Topography Flashcards
Anterior Cranial Fossa
The greater part of the anterior cranial fossa is formed by the orbital parts of the frontal bone. Their surface shows sinuous impressions that partially correspond to the orbital gyri of the frontal lobes.
More posteriorly lie the lesser wings of the sphenoid. with the sphenidal crest that medially continues into the anterior clinoid process.
Between both orbital parts of the frontal bone lies the die cribriform plate of the ethmoid, that connects the anterior cranial fossa with the nasal cavity.
In the center of the cribriform plate occurs the crista galli as a median ridge of the ethmoid bone. At its anterior end lies the small foramen caecum that continues into the frontal crest.
The anterior ethmoid foramen connects the anterior cranial fossa with the orbit.
Middle Cranial Fossa
The central part of the butterfly- shaped middle cranial fossa consists of the body of the sphenoid. Its surface is formed by the sella turcica and the hypophyseal fossa, where the pitutary gland is located.
The hypophyseal fossa is bounded anteriorly by the prominent tuberculum sellae and posteriorly by thedorsum sellae that continues superolaterally into theposterior clinoid process.
Laterally lies the carotid groove, where the internal carotid artery is situated.
The lateral parts of the middle cranial fossa are formed by the major wings of the sphenoid, the squamous part of the temporal bones and the anterior surface of the petrous part of the temporal bones.
The superior margin of the petrous part separates the middle cranial fossa from the posterior cranial fossa.
Middle Cranial Fossa Openings and Connections
The middle cranial fossa has the following (paired)openings and connections:
Superior orbital fissure: slit like opening between the lesser and major wings of the sphenoid - communicates with the orbit
Optic canal: situated between the body and the lesser wing of the sphenoid - connection to the orbit
Foramen rotundum: pierces the major wing of the sphenoid - communicates with the pterygopalatine fossa.
Foramen ovale and Foramen spinosum : pierce the major wing of the sphenoid - opens into theinfratemporal fossa.
Foramen lacerum: situated between the major wing of the sphenoid and the tip of the petrous part of the temporal bone, almost completely closed by a chondral plate - connection to the infratemporal fossa and thepterygopalatine fossa
Carotid canal: curved canal through the petrous part of the temporal bone, ends with the internal aperture - conncetion to the parapharyngeal space.
Posterior Cranial Fossa
The deepest cranial fossa extends from the superior margin of the petrous part of the temporal bones to the Sulcus sinus transversus.
The largest part of the posterior cranial fossa is made by occipital bone. Its body fuses with the dorsum sellae of the sphenoid forming the rampant clivus.
The posterior surface of the petrous part of the temporal bones border anteriorly the posterior cranial fossa.
At the inner surface of the squamous part of the occipital bone lies the paired groove for transverse sinus. It continues laterally into the groove for sigmoid sinus (here shown only at the left side) where the sigmoid sinus (here shown only at the right side) is situated.
The internal occipital crest ascends from theforamen magnum and ends in the internal occipital protuberance.
Posterior Cranial Fossa Openings and Connections
The posterior cranial fossa has the following openingsand connections:
Internal acoustic opening: lies at the posterior surface of the petrous part of the temporal bones and continues into the internal acoustic meatus - communicates with internal and middle ear.
Jugular foramen: Opening between the petrous part of the temporal bone and the lateral part of the occipital bone - opens into the parapharyngeal space
Foramen magnum: surrouded by the basilar and lateral parts of the occipital bone - conncetion to thevertebral canal
Hypoglossal canal: situated in the lateral wall of the foramen magnum - opens into the parapharyngeal space.
Frontal Region
- *Borders**
inferior: supraorbital margin
medial: midline
lateral: vertical line through the middle of the zygomatic arch
The supraorbital artery pierces together with the supraorbital nerve. the orbicularis oculi after passing the supraorbital notch or foramen . Both then ascend in the subcutaneous tissue and run along the frontalis up to the vertex.
At the medial end of the supraorbital margin lie thesupratrochlear artery and the supratrochlear nerve that enter the region through the frontal notch or foramen.
Nearby opens the frontal vein into the angular vein.
From laterally enters the frontal branch of the superficial temporal artery the region. It anastomoses with the branches of the supraorbital artery.
Temporal Region
- *Borders**
superior: superior temporal line
inferior: zygomatic arch
In the subuctaneous layer ascend the superficial temporal artery and the adjoining superficial temporal vein that divide into the frontal branchand the temporal branch.
Immediately anterior to the auricle lies the thinauriculotemporal nerve ; it is usually situated posterior to the blood vessels.
