ZOO 4990L - Gross Anatomy Lab III

Dissections of September 4 - 6, 2001

N.B.		In each dissection some names appear in parentheses. These are structures that may not readily be found during your dissection, i.e., look for them but do not spend too much time on them so that you have time to comlete the laboratory. Many of these structures will be exposed more completely in future dissections or are best observed in your atlas. Also, there will be important structures listed that are not found in your dissector (Hansen, 1998); information about these items can be found in your text (Jenkins, 1998; Moor and Augur, 1996; Stern, 1997).

SUPERFICIAL BACK (Ch. 4; pp. 63-8)

Dissection notes

be sure and be generous in skinning, particularly laterally in head
will see greater occipital n and occiptal a later (ignore)
reflect trapezius only from its vertebral origin for the time (and not also from scapula)
take care in reflecting the rhomboids that you do not remove the underlying serratus posterior superior

landmarks/regions 
	(triangle of auscultation)
	(lumbar triangle)
	vertebra prominens (C7)
	(external occipital protuberance)
	(mastoid processes)

osteology 
	scapula
		spine
		acromion
		superior angle
		inferior angle
		vertebral border

myology 
	trapezius 
	latissimus dorsi 
		thoracolumbar fascia 
	levator scapulae 
	rhomboideus major 
	rhomboideus minor 
 
neurology 
	accessory n (CN XI) 
	(dorsal scapular n)

DEEP BACK (Ch. 4; pp. 68-9)

Dissection notes

Expose erector spinae bilaterally by reflecting (partially) lattissimus dorsi
Contrá the dissector, on one side, carefully reflect the erector spinae in the lumbar region to reveal multifidis; ambitious students may wish to seek the underlying rotatores
Given the relatively short dissection, time will be available to clean up the superficial. back dissection and review
Models of the spinal cord are also available for study

myology 
	(serratus posterior superior) 
	(serratus posterior inferior)
	splenius 
	erector spinae 
		spinalis 
		longissimus 
		iliocostalis 
	transversospinalis muscles 
		semispinalis  
		multifidus 
		(rotatores) 
	levatores costarum 
	(interspinalis)
	(intertransverse)
 
arthrology 
	ligamentum nuchae

LAMINECTOMY (Ch. 4; pp. 69-71)

Dissection notes

This dissection is done as a prosection
Minimize relflection of erector spinae so as to preserve dorsal rami
Cuts through lamina need to be made medial to articular processes to preserve dorsal rami

arthrology
	supraspinous ligament
	interspinous ligament
	ligamentum flavum

neurology
	spinal cord
		conus medullaris
		cauda equina
		filum terminale
		dorsal roots
		ventral roots
	spinal (dorsal root) ganglion
	spinal nerve
		ventral (primary) ramus
		dorsal (primary) ramus

	spinal cord membranes and spaces
		epidural space
			dura mater
			arachnoid mater
				subarachnoid space
			pia mater
				denticulate ligaments

angiology
	internal vertebral venous plexus
	(posterior spinal aa)
	(anterior spinal a)

spinal cord models
	ventral roots
	dorsal roots
		spinal (dorsal root) ganglion
	spinal nerve
		dorsal (primary) ramus
		ventral (primary) ramus
		rami communicans
	gray matter
		dorsal horn
		ventral horn
		lateral horn (thoracic only)
		central canal
	white matter
		dorsal funiculus
		lateral funiculus
		ventral funiculus
	fissures/sulci
		ventral median sulcus
		dorsal median fissure
		ventrolateral sulcus
	vessels
		anterior spinal a
		posterior spinal aa

SUBOCCIPITAL REGION (Ch. 4; pp. 71-2)

Dissection notes

Contrá the dissector (p. 71), dissect only one side.
The key to dissecting the suboccipital region is to find the spinous process of C2.
- (1) If you haven't already done so, reflect splenius from its midline origin.
- (2) Next, detach completely semispinalis capitis from its attachment to the occiput (leave no trace).
- (3) Define semispinalis cervicis and trace it to its cranial-most attachment which is the spinous process of C2
- (4) From the spinous process of C2 define the origins of rectus capitis posterior major and inferior obliquus capitis and trace these muscles to their respective attachments.
- (5) Superior obliquus capitis arises from the transverse process of C1 adjacent to the attachment of inferior obliquus capitis.
- (6) Rectus capitis posterior minor arises from dorsal arch of C1 and thus lies deep and medial to RCP major.
Now wasn't that easy!

landmarks/regions
	suboccipital triangle

myology
	superior obliquus capitis
	inferior obliquus capitis
	rectus capitis posterior major
	rectus capitis posterior minor

neurology
	greater occipital n (dr C2)
	suboccipital n (dr C1)

angiology
	vertebral a

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