Exam 2 Flashcards
Nerve plexuses
At spinal cord levels, except for T2-T12, the anterior rami converge and diverge from each other forming these web-like plexuses. These fibers of the anterior rami intermingle and are redistributed
Why do &2-T12 not have nerve plexuses
Bc these nerves are mainly distributed exclusively to the truck
What are mutlisegmental peripheral nerve
A nerve that arises from the plexus that also conveys fibers to all or parts of other adjacent dermatomes
What arises from the nerve plexus
-Each anterior ramus contributes fibers to multiple peripheral nerves via the nerve plexuses , each of these peripheral nerve contain fibers from multiple spinal nerves
Two types of fibers
- the fibers carried by spinal nerves - segmental innervation (get dermatomes)
-fibers carried via branches of a plexus (mutlisegmental nerves)
Visceral sensory fibers (reflex and pain)
- Both visceral reflex senstations and pain impulses travel on on viseceral afferent fibers and travel info in opposite directions as the mother fiber they accompany
-reflex accompanies parasympathetic while pain is sympathetic
Visceral autonomic motor fibers
-organized into sympathetic and parasympathetic division; bth involve a 2-neuron chain btwn CNS & effector cell
-Pre & post synaptic neurons
Pre & post synaptic neurons
- pre = preganglionic have cell bodies w/in CNS gray matter and stretch out to autonomic ganglia
-post = postganglionic wh/ have cell bodies w/in autonomic ganglia & stretch out to smooth, Cardiac or gland cells
Sympathetic nervous system - division
Splits into paraveterbral ganglia or prevertebral ganglia
Paravertebral ganglia
Linked to form right and left sympathetic trunks (all motor) on each side of the vertebral column.
Prevertebral ganglia
Are in the plexuses that surround the origins of the main branches of the abdominal aorta
Celiac ganglia
-is a prevertebral ganglia that surrounds the origin of the celiac trunk
Superior cervical ganglion
- A paravertbral ganglia AKA superior paravertebral ganglion wh/ lies at the base of the cranium (1 per each of the sympathetic trunk)
Ganglion impar
-is an unpaired paravertebral ganglia that forms inferiorly where the 2 sympathetic trunks unite at the level of the coccyx
Sympathetic nervous system route (pregranglionic)
Preganglionic neurons leave the spinal cord thru anterior roots (bc they are motor fibers) & enter the anterior rami. Almost immediately after all preganglionic fibers leave the anterior rami of these spinal nerves & pass to the sympathetic trunk thru white rami communicates. Within the the sympathetic truck their are 3 possible courses
What are the three possible courses
- Synapse immediately w/ a postganglionic nervous of the paravertebral ganglion at the same level
- Ascend or descend in the sympathetic trunk to synapse w/ a postganglionic neuron of a higher or lower paravertebral ganglion
- Pass thru the sympathetic trunk w/o synapsing, continuing thru an adominopelvic splanchnic nerve to reach & synapse w/in a prevertebral ganglion
Sympathetic NS (postganglionic neurons)
Postganglionic fibers destined to reach structures of the neck, body wall, and limbs pass from the paravertebral ganglia thru grey rami communicantes & into both the anterior rami and the posterior rami of all 31 pairs of the spinal nerves
Splanchnic nerves of the postganglionic neurons
Convey visceral motor fibers to the visceral of the body cavities, these nerves also carry visceral sensory fibers from the same visceral towards the CNS
Sympathetic fibers destined for the viscera of the thoracic cavity
Pass thru cardiopulmonary splanchnic nerves to enter the cardiac, pulmonary, & esophageal pleaxyses, these fibers are postganglionic
Sympathetic fibers that are innervation of viscera of the abdominopelvic cavity
They pass thru the abdominopelvic splanchnic nerves, including the greater splanchnic, lesser splanchnic, least splanchnic & lumbar splanchnic nerves. These fibers are preganglionic and postganglionic fibers exiting prevertebral ganglia
Parasympathetic NS division
Fibers of preganglionic parasympathetic motor neurons exit the CNS
-W/in CN III, VII, IX, & X these neurons have cell bodies w/in brainsteam
-thru anterior roots of sacral spinal nerves S2-4, these neurons have cell bodies in the sacral segments of the spinal cord at levels S2-S4
Pelvic splanchnic nerves
Carry preganglionic parasympathetic fibers, arise from rami of spinal nerves S2-4 & innverate pelvic visceral plus the descending colon
Structures that innervated via parasympathetic NS
Sacral (descending colon & down)& cranial (head, Ascending & transverse colon) parasympathetic outflow wh/ innervates: strucures of the head, thoracic, abdominopelvic cavities, & erectile tissues of clit & penis.
