Thorax Flashcards
what are the insertion sites of the diaphragm
anteriorly bounded by the xiphoid sternum(T8/T9) and costal margin
- laterally by the ends of ribs 11and 12
- posteriorly by the lumbar vertabrae of L1-L3 of the right and L1-L2 on the left
It is morphologically it is a derivative of the transversus layer of the body wall
when do the IVC, oesophagus, and AA pass the diaphragm
T8- IVC
T10- Oesophagus+ vagus nerve
T12- Thoracic aorta(behind medial arcuate ligament) + thoracic duct + azygous + hemiazygous passes the crura of diaphragm
sympathetic trunk & least splachnic nerve pierces through diaphragm lateral to aortic hiatus
greater and lesser splachnic nerve pass through the crura
what is the blood supply of the diaphragm
- above:
1. pericardiacphrenic artery from internal thoracic artery
2. musculophrenic artery from internal thoracic artery
3. superior phrenic artery from thoracic artery
4. lower 5 intercostal arteries and costal vessels(Main vessel) - below
1. inferior phrenic arteries from abdominal aorta(major supply)
venous supply
drain in brachiocephalic
2. azygous system
3. abdominal system- suprarenal system or IVC
What is the lymphatic drainage of the Thorac/Abdomen
These lymphatic drainage follows the route of the veins, to the axillary and inguinal lymph nodes.
- Above the umbilicus, lymph from the bloody drain into the pectoral lymph node, back of the body to the scapular nodes.
- Below the umbilicus ant. aspect of the abdomen and perineum medial group of the superficial inguinal nodes. While lat and post. aspect of the abdomen to the lateral group
What are the nerves supplying the thorax
Until the 2nd rib it is supplied by the supraclavicular branches of the cervical plexus.
- Afterwards they are supplied by the Anterior Cutaneous Branches of the spinal nerve from T2-L1
- Laterally there is a lateral cutaneous nerve of the intercostal nerve
- Posteriorly the skin is supplied by a posterior rami of spinal nerves (medial part supplies the superior part and lateral part supplies the inferior part)
how do the myotomes of the trunk separate
They develop from the segmentation of the myotomes into dorsal and ventral parts, innervated by the dorsal and ventral nerves rami respectively
what do the ventral and dorsal muscle groups develop into
Dorsal Muscles: Erector Spinae(innervated by the dorsal rami)
Ventral into 3 layers:(innervated by the ventral rami)
i.External intercostal; Serratus posteior
ii.Internal intercostal and internal oblique
iii.inner layer forms the transversus thoracis group (innermost intercostals, transversus thoracis and subcostals, and the diaphragm which migrates caudally. In the abdomen, Transversus abdomins, Quadratus Lumborum and lavator ani
How is the thoracic cavity roofed?
It is roofed by the presence of the subprapleural membrane
What causes the of presence of paravertebral gutters in the thorax
Presence of the spinal cord in the chest wall
What causes the ridge on the angle of the ribs
It is formed by the attachment of the thoracolumbar fascia enclosing the erector spinae
what costal cartilage make the costal margine
7th-10th costal cartilage
What makes up the articular surfaces of the manubrium
The articular surfaces of the manubrium are covered in fibrocartiledge and will articulate with the ribs.
What is the blood supply of the body of the sternum
From the internal thoracic artery
What causes the digitations of the RIbs
The 1st digitations occur from the attachment of serratus anterior
i.1-8th Ribs
ii.the second digitations occur behind the origin of pectoralis minor
iii.External oblique from the last 8 ribs
iv. latissimus dorsi
v. Rectus abdominis on the anterior angle of the anterior surfaces of the 5th to 7th costal cartilage
vi. The costal cartilage contains the internal oblique
vii. Transverus abdominis and the diaphragm communicate with the internal surfaces of the lower 6 ribs
viii.Serratus Posterior communicate at the posteior angles of the subsequent ribs
ix. Scalen muscles
x. Quadratus lumborum
xi.iliocostalis and longissimus and levator costae
What leads to the ossification of the ribs
Cartilage is laid down via the mesoderm on the 6th week of life and a bony centre forms on the 8th week at the angle of the rib but the head and tubercle ossify only around age 15
Time period for ossification of the sternum
two longitudinal cartilaginous plates fuse in the midline and ossify on the 5th month, and fusion occurs from 15-25yrs xiphoid sternum ossify anytime after year 3
What are the atypical ribs of and what make them unique
1st rib- single head with a single facet for synovial joint, and contains a radiate ligament to reinforce ant. part of the capsule. The cervical dome and apex of the lung hold these vessels and nerve( from medial to lat: cervicothoracic ganglion, supreme intercostal vein then artery and finally thoracic nerves)
2nd rib-
10th rib-no articular Facet with single head
11th rib- Single faces for the head and no articular facet
12th rib- single head for articulation with the 12th Vertebra. There are no tubercles, angle or costal groove
What part of the ribs articulate with the vertebral column?
By their heads: joints of the head of the ribs superiorly head articulaters with the inferior articular surface of the vetebra and inferior head to the level of the vetebra
tubercles: via the costotransverse joints
What are the 3 joints that stabalize the costotransverse joint
i.Lateral costotransverse ligament
ii.costotransverse ligament
iii.superior costotransverse ligament
What are the layers of the intercostal muscles
i.External Intercostal Muscles/Posterior Serratus Muscles
ii.Internal Intercostal Muscles
iii. Subcostals, Innermost Intercostals, transversus thoracis
The neurovascular bundle lies in between iii. and ii.
What are the origin and sites of insertion of the Posterior Serratus Superior Muscles
Origin: C6 &C7 and T1 & T2 supraspinous ligaments
Insertion: Angle of ribs 2-5
What are the origin and sites of insertion for the Posterior serratus Inferior muscles
Origin: T11 and T12 supraspinous ligaments
Insertion: Aponeurosis which fuses with the posterior lamella of the lumbar fascia and lateral to the angles of the lowest 4 ribs
What are the origin levator costae and its insertion and its nerve supply
Origin : Come in pairs near the tip of the transverse process
Insertion: at the upper border of the rib below, latersal
Nerve supply: POSTERIOR rami of C8-T11
What is the course and the origin of the external costal muscles
Origin:Intercostal groove of the rib above
Insertion: Upper border of the rib below
it move obliquely inferior and forwards
Nerve Supply: