REGIONAL ANATOMY

Question 1

Layers of scalp, frontal and temporal regions

The cranial dura mater is a thick, tough, outer covering of the brain.

It consists of an outer periosteal layer and an inner meningeal layer

• the outer periosteal layer is
  
  • firmly attached to the skull,
  • is the periosteum of the cranial cavity,
  • contains the meningeal arteries
  • and is continuous with the periosteum on the outer surface of the skull at the foramen magnum and other intracranial foramina (Fig. 8.30B);
• the inner meningeal layer is in
  
  • close contact with the arachnoid mater and is
  • continuous with the spinal dura mater through the foramen magnum.

The two layers of dura separate from each other at numerous locations to form two unique types of structures (Fig. 8.30A):

• dural partitions, which project inward and incompletely separate parts of the brain;
• intracranial venous structures.

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Dural partitions

• The dural partitions project into the cranial cavity and partially subdivide the cranial cavity.
• They include the falx cerebri, tentorium cerebelli, falx cerebelli, and the diaphragma sellae.
• Falx cerebri
  
  • The falx cerebri is a crescent-shaped downward projection of meningeal dura mater from the dura lining the calva that passes between the two cerebral hemispheres.
  • It is attached anteriorly to the crista galli of the ethmoid bone and frontal crest of the frontal bone.
  • Posteriorly it is attached to and blends with the tentorium cerebelli.
• The tentorium cerebelli
  
  • horizontal projection of the meningeal dura mater that covers and separates the cerebellum in the posterior cranial fossa from the posterior parts of the cerebral hemispheres.
  • It is attached posteriorly to the occipital bone along the grooves for the transverse sinuses.
  • Laterally, it is attached to the superior border of the petrous part of the temporal bone, ending anteriorly at the anterior and posterior clinoid processes.
  • The anterior and medial borders of the tentorium cerebelli are free, forming an oval opening in the midline (the tentorial notch), through which the midbrain passes.
• Falx cerebelli

The falx cerebelli (Fig. 8.31) is a small midline projection of meningeal dura mater in the posterior

cranial fossa. It is attached posteriorly to the internal occipital crest of the occipital bone and

superiorly to the tentorium cerebelli. Its anterior edge is free and is between the two cerebellar

hemispheres.

Diaphragma sellae

The final dural projection is the diaphragma sellae (Fig. 8.31). This small horizontal shelf of

meningeal dura mater covers the hypophysial fossa in the sella turcica of the sphenoid bone. There

is an opening in the center of the diaphragma sellae through which passes the infundibulum,

connecting the pituitary gland with the base of the brain, and any accompanying blood vessels.

Answer 1

The scalp consists of 5 distincts layers:

• Skin
  
  • Similar structurally to skin throughout the body with the exception that hair is present on a large amount of it.
• Subcutaneous connective tissue
  
  • Anchors the skin to the third layer and contains the arteries, veins, and nerves supplying the scalp.
• Epicranial aponeurosis: Galea aponeurosis
  
  • The deepest layer of the first three layers is the aponeurotic layer.
  • Firmly attached to the skin by the dense connective tissue of the second layer,
  • This layer consists of the occipitofrontalis muscle
    
    • Function: Move the scalp, wrinkle the forehead, and raise the eyebrows. ​
    • Frontal belly, anteriorly→
      
      • ​temporal branches of the facial nerve [VII]
      • begins anteriorly where it is attached to the skin of the eyebrows→
        
        • passes upward, across the forehead, to become continuous with the aponeurotic tendon.
    • Aponeurotic tendon-the epicranial aponeurosis (galea aponeurotica)- connecting the two bellies
    • Occipital belly, posteriorly→
      
      • posterior auricular branch
      • Arises from the lateral part of the superior nuchal line of the occipital bone and the mastoid process of the temporal bone.
• Subgaleal loose connective tissue
  
  • A layer of loose connective tissue
  • separates the aponeurotic layer from the pericranium
  • and facilitates movement of the scalp proper over the calvaria
  • Because of its consistency, infections tend to localize and spread through the loose connective tissue.
• Pericranium (periostium)
  
  • Deepest layer of the scalp
    
    • is the periosteum on the outer surface of the calvaria.
    • It is attached to the bones of the calvaria, but is removable, except in the area of the sutures.

Innervation

Sensory innervation of the scalp is from two major sources, cranial nerves or cervical nerves depending on whether it is anterior or posterior to the ears and the vertex of the head

The occipitofrontalis muscle is innervated by branches of the facial nerve [VII].

Anterior to the ears and the vertex

• Branches of the trigeminal nerve [V] supply the scalp anterior to the ears and the vertex of the head
  
  • Supratrochlear, supra-orbital, zygomaticotemporal, and auriculotemporal nerves:

the supratrochlear nerve exits the orbit, passes through the frontalis muscle, continues

superiorly across the front of the forehead, and supplies the front of the forehead near the

midline;

the supra-orbital nerve exits the orbit through the supra-orbital notch or foramen, passes

through the frontalis muscle, and continues superiorly across the scalp as far back as the vertex

of the head;

the zygomaticotemporal nerve exits the skull through a foramen in the zygomatic bone and

supplies the scalp over a small anterior area of the temple;

the auriculotemporal nerve exits from the skull, deep to the parotid gland, passes just anterior to

the ear, continues superiorly anterior to the ear until nearly reaching the vertex of the head, and

supplies the scalp over the temporal region and anterior to the ear to near the vertex.

Posterior to the ears and vertex, sensory innervation of the scalp is by cervical nerves, specifically

branches from spinal cord levels C2 and C3 (Fig. 8.67). These branches are the great auricular, the

lesser occipital, the greater occipital, and the third occipital nerves:

the great auricular nerve is a branch of the cervical plexus, arises from the anterior rami of

the C2 and C3 spinal nerves, ascends on the surface of the sternocleidomastoid muscle, and

innervates a small area of the scalp just posterior to the ear;

the lesser occipital nerve is also a branch of the cervical plexus, arises from the anterior

ramus of the C2 spinal nerve, ascends on the posterior border of the sternocleidomastoid

muscle, and supplies an area of the scalp posterior and superior to the ear;

the greater occipital nerve is a branch of the posterior ramus of the C2 spinal nerve, emerges

just inferior to the obliquus capitis inferior muscle, ascends superficial to the suboccipital

triangle, pierces the semispinalis capitis and trapezius muscles, and then spreads out to supply

a large part of the posterior scalp as far superiorly as the vertex;

the third occipital nerve is a branch of the posterior ramus of the C3 spinal nerve, pierces the

semispinalis capitis and trapezius muscles, and supplies a small area of the lower part of the

scalp.

Calvaria and dura matter:

• Calvaria
• Cranial dura matter
• Subcutaneuous nerurovascular bundle
• supperior sagital sinus

***The cranial meninges are continuous with, and similar to, the spinal meninges through the foramen magnum, with one important distinction-the cranial dura mater consists of two layers, and only one of these is continuous through the foramen magnum

CRANIAL CAVITY

• The cranial cavity is the space within the cranium that contains the brain, meninges, proximal parts of the cranial nerves, blood vessels, and cranial venous sinuses.

Roof

• The calvaria is the dome-shaped roof that protects the superior aspect of the brain.
• It consists mainly of the
  
  • Frontal bone anteriorly,
  • Paired parietal bones in the middle,
  • Occipital bone posteriorly
• Sutures visible internally include:
  
  • Coronal suture, between the frontal and parietal bones;
  • Sagittal suture, between the paired parietal bones; and
  • Lambdoid suture, between the parietal and occipital bones.
  • Visible junctions of these sutures are the
    
    • Bregma, where the coronal and sagittal sutures meet,
    • Lambda, where the lambdoid and sagittal sutures meet.

From anterior to posterior, features seen on the bony roof of the cranial cavity are:

• Midline ridge of bone extending from the surface of the frontal bone (the frontal crest), which is a point of attachment for the falx cerebri (a specialization of the dura mater that partially separates the two cerebral hemispheres);
• at the superior point of the termination of the frontal crest the beginning of the groove for the superior sagittal sinus, which widens and deepens posteriorly and marks the position of the superior sagittal sinus (an intradural venous structure);
• on either side of the groove for the superior sagittal sinus throughout its course, a small number of depressions and pits (the granular foveolae), which mark the location of arachnoid granulations (prominent structures readily identifiable when a brain with its meningeal coverings is examined; the arachnoid granulations are involved in the reabsorption of cerebrospinal fluid);
• and on the lateral aspects of the roof of the cranial cavity, smaller grooves created by various meningeal vessels.
• • • • Covering the surface of your head, the scalp, extends from the top of your forehead across to the epicranial aponeurosis of the head.
• Laterally, it reaches down to the external auditory meatus and zygomatic arch (cheekbone of the skull).

Question 2

Topography of vertebral canal, anatomic backgrounds of spinal tap (lumbar puncture) and epidural anesthesia

Answer 2

Vertebral foramen

• Central space between the vertebral arch and vertebral body
• Segmental organization derived from neural tube and somites
• Topography:
  
  • Ventrally: lig. longitudinale posterius
  • Dorsally: arcus vertebrarum, ligg. flava
  • Laterally: pediculi arcus vertebrae, foramina intervertebralia
• All vertebral foramina together form the vertebral canal, containing:
  
  • The spinal cord
  • Meninges
  • Nerve roots
  • Blood vessels

Layers inside

• Periosteum = endorhachis
  
  • ​periosteum of the spinal canal
  • Spatium epidurale
    
    • Epidural anesthesia
    • The space between the dura mater and the endorhachis
    • Filled with thin ligament and fat
    • Vascular plexuses - plexus venosi vertebrales interni
• Dura mater spinalis
  
  • Mesoderm
  • Thick and strong outer layer
  • Adheres to bone
  • Spatium subdurale
    
    • Only potential space
    • ​​significant in case of injury and subsequent bleeding
      
      • (blood from the superficial veins of the brain or from venous sinuses forms a hematoma between the dura mater and the arachnoid, this hematoma enlarges and “creates” a subdural space).
• Arachnoidea mater spinales
  
  • Neural crest
  • Middle layer between the dura and the pia mater
  • It consists of a ligament of collagen and reticular fibers.
  • Attached to inner wall Dura mater spinalis
  • Apatium subarachnoideum – cisterna lumbalis
    
    • Lumbal puncture / spinal anesthesia / aplication of medicaments: CSF sample
    • Between the arachnoid and the pia mater
      • Contains small fibrous beams that connect the arachnoid and the pia mater.
      • Spatium subarachnoideum is filled with cerebrospinal fluid
• Pia mater spinalis
  
  • Neural crest
  • Lig. denticulatum:
    • Triangular shaped ligaments that anchor the spinal cord along its length, at each side, to the dura mater.
    • Arise in the pia mater and they are firmly attached to the arachnoid mater and dura mater
    • They maintain the correct position of the spinal cord inside the sacus durae matris during various movements of the spine.
    • Subarachnoid septum - fibrous sagittal septum in the midline (sometimes incomplete), pointing dorsally.

Blood supply:

Innervation

Lumbar puncture

• Diagnostic/medical procedure.
  
  • cerebrospinal fluid is removed
  • or medicinal products are administered.
• The area of ​​the lumbar spine is most often chosen
• Procedure
  
  • Possition:
    • Mimicking the prenatal position/ forward bend.
      
      • The position ensures sufficient spacing between the vertebral processes.
  • Palpably identify the intervertebral space L 3 / L 4 or L 4 / L 5 . We will color-code the place.
  • Disinfection of the injection site and surroundings.
  • Local anesthesia : subcutaneously around the injection site.
  • Injection direction : Needle angle and proc. spinalis grip 15 °, direction ventrocranial (ie navel). The tip of the needle should be sagittal to minimize traumatization of the spinal roots.
  • We progress through the skin, subcutaneous tissue, ligament, epidural space, dura and subarachnoid space between the spinal roots.

​

Innervation

• Dorsal rami of the spinal nerves:
  
  • Vertebrae, facet joints, superficial ligamenta flava, and overlying skin
• Sinuvertebral nerves
  
  • Walls of the vertebral canal, dura mater, outer annulus of intervertebral discs, and deep ligamenta flava
• Ventral rami of the C1 and C2 nerves:
  
  • Atlanto-occipital and atlanto-axial joints

Blood supply:

• one anterior spinal artery
• two posterior spinal arteries
• anterior and posterior radicular arteries
• arterial vasocorona (anastomose between the spinal arteries)

Lead to:

• Muscles
  
  • The intrinsic muscles of the back are innervated by dorsal rami of the spinal nerves and enable extension, rotation, and lateral flexion of the head and spine.