*W/ expection of the penis & clit. The parasympathetic NS Doesn’t reach the body wall or limbs
What are the pairs of synapse-containing parasympathetic ganglia that occur in the head?
-Ciliary ganglion
-Pterygopalatine ganglion
-Submandibular ganglion
-Otic ganglion
Intrinsic or enteric ganglion
-They are preganglionic fibers synapse w/ postganglionic cell bodies that occur in or on the walls of the target organs
Enteric NS
-Contains Sensory & motor neurons
-includes two interconnected plexuses w/in the walls of the GI tract (myenteric plexus & submucosal plexus)
-The motor neurons receive input form the CNS via autonomic pathways. They synapse on & regulate activity of: smooth musicale contractions, exocrine glandular secretions, & endocrine secretions of the GI tract wall
Somatic sensory
Somatic motor
Visceral sensory
Visceral motor (symp & parasymp)
Are from or go to:
-from skin
-to skeletal muscle
-from viscera
-to viscera (smooth muscle, cardiac, glands)
Functions of the vertebral column
-protects the spinal cord & SN
-Supports the weight of the body superior to the level of the pelvis
-provides a partly rigid yet flexible axis for the body & a base on which the head is placed & pivots
-plays an important role in posture & locomotion
Adult vertebral column is arranged in 5 regions
7 cervical
12 thoracic
5 lumbar & sacral
4 coccygeal
The sacrum & coccyx formation
-the 5 sacral fuse in the adult to for the sarcum & after the age of 30 the 4 coccygeal fuse to form the coccyx
Intervertebral (IV) disc
The joints where adjacent vertebrae meet
*No IV disc btwn C1 &2
Zygapophysial joints
-where the two articular process of two vertebra (inferior process of one and superior process of another vertbrea) meet
Body (vertebral body)
Vertebral arch
-supports weight
- consist of 2 Pericles (R & L) and 2 laminae (R & L)
DRAW
Vertebral foramen
Vertebral canal
Intervertebral foramen
-formed by the vertebral arch + part of the body &b protects the spinal cord
-formed by all vertebral foramina in the articulated column stacked together, contains the spinal cord, roots of the spinal nerves, membranes, fat & vessels (goes superior to inferior)
-hole btwn 2 adjacent vertebra, spinal nerves emerge from the vertebral column thru these holes (goes lateral to medial)
What are the 7 processes of the vertebra
-spinous process- projects posteriorly (us. Inferiorly), functions in muscle attachment & movement. (Single & median)
-transverse process(s)- projects laterally; functions in muscle attachment & movement (R & L)
-Superior articular processes (2) & inferior articular processes (2) - each bears a cartilage-covered articular facet * all have R & L
What do the articular processes do?