The temporal branches of the facial nerve enter the region at the superior margin of the parotid gland. They run anteriosuperiorly to the frontalis and theorbicularis oculi.
Temporal Region cont’d
The temporalis forms the muscular floor of the region. It is covered by the tough temporal fascia. The latter consists of an external layer that extends from the superior temporal line to the outer surface of the zygomatic arch, and an internal layer that follows the temporalis up to its insertion at the mandible. The space between both layers is filled by fat tissue.
The branches of the middle meningeal artery that run between the dura and the bones of the calvaria may be reached by the trepanation of the sqamous part of the temporal bone and the squamous part of the parietal bone.
Anterior branch of the middle meningeal artery:
It is found by the trepanation of the pterion at thecross-over of a horizontal line through the supraorbital margin with a vertical line through the middle of the zygomatic arch.
Posterior branch of the middle meningeal artery : It is found by the cross-over of a horizontal line through the supraorbital margin and a vertical line through the posterior margin of the mastoid process.
Regio Axillaris
Apex – Also known as the axillary inlet, this is formed by lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle.
Lateral wall – Formed by intertubecular groove of the humerus.
Medial wall – Consists of the serratus anterior and the thoracic wall (ribs and intercostal muscles).
Anterior wall – Contains the pectoralis major and the underlying pectoralis minor and the subclavius muscles.
Posterior wall – Formed by the subscapularis, teres major and latissimus dorsi
There are three sections of the basin according to its front wall: 1) trigonum clavipectorale - hollow to the top edge of the pectoralis minor, 2) trigonum pectorale - the pectoralis minor, 3) trigonum subpectorale - is located between the bottom edge of the small breast and chest muscles.
On the back armpits has two holes - for. trilaterum and for. quadrilaterum; triangular hole formed mm. subscapularis, teres minor top, m. teres major bottom and long head m. triceps brachii outside. Square hole (four-sided) is more than outwards and bounded from above mm. subscapularis, teres minor, bottom - m. teres major, from the inside - long head m. triceps brachii, outside - surgical neck of the humerus.
Regio Deltoidea
- borders:
- superior: line drawn on the deltoid muscle from lateral third of clavicle, acromion and lateral thrird of spine of scapula
- inferior: horizontal line drawn on the lower margin of pec major and lat dorsi
- anterior: ant margin of deltoid
- posterior: post margin of deltoid
Regio Infraclavicularis
subclavian region
- borders:
- superior: clavicle
- inferior: horizontal line drawn through the 3rd rib (men), upper margin of mammary gland (women)
- medial: lateral margin of sternum
- lateral: anterior margin of deltoid muscle
Regio Brachii Anterior
- borders:
- superior: horizontal line from pec major and lat dorsi
- inferior: imaginary line 2 fingers above the lateral and medial epicondyles of the humerous
- medial and lateral: vertical lines on medial and lateral epicondyles
- muscles:
- corachobrachialis
- brachialis
- biceps brachii
- bones:
- humerous
Inguinal Canal
- borders:
- inf wall: inguinal ligament
- ant wall: aponeurosis externsl oblique
- post wall: fascia transversalis
- sup wall: aponeurosis internal oblique and transverse abdominal
- The two openings to the inguinal canal are known as rings. The deep (internal) ring is found above the midpoint of the inguinal ligament. which is lateral to the epigastric vessels. The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal.
The superficial (external) ring marks the end of the inguinal canal, and lies just superior to the pubic tubercle. It is a triangle shaped opening, formed by the evagination of the external oblique, which forms another covering of the inguinal canal contents. This opening containsintercrural fibres, which run perpendicular to the aponeurosis of the external oblique and prevent the ring from widening.
- contents:
- genital branch of genitofem
- ilioinguinal nerve
- art and ven testicularis
- art and ven ductus deferens (in spermatic cord with vas def and ductus def)
- in females- round ligament
Posterior Mediastinum
- borders:
- Lateral borders: Mediastinal pleura (this is a portion of the parietal pleural membrane).
- Anterior border: Pericardium.
- Posterior border: T5-T12 vertebrae.
- Roof: Continuous with the superior mediastinum at the transverse thoracic plane.
- Floor: Diaphragm.
- Contents:
- thoracic aorta (descending)
- oesophagus
- nervi vagi
- thoracic duct
- azygous
- hemiazygous
- sympathetic trunk
Submandibular Triangle
- borders:
- inferior margin of mandible
- ant and post digastric bellies
- contents:
- lymph nodes
- submandibular gland
- submental artery - branch of facial
- mylohyoid nerve
- hypoglossal nerve
- lingual nerve
