BMS 561 Lecture 2+3 MINUS OIANs

What are the 3 meninges layers of the spinal cord?

Dura Mater

Arachnoid Mater

Pia Mater

Describe Dura Mater

• “tough mother”

• Thick

• Most superficial layer

• Envelop the CNS; no direct contact with spinal cord

Describe Arachnoid Mater

• spider web like

• Internal surface adheres to dura mater

• Envelop the CNS; no direct contact with spinal cord

Describe Pia Mater

• Directly adhering to the spinal cord

• Serves to nourish and protect the spinal cord

What is the purpose of the denticulate ligaments?

To stabilize the spinal cord to the dura mater during movement

• they are extensions of Pia mater

The Epidural Space is found…

Above the dura mater

The subdural space is found…

POTENTIAL SPACE b/w dura mater and arachnoid mater

• “potential” due to arachnoid mater adhering to dura mater

Subarachnoid space

• b/w arachnoid and Pia mater

• ONLY PRESENT if infection is present in the patient

Where are the lateral horns of gray matter present?

• in the spinal cord of the thoracic region

• Due to autonomic function that the lateral horn contributes to which is found in the visceral around this region

LABEL THE STRUCTURES OF A SPINAL CORD

see lecture

Recurrent meninges branches of spinal nerves

Come off the spinal nerve and Renter the intervertebral foramen to innervate the IVD/Facet joints

Numbering convention of spinal nerves

8 cervical spinal nerves (C1-C8)

12 Thoracic spinal nerves (T1-T12)

5 lumbar spinal nerves (L1-L5)

Why are there cervical and lumbar enlargements in the spinal cord?

House more nervous tissue and neurons to contribute to cervical and lumbar plexuses

Film Terminale Interna

• Function: Anchors spinal cord/provides longitudinal stability

• Derived from Pia mater

• Anchored to pia mater superiority and coccyx inferiorly

Suboccipital Triangle Borders

• Rectus Capitis Posterior Major

• Obliquus Capitis inferior

• Obliquus Capitis Superior

Suboccipital triangle FLOOR

• Posterior Atlantooccipital membrane

• Posterior Arch of the Atlas

Suboccipital Traingle ROOF

Semispinalis Capitis

What two structures lie within the Suboccipital Triangle?

Vertebral artery and Suboccipital n (C1)

What is special about the C1 Dorsal Ramus (Suboccipital n)

• Dedicated motor nerve

• C1 dermatome is innervated by C2 (greater occipital nerve) to provide sensory innervation to back of scalp

What nerve pierces semispinalis capitis

The greater occipital n (C2)

Describe the contents of the Posterior Layer of thoracolumbar fascia

• lies posteriorly to epaxial muscles

• Layer thickened from spinous processes

• Aponeurosis from erector spinal, latissimus dorsi, serrated posterior inferior

Describe the contents of the middle layer of thoracolumbar fascia

• lies anterior to expaxial muscles

• Layer thickened fromTP (anterior to erector spinae)

• Aponeurosis from external abdominal oblique, internal abdominal oblique, transversus abdominis

Describe the contents of the anterior layer of thoracolumbar fascia

• layer from TPs

• Lies anterior to QL

• Aponeurosis from quadratic lumborum, psoas major

What do the lateral layers of thoracolumbar fascia fuse to form?

The origin of the transverse abdominis

What Aponeurosis contributions for linea alba?

External abdominal obliques

Internal abdominal obliques

Transversus abdominis

What are the components of the sternum?

Manubrium

Sternal Body (4 sternebrae)

Xiphoid process

Thoracic INLET is defined by what structures?

Vertebral body of T1

R/L Rib 1

Manubrium

What passes through the thoracic inlet?

Jugular veins, subclavian artery, brachial plexus

Thoracic Outlet is defined by what structures?

Body of T12

Ribs 11-12

11-12 costal margins

Inferior body of the sternum

Xiphoid

What muscle attaches to the thoracic outlet?

Diaphragm!

What passes through the thoracic outlet?

Inferior vena cava

Descending abdominal aorta

Sternomanubrial joint

Articulation of the Manubrium with the sternal body

• cartilaginous joint forming the sternal angle

Intersternebral joint

Articulation between adjacent sternebrae

• Cartilaginous joint forming synostoses from inferior to superior (NOT MOVABLE/FUSE TOGETHER)

Xiphisternal

Articulation b/w Xiphoid process and sternal body

• Cartilaginous joint, forms a synostosis

Sternocostal joints

Articulation b/w costal cartilage of ribs 1-7 (true ribs) and sternal body

• radiate ligaments reinforce the costal cartilages

• Synovial joints (2-7) to allow for respiration

• No movement at rib 1

Interchondral joints

Articulation b/w costal cartilages of ribs 7-10 (false ribs)

• functional gliding joints (no slide + glide movement)

Articulation of rib pairs 1-7 with sternum

True ribs articulate directly with the sternum

Articulation of rib pairs 8-10

False ribs that articulate with costal cartilages

Articulations of rib pairs 11-12

False ribs “floating ribs” that have no attachment of costal cartilage or sternum

What makes up the neurovascular bundle in the thoracic cavity?

Intercostal VEIN

Intercostal ARTERY

Intercostal NERVE

VAN SUPERIORLY TO INFERIORLY

Where does the neurovascular bundle lie in the ribs?

Lies between the internal intercostals and innermost intercostals

(Dives deep into innermost intercostals)

What muscles of the thorax DEPRESS THE RIBS during FORCED EXHALATION?

Subcostals

Innermost intercostals

Internal Intercostals

Transversus thoracis

Diaphragm OIAN

O:

sternal- inner part of the xiphoid process,

coastal- inner surfaces of the lower 6 ribs + their cartilage

lumbar- bodies of lumbar vertebrae 2-4 + tendinous arches (medial + lateral arcuate ligaments), which are from QL + psoas major

I: central tendon of the diaphragm

A: draws inferior tendon inferiorly, to expand the thorax cavity during inhalation

N: phrenic n. (C3, C4, C5)

Blood supply to the 1st and 2nd posterior intercostal mm on the RIGHT SIDE

Aorta

BC trunk

R subclavian

Costocervical trunk

Superior intercostal a

Posterior intercostal aa

Descending thoracic aorta —> Posterior intercostal a. Provides blood supply to which intercostal muscles?

Posterior intercostal muscles in spaces 3-11

Descending thoracic aorta—> Subcostal a provides blood supply to where

Subcostal space INFERIOR to rib 12

Blood supply to the anterior UPPER 6 Intercostal spaces/muscles

Aorta

BC trunk

R subclavian

Internal thoracic artery

Anterior intercostal arteries

Blood supply to the anterior LOWER (7-12) intercostal spaces/muscles near costal margin and diaphragm

Aorta

BC trunk

R subclavian

Internal thoracic artery

Musculophrenic artery

Anterior intercostal aa

The Internal thoracic artery bifurcates into what?

Musculophrenic artery (lateral)

Superior epigastric artery (medial)

Explain the route of venous drainage of the posterior wall on the right side starting at different locations

…