Question 3

Superficial regions of face

Question 4

Infratemporal fossa and pterygoplatine fossa

→

Answer 4

TEMPORAL AND INFRATEMPORAL FOSSAE

Interconnected spaces on the lateral side of the head

• Their boundaries are formed by bone and soft tissues.
• The temporal fossa is superior to the infratemporal fossa,
  
  • Above the zygomatic arch, and communicates with the infratemporal fossa below through the gap between the zygomatic arch and the more medial surface of the skull.

Infratemporal fossa

Passageway for many neurovascular structures

Summary:

• Borders:
  
  • Sup.: infratemporal crest of temporal bone and greater wing sphenoid bone
  • Ant.: maxillary tuberosity
  • Lat.: ramus of the mandible
  • Med.: lateral plate of the pterygoid process
• Content:
  
  • Pterygoid muscles
  • Pterygoid plexus
  • Maxillary artery
  • Branches of the mandibular nerve:
  • Otic ganglion
  • Buccal adipose body
  • Sphenomadnibular mandibular
• Infratemporal fossa openings
  
  • Mandibular nerve (oval foramen)
  • Middle meningeal art (spinous foramen) (maxillary artery)
  • Inf. alveolar nerve (mandibular canal)
  • Mylohyoid nerve (mylohyoid groove)
  • Inf.ophthalmic vein (inf. orbital fissure)

Pterygopalatine fossa

• Borders:
  
  • Anterior wall: posterior surface of the maxilla;
  • Medial wall: perpendicular plate the palatine bone;
  • Posterior wall: pterygoid process of sphenoid
  • Roof: greater wing of sphenoid
  • Lateral wall: pterygomaxillary fissure
  • Inferior wall: foramen palatinum majus
• Content:
  
  • Maxillary nerve [V2]
    
    • zygomatic n.
    • infraorbital n.
    • posterior superior alveolar nn.
  • Pterygopalatine ganglion
  • terminal part of the maxillary artery
    
    • infraorbital a.
    • sphenopalatine a.
  • Greater palatine n.
  • veins, as well as their associated branches: pterygoid plx
• Openings:
  
  • Orbita via inferior orbital fissure (to orbit)
    
    • zygomatic n
    • infraorbital n. and a.
    • inf. ophtalmic v.
    • orbitalis
  • Middle cranial fossa via foramen rotundum (from cranial cavity)
    
    • maxillary n.
  • Pterygoid canal (to palate)
    
    • n. of pterygoid canal
    • a. and v. of pterygoid canal
  • Nasal cavity via sphenopalatine foramen
    
    • sphenopalatine vessels
    • medial and lateral superior posterior nasal branchs of maxillary n
  • Infratemporal fossa via pterygomaxillary fissure
    
    • maxillary a
    • parts of pterygoid plexsus
  • Greater palatine foramen and lesser palatine foramen (to palate)
    
    • Lesser palatine n. and vessels
    • greater palatine n. and desensing palatine vessels

INFRATEMPORAL FOSSA EXTRA

1-Roof

• Formed by the inferior surfaces of the greater wing of the sphenoid and the temporal bone,
• Contents:
  
  • Foramen spinosum,
  • Foramen ovale,
  • Petrotympanic fissure,
  • Lateral to the infratemporal crest of the greater wing of the sphenoid: is open superiorly to the temporal fossa;

2- Lateral wall

• The medial surface of the ramus of mandible
• Contents:
  
  • Opening to the mandibular canal;

3- Medial wall

• Formed anteriorly by the lateral plate of the pterygoid process
• Posteriorly by the pharynx and by two muscles of the soft palate (tensor and levator veli palatini muscles),
• Contents:
  
  • Pterygomaxillary fissure anteriorly, which allows structures to pass between the infratemporal and pterygopalatine fossae;

4- Anterior wall

• Formed by part of the posterior surface of the maxilla
• Contents:
  
  • Alveolar foramen,
  • Upper part opens as the inferior orbital fissure into the orbit.

5- Inferiorly

• There is no bony anatomical structure to limit it,
• But there is the medial pterygoid muscle that runs anteriorly to attach to the mandible.

​Contents

1. Sphenomandibular ligament,
2. Medial and lateral pterygoid muscles
3. Maxillary artery
4. Mandibular nerve [V3]
5. Branches of the facial nerve [VII]
6. Glossopharyngeal nerve [IX]
7. Pterygoid plexus of veins.

1-Sphenomandibular ligament

• Extracapsular ligament of the temporomandibular joint.
• Attached superiorly to the spine of the sphenoid bone → expands inferiorly to attach to the lingula of the mandible and the posterior margin of the mandibular foramen

Medial pterygoid

• Quadrangular in shape
• Deep head
  
  • O: attached above to the medial surface of the lateral plate of the pterygoid process and the associated surface of the pyramidal process of the palatine bone
  • C: descends obliquely downward, medial to the sphenomandibular ligament,
  • I: roughened medial surface of the ramus of mandible near the angle of mandible
• Superficial head
  
  • O: from the tuberosity of the maxilla and adjacent pyramidal process of the palatine bone
  • I: joins with the deep head to insert on the mandible.
• F: elevates the mandible.
  
  • Because it passes obliquely backward to insert into the mandible, it also assists the lateral pterygoid muscle in protruding the lower jaw.
• N: n. to medial pterygoid from the mandibular nerve [V3]
• Fibers tend to be oriented vertically

Lateral pterygoid

• Thick triangular muscle
• Upper head
  
  • O: roof of the infratemporal fossa (inferior surface of the greater wing of the sphenoid and the infratemporal crest) lateral to the foramen ovale and foramen spinosum;
• Lower head: is larger than the upper head
  
  • O: Lateral surface of the lateral plate of the pterygoid process, and the inferior part insinuates itself between the cranial attachments of the two heads of the medial pterygoid.
• I- both heads:
  
  • Converge to insert into the pterygoid fovea of the neck of mandible and into the capsule of the temporomandibular joint in the region where the capsule is attached internally to the articular disc.
• F: Fibers oriented horizontally.
  
  • As a result, when the lateral pterygoid contracts it pulls the articular disc and head of mandible forward onto the articular tubercle and is therefore the major protruder of the lower jaw.
• N: nerve to lateral pterygoid from the mandibular nerve [V3].

When the lateral and medial pterygoids contract on only one side, the chin moves to the opposite side.

When opposite movements at the two temporomandibular joints are coordinated, a chewing movement results.

Maxillary artery

• The maxillary artery originates within the substance of the parotid gland → then passes forward, between the neck of mandible and sphenomandibular ligament→ into the infratemporal fossa→ pterygomaxillary fissure. → pterygopalatine fossa
  
  • Deep temporal: ant and post (up)
  • Masseteric (down)
  • pterygoid (down)
  • Buccal (down)

Mandibular nerve [V 3]

• Divisions of the trigeminal nerve [V]: both motor and sensory.
• General sensation
  
  • Teeth and gingivae of the mandible, the anterior two-thirds of the tongue, mucosa on the floor of the oral cavity, the lower lip, skin over the temple and lower face, and part of the cranial dura mater, the mandibular nerve [V3]
• Motor innervation
  
  • Most of the muscles that move the mandible, one of the muscles (tensor tympani) in the middle ear, and one of the muscles of the soft palate (tensor veli palatini).
• All branches of the mandibular nerve [V3] originate in the infratemporal fossa.

Pterygopalatine fossa – deepest part of theinfratemporal fossa

Question 5

External and internal cranial base - openings for vessels and nerves

GOO OVER THIS ITS MISSING MANY THINGS

Answer 5

The floor of the cranial cavity is divided into:

• Anterior
• Middle,
• Posterior cranial fossa

Overview of openings:

• Anterior cranial fossa
  
  • Foramen cecum
    
    • Emissary veins from nasal cavity
      
      • to superior sagittal sinus
  • Olfactory foramina in cribriform plate
    
    • Olfactory nerves [I]
  • Anterior and posterior ethmoidal foramen:
  • Optic canal
    
    • Optic nerve [II]; ophthalmic artery
• Middle cranial fossa
  
  • Superior orbital fissure ADDDDD MORE THINGS
    
    • Oculomotor nerve [III];
    • Trochlear nerve [IV];
    • Ophthalmic division of the trigeminal nerve [V1];
    • Abducent nerve [VI];
    • Ophthalmic veins
  • Foramen rotundum
    
    • Maxillary division of the trigeminal nerve [V2]
  • Foramen ovale
    
    • Mandibular division of the trigeminal nerve [V3];
    • Lesser petrosal nerve
    • acessory meningeal artery
    • venous plexsus foramen ovale
  • Foramen spinosum
    
    • Middle meningeal artery and nerve
• Posterior cranial fossa
  
  • Foramen magnum
    
    • End of brainstem/beginning of spinal cord;
    • vertebral arteries;
    • spinal roots of the accessory nerve;
    • meninges
  • Internal acousticmeatus
    
    • Facial nerve [VII];
    • vestibulocochlear nerve [VIII];
    • labyrinthine artery
  • Jugular foramen
    
    • Glossopharyngeal nerve [IX];
    • vagus nerve [X];
    • accessory nerve [XI];
    • inferior petrosal sinus,
    • sigmoid sinus (forming internal jugular vein)
  • Hypoglossal canal
    
    • Hypoglossal nerve [XII];
    • meningeal branch of the ascending pharyngeal artery
  • Condylar canal
    
    • Emissary vein

Anterior cranial fossa

• Parts of the frontal, ethmoid, and sphenoid bones form the anterior cranial fossa
• Its floor is composed of:
  
  • Medially: ethmoid bone
  • Anterior and Laterally: the orbital part of the frontal bone, which also forms the roof of the orbit below.
  • Posterior to both the frontal and ethmoid bones:
    
    • the body (midline),
    • the lesser wings (laterally).
• The boundary between the anterior and middle cranial fossae in the midline is the anterior edge of the chiasmatic sulcus, a smooth groove stretching between the optic canals across the body of the sphenoid.
• The anterior cranial fossa is above the nasal cavity and the orbits
• Contents: filled by the frontal lobes of the cerebral hemispheres.
• Features:
  
  • Frontal crest:
    
    • A small wedge-shaped midline crest that projects from the frontalbone.
    • This is a point of attachment for the falx cerebri.
  • Foramen cecum
    
    • Immediately posterior to the frontal crest
    • This foramen between the frontal and ethmoid bones may transmit emissary veins connecting the nasal cavity with the superior sagittal sinus.
  • Crista galli
    
    • Posterior to the frontal crest
    • A prominent wedge of bone projecting superiorly from the ethmoid
    • Another point of attachment for the falx cerebri, which is the vertical extension of dura mater partially separating the two cerebral hemispheres
  • Cribriform plate of the ethmoid bone
    
    • Lateral to the crista galli
    • Allows small olfactory nerve fibers to pass through its foramina from the nasal mucosa to the olfactory bulb.
  • Anterior clinoid process
    
    • Medially each lesser wing widens, curves posteriorly, and ends as a rounded process that serve as the anterior point of attachment for the tentorium cerebelli, which is a sheet of dura that separates the posterior part of the cerebral hemispheres from the cerebellum.

Middle cranial fossa

The middle cranial fossa consists of parts of the sphenoid and temporal bones

Boundaries

• between the anterior and middle cranial fossae
  
  • in the midline
    
    • is the anterior edge of the chiasmatic sulcus,
    • which is a smooth groove stretching between the optic canals across the body of the sphenoid.
• Posterior boundaries
  
  • formed by the anterior surface, as high as the superior border, of the petrous part of the petromastoid part of the temporal bone.
• Its floor is composed of:
  
  • Body of the sphenoid
  • Greater wing of sphenpois
  • Temporal bone?
  • Anterior surface of the petrousmpart of the petromastoid part of the temporal bone
  • squamous part of the temporal bone.???

