Gross Anatomy Flashcards
What is the role of dendrites?
Increase surface area
Communicate with adjacent neurones
What is the role of myelin sheath?
Coat axons to help speed up action potentials
What is the myelin sheath produced by in the PNS versus the CNS?
Shwann cells
Oligodendrocyte
What are the two types of neurones?
Multipolar - 2 or more dendrites and cell body in CNS
Unipolar - double process (pseudounipolar) and cell body in PNS
What neurones are classed as multipolar?
All motor neurones of SkM and ANS (pre-synaptic)
What neurones are classed as unipolar?
Sensory post-synaptic neurones in the ANS
In what direction do efferent impulses move?
MOTOR - Exits brain and moves towards body wall, cavity or organ
In what direction do afferent impulses move?
SENSORY - impulse Arrives at brain
What is a nerve? What is this referred to in the CNS?
Collection of axons surrounded by CT and blood vessels
Tract
What are the two types of nerves?
Single modality - one of somatic motor/ sensory, special sensory, sympathetic, parasympathetic or visceral afferent
Mixed modality - somatic motor, somatic sensory and sympathetic all in one nerve
A tract is most likely to be single modality. True/ False?
True
Give the first cranial nerve, it’s modality, function and foramen
1 (CNI) Olfactory - Cribiform plate (Forebrain) - Sensory (special) - Smell
Give the second cranial nerve, it’s modality, function and foramen
2 (CNII) Optic - Optic canal (Forebrain) Sensory (special) - Vision
Give the third cranial nerve, it’s modality, function and foramen
3 (CNIII) Oculomotor - Superior orbital fissure (Midbrain) -Motor - 4 extrinsic eye muscles and levator palpebrae superioris
- PS - pupillary sphincter
Give the fourth cranial nerve, it’s modality, function and foramen
4 (CNIV) Trochlear - Superior orbital fissure (Midbrain) Motor - Superior oblique
Give the fifth cranial nerve, it’s modality, function and foramen
5 (CNV) Trigeminal: PONS
Ophthalmic - Superior orbital fissure - Sensory - Scalp, forehead and nose.
Maxillary - F. rotundum - Sensory - Cheeks, lower eye lid, nasal mucosa, upper lip, upper teeth and palate.
Mandibular - F. ovale
Sensory - anterior 2/3 tongue, skin over mandible and lower teeth.
Motor: muscles of mastication
Give the sixth cranial nerve, it’s modality, function and foramen
6 (CNVI) Abducens - Superior orbital fissure (Junction between pons and medulla) - Motor - Lateral rectus
Give the seventh cranial nerve, it’s modality, function and foramen
7 (CNVII) Facial - Internal acoustic meatus > stylomastoid f. (Junction between pons and medulla) - Both - Sensory (special): sensation to part of ext. ear., taste from ant. 2/3 tongue, hard and soft palate., muscles of facial expression.
Motor and PS: lacrimal, submandibular, sublingual glands and mucous glands of mouth and nose.
Give the eighth cranial nerve, it’s modality, function and foramen
8 (CNVIII) Vestibulocochlear - Internal acoustic meatus - (Junction between pons and medulla) - Sensory (special) - Hearing and balance
Give the ninth cranial nerve, it’s modality, function and foramen
9 (CNIX) Glossopharyngeal - Jugular f. (Medulla) - Both:
Sensory: post. 1/3 tongue, nasopharynx, oropharynx, laryngopharynx, palatine tonsil, eustachian tube, ext. ear, and middle ear cavity.,
Special sensory: taste from post. 1/3 tongue(vallate papillae)
VA: carotid sinus receptors and carotid body
Motor: stylopharyngeus
PS: to parotid gland
Give the tenth cranial nerve, it’s modality, function and foramen
10 (CNX) Vagus - Jugular f. (Medulla) - Both:
Sensory: ext. ear, larynx and pharynx., larynx, pharynx and, thoracic & abdominal viscera., taste from epiglottis region of tongue
Motor and PS: smooth muscles of pharynx, larynx and most of the GIT
Give the eleventh cranial nerve, it’s modality, function and foramen
11 (CNXI) Spinal accessory - Jugular f. (Spinal cord) Motor: trapezius and sternocleidomastoid., a few fibres run with CNX to viscera.
Give the twelth cranial nerve, it’s modality, function and foramen
12 (CNXII) Hypoglossal - Hypoglossal canal (Medulla) Motor: Intrinsic and extrinsic tongue muscles (except the palatoglossus).`
There are 31 pairs of spinal nerves, how are they divided in the spinal cord?
Cervical (C1 - C8) Thoracic (T1 - T12) Lumbar (L1 - L5) Sacral (S1 - S5) Coccygeal (Co1)
There are 8 cervical spinal nerves, but how many vertebrae are there?
7
Where are spinal nerves found at the vertebrae, and what do they branch into?
