Scalp & Cranial Cavity Flashcards
what does the scalp consist of?
skin & subcutaneous tissue
where is the scalp located?
- from the superior nuchal line of the occipital bone to the supraorbital margins of the frontal bone
- laterally extends over the temporal fascia to the zygomatic arch
what is the face?
the anterior aspect of the head from forehead to chin & from one ear to another
why is the face an important anatomical structure?
plays an important role in communication by making expressions through the facial muscles
what does individuality of the face arise from?
primarily from anatomical variation in the shape & relative prominence of the features of underlying cranium
what does the SCALP mnemonic stand for?
Skin
Connective tissue
epicranial Aponeurosis
Loose connective tissue
Pericranium
what is the dense connective tissue layer in the scalp?
subcutaneous layer rich in neurovascular structures
- richly vascularised
- cutaneous nerves
If a scalp wound compromised the epicranial aponeurosis, what would occur?
gaping wound that require sutures to close
what is the function of the loose connective tissue in the scalp?
separates scalp properly from underlying pericranium and calvaria
- allows free movement of outer layers over underlying calvaria
what is the pericranium?
external periosteal layer
what can be found in the skin of the scalp?
- hair follicles
- sweat glands
- sebaceous glands
where is the skin of the scalp the thickest?
over the occipital bone
What is located in the epicranial aponeurosis? what is its function?
tendon & muscle of occipitofrontalis
- this layer PREVENTS superficial wounds from gaping open
what is an important clinical implication of infection reaching the loose connective tissue of the scalp?
loose connective tissue contains spaces susceptible to distension with fluid or infection spread
- fluid/infection may spread to eyelids or root of nose because the frontal belly of the occipitofrontalis inserts into skin & subcutaneous tissue (and NOT into bone)
how can scalp infections spread to the intracranial structures?
via emissary veins
what are the cervical nerves that supply cutaneous/sensory innervation to the scalp?
- lesser occipital nerve (C2)
- greater occipital nerve (C2)
- great auricular nerve (C2 & C3)
- third occipital nerve (C3)
What is considered the “danger area” of the scalp?
Loose connective tissue
- contains emissary veins (valveless veins that connect the extracranial veins of scalp to intracranial dural venous sinuses)
- potential pathway for spread of infection
What are the trigeminal nerves that supply the scalp?
- supratrochlear nerve
- supraorbital nerve
- zygomaticotemporal nerve
- auriculotemporal nerve
what is the skin over the mandible innervated by?
the cervical plexus with the great auricular nerve
what arteries supply the scalp?
anterior scalp = internal carotid artery
lateral & posterior scalp = external carotid artery
where does lymphatic drainage in the posterior of the scalp take place?
mastoid and occipital nodes drain to deep cervical nodes
where does anterior lymphatic drainage of the scalp occur?
pre-auricular and parotid nodes
what lobe of the brain sits in the anterior cranial fossa?
frontal lobe
what is the shallowest part of the cranial base?
anterior cranial fossa
what bones make up the middle cranial fossa?
sphenoid and temporal bones
what lies in the hypophyseal fossa?
the pituitary gland
what bones make up the posterior cranial fossa?
sphenoid, occipital & temporal bones
what is a buttress?
a thicker portion of cranial bone that transmits forces around weaker regions of the cranium
where can the frontonasal buttress be found?
from the region of the canine teeth between the nasal and the orbital cavities to the central frontal bone
what is the function of the occipital buttress?
transmits forces received lateral to the foramen magnum from the vertebral column
what is the function of cranial meninges?
membranous layers that help in protection of the brain (and spinal cord)
what are the different layers of cranial meninges?
- dura mater
- arachnoid mater
- subarachnoid space
- pia mater
what are the layers of the dura mater?
- periosteal layer (attached to bone)
- meningeal layer (in contact with arachnoid mater)
what lines the dura mater?
the arachnoid mater
what is the subarachnoid space?
a fluid filled space that contain cerebrospinal fluid and blood vessels
what is the difference between the pia mater & the arachnoid mater?
- pia mater enters the sulci of the brain
- arachnoid mater does not
what is the function of the dura mater folds?
limits the movement of the brain within the cavity
what are examples of dura mater folds?
- falx cerebri
- tentorium cerebelli
- falx cerebelli
- diafragma sellae
what is the blood supply of the dura mater?
supplied by meningeal arteries that are in the periosteal layer
- anterior meningeal arteries
- middle & accessory meningeal arteries
- posterior meningeal arteries