Contents: temporal lobes of the brain

Features: Sphenoid bone

• Sella turcica
  
  • Posterior to the chiasmatic sulcus
  • Body of the sphenoid
  • Hypophysial fossa→ a deep central area
    
    • Containing the pituitary gland with anterior and posterior vertical walls of bone
  • Dorsum sellae
    
    • The posterior wall of the sella turcica
    • A large ridge of bone projecting upward and forward.
    • Posterior clinoid processes
      
      • Rounded projections at the top of this bony ridge the lateral
      • Points of attachment for the tentorium cerebelli.
• Superior orbital fissure
  
  • A diagonal gap
  • Separates the greater and lesser wing of the sphenoid
  • Major passageway between the middle cranial fossa and the orbit.
  • Passing structures:
    
    • Oculomotor nerve [III],
    • Trochlear nerve [IV],
    • Ophthalmic nerve [V1],
    • Abducent nerve [VI],
    • Ophthalmic veins.
• Foramen rotundum
  
  • Posterior to the medial end of the superior orbital fissure on the floor of the middle cranial fossa
  • Rounded foramen projecting in an anterior direction
  • Passing structures:
    
    • Maxillary nerve [V2] passes from the middle cranial fossa to the pterygopalatine fossa.
• Foramen ovale
  
  • Posterolateral to the foramen rotundum
  • Large oval opening
  • Allows structures to pass between the extracranial infratemporal fossa and the middle cranial fossa.
  • Passing structures:
    
    • Mandibular nerve [V3],
    • Lesser petrosal nerve
      
      • (carrying fibers from the tympanic plexus that originally came from the glossopharyngeal nerve [IX])
      • Occasionally, a small vessel (the accessory middle meningeal artery)
• Foramen spinosum
  
  • Posterolateral from the foramen ovale
  • Small opening
  • This opening also connects the infratemporal fossa with the middle cranial fossa.
  • Passing structures: ​
    
    • Middle meningeal artery and its associated veins
      
      • Once inside, the groove for the middle meningeal artery across the floor and lateral wall of the middle cranial fossa clearly marks their path.
• Carotid canal
  
  • Posteromedial to the foramen ovale
  • Rounded intracranial opening
• Foramen lacerum
  
  • Directly inferior to this opening is an irregular foramen
  • Closed in life by a cartilaginous plug and no structures pass through it completely.

Features: Temporal bone

• Trigeminal impression
  
  • A slight depression in the anterior surface of the petrous part of the temporal bone
  • Marks the location of the sensory ganglion for the trigeminal nerve [V].
• Groove and hiatus for the greater petrosal nerve
  
  • Lateral to the trigeminal impression and on the anterior surface of the petrous part of the temporal bone
  • a small linear groove that passes in a superolateral direction, and ends in a foramen
  • The greater petrosal nerve is a branch of the facial nerve [VII]
• Groove and hiatus for the lesser petrosal nerve,
  
  • Anterolateral to the groove for the greater petrosal nerve
  • Smaller groove
  • The lesser petrosal nerve: a branch from the tympanic plexus carrying fibers that originally came from the glossopharyngeal nerve [IX]
• Arcuate eminence
  
  • A rounded protrusion of bone
  • Produced by the underlying anterior semicircular canal of the inner ear.
  • Above and lateral to the small openings for the greater and lesser petrosal nerves,
  • Near the superior ridge of the petrous part of the temporal bone,
• Tegmen tympani
  
  • Depressed surface of anterior surface of the petrous part of the temporal bone
  • Marks the thin bony roof of the middle ear cavity.
  • Just anterior and lateral to the arcuate eminence

Posterior cranial fossa

• Composed of
  
  • parts of the temporal and occipital bones
  • with small contributions from the sphenoid and parietal bones
• It is the largest and deepest of the three cranial fossae
• Contains
  
  • The brainstem (midbrain, pons, and medulla)
  • The cerebellum.
• Boundaries
  
  • Anterior:
    
    • Medially: dorsum sellae and the clivus
      
      • The clivus is a slope of bone that extends upward from the foramen magnum.
        
        • It is formed by contributions from the body of the sphenoid and from the basilar part of the occipital bone.
    • Laterally: superior border of the petrous part of the petromastoid part of the temporal bone.
  • Posteriorly:
    
    • The major boundary: the squamous part of the occipital bone to the level of the transverse groove,
    • Laterally: the petromastoid part of the temporal bone and small parts of the occipital and parietal bones border the fossa.
• Foramen magnum
  
  • Centrally is the largest foramen in the skull
  • In the deepest part of the posterior cranial fossa
  • Surrounded by the
    
    • Basilar part of the occipital bone anteriorly,
    • The lateral parts of the occipital bone on either side,
    • The squamous part of the occipital bone posteriorly.
  • Contents:
    
    • The spinal cord passes superiorly through the foramen magnum to continue as the brainstem.
    • Vrtebral arteries
    • The meninges,
    • The spinal roots of the accessory nerve [XI].

Grooves and foramina

The clivus slopes upward from the foramen magnum. is a groove for the

• Inferior petrosal sinus
  
  • between the basilar part of the occipital bone and the petrous part of the petromastoid part of the temporal bone
  • Lateral to the clivus
• Internal acoustic meatus
  
  • Laterally, across the upper half of the posterior surface of the petrous part of the temporal bone
  • an oval foramen
  • Contents
    
    • The facial [VII]
    • vestibulocochlear [VIII] nerves,
    • Labyrinthine artery pass through it.
• Jugular foramen
  
  • Inferior to the internal acoustic meatus
  • causes seperation of the temporal bone from the occipital bone
  • Leading to this foramen from the medial side is the:
    
    • Groove for the inferior petrosal sinus,
    • and from the lateral side the groove for the sigmoid sinus.
  • Sigmoid sinus passes into the jugular foramen, and is continuous with the internal jugular vein, while the inferior petrosal sinus empties into the internal jugular vein in the area of the jugular foramen.
  • Contents:
    
    • Glossopharyngeal nerve [IX],
    • Vagus nerve [X],
    • the accessory nerve [XI]
• Jugular tubercle
  
  • Medial to the jugular foramen is a large rounded mound of the occipital bone
• Hypoglossal canal
  
  • Just inferior to the jugular tubercle, and superior to the foramen magnum,
  • through which the hypoglossal nerve [XII] leaves the posterior cranial fossa, and a meningeal branch of the ascending pharyngeal artery enters the posterior cranial fossa.
• Condylar canal
  
  • Just posterolateral to the hypoglossal canal
  • When present, transmits an emissary vein.

Squamous part of the occipital bone

The squamous part of the occipital bone has several prominent features

is the

internal occipital crest:

running upward in the midline from the foramen magnum

on either side of the internal occipital crest, the floor of the posterior cranial fossa is concave to accommodate the cerebellar hemispheres;

the internal occipital crest ends superiorly in a bony prominence (the internal occipital protuberance

extending laterally from the internal occipital protuberance are grooves produced by themtransverse sinuses, which continue laterally, eventually joining a groove for each sigmoid sinuseach of these grooves then turns inferiorly toward the jugular foramina.

External foramina of the skull

Anterior view

• Supra-orbital foramen
  
  • Supra-orbital nerve and vessels
• Infra-orbital foramen
  
  • Infra-orbital nerve and vessels
• Mental foramen
  
  • Mental nerve and vessels

Lateral view

• Zygomaticofacial foramen
  
  • Zygomaticofacial nerve

Superior view

• Parietal foramen
  
  • Emissary veins

Inferior view

• Incisive foramina
  
  • Nasopalatine nerve; sphenopalatine vessels
• Greater palatine foramen
  
  • Greater palatine nerve and vessels
• Lesser palatine foramina
  
  • Lesser palatine nerves and vessels
• Pterygoid canal
  
  • Pterygoid nerve and vessels
• Foramen ovale
  
  • Mandibular nerve [V3]; lesser petrosal nerve
• Foramen spinosum
  
  • Middle meningeal artery
• Foramen lacerum
  
  • Filled with cartilage
• Carotid canal
  
  • Internal carotid artery and nerve plexus
• Foramen magnum
  
  • Continuation of brain and spinal cord; vertebral arteries and nerve plexuses; anterior spinal artery; posterior spinal arteries; roots of accessory nerve [XI]; meninges
• Condylar canal
  
  • Emissary veins
• Hypoglossal canal
  
  • Hypoglossal nerve [XII] and vessels
• Jugular foramen
  
  • Internal jugular vein; inferior petrosal sinus; glossopharyngeal nerve [IX]; vagus nerve [X]; accessory nerve [XI]
• Stylomastoid foramen
  
  • Facial nerve [VII]

Internal foramina of the skull

Question 6

Submandibular triangle, carotid triangle (draw scheme)

→

Answer 6

Submandibular triangle

Borders:

• Cranially: inferior margin of mandibular body;
• medially: anterior belly m. digastrici;
• laterally: posterior belly m. digastrici;
• base: mylohyoid muscle, hyoglossus muscle

Content:

• Submandibular gland
  
  • Parasympathetic innervation to the submandibular glands is provided by the superior salivatory nucleus via the chorda tympani, a branch of the facial nerve, that becomes part of the trigeminal nerve’s lingual nerve prior to synapsing on the submandibular ganglion.
• Submandibular duct:
  
  • Emerges from the gland in the forward direction and is inserted between the mylohyoid muscle and the hyoglossus muscle
• Facial vien - on the outer surface of the gland;
• Facial a.
  
  • from the carotid triangle
• Lingual n. and submandibular ganglion
  
  • Runs through the upper part of the trigon, inside from the edge of the mandible, arches forward
  • In the arch is suspended prasympathetic ganglion submandibulare;
• Hypoglossus n -
  
  • points forward into the sublingual region through the cleft between the mylohyoid muscle and the hyoglossus muscle;
• Lingual a.
• Nodi lymphoidei submandibulares -
  
  • distributed below the edge of the mandible and around the submandibular gland, collectors of superficial and deep layers of all facial lands.

Carotid triangle

• Borders:
  
  • Lateral: sternocleidomastoid muscle.
  • Anteroinferiorly: omohyoid muscle
  • Anterosuperior: posterior belly of the digastric muscle.
  • FLOOR: PHARYNGEAL CONSTRICTOR< THYROID MEMBRANE
  • ROOF: platysma, superfical cervial fasia
• The hyoid bone can be seen in the most anterior angle of the carotid triangle
• Content:
  
  • Inside carotid sheet
    
    • Common carotid A
    • Internal jugular v.
    • Vagus n.
    • the ansa cervicalis profunda?
  • Outside carotid sheet
    
    • Branches of the external carotid artery:
      
      • the superior thyroid artery-
      • the lingual artery
      • the facial artery
    • Nerves
      
      • Arch of hypoglossal nerve (CN XII)
      • Accessory nerve (CN XI),
      • sympathetic trunk and superior cervial ggl
      • lateral group of deep cervial lymph nodes
      • SUP LARYNGEAL?? running with sup thyroid a?

Question 7

Lateral neck region, scalenic fissure

Question 8

Axilla - boundaries, content

Answer 8

Axilla - area underneath the glenohumoral joint, at the junction of upper limb and thorax

 

Borders -

• Apex - lateral border 1st rib, superior border of scapula, posterior border of clavicle.
• Lateral wall - humorous
• Medial wall - serratus anterior and thoracic wall.
• Anterior wall - pec. major and minor and subclavius
• Posterior wall - subscapularis, teres major, latissimus dorsi

Contents -

• Axillary artery and vein
• Brachial Plexus
• Biceps and coracobrachialis tendon
• Axillary lymph node

Question 9

Brachial region (draw transverse section)

Question 10

Cubital fossa

Answer 10

Cubital Fossa –

Borders -

• Superior – Biceps Brachii
• Inferior Medial - Pronator Teres
• Inferior Lateral – Brachioradialis
• Floor – Brachialis
• Roof – Bicipital Aponeurosis

Contents (Lateral to medial) - “Really Need Beer To Be At My Nicest” (Radial n, Biceps tendon, Brachial artery, median nerve)

• Radial Nerve
• Biceps Tendon
• Brachial Artery (which bifurcate to deep ulnar artery and superficial radial artery) + Vein
• Median Nerve
• Cubital lymph nodes

Clinical aspect - During blood pressure measurement, the stethoscope is placed over the brachial artery in the cubital fossa. The ulnar nerve is in the area, but outside of the cubital fossa (occupies a groove on the posterior aspect of medial epicondyle), several veins are also present but not considered as part of the cubital fossa – cephalic, basilica, median cubital vein – they are more superficially to the cubital fossa.

Pronator Canal – It is a canal between humeral head (medial epicondyle) and ulnar head (coronoid process) of Pronator teres, which continues between this area to the radial head of flexor digitorum superficialis. Median nerve runs here from cubital fossa.

Cubital Canal – It is a similar canal, between humeral head and ulnar head of flexor carpi ulnaris. Content of the canal is ulnar nerve.

