Lecture 15: Anterior Trunk Muscles Flashcards
Xiphisternal joint is where?
Superior limit of liver. Central tendon of diaphragm
Xiphoid process is at what level?
T10 vertebral level. Ossified > 40 yrs old.
Dermatomes
What level are the nipple, xiphoid, umbilicus and Inguinal ligament
Region of skin innervated by sensory fibres from a SINGLE spinal nerve. Nipple: T4 Xiphoid process: T7 Umbilicus: T10 Inguinal ligament: L1
The sternum is at what level?
T5-T9
Sternum sternebrae
Sternal body fuses from 4 sternebrae
Fusion complete by 25 years of age.
What ribs are true, false and floating ribs?
True
(vertebrocostal)
ribs: 1-7
False
(vertebrochondral)
ribs: 8-10
Floating (free) ribs:
11-12
The first rib has two groves for what?
Subclavian veins and artery
What makes up the boundaries of the superior thoracic aperture?
T1 vertebra + first ribs + superior border of manubrium
What makes up the boundaries of inferior thoracic aperture?
T12 vertebra + ribs 11 & 12 + costal margin + xiphisternal joint.
What is Thoracic ‘outlet’ syndrome?
Entrapment of structures passing between the neck and thorax/axilla.
Usually brachial plexus between anterior and middle scalene
E.g Costoclavicular syndrome, pallor and coldness of
upper limb, Diminished radial pulse
Sternocostal joints
1st: primary cartilaginous joint
2nd-7th: synovial plane joints
“Dislocated” ribs occur at these joints
Costochondral joint
Costochondral:
Primary cartilaginous articulation between ribs and costal
cartilages.
Interchondral joints
Interchondral:
Synovial plane joint between costal cartilages of 6th-7th, 7th-8th, 8th-9th.
Fibrous articulation between costal cartilages of 9th-10th ribs.
Costochondritis
One of the most common identifiable cause of chest pain in children and adolescents.
• Musculoskeletal chest pain generally reproducible on palpation and is exaggerated by physical activity or breathing.
• Costochondral joint pain due to inflammation.
• Treat with NSAIDs, corticosteroids.
Which intercostal is most important for breathing?
External intercostals
External intercostals
External intercostals between adjacent ribs LATERAL to
costochondral joint.
Only Internal intercostals are between what?
costal cartilages.
Intercostal nerves originate where?
Primary ventral rami of first 11 thoracic spinal nerves.
12th intercostal space innervated by what nerve!
Subcostal nerve
Intercostal neurovascular bundles lie where?
inferior to each rib, running in the costal groove deep to the internal intercostal muscles.
Intercostal nerves contain what type of fibres?
motor, sensory and sympathetic fibres.
Rectus sheath contains:
rectus abdominis & pyramidalis muscles, superior & inferior epigastric arteries, anterior rami of T7-T12.
External oblique origin and insertion
External oblique fibres originate on external surfaces of ribs 5-12 and fan out inferomedially to insert in linea alba.
Internal oblique origin and insertion
Internal oblique fibres originate from thoracolumbar fascia and anterior 2/3 iliac crest and fan out superomedially to insert into
linea alba.
External spermatic fascia
Superficial inguinal ring breaches the aponeurosis of external oblique. External oblique continues as external spermatic
fascia…..
Cremasteric fascia
Derived from fascia of both superficial and deep surfaces of internal oblique muscle.
Cremaster muscle reflexively draws testis superiorly in
the scrotum, particularly when cold.
Superior and inferior epigastric anastomoses
Superior epigastric (branches from internal thoracic artery) and inferior epigastric (branches from external iliac artery) arteries anastomose in the rectus sheath to supply the muscles of anterior abdominal wall.
Umbilical folds
Lateral umbilical fold contains the inferior epigastric vessels!
Medial umbilical folds are remnants of umbilical arteries.
Median umbilical fold is remnant of urachus connecting fetal bladder to umbilicus.
Surgeons making abdominal incisions must be careful not to cut the lateral umbilical fold!!!
12th intercostal nerve is also know as?
Sub costal nerve
Nerves of thoracic wall
Post-ganglionic sympathetic fibres distributed (via gray rami) to all the spinal nerves to reach all the blood vessels, sweat glands and smooth muscle of the body wall (and limbs).
Neurovascular bundles run between which intercostal muscles?
Between internal and innermost intercostal muscles
What type of joint is the sternoclavicular joint?
Saddle-type synovial joint
What blood vessel supplies rectus abdominis?
Superior epigastric
Aponeurosis of internal oblique splits to enclose what?
Rectus abdominis
transversus abdominis aponeurosis passes deep to?
Rectus abdominis