-they (Inf & sup of 2 vertebra ) form the zygapophysial joints
-determine the type of movement allowed and not allowed between adjacent vertebra of each region
-keep adjacent vertebrae aligned
Cervical vertebrae
-Have a foramen transversarium (transverse foramen) wh/ is a hole in the transverse process (not C7) allows passage of the vertebral artery & accompanying vein
-Spinous process may be bifid (notched)
Atlas
-C1
-has neither a body nor spinous process
-Has paired superior articular surfaces Wh/ articulate/aline with the occipital condyle of the skull
-Transverse ligament of atlas holds their dens of the axis against the anterior part of the atlas
Axis
-C2
-has a tooth-like density which projects superior from its body, C1 wh/ carries the cranium rotates on C2
Vertebra prominens
-C7, has a particularly long spinous process, allowing you to fill it at the base of your neck
Thoracic Vertebrae
-Ribs join all 12 of these, thus they all posses smooth, cartilage-covered costal facets ( 2 on each side of the body, 1 on each transverse process)
The costal facet on the vertebra’s transverse process makes a joint with:
The costal facet on the vertebra’s body makes a joint with:
-a rib tubercle
-a rib head
*In most locations it takes facets from two adjacent vertebral bodies to receive a single rib head
Epidural space
-separates the spinal dura mater, to which it’s superficial from the periosteum-covered bone & ligaments that form the walls of vertebral canal-> contain fat
Lumbar vertebrae
-Have large bodies & posses neither foramina transversaria nor costal. Facets
-Spinous processes are square-ish and mostly don’t slope inferiorly
-L5 carries the weight of the complete upper bodyt which transmits to the base of the sarcum
Sacrum
Usually composed of five fused sacral vertebrae in adults
-located btwn & articulates with the hip bones
-provides strength & stability to pelvis & transmits the weight of the body to the pelvic girdle
-inferior half not weight bearing
Sacral canal
-continuation in the sacrum of the vertebral canal, contains bundle of SN roots = cauda equina
Base of sacrum
Formed by the superior surfaces of the S1 vertebra
Apex of the sacrum
-formed by the inferior surface of S5
Sacral promontory
-the anterior projecting edge of the body of s1 vertebra- base
Median sacral crest
-the fused rudimentary spinous processes of the superior three or four sacral vertebrae
Sacral hiatus
-an inverted U due to the absence of spinous processes of S5 and sometimes S4, leads into sacral canal
Anterior sacral foramina & posterior sacral foramina
-pairs of holes for the exit of the anterior and posterior rami, respectively of the SN, both communicate with the sacral canal
Why is the sarcum titled
So that it can articulate with the L5 vertebra at the lumbosacral angle which can vary from 130 to 160
Coccyx
-tailbone
-formed by fusion of 3-5 rudimentary coccygeal vertebrae, provides attachments for a few muscles
Intervertebral disc
-btwn the bodies of adjacent vertebrae; annulus fibrosus + nucleus pulposus
Annulus fibrosus
-a bulging fibrous ring consisting of concentric layers of fibrocartilage (outside; goes around nucleus pulposus)
Nucleus pulposus
-semifulid, gelatinous core of the disc
What is the anterior longitudinal ligament
-connects the antihero aspects of the vertebral bodies & IV discs it extends from the sacrum to C1 & the skull & resists hyper extension
What is a herniated disc?
You get a protrusions of the nucleus pulposus into or thru the annulus fibrosus
*a well recognized cause of lower back pain and low limb pain
Zygapophysial joints
-btwn an inferior articular process & the superior articular process of the next most inferior vertebra
Ligaments flava
Extend almost vertically from the laminate above to the laminate of the next vertebra below, they resist separation of the vertebral laminate by limiting flexion of the column, prevents injury of IV disc
Nuchal ligament
-from skull to the spinous processes of vertebrae; provides attachment for muscles
Atlanta-occipital joints
-paired synovial joints btwn C1 superior articular sufaces & the occipital bone of the skull, permit the yes flexion
Atlanta-axial joints
- 3 synovial joints btwn c1 & 2 which allows the rotation of the head when one shakes “no”
-R&L lateral and a single median Atlanto-axial joint
Primary curvatures
Develop during fetal period & are retained thruout life, are concave anteriorly
-thoracic kyphosis & sacral kyphosis
Secondary curvatures
-develop during infancy & childhood, they are concave posteriorly
-cervical & lumbar lordosis
Excessive thoracic kyphosis
-an abnormal increases in the thoracic curvature (hunchback)
Excessive lumbar lordosis
-an abnormal increase in the lumbar curvature
Scoliosis
-an abnormal lateral curvature