Question 11

Antebrachial region (draw transverse section)

Question 12

Topographic anatomy of the hand (draw transverse section) and fingers

Answer 12

Carpal Tunnel – The Space between the flexor retinaculum and the carpal bones -

• Superior – Flexor Retinaculum
• Inferior – Trapezius, Trapezoid, Capitate, Hamate
• Medial – Hamate
• Lateral - Trapezoid

Contents -

• Median nerve
• Tendons of Flexor digitorum profondus + superficialis
• Tendon of Flexor Pollicis Longus
• Tendon of Flexor Carpi Radialis

Clinical - Carpal tunnel syndrome – too much typing – loss sensation of lateral 3.5 fingers (that median nerve innervates)

Ulnar Canal = Guyon’s canal -

• Borders -
  
  • Inferior - flexor retinaculum
  • Superior – Palmaris Brevis
• Contents: Ulnar nerve and artery

Clinical - Ulnar canal syndrome – cycling marathons – entrapment of the ulnar nerve, feeling of pins and needles in the ring and little fingers 1.5 medial fingers (other 3.5 lateral fingers by median nerve) à loss sensation or impaired motor function.

Anatomical Snuff box -

• Borders -
  
  • Anterior - Abductor Pollicis Longus, Extensor Pollicis Brevis
  • Posterior - Extensor Pollicis Longus
• Contents -
  
  • Radial Artery
  • Dorsal cutaneous branch of the radial nerve (superficial radial nerve)
  • Cephalic Vein

Clinical - Radial artery palpation point, pain – broken scaphoid

Question 13

Gluteal region

Answer 13

Gateways to the lower limb

• There are four major routes by which structures pass from the abdomen and pelvis into and out of the lower limb.
• These are the
  
  • Obturator canal,
  • Greater sciatic foramen,
  • Lesser sciatic foramen
  • And the gap between the inguinal ligament and the anterosuperior margin of the pelvis

1- Obturator canal

• The obturator canal is an almost vertically oriented passageway at the antero-superior edge of the obturator foramen
• Borders:
  
  • Superiorly:
    
    • Obturator groove: on the inferior surface of the superior ramus of the pubic bone;
  • Inferiolly:
    
    • Upper margin of the obturator membrane,
      
      • Which fills most of the obturator foramen,
    • And by muscles (obturator internus and externus)
      
      • attached to the inner and outer surfaces of the obturator membrane and surrounding bone.
• Function:
  
  • Connects the abdominopelvic region with the medial compartment of the thigh.
• Content:
  
  • The obturator nerve and vessels

2- Greater sciatic foramen

• On the posterolateral pelvic wall and is
• Major route for structures to pass between the pelvis and the gluteal region of the lower limb
• The margins of the foramen are formed by:
  
  • The greater sciatic notch
  • Parts of the upper borders of the:
    
    • Sacrospinous
    • Sacrotuberous ligaments;
  • Lateral border of the sacrum.
• The piriformis muscle passes out of the pelvis into the gluteal region through the greater sciatic foramen and separates the foramen into two parts, a part above the muscle and a part below:
  
  • Suprapiriform foramen
    
    • Borders:
      
      • G. sciatic notch, pitiformis m., sacrum
    • Content:
      
      • Superior gluteal nerve and vessels
  • Infrapiriform foramen
    
    • Borders:
      
      • S: Piriformis m.,
      • L: greater sciatic notch
      • M: sacrotuberal ligament
      • I: sacrospinal ligament
    • Content
      
      • Inferior gluteal nerve and vessels,
      • Sciatic nerve
      • Posterior femoral cutaneous nerve of thigh
      • Pudendal nerve and internal pudendal vessels
      • Inferior gluteal nerve and vessles

3- Lesser sciatic foramen

• The lesser sciatic foramen is inferior to the greater sciatic foramen on the posterolateral pelvic wall
• It is also inferior to the lateral attachment of the pelvic floor (levator ani and coccygeus muscles) to the pelvic wall and therefore connects the gluteal region with the perineum
• Borders
  
  • Lateral/ventral: lesser sciatic notch
  • Medial: Sacrotuberal ligament
  • Cranial: sacrospinal ligament
• Contents:
  
  • Pudendal nerve and internal pudendal vessels
    
    • First exit the pelvis by passing through the greater sciatic foramen below the piriformis muscle
    • Enter the perineum below the pelvic floor by passing around the ischial spine and sacrospinous ligament and medially through the lesser sciatic foramen.
    • →into ischioanal fossa
    • Pudendal canal, alcock canal
      
      • Passage in double layer of fascial of the medio-caudal edge of the obturator internus m.
      • Located in the lischioanal fossa
      • Passage of pudendal n. and internal pudendal vessels
  • The tendon of obturator internus
    
    • Passes from the lateral pelvic wall→
    • Through the lesser sciatic foramen→
    • Into the gluteal region→ to insert on the femur

OVERVIEW AND GENERAL

3 main muscles -

• Gluteus maximus - inferior gluteal n. a. & v.
• Gluteus medius and minimus - superior gluteal n. a. & v.

 

Cutaneous innervation of the gluteal region - clunial nerves

• Superior clunial - posterior rami of Lumbar nerves (L1-L3)
• Medial clunial - posterior rami of sacral nerves (S1-S3)
• Inferior clunial - from posterior cutaneous nerve of thigh

 

Note -

All structures exit to the posterior gluteal region and/or continue down the leg EXCEPT internal pudendal vessels & pudendal nerve.

Re-enters the pelvis via lesser sciatic foramen ! Alcok’s canal ! perineum.

Question 14

Anterior thigh region, iliopectineal fossa, femoral triangle (draw schema)

Across the whole canal runs .

Femoral vessels come here from femoral triangle. Sensitive saphenous nerve, which is also located in the canal, perforates lamina vastoadductoria together with saphenous branch of descending genicular artery, which branch from femoral artery in adductor canal. (picture of adductor canal – see femoral triangle)

Ischial tuberosity

The ischial tuberosity is posteroinferior to the acetabulum and is associated mainly with the

hamstring muscles of the posterior thigh (Fig. 6.23). It is divided into upper and lower areas by a

transverse line.

The upper area of the ischial tuberosity is oriented vertically and is further subdivided into two parts

by an oblique line, which descends, from medial to lateral, across the surface:

the more medial part of the upper area is for the attachment of the combined origin of the

semitendinosus muscle and the long head of the biceps femoris muscle;

the lateral part is for the attachment of semimembranosus muscle.

The lower area of the ischial tuberosity is oriented horizontally and is divided into medial and lateral

regions by a ridge of bone:

the lateral region provides attachment for part of the adductor magnus muscle;

the medial part faces inferiorly and is covered by connective tissue and by a bursa.

Regional Anatomy 726 / 1534

726

Answer 14

Muscular and vascular space

• Area under the inguinal ligament
• Divided into 2 spaces

MUSCULAR LACUNA

• Lateral part of the space
• Borders:
  
  • Ventrally: inginal ligament
  • Dorsally: illium
  • Medially: iliopectineal arch (thickened medial fascia of iliopsoas).
• Contents
  
  • Iliopsoas
  • Two nerves
    
    • Laterally: lateral femoral cutaneous nerve
    • Medially: femoral nerve

VASCULAR LACUNA

• Borders:
  
  • Ventrally: inguinal ligament
  • Laterally: illiopectinal notch
  • Medially: lacunar ligament
• Content: from lateral to medial
  
  • femoral branch of genitofemoral nerve
  • femoral artery
  • Common femoral vien
  • “empty space”
  • Proximal deep inguinal lymph node, Cloquet

Nerves of skin:

• Lateral femoral cutaneous nerve - for lateral skin innervation.
• Anterior femoral cutaneous nerve - for anterior skin innervation.
• Obturator nerve - medial skin innervation.

Femoral triangle and fasial compartments of the thigh

• Femoral triangle
  
  • Boundaries
    
    • Superior: inguinal ligament
    • Lateral: medial border of the sartorius
    • Medial: medial border of the adductor longus
• Illiopectinal fossa:
  
  • Boundries:
    
    • Medially: pectinus m
    • Laterally: illiopsoas
    • Floor: iliopectineal fascia, stretched between iliopsoas and pectineus
• Content: (lateral to medial)
  
  • Lateral cutaneous nerve of the thigh
  • Femoral nerve
  • Femoral branch of the genitofemoral nerve
  • Femoral artery
  • Femoral vein
    
    • Saphenous opening
  • Lymphatics: deep and superficial inguinal lymph nodes
• Saphenous star/ ring
  
  • ​Saphenous ring is a passage through fascia cribrosa (part of fascia lata) into iliopectineal fossa
  • Which is margined from lateral side by thickened ligament – margo falciformis.
  • Superficial great saphenous vein passes into depth, joined by its tributaries:
    
    • Superficial epigastric vein,
    • Superficial external pudendal vein and
    • Superficial circumflex iliac vein.
  • From depth to the surface through saphenous ring pass superficial external pudendal artery.
  • Region above femoral triangle where the fascia latae is weak, through the hiatus passes
    
    • Thumb - external pudendal vein
    • Index - superficial epigastric vein
    • 2 middle – great saphenous vein (includes accessory saphenous)
    • Little finger - superficial circumflex iliac vein
    • Arm - femoral vein
• *

 

Femoral triangle

• Borders -
  
  • Superior - inguinal ligament
  • Lateral - sartorius muscle
  • Medial - adductor longus
  • Floor - pectineus muscle and iliopsoas muscle
  • Roof - fascia Lata except at the saphenous opening where it is formed by the cribriform fascia

Contents (lateral to medial) -

• Femoral nerve
• Femoral sheath
• Femoral artery
• Femoral vein
• Deep inguinal lymph nodes

Iliopectineal fossa

• Located deeply in superior part of femoral triangle
• Border -
  
  • Medially -pectineus
  • Laterally - iliopsoas

Femoral canal

• in lacuna vasorum, medially to femoral vein & lateral to lacunar lig. Contains deep inguinal lymph node.

Lacuna Musculorum

• Borders -
  
  • Posterior -inferior to inguinal ligament
  • Lateral -iliopectineal arch, thickened band of iliac and psoas fascia, forms a septum which subdivides the space deep to the inguinal lig.
• Contents (lateral to medial) -
  
  • Lateral femoral cutaneous nerve
  • Femoral nerve

Lacuna Vasorum

• Position - medially to Iliopectineal arch
• Contents -
  
  • Genital branch of genitofemoral nerve
  • Femoral Artery
  • Femoral Vein
  • Empty space (femoral hernia)
  • Lymph node – cloquet
  • Iliopsoas muscle

Obturator canal

• Contains the obturator nerve & vessels to the thigh, runs between the abductors

Question 15

Popliteal fossa, adductor canal

Answer 15

Adductor canal/ Hunter’s canal

• Distally from femoral triangle
• Connects the femoral triangle to the popliteal fossa
• Located bwtween the anterior and medial comparments of the thigh
• Borders:
  
  • Lateral - vastus medialis
  • Medial - adductor magnus
  • Ventrally: - vasto-adductor membrane.
  • Floor: adductor magnus
  • Sartorius run across the surface of the canal
• Ends distally between the 2 indertions of the adductor magnus, which forma the adductor hiatus
• Content -
  
  • Femoral vessels from femoral triangle
    
    • after leaving the canal they become popliteal vessels
  • Perforating the vasoadductor membrane:
    
    • saphenous nerve
    • saphenous branch of desending geniculate artery

Popliteal fossa

• Adductor hiatus opens into popliteal fossa, and area located behind ther knee joint
• The

Contents (from superficial to deep)

Nerves: tibial nerve and common peroneal nerve (See leg, ankle, and foot for more details.)

Vein: Popliteal vein

Origin: formed by the union of anterior tibial, posterior tibial, and the fibular veins at the inferior border of the popliteus

Becomes the femoral vein at the adductor hiatus

Main tributary: short saphenous vein

Artery: Popliteal arteryOrigin

Continuation of the femoral artery

Begins at the adductor hiatus

Ends at the inferior border of the popliteus by dividing into the anterior tibial artery and the tibioperoneal trunk

Clinical significance

Popliteal cyst (Baker cyst)

Popliteal artery aneurysm

Question 16

Leg region (draw transverse section)

Question 17

Retromalleolar regions (med.+ lat.)

Question 18

Topography of foot (draw transverse section)

Question 19

Mediastinum - division, borders (draw transverse section)

Answer 19

MEDIASTINUM

• Broad central partition that separates the two laterally placed pleural cavities
• It extends:
  
  • from the sternum to the bodies of the vertebrae;
  • and from the superior thoracic aperture to the diaphragm
• Contents: thymus gland, the pericardial sac, the heart, the trachea, and the major arteries and veins.
• Serves as a passageway for structures: such as the esophagus, thoracic duct, and various components of the nervous system as they traverse the thorax on their way to the abdomen.

