ZOO 3733L - Gross Anatomy Lab I

Dissections of May 13 - 16, 2002

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; Moore & Agur, 2002; Stern, 1997).

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

PECTORAL REGION; ANTERIOR THORACIC WALL (Ch. 1; pp. 1-6)

Dissection notes

Contrá figure in dissector, need to skin cranial to clavicles to expose pectoralis major; need not encircle nipples
Skip dissection of breast, breast structures will be studied on model
Contrá dissectior, innermost intercostals cannot be seen in this dissection; these will be examined in posterior mediastinum
Modify the breastplate cuts to expand opening; detach serratus anterior from its attachments to ribs 2-6, leaving attachments to ribs 7 & 8; then cut ribs 2-6 close to mid-axillary line
Contrá your text, it is well established that both pectoral muscles (major and minor) are innervated by both pectoral nerves (medial and lateral)

landmarks/regions
	
	suprasternal notch (jugular notch)
	sternal angle
	deltopectoral triangle

osteology
	clavicle
	scapula
		coracoid process

myology
	pectoralis major
	pectoralis minor
	serratus anterior
	external intercostal
	internal intercostal
	(innermost intercostal)
	transversus thoracis

angiology
	cephalic 
	axillary a
		thoracoacromial a
	anterior intercostal a 
	anterior intercostal v
	(posterior intercostal a)
	(posterior intercostal v)
	internal thoracic a
	internal thoracic v

neurology
	lateral pectoral n
	medial pectoral n
	(intercostal nn)

misc. 
	breast - on model only
		gland lobe
			gland lobule
		lactiferous duct
		ampulla (of milk duct) = lactiferous sinus 
		areola (areola mammae)
		nipple (papilla mammae)
		retromamillary space
		pectoralis major

PLEURAE AND LUNGS (Ch. 1; pp. 6-8)

Dissection notes

When removing lungs take care not to damage phrenic and vagus nn
The key to cleanly and completely removing the lungs is to clearly define the bronchi and pulmonary vessels in the hilum before cutting them
Structures listed in steps 3 and 4 of section C (page 8) will be dissected with the posterior mediastinum

landmarks/regions
	(mediastinum:  superior, inferior (anterior, middle, posterior)

neurology
	phrenic n
	(vagus (CN X) n)

angiology
	pulmonary a
	pulmonary vv

splanchnologoy
	pleural cavity
		visceral pleura
		parietal pleura:  costal, mediastinal, diaphragmatic, cervical (cupula)
		pleural recesses
			costodiaphragatic
			costomediastinal
		root of the lung
		pulmonary ligament
	lung
		hilum
		primary bronchi
			lobar (secondary bronchi)
				segmental (tertiary bronchi)
		bronchopulmonary segment
		right lung
			superior lobe
				horizontal fissure
			middle lobe
				oblique fissure
			inferior lobe
		left lung
			superior lobe
				oblique fissure
			inferior lobe
	(pulmonary lymph nodes)

MEDIASTINUM AND HEART (Chap. 1; pp. 9-15)

Dissection notes

1. The key to cleanly removing the heart is to clearly define the great vessels before cutting them. Take special care to cut the pulmonary trunk and aorta proximal to the ligamentum arteriosum.
2. The chambers of the heart will be opened using cuts different from those described in your dissector; this image (heartct2.gif) illustrates the cuts. It is important that the cardiac vessels be traced and cleaned prior to making these cuts.
Right atrium: Cut with scissors across the posterior wall from the superior vena cava to the inferior vena cava.
Right ventricle: Start at the pulmonary trunk and cut with scissors to the inferior margin through the anterior wall, roughly halfway between the right margin and interventricular sulcus; check your progress to avoid damaging the tricuspid valve.
Left atrium: Make a vertical cut with scissors between the right and left pulmonary veins; a second transverse cut may be necessary to open the chamber sufficiently.
Left ventricle: Start at the aorta and cut with scissors to the apex along the interventricular sulcus. Star dissectors will avoid cutting the left coronary artery when making this cut by freeing the proximal end of the circumflex artery and cutting beneath it.

neurology
	vagus (CN X) n
	left recurrent laryngeal nerve

angiology
	aorta
	pulmonary trunk 
		pulmonary aa
	ligamentum arteriosum (remnant of ductus arteriosum)
	superior vena cava
	inferior vena cava
	pulmonary vv
	coronary aa
		right coronary a
			(right atrial / artery to sinoatrial (SA) node)
			right marginal a
			posterior interventricular a
		left coronary a
			anterior interventricular a
			circumflex a
	coronary veins
		great cardiac v 
		middle cardiac v
		small cardiac vv
		coronary sinus
		(anterior cardiac vv)

splanchnology
	pericardium
		transverse pericardial sinus
		oblique pericardial sinus
	heart
		coronary (atrioventricular) sulcus 
		interventricular sulci:  anterior and posterior
		right atrium
			auricle
			crista terminalis
			pectinate muscles
			site of sinoatrial (SA) node
			fossa ovalis
			opening of coronary sinus
			right atrioventricular opening
		right ventricle
			trabeculae carnae
			conus arteriosus (infundibulum)
	
			right atrioventricular (tricuspid) valve:  
				cusps; chordae tendineae; papillary muscles
			septomarginal trabecula (moderator band)
			valve of pulmonary trunk
				semilunar cusps with nodules
		left atrium 
			auricle
			pectinate muscles
			atrial septum
			left atrioventricular opening
		left ventricle
			interventricular septum
			left atrioventricular (mitral or bicuspid) valve:
				cusps; chordae tendineae; papillary muscles
			valve of the aorta
				semilunar cusps with nodules

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1.	The key to cleanly removing the heart is to clearly define the great vessels before cutting them. Take special care to cut the pulmonary trunk and aorta proximal to the ligamentum arteriosum.
2.	The chambers of the heart will be opened using cuts different from those described in your dissector; this image (heartct2.gif) illustrates the cuts. It is important that the cardiac vessels be traced and cleaned prior to making these cuts.
	Right atrium:	Cut with scissors across the posterior wall from the superior vena cava to the inferior vena cava.
	Right ventricle:	Start at the pulmonary trunk and cut with scissors to the inferior margin through the anterior wall, roughly halfway between the right margin and interventricular sulcus; check your progress to avoid damaging the tricuspid valve.
	Left atrium:	Make a vertical cut with scissors between the right and left pulmonary veins; a second transverse cut may be necessary to open the chamber sufficiently.
	Left ventricle:	Start at the aorta and cut with scissors to the apex along the interventricular sulcus. Star dissectors will avoid cutting the left coronary artery when making this cut by freeing the proximal end of the circumflex artery and cutting beneath it.