly, the external intercostal muscle is continuous with the external abdominal oblique muscle
Action- elevate the ribs
Innervation- intercostal nerve
Internal intercostal muscles
11 pair; posteriorly, muscle fibers are replaced by the internal intercostal membrane
Inferiorly, the internal intercostal muscle is continuous with the internal abdominal oblique muscle
Action- depress ribs
Innervation- intercostal nerve
Innermost intercostal muscle
11 pair; the deepest fibers of the internal intercostal muscle separated by the intercostal nerve and vessels
Action- undetermined, probably the same as internal int. muscle
Nerve- intercostal nerve
Thoracentesis
Insertion of a hypodermic needle through the intercostal musculature b/w ribs to obtain a fluid sample or drain blood from pleural cavity.
Needle is inserted inferior to intercostal neurovascular bundle, but superior to the collateral branches
Thoroscopy
Insertion of a thoroscope into the pleural cavity through small incisions for visualizing and biopsying the space inside the cavity
Transverse thoracic muscle
O- posterior surface of lower part of sternal body
I- internal surface of 2-6th costal cartilages
A- depress ribs
N- intercostal n.
Subcostal muscle
O- inferior border of rib
I- superior border of rib
A- similar to internal intercostal
N- intercostal n.