Superior mediastinum

• Borders:
  
  • cranial: superior thoracic aperture (Th 1, 1
  • ventral: manubrium, ribs and muscles
  • dorsal: vertebral columb
  • caudal: transverse plane passing though T4 and angle of sternum
• Content: organized in 5 layers
  
  • layer 1:
    
    • Thymus,
    • insertions of sternothyroid and sternohyoid mm.
    • internal thoracic a. and branchs
  • Layer 2: layer of viens
    
    • unpaired thyroid plx
    • L/R subclavian v
    • Brachiocephalic veins
      
      • → Superior vena cava
    • Thoracic duct
    • Phrenic nerves
  • Layer 3: layer of arteries
    
    • aortic arch and its arteries
  • layer 4: layer of organs
    
    • trachea and bifurcation: at level of T4
    • principal bronchi
    • eosophagus+ vagus nn. ?????????? POST TO AORTA
      
      • L: behind
      • R: in from
      • the left RLN loops under the aortic arch, the right RLN goes under the subclavian artery. As both RLNs ascend to the larynx behind the thyroid gland,
      • cardiac rr- branch?
    • L reccurent larygneal n
    • tracheabronchiales LN
    • paratracheales LN
    • bronchopericardic membrane
  • layer 5:
    
    • L/R sympathetic trunk
    • nn. cardiac
    • juxtaeosophagal LN
    • longus coli m.

Inferior mediastinum

• The inferior mediastinum extends from the inferior border of the superior mediastinum to the diaphragm. It is subdivided anterior-to-posterior into three spaces:
  
  • Anterior mediastinum - posterior to the body of the sternum and anterior to the pericardium
  • Middle mediastinum - bounded by the pericardium, which encloses the heart and origins of the great vessels
  • Posterior mediastinum - posterior to the pericardium and anterior to the vertebrae

Anterior mediastinum

• Borders:
  
  • Cranially: plane between sternal angle and intervertebral disc between Th4–5
  • Caudally - diaphragm
  • Ventrally - sternal bone body
  • Dorsal - pericardium
  • Lateral - pleura mediastinalis
• Content:
  
  • sternopericardial lig.
  • parasternal lymph nodes
  • pericardi lymph nodes
  • internal thoracic vessles and branchs
  • transvers thoracic m.
  • PHRENIC N

Mediastinum medium :

• Borders:
  
  • Cranially: plane between sternal angle and intervertebral disc between Th4–5
  • Caudally - diaphragm
  • Ventrally: pericardium
  • Dorsally - pericardium, resp. bifurcatio tracheae
  • Lateral - pleura mediastinalis
• ​Content
  
  • Heart in pericardium
  • assending aorta
  • pulmonary trunk
  • SVC+ ? of azygos
  • IVC
  • phrenic nn- NOT HERE!!!!!
  • percardiacophernic vessels
  • cardial plx
  • pulmonary vv.
  • lateral pericardial lymph nodes

Posterior mediastinum :

• Borders:
  
  • Cranially: plane between sternal angle and intervertebral disc between Th4–5
  • Caudally - diaphragm
  • Ventral - pericardium, bronchopericardiac membrane , bifurcatio tracheae , aa. et vv. pulmonales ;
  • Dorsal - bodies of vertebrae Th5–12;
  • Lateral - pleura mediastinalis
• CONTENT:
• oesophagus + plexus esophageus
• truncus sympathicus + nn. splanchnici (major, minor, imus)
• nodi lymphoidei prevertebrales,
• juxtaesophageales ductus thoracicus
• v. azygos ON THE RIGHT
• v hemiazygos et hemiazygos accessoria (+ its tributaries)
• aorta thoracica + its branches
• VAGUSSSSS

Question 20

Topography of chest wall (draw scheme of intercostal space)

Answer 20

Intercostal spaces:

General:

• The eleven paired intercostal spaces contain the intercostal muscles, nerves, arteries, veins and investing fascia.
• Bordered by:
  
  • the rib, above and below, the deep fascia of the thorax, superficially, and the endothoracic fascia and pleura, internally,
• Contains: essential respiratory muscles, the nervous and vascular supply to the thoracic wall, and contributes to the integrity of the thoracic cage.

Intercostal muscles

• External intercostal muscles
  
  • Run anteroinferiorly
  • Elevate the ribs during inspiration (widens ICSs → ↑ thoracic volume)
• Internal intercostal muscles
  
  • Run posteroinferiorly
  • Lower the ribs during expiration (narrows ICSs → ↓ thoracic volume)
• Innermost intercostal muscles
  
  • Run posteroinferiorly
  • Lower the ribs during expiration (narrows ICSs → ↓ thoracic volume)
• Subcostal muscles: Run posteroinferiorly
• Transversus thoracis muscle: Runs craniolaterally from posterior surface of lower sternum to cartilage of 2nd–6th ribs

Topography of chest wall:

• Parasternal
  
  • superficiall thoracic fasia
  • ex. intercostal membrane
  • internal intercostal m.
  • vessels
  • transverse thoracic m.
  • endothoracic fascia
  • parietal pleura
• Ant. axilliary
  
  • superficiall thoracic fasia
  • ex intercostal m.
  • internal intercostal m.
  • vessels
  • innermost intercostal m
  • endothoracic fascia
  • parietal pleura
• Paravertebral
  
  • superficiall thoracic fasia
  • ex intercostal m.
  • innermost intercostal membrane
  • vessels
  • endothoracic fascia
  • parietal pleura

Neurovascular bundle

• Located in the costal groove in the undersurface of each rib
• between the internal intercostal muscle and innermost intercostal muscle,
• The neurovascular bundle is arranged as Vein, Artery and Nerve, from the most superior to the most inferior.
• An easy way to remember that is to use a mnemonic VAN.

Intercostal nerves

• Originate segmentally from the ventral rami of the thoracic spine from T1 through T11.
• In addition to motor nerves to the intercostal muscles, they contain sensory afferents from the skin, intercostal muscle, ribs, pleura, and peritoneum.

Intercostal vessels

• Anterior:
  
  • The six-upper: from the internal thoracic artery,
  • Lower five: from the musculophrenic artery, itself a branch of the internal thoracic artery.
  • Anterior intercostal arteries form anastomoses with the posterior intercostal arteries.
  • The anterior intercostal veins drain into the internal thoracic vein, adjacent to the internal thoracic artery.
• Posterior
  
  • The superior (supreme) intercostal artery: a branch of the costocervical trunk of the subclavian artery, branches into the first two posterior intercostal arteries.
  • Remaining nine posterior intercostal arteries: branch directly from the aorta.
  • The first two posterior intercostal veins drain into the brachiocephalic vein, adjacent to the internal thoracic vein.
  • The lower nine posterior intercostal veins accompany the posterior intercostal arteries, draining into the azygos system.

Intercostal lymphatics

• The superficial tissues, including the breast, are drained by the axillary, and parasternal nodes.
• Lymphatics drain posteriorly into the intercostal lymph nodes, lying adjacent to the azygous and hemizygous veins.

Intercostal surface projections

• Nipples in men: ∼ 5th ICS, can be lower in women
• Dome of the diaphragm and liver: right 5th ICS at the midclavicular line
• Lung: see pulmonary examination
• Heart
  
  • Right margin: extends from right 3rd costal cartilage to right 6th costal cartilage
  • Left margin: extends from left 2nd ICS to the apex at the midclavicular line of the 5th ICS
  • Anterior interventricular sulcus: 2.5 cm lateral of the midline at 3rd left ICS
  • For the projection of the heart valves and the auscultation of the heart sounds, see cardiovascular examination.

Question 21

Projections of heart, lungs and pleura onto thoracic wall, puncture of thorax

→

Answer 21

The thorax consists of the following regions:

• Ventral
  
  • Regions:
    
    • Infra-clavicular
    • Mammary
    • Infra-mammary
    • Upper sternal
    • Lower sternal
  • Lines:
    
    • Anterior median (midsternal) line
      
      • indicates the intersection of the median plane with the anterior thoracic wall
    • Midclavicular lines
      
      • pass through the midpoints of the clavicles, parallel to the anterior median line
    • Anterior axillary line
      
      • runs vertically along the anterior axillary fold, which is formed by the border of the pectoralis major as it spans from the thorax to the humerus (arm bone)
    • Midaxillary line
      
      • runs from the apex (deepest part) of the axilla, parallel to the anterior axillary line.
    • Posterior axillary line,
      
      • also parallel to the anterior axillary line, is drawn vertically along the posterior axillary fold formed by the latissimus dorsi and teres major muscles as they span from the back to the humerus
    • Posterior median (midvertebral) line
      
      • is a vertical line at the intersection of the median plane with the vertebral column.
• Dorsal
  
  • Regions:
    
    • Suprascapular
    • Scapular
    • Infrascapular
    • Interscapular
  • lines:
    
    • Scapular lines are parallel to the posterior median line and cross the inferior angles of the scapulae
    • Posterior median line

Key facts about the surface projections of the heart

Heart borders

• Superior
  
  • Inferior border of the second left costal cartilage → superior border of the third right costal cartilage
• Right
  
  • Third right costal cartilage → sixth right costal cartilage
• Inferior
  
  • Sixth right costal cartilage → fifth left intercostal space, midclavicular line
• Left
  
  • Inferior border of the second left costal cartilage→ Fifth left intercostal space, midclavicular line

Heart valve projections/ Heart auscultation points

• Left atrioventricular valve
  
  • Projection:
    
    • Posteriorly to the left side of the sternum at the level of the left fourth costal cartilage
  • Auscultation:
    
    • The left fifth intercostal space at the midclavicular line
• Right atrioventricular valve
  
  • Projection:
    
    • Posteriorly to the right side of the sternum at the level of the right fourth costal cartilage
  • Auscultation:
    
    • Left fifth intercostal space, parasternally
• Aortic valve
  
  • Projection:
    
    • Posteriorly to the left side of the sternum at the level of the third intercostal space
  • Auscultation:
    
    • Right second intercostal space, parasternally
• Pulmonary valve
  
  • Projection:
    
    • At the junction of sternum and left third costal cartilage
  • Auscultation:
    
    • Left second intercostal space, parasternally

Lung projections

• Anterior borders
  
  • lie adjacent to the anterior line of reflection of the parietal pleura between the 2nd and 4th costal cartilages
    
    • Left side:
      
      • Margin of the left pleural reflection moves laterally and then inferiorly at the cardiac notch to reach the level of the 6th costal cartilage.
    • Right side
      
      • Pleural reflection continues inferiorly from the 4th to the 6th costal cartilage, paralleled closely by the anterior border of the right lung.
  • Both pleural reflections pass laterally and reach:
    
    • the midclavicular line at the level of the 8th costal cartilage,
    • the 10th rib at the midaxillary line,
    • and the 12th rib at the scapular line,
    • proceeding toward the spinous process of the T12 vertebra.
  • Thus, the parietal pleura extends approximately two ribs inferior to the lung.
• The oblique fissure of the lungs
  
  • extends from the level of the spinous process of the T2 vertebra posteriorly to the 6th costal cartilage anteriorly,
    
    • Coincides approximately with the medial border of the scapula when the upper limb is elevated above the head (causing the inferior angle to be rotated laterally).
• The horizontal fissure of the right lung extends from the oblique fissure along the 4th rib and costal cartilage anteriorly.

Clinical:

Pneumothorax, Hydrothorax, Hemothorax, and Chylothorax

• Pneumothorax:
  
  • Entry of air into the pleural cavity
  • Spontaneous pneumothorax
    
    • Primary spontaneous pneumothorax: occurs in patients without clinically apparent underlying lung disease
    • Secondary spontaneous pneumothorax: occurs as a complication of underlying lung disease
  • Traumatic pneumothorax: a type of pneumothorax caused by a trauma (e.g., penetrating injury, iatrogenic trauma)
  • Tension pneumothorax: a life-threatening variant of pneumothorax characterized by progressively increasing pressure within the chest and cardiorespiratory compromise
• Hydrothorax
  
  • The accumulation of a significant amount of fluid in the pleural cavity
    
    • May result from pleural effusion (escape of fluid into the pleural cavity).
    • Hemothorax: With a chest wound, blood may also enter the pleural cavity
      
      • this condition results more often from injury to a major intercostal vessel than from laceration of a lung.
    • Chylothorax: Lymph from a torn thoracic duct may also enter the pleural cavity .

