Gross Anatomy I Midterm 2

Synovial Articulations

Articulating bones are separated by a articulation cavity

Synovial fluid is found in the articulation cavity

Sutures

-fibrous joints between the bones of the skull

-Sharpey's fibers hold them together

Function of Sutures

shock absorption

Syndesmosis

bones united by fibrous connective tissue, forming an interosseous membrane or ligament

-Ex. radioulnar interosseus ligament, ligamentum flavum

Function of Syndesmosis

dynamic stabilization, resist forces that separate bones

Symphyses

A cartilaginous joint in which the bones are connected by fibrocartilage (secondary cartilaginous disc)

Function of Symphyses

Stability, resist forces at weight bearing joints

Location of Symphyses

-Manubriosternal, Xiphsternal, Mandibular symphysis (undergo synostosis)

-Intervertebral disc, Pubic symphysis

Extrinsic Ligaments

-outside of the fibrous joint capsule

-Ex. lateral collateral ligament (LCL) of the knee

Intrinsic Ligament

-within or on the surface of the fibrous joint capsule

-Ex. ischiofemoral/pubofemoral ligaments of hip

Intracapsular Ligament

-inside of the synovial cavity

-ex. ligamentum teres of hip, ACL/PCL of knee

Fat Pads

Areas of adipose tissue within the joint capsule to cushion the articulation

Fibrocartilaginous discs

-disperse weight and remove friction during movement

-Ex. mensicus

Plane Synovial Joint

-uniaxial joint that translates motion across flat joint surfaces in apposition

-ex. sygaphophyseal joints

-Movements: Flexion and Extension

Ginglymus (Hinge) Synovial Joints

-uniaxial joint allowing motion with one degree of freedom

-ex. elbow joint

-Movement: Flexion and Extension (in sagittal plane)

Trochoid (Pivot) Joints

-uniaxial joint that allows rotation of a bone around a single axis

-ex. medial atlantoaxial joint, radioulnar joint

-Movement: Rotation

Meninges of Spinal Cord

Connective tissue membrane including the dura mater, arachnoid mater, pia mater

Subarachnoid Space

a space in the meninges between the arachnoid membrane and the pia mater that's filled with cerebrospinal fluid and arteries

Subdural Space

space between dura mater and arachnoid mater that is the location of veins

Epidural Space

space between the dura mater and the wall of the vertebral canal filled with fat

Conus Medullaris

Conical distal end of the spinal cord located at the L1-L2 vertebral level

Cauda equina

collection of spinal nerves extending beyond the conus medullaris

Bell-Magendie Law

-sensory information goes into the spinal cord via dorsal roots of spinal nerves

-motor "commands" leave the spinal cord via ventral roots of spinal nerves

Gray Matter of Spinal Cord

nerve cell bodies arranged in a butterfly shape with anterior and posterior "horns"

Ventral Horn

Cell bodies of alpha and gamma motor neurons (LMN)

Intermediolateral Gray

-T1-L2: preganglionic sympathetic neurons

-S2-S4: preganglionic parasympathetic fibers

-controls heart rate

Columns in Spinal Cord

-dorsal column carries sensory information up the spinal cord to the brain (fasciculus gracious and fasciculus cuneatus)

-ventral and lateral columns have bundles of fibers call tracts overlap for several functions (mostly motor)

Pairs of Spinal Nerves

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Dorsal Root

-sensory (afferent) route of information

-formed by union of smaller dorsal rootless which emerge from the dorsal side of spinal cord

-larger than ventral root

Dorsal Root Ganglion

Ganglion on dorsal root commanding cell bodies of sensory neurons in the dorsal route (pseudounipolar)

Ventral Root

Motor (efferent) root formed by the union of smaller ventral rootlets from the ventral side of spinal cord

Dorsal Rami

-branch of spinal nerve that supplies nerves to muscle of the back

-carry mixed motor and sensory fibers

-generally smaller than ventral rami

Ventral Rami

-branch of spinal nerve that supplies limbs and anterior side of body

-carry mixed motor and sensory fibers

-generally larger than dorsal rami

Medial Branch of Dorsal Rami

all levels supply muscles, only levels T6 and up are also cutaneous (sensory to skin) to upper back

Lateral Branch of Dorsal Rami

all levels supply muscles, only levels T6 and below are also cutaneous to lower back and medial gluteus region

Dorsal Rami from T6 and up

-medial branch does sensory and motor information

-lateral branch does only motor information

Dorsal Rami from T7 and down

-medial branch does only motor information

-lateral branch does sensory and motor information

Dorsal Rami that don't split into branches

Cervical nerve (C1), fourth and fifth sacral nerves (S4 and S5), and coccygeal nerve (Cx1)

Cervical Dorsal Rami Special Significance

C1, C2, C3,

Suboccipital Nerve (C1)

-does not divide into medial and lateral branches

-larger than the ventral ramus of C1

-supplies the muscles of the suboccipital triangle

Greater Occipital Nerve (C2)

-largest dorsal rami that is lightly larger than ventral rami

-medial branch is cutaneous to a large area of the back of the scalp; may be joined by a twig from the dorsal ramus of C3

-lateral branch is entirely muscular in its distribution; may be joined by a filament from C3

Third Occipital Nerve (C3)

-medial branch gives off a twig deep to trapezius; this twig pierces the trapeziusa and become cutaneous at the base of the occipital region

-lateral branch is purely muscular and may join the lateral branch of C2

Thoracic Dorsal Rami from T1-T6

-medial branch becomes cutaneous after innervating intrinsic muscles (pass between semi spinal is and multifidus and then pierce the rhomboids and trapezius)