Intervertebral foramina
Anterior (supply larger anterolateral body wall) and posterior ramus (smaller posterior wall)
What is the route taken by all sensory axons to the horn of the spinal cord?
Posterior root –> rootlets —> horn
What is the route taken by all motor axons to the spinal nerve?
Anterior horn of the spinal cord –> rootlets –> root –> spinal nerve
What is the function of the dorsal root ganglion?
Location of cell bodies of primary afferent neurones
Roots/rootlets are ____ modality and ramii are ____ modality
Single
Mixed
What three types of nerve supply does a spinal nerve supply to unilateral area of the body?
General sensory to all structures
Somatic motor to skeletal muscle
Sympathetic to skin and smooth muscle of arterioles
NOT PARASYMPATHETIC
What is a dermatome?
Area of skin supplied with sensory innervation from a single spinal nerve
What is a myotome?
SkM supplied with motor innvervation from single spinal nerve
In the dermatome map, what level is the male nipple at?
T4
In the dermatome map, what level is the umbilicus at?
T10
In the dermatome map, what level is the posterior scalp, neck and shoulder at?
C2-C4
In the dermatome map, what level is the upper limb at?
C5-T1
In the dermatome map, what level is the lower limb, gluteal region, perineum at?
L2-Co1
What is a nerve plexus?
Intermingled anterior rami from a number of adjacent spinal nerves
What levels is the cervical plexus, and what does it supply?
C1-C4
Posterior scalp, neck and diaphragm
What levels is the brachial plexus, and what does it supply?
C5-T1
Upper limb
What levels is the lumbar plexus, and what does it supply?
L1-L4
Lower limb
What levels is the sacral plexus, and what does it supply?
L5-S4
Lower limb, gluteal region, perineum
Sympathetic outflow from the brain enters the spinal cord at what levels? What is this known as?
T1 - L2
Thoracolumbar outflow
What is the route taken by sympathetic nerves to the area it is supplying?
Lateral horns of T1-L2 —> sympathetic chain —> spinal nerves —> anterior and posterior rami —> hitch a ride with arteries —> supply sweat glands, skin arrectors, arterioles
What are the four nerve routes taken by sympathetic outflow in all spinal nerves?
Heart
Lungs
Abdomniopelvic organs
Adrenal medulla
What allows a sympathetic axon to pass onto a paravertebral ganglion of the sympathetic trunk?
Rami communicans
Where do sympathetic presynaptic axons in the heart synapse?
Synapse in T1 or cervical paravertebral ganglia
What is the route taken by sympathetic postsynaptic axons in the heart?
Pass in cardiopulmonary splanchic nerves to the SA and AV nodes and myocardium
Where do sympathetic presynaptic axons in the lungs synapse?
Synapse in upper thoracic paravertebral ganglia
What is the route taken by sympathetic postsynaptic axons in the lungs?
Pass in cardiopulmonary splanchic nerves to bronchiolar SM and mucous glands
Where do sympathetic presynaptic axons of the abdominopelvic organs synapse?
In one of the prevertebral ganglia
List the sympathetic prevertebral ganglion associated with abdominopelvic organs for the foregut, midgut and hindgut respectively
Celiac ganglion of celiac plexus (FOREGUT)
Superior mesenteric ganglion of SM plexus (MIDGUT)
Inferior mesenteric ganglion of IF plexus (HINDGUT AND PELVIC/PERINEAL ORGANS)
List the sympathetic prevertebral ganglion associated with abdominopelvic organs, in this case for the kidney
Aorticorenal ganglion
Where are these sympathetic prevertebral ganglion located anatomically?
At named artery as it branches from the abdominal aorta
What is the route taken by presynaptic sympathetic axons to reach the adrenal medulla?
Pass through aorticorenal ganglion
Synapse DIRECTLY onto adrenaline/ NA secreting cells of the adrenal medulla
How do presynaptic axons of parasympathetic outflow leave the CNS? What is this known as?
Via CN III, VII, IX, X and sacral spinal nerves
Craniosacral outflow
What do presynaptic parasympathetic axons travel on to reach the eye?
Ciliary ganglion
What do presynaptic parasympathetic axons travel on to reach the lacrimal and salivary glands?
Parasympathetic ganglia in the head
What do presynaptic parasympathetic axons travel on to reach the organs of the head, neck, chest and abdomen as far as the midgut?
Vagus nerve
What do presynaptic parasympathetic axons travel on to reach the hindgut, pelvis and perineum?
Sacral spinal nerves
What is a classical clinical example of impaired sympathetic innervation to head and neck?
Horner’s syndrome
What are the symptoms of Horner’s syndrome?
Miosis
Ptosis
Reduced sweating (anhydrosis)
Increased warmth and redness
What are the causes of compression of the cervical parts of the sympathetic trunk in Horner’s syndrome?