Thoracentesis

• Sometimes it is necessary to insert a hypodermic needle through an intercostal space into the pleural cavity to obtain a sample of pleural fluid or to remove blood or pus (thoracentesis).
• Management of a pneumothorax involves placement of a chest tube via an incision made through the intercostal space just superior to a rib in order to avoid the neurovascular bundle (blue, red, and yellow dots). The pleural drain is inserted into the pleural space and is connected to a water seal to prevent air from entering the pleural space.

Auscultation and Percussion of Lungs

• Auscultation of the lungs
  
  • (assessing air flow through the tracheobronchial tree into the lung with a stethoscope)
• Percussion of the lungs
  
  • (tapping the chest over the lungs with the finger)
  • Helps establish whether the underlying tissues are
  • air-filled (resonant sound), fluid-filled (dull sound), or solid
  • (flat sound).

LUNG GENERAL:

Pleura

• Each pleural cavity is lined by a single layer of flat cells, mesothelium, and an associated layer of supporting connective tissue; together, they form the pleura.
• The pleura is divided into two major types, based on location:
  
  • pleura associated with the walls of a pleural cavity is parietal pleura;
  • pleura that reflects from the medial wall and onto the surface of the lung is visceral pleura which adheres to and covers the lung.
• Each pleural cavity is the potential space enclosed between the visceral and parietal pleurae. They normally contain only a very thin layer of serous fluid.
  
  • As a result, the surface of the lung, which is covered by visceral pleura, directly opposes and freely slides over the parietal pleura attached to the wall.
• Parietal pleura
  
  • The names given to the parietal pleura correspond to the parts of the wall with which they are associated:
    
    • pleura related to the ribs and intercostal spaces is termed the costal part;
    • pleura covering the diaphragm is the diaphragmatic part;
    • pleura covering the mediastinum is the mediastinal part;
    • the dome-shaped layer of parietal pleura lining the cervical extension of the pleural cavity is cervical pleura (dome of pleura or pleural cupola).
  • Covering the superior surface of the cervical pleura is a distinct dome-like layer of fascia, the suprapleural membrane
    
    • This connective tissue membrane is attached laterally to the medial margin of the first rib and behind to the transverse process of vertebra CVII.
    • Superiorly, the membrane receives muscle fibers from some of the deep muscles in the neck (scalene muscles) that function to keep the membrane taught.
    • The suprapleural membrane provides apical support for the pleural cavity in the root of the neck.

Pleural recesses

• The lungs do not completely fill the anterior or posterior inferior regions of the pleural cavities → recesses: in which two layers of parietal pleura become opposed.
  
  • Expansion of the lungs into these spaces usually occurs only during forced inspiration;
  • Provide potential spaces in which fluids can collect and from which fluids can be aspirated.
• Costomediastinal recesses: ventrally- medially
• Vertebromediastinalis recess: caudally- medially
• Ohernicomediastinalis recess: ventrally- medial inferior
• ​Costodiaphragmatic recesses: ventrally- laterally inferior
  
  • The largest and clinically most important
  • Between the inferior margin of the lungs and inferior margin of the pleural cavities.
  • They are deepest after forced expiration and shallowest after forced inspiration.
  • During expiration, the inferior margin of the lung rises and the costodiaphragmatic recess becomes larger.

Question 22

Projections of abdominal organs onto abdominal wall

Answer 22

Borders of the abdominal cavity

• Costal margin above
  
  • Separates the abdominal wall from the thoracic wall.
• Pubic tubercle, anterior superior iliac spine, and iliac crest below
  
  • A line between the anterior superior iliac spine and the pubic tubercle
    
    • marks the position of the inguinal ligament, which separates the anterior abdominal wall above from the thigh of the lower limb below.
  • The iliac crest
    
    • separates the posterolateral abdominal wall from the gluteal region of the lower limb

Topographical divisions

• The two schemes most often used are:
  
  • a four-quadrant pattern
  • a nine-region pattern

Four-quadrant pattern

• Horizontal transumbilical plane passing through the umbilicus the intervertebral disc between vertebrae LIII and LIV
  
  • Intersecting with the
• vertical median plane
• Divides the abdomen into four quadrants:
  
  • the right upper, left upper, right lower, and left lower quadrants

Nine-region pattern

The nine-region pattern is based on two horizontal and two vertical planes

• Xiphosternal line: through synchondrosis
• LI vertebra-transpyloric plane
  
  • a horizontal plane passes through the medial ends of the ninth costal cartilages and the body of the LI vertebra
• LIII vertebra: subcostal plane, ​ the superior horizontal plane
  
  • is immediately inferior to the costal margins, which places it at the lower border of the costal cartilage of rib X and passes posteriorly through the body of vertebra LIII.
• LV vertebra: the intertubercular plane, the inferior horizontal plane
  
  • connects the tubercles of the iliac crests, which are palpable structures 5 cm posterior to the anterior superior iliac spines, and passes through the upper part of the body of vertebra LV.
• The vertical planes (midclavicular lines)
  
  • pass from the midpoint of the clavicles inferiorly to a point midway between the anterior superior iliac spine and pubic symphysis.

The following designations are used for each region:

Superiorly

• 1-Right hypochondrium
  
  • Greater part of the right lobe of liver
  • Gallbladder
  • Part of right kidney
• 2- Epigastric region
  
  • the esophagus
  • Greater part of stomach: including cardiac and pylotic orfices
  • Left lobe and part of right lobe of liver
  • the pancreas
  • spleen..
  • Suprarenal capsules and parts of kidney
• 3-Left hypochondrium
  
  • Fundus of stomach
  • Spleen
  • tail of pancreas
  • part of L kidney

Middle

• 4- Right lumbar region (lateral region)
  
  • Assending colon
  • part of right kidney
  • some convolutions of small intestines
• 5- Umbilical region
  
  • transverse colon
  • part of greate omentum and mesentary
  • transverse part of duodenum
  • some concolutions of jejunum and illium
  • parts of both kidneys
• 6- Left lumbar region (lateral region)
  
  • desending colon
  • part of omentum
  • part of left kideny
  • some convolutions of small intestines

Inferiorly

• 7- Right illiac/groin (inguinal region)
  
  • cecum and veriform appendix
  • right illiac fossa
• 8- Hypogastric/ pubic region
  
  • convolution of samll intestines
  • bladder in small children
  • uterus during pregancy
• 9- Left illiac/groin (inguinal region)
  
  • sigmoid flexture of colon
  • left illiac fossa

Major blood vessels:

• Celiac trunk: originates from the aorta at the upper border of the LI vertebra
• Superior mesenteric artery: originates at the lower border of the LI vertebra
• Renal arteries: originate at approximately the LII vertebra;
• Inferior mesenteric artery: originates at the LIII vertebra;
• Aorta bifurcates into the right and left common iliac arteries: at the level of the LIV vertebra
• Left and right common iliac veins: join to form the inferior vena cava at the LV vertebral level

Surgical incisions.

• Currently, the most commonly used large abdominal incision is a central craniocaudad incision from the xiphoid process to the symphysis pubis, which provides wide access to the whole of the abdominal contents and allows an exploratory procedure to be performed (laparotomy).
• Other approaches use much smaller incisions.
  
  • Labbe triangle
    
    • projection of stomach on abdominal wall
      
      • Base: fromed by transpyloric line,
      • left angle: left costal arch
      • right angle: a line connecting the 9th rib on the right side with the 8th rib cartilage on the left
  • Murphy’s point:
    
    • projection of the fundus of gal bladder
    • at intersection of right costal arch and right middclavicualr line
  • Desjardins point:
    
    • projection of the majot duodenal papillae
    • located on a line connecting the umbilicus to the apex of the right axila, 6-7 cm from umbilicus
  • McBurney’s point
    
    • is the name given to the point over the right side of the abdomen that is one-third of the distance from the anterior superior iliac spine to the umbilicus (navel).
    • This point roughly corresponds to the most common location of the base of the appendix where it is attached to the cecum
    • on line of monro
  • Lanz point:
    
    • projection of the tip of the veriform appendix in pelvic possition

Major blood vessels:

• Celiac trunk: originates from the aorta at the upper border of the LI vertebra
• Superior mesenteric artery: originates at the lower border of the LI vertebra
• Renal arteries: originate at approximately the LII vertebra;
• Inferior mesenteric artery: originates at the LIII vertebra;
• Aorta bifurcates into the right and left common iliac arteries: at the level of the LIV vertebra
• Left and right common iliac veins: join to form the inferior vena cava at the LV vertebral level

Question 23

Topography of abdominal wall, rectus abdominis sheath (draw transverse section), blood supply, innervation, surgical approaches

Answer 23

General:

Layers from superficial to deep:

• Skin and subcutaneous tissue
• Superficial fascia: (Hypodermis, Subcutis)
  
  • Superficial fatty layer (Camper fascia)
  • Deep membranous layer (Scarpa fascia)
• External oblique muscle
• Internal oblique muscle
• Transversus abdominis muscle
• Deep fascia (transversalis fascia): fuses with the deep fascia of the thigh (fascia lata)
• Fascia extraperitonealis + preperitoneall fat pad
• Parietal peritoneum

Rectus sheath:

• Formed by the fusion of aponeuroses (broad tendons) of the flat muscles
  
  • (external oblique, internal oblique, and transversus abdominis muscles),
• Encloses the vertical muscles
  
  • (rectus abdominis and pyramidalis muscles)
• Above the arcuate line
  
  • Anterior layer:
    
    • External oblique aponeurosis
    • Anterior lamina of the internal oblique aponeurosis
  • Posterior layer:
    
    • Transversus abdominis aponeurosis
    • Posterior lamina of the internal oblique aponeurosis
• At the arcuate line
  
  • Transversus abdominis aponeurosis and the posterior lamina of the internal oblique aponeurosis pass anterior to the rectus muscle.
  • Lower 1/3rd of the rectus muscle is in direct contact with the peritoneum.
• Below the arcuate line
  
  • Only the anterior layer of the rectus sheath is present
  • Composed of all 3 aponeuroses

Arcuate line (linea semicircularis)=

• Inferior limit of the posterior rectus sheath
• The inferior epigastric vessels perforate the rectus abdominis here.
• Herniation of intra-abdominal contents through the linea semilunaris is known as a Spigelian hernia.
  
  • occur most commonly below the arcuate line (i.e., below the umbilicus)

Linea alba:

• A tendinous median line that extends from the xiphoid process to the pubic symphysis
• Formed by the fusion of the aponeuroses of the external oblique, internal oblique, and transversus abdominis muscles.
• A defect in the upper linea alba can cause an epigastric hernia.

Structures in the anterior wall

• lig. umbilicale medianum (chorda urachi)
  
  • median umbilical fold
• Suprevesica fossa
  
  • hernia supravesicalis: passes through fovea supravesicalis and anulus inguinalis superficialis
• lig.umbilicale laterale (chorda arteriae umbilicalis)
  
  • medialis umbilical fold
• vasa epigastrica inferiora
  
  • lateralis umbilicalis fold (plica epigastrica)

Blood supply:

• Superior epigastric artery
  
  • Branch of internal thoracic artery
  • Runs in the rectus sheath behind the rectus muscle and supplies it.
  • Ends by anastomosing with the inferior epigastric artery.
• The Inferior epigastric artery
  
  • Branch of external iliac artery
  • Enters the rectus sheath after piercing the fascia transversalis.
  • Runs upwards, supplies the lower central part of anterior abdomen and anastomoses with superior epigastric artery.
• The lower two posterior intercostal arteries and the deep circumflex iliac arteries also contribute in the arterial supply.
• The deep veins follow the arteries of the same name.

Lymphatics

• Upper abdominal wall: axillary lymph nodes
• Lower abdominal wall: superficial inguinal nodes

Cutaneous innervation and dermatomes

• Cutaneous innervation:
  
  • from T7–T12 (via the lower intercostal nerves and the subcostal nerve)
  • from L1 (via the iliohypogastric and ilioinguinal nerves)
• Each intercostal nerve supplies a band-shaped dermatome.
• Important abdominal dermatomes:
  
  • T7: xiphoid process
  • T10: umbilicus (site of referred pain for appendicitis)
  • L1: area just above the inguinal ligament
• Muscles of the anterior abdominal wall
  
  • lower six thoracic nerves,
  • iliohypogastric nerve and the ilioinguinal nerve.
  • The pyramidalis is supplied by 12th thoracic nerve.