-lateral branch remains purely muscular (passes between longissimus and iliocostalis and supplies the remaining intrinsic muscle s

Thoracic Dorsal Rami from T7-T12

-medial branch remains purely muscular

-lateral branch becomes cutaneous after innervating intrinsic muscles

Lumbar Dorsal Rami

-medial branch remains purely muscular (short and supply the multifidus)

-lateral branch is muscular and cutaneous (supply the erector spinae; pierce ther aponeurosis of latissimus dorsi and supply skin of the gluteal region)

Sacral Dorsal Rami from S1-S3

-medial branch remains purely muscular

-lateral branch is muscular and cutaneous

Sacral Dorsal Rami from S4-S5

Dorsal rami does not divide and the medial branch is muscular and cutaneous

Coccygeal Doral Rami

Does not divide and the medial branch is muscular and cutaneous

Ventral Rami

-much larger than the dorsal rami at most levels, appear to be continuation of the spinal nerve

-mother innervating to hypoxia muscles including the limbs

-has cutaneous innervating to most of the body besides head and back

Cervical Plexus

C2-C4; innervates neck, parts of head and shoulders

Brachial Plexus

C5-T1; innervates the pectoral girdle and upper limbs

Lumbosacral Plexus

L1-S4; innervates pelvic girdle and lower limb

Dermatomes

area of skin innervated by cutaneous branches of single spinal nerve

Dermatome of C5

Thumb

Dermatome of C7

Middle finger

Dermatome of C8

Pinky

Dermatome of T4

Nipple

Dermatome of T10

Umbilicus

Dermatome of L1

Groin

Dermatome of L4

Shin and medial foot

Dermatome of L5

Lateral leg and top of foot

Dermatome of S1

Pinky toe and bottom of foot

Cutaneous Blood Supply of the Back

-small arteries and veins accompany the dorsal rami forming segmentally arranged neurovascular bundles

Thoracic Region Blood Supply

Artery are dorsal branches of the posterior intercostal arteries

Right Side of Heart

Receives de-oxygenated blood and sends the blood to the lungs for oxygenation

Left Side of Heart

Receives oxygenated blood from the lungs and returns it to the body

Arteries

Vessel that takes blood away from the heart

Vein

Vessels that will drain blood into the heart

Anastomoses

a connection between two blood vessels or tubes

Capillaries

-microscopic vessel through which exchanges take place between the blood and cells of the body

-connects arterioles on the arterial side to ventless on the venous side

Collateral Circulation

Alternative route of circulation to a body part created by anastomoses of arterial channels; can be collateral venous return created by anastomoses of venous channels

Collateral Vessel

Anastomostic vessels proceeding from superior to inferior

Recurrent Vessels

Anastomotic vessels proceeding from inferior to superior

Pulmonary Circulation

from the right ventricle to the lungs to the left atrium

Systemic Circulation

from the left ventricle to the body to the right atrium

Branches of the Aorta

Ascending aorta divides into the right and left coronary artery

Arch of the Aorta

-Brachiocephalic Trunk divides into the right subclavian artery and the right common carotid artery

-Left common carotid artery and left subclavian artery comes off the left side

Right Subclavian Artery

-branches off the brachiocephalic into the vertebral artery, thyrocervical trunk, and the costocervical trunk

Vertebral Artery

Supplies blood to the spinal column (C6-C1) and brain stem

Superficial Branch of Transverse Cervical Artery

Supplies the back muscles

Deep Branch of the Transverse Cervical Artery

Supplies the deep neck muscles

Internal Throacic Artery

Supplies the muscles of anterior internal chest wall; located lateral to the sternum

Thyrocervical Trunk

Divides into the Transverse Cervical Artery (Superficial and deep branches) and the Internal Thoracic Artery

Costocervical Trunk

Divides into the highest intercostal and the deep cervical

Right Common Carotid Artery

branches off brachiocephalic artery; goes into the occipital artery

Left Common Carotid Artery

branches off the arch of the aorta and goes into the occipital artery

Left Subclavian Artery

branches off the arch of the aorta and divides into the vertebral artery, thyrocervical trunk, and costocervical trunk

Internal Carotid Artery

Supplies the brain; enters skull via the carotid canal

External Carotid Artery

supplies the arteries to deep neck and face and the posterior superficial neck

Occipital Artery

Supplies the back of scalp, superior neck; runs in the occipital groove and above then superior nuchal line

Descending Aorta

the descending part of the aorta that branches into the thoracic and abdominal aortae

Accessory Azygous Vein and Hemiazygous Vein

drain the left side of the thorax (accessory is from the upper half and hemiazygous is from the lower half)

Azygous Vein

a large vein on the right side at the back of the thorax, draining into the superior vena cava and the inferior vena cava

Lymph

-watery fluid similar to blood plasma that circulates in a separate system of lymph channels, but drain into the blood circulatory system

-cells are lymphocytes

Function of the Lymphatic System

-drains interstitial fluid from spaces

-cleans and returns cellular wastes to blood

-produces a granular leukocytes to develop immunity

Afferent Lymph Vessels

drains lymph into nodes

Efferent Lymph Vessels

drain lymph from nodes to larger lymph channels

Thoracic Duct

-major lymph channel of the body

-receives drainage from the left side of head and neck, left side of thorax, left arm, abdomen, pelvis, perineum, and both legs

Intervertebral Discs

-fibrocartilage pads that separate and cushion the vertebrae

-thicker anteriorly than posterioly in the cranial and lumbar regions because it helps to create spinal curvatures

-flat in thoracics with the upper thoracic being the thinnest

-lumber region has the thickest discs

Kyphosis

Convex posteriorly; found in the thoracic and sacral spine