Root of neck trauma Carotid dissection Internal jugular vein engorgement Deep cervical node metastases Pancoast tumour (lung apex)
What vertebrae can be palpated first on the back?
T1 spinous process
What do skin dimples on the lower back represent?
PSIS
What are the three parts of the trapezius, relative to their position on the back?
Descending (superior)
Transverse (middle)
Ascending (inferior)
Which rotator cuff muscle can be palpated on the back?
Teres major
Which muscle may be affected in lower back pain?
Erector spinae
What are the extrinsic back muscles (top - bottom), and what do they attach to?
Levator scapulae Rhomboid major and minor Trapezius Latissimus dorsi PECTORAL GIRDLE
What is the function of the extrinsic back muscles?
Move upper limb
What is the function of the intrinsic back muscles?
Maintain posture and extend the spine (ES) or rotate the spine (TVSPS)
What is the main superficial intrinsic back muscle? Where does it attach inferiorly?
Erector spinae
Common tendon to sacrum and iliac crest
What are the divisions of the erector spinae, and thus where do they attach superiorly?
Rib (Costalis)
Transverse process of vertebra (Longus)
Spinous process of vertebra (Spinous)
What is the main deep intrinsic back muscle? Where is it located?
Transversospinalis
Within grooves between transverse and spinous processes
Where do the muscle fibres of transversospinalis attach between?
Vertebra and skull
Vertebra and rib
One vertebra and another
Sacrum and vertebra
What is the nerve supply to the back muscles?
Segmental (as per dermatome/ myotome)
Via posterior ramii branches (cervical , thoracic, lumbar)
What muscles lie laterally to the vertebral column?
MUSCLES OF POSTERIOR ABDO WALL
Psoas major
Quadratus lomborum
What muscles lie posterally to the vertebral column?
INTRINSIC BACK MUSCLES
Transversospinalis
Erector spinae
What muscles lie laterally to the posterior abdominal wall muscles?
MUSCLE OF UL Latissimus dorsi MUSCLES OF ANTEROLATERAL ABDO WALL Transverse abdominus Internal oblique External oblique
If the erector spinae muscle contracts bilaterally the spine will undergo…
Extension
If the erector spinae muscle contracts unilaterally the spine will undergo …
Lateral flexion
What muscles control flexion of the spine?
Rectus abdominus
Psoas major
How many vertebrae are there in the adult vertebral column?
33
How are the vertebrae divided?
7 cervical (C1 - C8) 12 thoracic (T1 - T12) 5 lumbar (L1 - L5) 5 sacral (1 sacrum) 4 coccygeal (1 coccyx)
What are the 3 functions of the vertebrae?
Support head and trunk when upright
Protect spinal cord and nerves
Allow movement of head on neck and trunk
What are the main curvatures of the spine and are they primary or secondary?
Cervical lordosis (2) Lumbar lordosis (2) Thoracic kyphosis (1) Sacral kyphosis (1)
What curvature pathology is caused by excessive anterior weight e.g. in pregnancy or obesity?
Excessive lumbar lordosis
What curvature pathology is caused by old age typically?
Excessive thoracic kyphosis
List the parts of a vertebra
Spinous process x 1
Transverse process x 2
Inferior and superior articular processes x 4
Vertebral foramen
Vertebral body
Vertebral arch (made up of 2 x pedicle (superior) and 2 x lamina)
What type of joint is the articulation between articular processes and adjacent vertebrae?
Synovial facet joint
Which structure contains and protects the spinal cord and nerves?
Intervertebral foramen
What joints are affected in arthritis of the spine?
Facet joint
Where are IV discs found? What are they at risk of?
Between adjacent vertebral bodies
Disc herniation
Where is there an abscence of IV discs?
Between C1 and C2
Describe the structure of an IV disc
Outer fibrous ring - annulus fibrosis
Inner soft pulp - nucleus pulposis
Which short ligament connects the adjacent lamina posteriorly to the spinal cord?
Ligamentum flavum
What is the function of the posterior longitudinal ligament?
Narrow and weak
Prevents overflexion
What is the function of the anterior longitudinal ligament?
Broad and strong
Prevents overextension
What is the function of the supraspinous ligaments?
Strong, fibrous
Connects tips of spinous processes
What is the function of the interspinous ligaments?
Weak, membranous
Connect superior and inferior parts of adjacent spinous processes
List the ligaments of the vertebral column
Ligamentum flavum Posterior longitudinal ligament Anterior longitudinal ligament Supraspinous ligaments Interspinous ligaments
Which vertebra are classed as atypical and why?
C1: ATLAS - no body or spinous process - A + P arch instead
C2: AXIS - odontoid process, which projects superiorly from body
C7: VERTEBRA PROMINENS - 1st palpable spinous process
Which ligament connects C1 and C2 vertebra?
Transverse ligament