Question 24

Inguinal region, inguinal canal, hernias

Question 25

Topography of peritoneal cavity - supra and inframesocolic part (draw transverse section through lesser sac) →

Answer 25

​**Key facts about the peritoneum** * **Definition** * Serous membrane lining viscera and abdominal cavity wall * **Parts** * **Parietal** **peritoneum**: lines the walls of the cavity * **Visceral** **peritoneum**: covers the viscera. * **Peritoneal** **cavity**: potential space * **Peritoneal formations** * **Mesentery**: * mesentery proper, transverse mesocolon, sigmoid mesocolon, mesoappendix * **Omenta**: * greater omentum, lesser omentum * **Peritoneal ligaments:** * hepatogastric, hepatoduodenal, gastrophrenic, gastrosplenic, splenorenal, gastrocolic ligament * **Peritoneal divisions** * Lesser sac (omental bursa) * Greater sac (supracolic and infracolic compartments) * **Function** * Protection of the abdominopelvic organs * Connect organs with each other * Maintain the position of organs by suspending them with ligaments * Prevent friction while organs move * Organs in relation to... * Intraperitoneal organs: * **Suspended** in the peritoneal cavity by folds of peritoneum (**mesenteries**) * **Retroperitoneal organs:** * **​**Or are outside the peritoneal cavity. * with only one surface or part of one surface covered by peritoneum **Peritoneal cavity is divided into two main compartments by the transverse colon and its mesentry:** * **Supra-mesocolic – above transverse colon** * Liver * gall bladder and cystic duct * eosophagus * Stomach * Spleen * duodenum: ampulla and duodenal cap * supplying artery: * coeliac trunk * **Root of transverse mesocolon:** * right kidney → duodenum: desending part→ pancreas (head and body) → left kidney * **Infra-mesocolic – below transverse colon** * blood supply: superior and inferior mesenteric arteries * **Right infra-mesocolic space** * **​Boundries:** * **​**Superiorly: transverse mesocolon * medially/oblique: root of mesentary * laterally: assending colon * is smaller than the left space * contents * jejunum * illium * caceum, veriform apendix * **Left infra-mesocoli space** * Boundries: laterally by desending mesocolon * Larger * sigmoid colon * rectum (upper 1/3) * \*\*\*assending and desending: are retroperitoneal??? Paracolic spaces: Innervation of the peritoneum * Parietal peritoneum * associated with the abdominal wall * innervated by somatic afferents carried in branches of the associated spinal nerves * therefore sensitive to well-localized pain. * Visceral peritoneum * innervated by visceral afferents that accompany autonomic nerves (sympathetic and parasympathetic) back to the central nervous system. * Activation of these fibers can lead to **referred** and **poorly** **localized** **sensations** of **discomfort**, and to reflex visceral motor activity. Peritoneal cavity * Subdivided * Greater sac * ccounts for most of the space in the peritoneal cavity, beginning superiorly at the diaphragm and continuing inferiorly into the pelvic cavity. It is entered once the parietal peritoneum has been penetrated. * Omental bursa= lesser sac * smaller subdivision of the peritoneal cavity posterior to the stomach and liver and is continuous with the greater sac through an opening, the omental (epiploic) foramen * * Surrounding the omental (epiploic) foramen are numerous structures covered with peritoneum. They include the portal vein, hepatic artery proper, and bile duct anteriorly; the inferior vena cava posteriorly; the caudate lobe of the liver superiorly; and the first part of the duodenum inferiorly.

Question 26

GIT: Peritoneum - parietal and visceral, greater and lesser omentum Lesser sac (omental bursa), its recesses → GIT: Development of visceral situs and mesentery, intestinal rotation →

Answer 26

Omenta, mesenteries, and ligaments * Throughout the peritoneal cavity numerous peritoneal folds connect organs to each other or to the abdominal wall. * These folds (omenta, mesenteries, and ligaments) develop from the original dorsal and ventral mesenteries, which suspend the developing gastrointestinal tract in the embryonic coelomic cavity. * Some contain vessels and nerves supplying the viscera, while others help maintain the proper positioning of the viscera. Omenta * The omenta consist of two layers of peritoneum, which pass from the stomach and the first part of the duodenum to other viscera. * There are two: * the greater omentum derived from the dorsal mesentery; * the lesser omentum derived from the ventral mesentery. **_Greater omentum_** * Large, apron-like, **peritoneal fold,** contains 4 layers * **Anterior sheet:** * ​Extends from the **greater** **curvature** of the **stomach** and proximal **duodenum**. * From here, it **descends** **inferiorly** **over** the **transverse** **colon**, **jejunum** and **ileum**. * **Posterior sheet** * It then **folds** **posteriorly** and **ascends** to **attach** to the **transverse mesocolon.** * The greater omentum contains large amounts of fat, which is highly variable between individuals * **Blood supply:** * Supplied by the gastro-omental arteries * Right gastro-omental artery: * Branch of the **gastroduodenal** **artery**. * It runs through the layers of the greater omentum along the greater curvature of the stomach in a **right** to **left** direction. * **Left gastroduodenal artery** * Branch from the **splenic artery.** * It runs in the greater omentum along the greater curvature of the stomach in a **left** to **right** direction. * Form **anastomosis** along the greater curvature. * The veins follow the direction of the arteries in the greater omentum * Left gastro-omental vein→ drains into the **splenic** vein * Right gastro-omental vein→ drains to the **superior** **mesenteric** **vein**. * Unite posterior to the neck of the pancreas to form the **hepatic portal vein**→ which carries venous blood **from** the **gastrointestinal** **tract** to the **liver**. * → drain into the **portal system** * **Function of the greater omentum** * Prevents the parietal and visceral peritoneum of the abdominal cavity from adhering to each other. * It is very mobile, and moves around the abdomen with rhythmic, peristaltic motion of the intestines. * It can also adhere to an inflamed organ, such as the appendix, to protect the healthy organs in the abdomen. **_Lesser omentum_** * Extends from the lesser curvature of the stomach and duodenal bulb (first part of duodenum)→ to the liver. * Function: * Separate the greater sac from the omental bursa. * The lesser omentum consists of two ligaments: * **The hepatogastric ligament→** medially * connects the lesser curvature of the stomach to the visceral surface of the liver. * **The hepatoduodenal ligament**→ laterally: * passes from the duodenal bulb towards the visceral surface of the liver. * It ends as a free border, forming the anterior margin of the omental foramen, * **Carries the portal triad** (hepatic portal vein, proper hepatic artery and bile duct). * Blood supply and passage of vessels * Transports the arteries for the lesser curvature of the stomach; the right and left gastric arteries. * The left gastric artery * (one of the three branches of the celiac trunk) * passes into the lesser omentum and travels downwards along the lesser curvature of the stomach in a left to right direction. * The right gastric artery * branches from the proper hepatic artery (also a branch of the celiac trunk). * It ascends along the lesser curvature of the stomach in a right to left direction to form an anastomosis with the left gastric artery. * The right and left gastric veins follow the same direction as the arteries through the lesser omentum. * They drain directly into the hepatic portal vein. The visceral branches of the vagus nerve and the hepatic and gastric lymph nodes also pass through the lesser omentum. **Omental bursae:** lesser sac Hollow space that is formed by the greater and lesser omentum and its adjacent organs. * **Borders** * Superiorlly * quadrate lobe of liver, * lesser omentum * Inferiorlly * transverse mesocolon * gastrocollic ligament * Floor/Posteriorly * pancreas * parietal peritoneum and organs behind them in the retroperitoneal space * Left: * left kidney, left adrenal gland * Gastrosplenic ligament * contains the short gastic vessels and the left gastro- epiploic vessels * Right: * foramen of winslow/ epiploic foramen * only comminucation with the greater sac * bound superioly by hepatoduodenal ligament * lesser omentum * greater sac * Communications * Superior recess * The greater part of the omental bursa consists of its superior recess * which extends cranially between the esophagus and the inferior vena cava. * splenic recess * extends to the left between the splenic ligaments and the stomach * inferior recess * Extends caudally between the stomach and the transverse colon * folds and recesses around the cecum and duodeum * *Blood* * *coeliac trunk* * *in retro peritoneal space* * *Branchs that are?* * *left gastric a.* * *lesser curvature of stomach* * *common heatic a.* * *liver, duodenum* * *gastroduodenal a: proximal duodenum, and head od pancreas* * *right gastro omental a* * *greater curvature of the stomach* * *runs in gastrocolic ligament* * *superior panreatico duodental a* * *Splenic a* * *body and tail of pancreas, and spleen* which is known as the general cavity of the abdomen that sits within the peritoneum, but outside the lesser sac. Falciform ligamern round ligament of liver: free edge * Turning **posteriorly**, it ascends to associate with, and become **adherent** to, the **peritoneum** on the superior surface of the transverse colon and the anterior layer of the transverse mesocolon before arriving at the posterior abdominal wall. * Usually a thin membrane, the greater omentum always contains an accumulation of fat, which may become substantial in some individuals. * Additionally, there are two arteries and accompanying veins, * the right and left gastro-omental vessels, between this double-layered peritoneal apron just inferior to the greater curvature of the stomach. Lesser omentum * The other two-layered peritoneal omentum is the lesser omentum * **It extends from the lesser curvature of the stomach** and the first part of the duodenum to the **inferior surface of the liver** * A thin membrane continuous with the peritoneal coverings of the anterior and posterior surfaces of the stomach and the first part of the duodenum, the lesser omentum is divided into: * a medial **hepatogastric ligament**, which passes between the stomach and liver; and * a lateral **hepatoduodenal ligament,** which passes between the duodenum and liver. * ends laterally as a free margin and serves as the anterior border of the omental foramen * Enclosed in this free edge are the hepatic artery proper, the bile duct, and the portal vein. Additionally, the right and left gastric vessels are between the layers of thelesser omentum near the lesser curvature of the stomach.? --------------------------- Mesentery: Key facts * Function * Storing fat, vessels and nerves; attaching the intestines to the abdominal wall * Structure * Mesentary definition: * A thin layer of connective tissue is contained within the two layers of peritoneum * And provides a passageway for lymphatics, nerves, arteries and veins * To reach the viscera, allowing communication between the body wall and internal organs. Types of mesentary * **Mesentery proper "the mesentary"** * from small intestine (jejunum and ileum) to posterior abdominal wall * Contains * superior mesenteric artery * autonomic nerve plexuses * lymphatics, fat * Superiorly→ connects to the junction between the duodenum and jejunum → travels obliqully downswards → ends at illicecal junction * **Transverse mesocolon** * transverse colon -\> posterior abdominal wall * from anterior surface of pancreas and travels to the posterior surface of the transverse colon * Contents: * Middle colic artery * nerves and lymph * **Sigmoid mesocolon** * Sigmoid colon→ pelvic wall * Contains: * (sigmoid arteries, superior rectal artery, nerves and lymph * **Mesoappendix** * mesentery of ileum→ appendix (appendicular artery) Mesenteries are also important as they suspend or hold the organs in place to the posterior abdominal wall. Those that are totally suspended in the cavity (i.e. are covered in visceral peritoneum) are known as intraperitoneal organs (such as the liver, ileum and stomach) whereas those that lie posterior to the peritoneum and are only covered by the visceral peritoneum on the anterior surface are known as retroperitoneal organs. Retroperitoneal organs include the distal part of the duodenum, abdominal aorta and pancreas. The mesenteries also store fat as a means of padding. There are also other specialty peritoneal folds named the greater and lesser omenta derived from the original dorsal and ventral mesenteries, respectively, in development.

Question 27

Topography of duodenum and pancreas (draw schema) →

Answer 27

Anatomy of the doudenum * The duodenum is about 25 to 30 cm long * C-shaped and is located in the upper abdomen at the level of L1-L3. * The head of the pancreas lies in the C loop. * It may be subdivided into four sections: * superior part, * descending part, * horizontal part and * ascending part. * **Superior part** * lies intraperitoneally and is enlarged proximally (duodenal bulb). * It is connected to the liver by the hepatoduodenal ligament. * The superior part ends at the superior duodenal flexure and becomes the descending part. * *Descending part and the rest of the duodenum lie **retroperitoneally**.* * **Descending** * The common bile duct and the pancreatic duct unify to a conjoint duct at the hepatopancreatic ampulla (=ampulla of Vater) and empties into the descending part of the duodenum. * At the opening there is an elevation of the mucosa, the major duodenal papilla **(=papilla of Vater).** * Many people have an **accessory pancreatic duct** which empties into an additional papilla: the minor duodenal papilla **(=papilla of Santorini).** * The **transition** from the descending to the horizontal part of the duodenum takes places at the **inferior duodenal flexure.** * **Horizontal part** * Runs from right to left ventrally from the abdominal aorta and inferior vena cava. * **Ascending part** * Runs cranially along the left side of the vertebral column. * This last part of the duodenum joins the intraperitoneally lying jejunum at the duodenojejunal flexure. * Here the duodenum is attached to the back of the abdominal wall through the suspensory ligament of duodenum **(=ligament of Treitz).** * Clinically the ligament of Treitz marks the border between the upper and lower gastrointestinal tract. **Innervation** * The sympathetic innervation is carried by nerves of the coeliac plexus * Parasympathetic innervation by the vagus nerve (cranial nerve X). Key facts about the pancreas * Location * Retroperitoneal * With the exception of the tail, the pancreas is situated in the retroperitoneal space of the abdominal cavity, in other words, behind the peritoneum. * Spans the epigastric, left hypochondriac, and a portion of the umbilical abdominal regions * Parts * External: head, uncinate process, neck, body, tail * Internal: main pancreatic duct (of Wirsung), accessory pancreatic duct * Function * Digestion by releasing peptidases, lipases, nucleases, amylases * Hormonal regulation by releasing insulin (beta cells), glucagon (alpha cells), and somatostatin (delta cells) * Blood vessels * Pancreaticoduodenal, * splenic, * gastroduodenal, * and superior mesenteric arteries * **Innervation** * **Parasympathetic: vagus nerve (CN X)** * **Sympathetic: greater and lesser splanchnic nerves** * Lymphatics * Pancreaticosplenic and pyloric lymph nodes * Anatomical relations of the pancreas * Anterior * Stomach, lesser sac (omental bursa), transverse mesocolon, superior mesenteric artery * Posterior * Aorta, inferior vena cava, right renal artery, right and left renal veins, superior mesenteric vessels, splenic vein, hepatic portal vein, left kidney, left suprarenal gland * Superior * Splenic artery * Lateral * Spleen * Medial * Duodenum (descending and horizontal parts) **Relation with duodenum and other structures:** * The head is the expanded medial part of the pancreas. * It lies directly against the descending and horizontal parts of the C-shaped duodenum which wraps around the pancreatic head. * Projecting inferiorly from the head is the uncinate process, which extends posteriorly towards the superior mesenteric artery. * Continuing laterally from the head is the neck, a short structure of approximately 2 cm that connects the head with the body. * Posterior to the neck are the superior mesenteric artery and vein and the origin of the hepatic portal vein – formed by the union of the superior mesenteric and splenic veins. * After the neck, the pancreas continues with the body, which consists of two surfaces (anterior and posterior) and two borders (superior and inferior). * It is located anterior to the L2 vertebra, and also forms the floor of the omental bursa (lesser sac). * The aorta, superior mesenteric artery, left renal vessels, left kidney, and left suprarenal gland are situated posterior to the pancreatic body. * Finally, the intraperitoneal tail is the last part of the pancreas. It is closely related to the hilum of the spleen and runs with the splenic vessels in the splenorenal ligament. BLOOD SUPPLY Descending abdominal aorta: * *Dorsal group: inferior phrenic arteries, lumbar arteries, median sacral artery* * *Lateral group: suprarenal, renal, gonadal (testicular in males, ovarian in females) arteries* * **Anterior group: celiac trunk, superior mesenteric, inferior mesenteric arteries** * *Terminal branches: left and right common iliac artery* **Celiac trunk:** Unpaired short vessel, Blood supply to the forgut→ * Arises just inferior to the aortic orifice of the diaphragm at the level of the **lower border of T12 vertebra.** * Shortly after its origin, the trunk gives off its three branches: *1-Celiac trunk→ Left gastric artery* **2- Celiac trunk**→Common hepatic artery→ runs towards the right towards the liver * → Right gastric artery (above the first part of the duodenum)→ from right to left → which runs between the peritoneal layers of lesser omentum→ supply the lesser curvature of the stomach*→ *Anastomoses with the left gastric artery.* * → Hepatic artery proper divides into→ Right and left hepatic arteries and enter the liver: further into lobar arteries→ right branch gives branch: cystic artery for gall bladder* → **Gastroduodenal artery** → Arises posterosuperior to the first part of duodenum, giving off → the right gastromental artery→ *(sends branchs to greater omentum, which supplies the greater curvature of the stomach, anastamoses with: left gastrosplenic artery -from splenic a.)*→ Passes to the left: **Terminates as → anterior superior pancreaticoduodenal artery:** * Arieses behind duodenum * which supplies the head of the pancreas and the anterior and posterior surfaces of the duodenum. * It anastomose with the **inferior pancreaticoduodenal artery (first branch of the superior mesenteric artery).** **3- Celiac trunk**→ Splenic artery→ runs towards the hilum of the spleen on the superior border of the pancreas→ branch to supply the neck, body and tail of the **pancreas**. * *Also:* * *Short gastric arteries:* * *Before it enters the spleen: Left gastrosplenic artery:* * *that supplies the greater curvature of the stomach,* * *and anastomoses with the right gastroepiploic artery.*

Question 28

Retroperitoneal space, topography of its organs including vessels and nerves

Answer 28

Retroperitoneal space: * Located in the dorsal part of the abdominal cavity behind the peritoneium * Filled with loose CT * Contains organs, vessels and nerves Boundries: * **Ventrally**: pariental peritoneum * **Dorsally**: parietal abdominal fascia * **Cranially**: connected with the posterior inferior mediastinum, through the appertures of the diaphragm * **Caudally**: continues as the subperitoneal space of the pelvic cavity Content: * Retroperitoneal organs * Covered by parietal peritoneum * Not suspended by mesentery * suprarenal gland * Kidney and theri covers * Ureters * Abdominal aorta and branchs * IVC and branchs * Sympathetic trunk and branchs * Lumbar plexsus * Abdominal aortic plexsus (autonomic) * cisterna chyli, lumbar trunks and lumbar lymph nodes * Secondary retroperitoneal organs * Organs suspended by mesentery during the embryonic period * Fusion of the visceral and parietal peritoneum fixes organs to the abdominal wall. * duodenum: all parts except for ampula and duodenal cap * Pancreas: head and body (tail is intraperitoneal) * assending and desending colon * Intraperitoneal organs * Covered by the visceral peritoneum * Suspended by mesentery * *

Question 29

Topographic anatomy of male pelvis (draw sagittal section)

Question 30

Topographic anatomy of the female pelvis (draw sagittal section), mechanism of continence

Question 31

Pelvic floor muscles, ischioanal fossa (draw frontal section of pelvis), perineal region → while the true pelvis is the

Answer 31

GENERAL DESCRIPTION * The pelvis and perineum are interrelated regions associated with the pelvic bones and the terminal parts of the vertebral column. * The pelvis is divided into two regions: * **False pelvis (greater pelvis):** The superior region * Related to upper parts of the pelvic bones and lower lumbar vertebrae * Generally considered part of the abdomen * Wide area just above the inlet between the ala of the ilia * **True pelvis (lesser pelvis)** * area between the inlet and the outlet. * Related to the inferior parts of the pelvic bones, sacrum, and coccyx, and has an inlet and an outlet. * This cavity is continuous superiorly with the abdominal cavity and contains elements of the urinary, gastrointestinal, and reproductive systems. * **_The perineum_** * Inferior to the floor of the pelvic cavity; * its boundaries form the pelvic outlet. * The perineum contains the external genitalia and external openings of the genitourinary and gastrointestinal **Pelvic outlet** * Diamond shaped * **Terminal parts of the urinary and gastrointestinal tracts and the vagina pass through the pelvic outlet.** * Anterior part of the diamond defined predominantly by bone * Midline anteriorly: the boundary of the pelvic outlet is the pubic symphysis. * Extending laterally and posteriorly, the boundary on each side is the: * inferior border of the body of the pubis, * the inferior ramus of the pubis, * the ramus of the ischium, * and the ischial tuberosity. * Together, the elements on both sides form the pubic arch. * Posterior part mainly by ligaments * From the ischial tuberosities, the boundaries continue posteriorly and medially along the sacrotuberous ligament on both sides to the coccyx. * The area enclosed by the boundaries of the pelvic outlet and below the pelvic floor is the perineum. --------------------------------------------- Pelvic floor * **The pelvic floor is formed by** * **Muscular pelvic diaphragm** * **Perineal membrane** * There are two (males) or three (females) openings that allow passage of the outlet components of the pelvic viscera in the pelvic floor. * The muscles of the pelvic floor contribute to maintaining continence and help prevent the contents of the pelvic cavity from falling through its outlet. **The pelvic diaphragm** * The pelvic diaphragm is the muscular part of the pelvic floor. * Shaped like a bowl or funnel and attached superiorly to the pelvic walls, * it consists of the levator ani and the coccygeus muscles Muscles . The muscles are attached along the inner walls of the true pelvis to a condensed area of the obturator fascia known as the tendinous arch of levator ani muscle. Note that the levator ani is made up of the puborectalis, pubococcygeus, and iliococcygeus muscles. The coccygeus (also referred to as ischiococcygeus) is not part of the levator ani. The pelvic surface of the levator ani is separated from the visceral organs by their associated fascia. The perineal surface functions as the medial and superior walls of the ischioanal fossa and its associated anterior recess respectively. There is loose connective tissue between the posterior border of the muscle and the coccyx. Finally, the outlets of the visceral organs separate the medial border of the two muscles. Summary of the pelvic floor muscles Levator ani: 1,2,3 Puborectalis * Origin: Posterior surface of bodies of pubic bones * Insertion: None (forms 'puborectal sling' posterior to rectum) * Innervation: Nerve to levator ani (S4) Pubococcygeus * Origin: Posterior surface of bodies of pubic bones (lateral to puborectalis) * Insertion: Anococcygeal ligament, Coccyx, Perineal body and musculature of prostate/vagina * Innervation: Nerve to levator ani (S4); branches via inferior rectal/perineal branches of the pudendal nerve (S2-S4) Iliococcygeus * Origin: Tendinous arch of the internal obturator fascia, Ischial spine * Insertion: Anococcygeal ligament, Coccyx * Innervation: Nerve to levator ani (S4) Coccygeus (ischiococcygeus)Origin: Ischial spine Insertion: Inferior end of sacrum, Coccyx Innervation: Anterior rami of spinal nerves S4-S5 Pelvic floor * The pelvic floor, which separates the pelvic cavity from the perineum, is formed by muscles and fascia * Two levator ani muscles attach peripherally to the pelvic walls and join each other at the midline by a connective tissue raphe. * Together they are the largest components of the bowl- or funnel-shaped structure known as the pelvic diaphragm, which is completed posteriorly by the coccygeus muscles. * These muscles overlie the sacrospinous ligaments and pass between the margins of the sacrum and the coccyx and a prominent spine on the pelvic bone, the ischial spine. * The pelvic diaphragm forms most of the pelvic floor and in its anterior regions contains a U-shaped * defect, which is associated with elements of the urogenital system. * The anal canal passes from the pelvis to the perineum through a posterior circular orifice in the * pelvic diaphragm. * The pelvic floor is supported anteriorly by: * the perineal membrane; and * muscles in the deep perineal pouch.

Question 32

Topography of vertebral canal, anatomic backgrounds of spinal tap (lumbar puncture) and epidural anesthesia

Question 33

Bony pelvis as complex, connections, passages, diameters, planes, sexual differences SKELETON AND CONNECTIONS

Answer 33

Pelvic inlet * Location: * Superior rim of the pelvic cavity (upper pelvic aperture) * Boundaries * Anterior: * Pectineal line, pubic crest, and the superior margin of the pubic symphysis * Posterior: * Sacral promontory and anterior border of the sacral ala * Lateral: * Arcuate line (iliopectineal line) of the ilium * Diameters: * Transverse, oblique, conjugate (anteroposterior), anatomical conjugate, diagonal, straight, median * Structures passing through the pelvic inlet: * Ureter, spermatic cord, round ligament of the uterus, suspensory ligament of the ovary, middle sacral vessels, gonadal vessels, iliolumbar vessels, lumbosacral trunk, sympathetic trunk, obturator nerve Pelvic outlet * Location: * Lower pelvic aperture. * It is narrower than the pelvic inlet. * Boundaries: * Anterior: * Pubic symphysis, ischiopubic ramus, and the arcuate pubic ligament * Posterior: * Sacrum and coccyx * Lateral: * Ischial tuberosities and sacrotuberous ligaments * Inferior: * Pelvic diaphragm and the urogenital diaphragm * Diameters: sagittal and intertuberous