Segmental arteries
Such as lumbar arteries supply blood to the vertebral column
Internal & external vertebral venous plexuses
-collect blood from the vertebrae & drain into larger veins that lead back to the heart
Splenius Capitis
O, I, innervation, action
-from nuchal ligament & spinous processes of vertebrae
-temporal & occipital bones of the skull
-posterior rami of the SN
-extend head & neck; laterally flex neck and rotate head
Splenius cervicis
O,I, innervation, A
-from nuchal lig & spinous processes of vertebrae
-transverse processes of cervical vertebrae
-posterior rami of SN
-extend head & neck; laterally flex neck and rotate head
Erector spinae
-main extensor of the vertebral column, 3 parts
Iliocostalis
O,I, innervation, A
-from hipbone, sacrum, & spinous processes of lumbar vertebrae
-lower ribs & cervial transverse process
-posterior rami of SN
-extend vertebral column
Longissimus
O,I, innervation, a
-from hipbone, sacrum & spinous processes of lumbar vertebrae
-tor it’s, transverse processes of thoracic and cervical vertebrae & skull
-posterior rami of SN
-extend vertebral column
Spinalis
-O,I, innervation, a
-spinous process of lumbar vertebra
-spinous process of thoracic vertebrae
-posterior rami of SN
-extend vertebral column
Transversospinalis
-semispinalis
-multifidus
-rotatores
Semispinalis, multifidus, retatores O,I,A
-transverse processes of vertebrae
-spinous processes of more superior vertebrae
-extend vertebral column
Thoracolumbar fascia
-deep fascia which extends laterally from the spinous processes of vertebrae & forms a thin covering over the deep or intrinsic back muscles. * all three layers of muscles
Posterior cervical region
Contains the suboccipital triangle
Suboccippital triangle
-rectus capitis posteiror major
-obliques capitis superior
-obliques capitis interior
The suboccipital muscles
-suboccipital triangle + rectus capitis posterior minor
-are deep to the semispinalis
-extend btwn vertebrae c1/c2/skull
-produce movements btwn joints @ c1 and skull & C1 and C2
Contents of the suboccipital triangle
-suboccipital nerve which innervates the 4 suboccipital muscles
-vertebral artery -> branch of the subclavian artery which ascends thru the neck to supply to Brain
Spinal cord
-is w/in vertebral canal
-extends from Forman magnum of the skull typicallly to the level of the L1 or L2 vertebra
Conus medullaris
-cord’s tapering end
Cervical enlargement
Wide region the cord, gives rise to anterior rami of the SN -> forms brachial plexus which innervates upper limb
Lumbosacral (lumbar) enlargement
-wide region of the cord gives rise to the antibodies rami of the SN -> forms lumbar & sacral plexuses of the nerves which innervates lower limbs
Why does spinal cord stop at L1/L2?
In postnatal life, the spinal cord is shorter than the vertebral column, as you grow your vertebral column grows faster than your spinal cord. Thus as the stance btwn the origin of the nerve’s roots from the SC & the nerve’s exit form the vertebral canal increases as the inferior end of the VC is approached
Cauda equina
Loose bundle of SN roots, arising from the lumbosacral enlargement and the conus medullaris and travels inferiorly in the VC
Filum terminals
Descends among the SN roots in the cauda equina & consist of CT and vestiges of neural tissue and is covered by the membranes (meninges)-one string
Filum terminals externum
-coccygeal ligament-> inferior part of the Filum terminals which attaches to the coccyx. Serves as an anchor for the inferior end of the SC and spinal meninges
Epidural space
-separates spinal dura mater from the periosteum covered bone & logs which forms the walls of the vertebral canal -> contains fat
*spinal tap (LP)
Spinal arachnoid mater
Middle menix of the cord
Spinal dura mater
-outermost covering membrane (meninx) of SC tough and fibrous
Subarachnoid space
Filled with cerebrospinal fluid
-deep to arachnoid material but superficial to the pia encloses SC, SNR, and spinal ganglia
Pia mater
Deepest covering meninx of SC, thin closely follows all the surface features of SC
What do the spinal meninges do
These 3 membranes surround, support, protect SC and SNR including those of the cauda equina
Pectoral girdle
-two scapulae and two clavicles connected to sternum of axial skeleton
Pelvic girdle
-two hip bones connected to the sacrum of the axial skeleton
Pectoral girdle has
Thinner and lighter bones
No joints btwn the scapulae
The joint between sternum and clavicle is small and mobile
Not a true girdle
Ball and socket is small and shallow
Movement of one limb does not affect the movement of the other
Pelvic girdles
-thicker and heavier bones
-pubic symphysis connects the hip bones
-joint between the sacrum and lilac is large and mostly immobile
-true girdle (complete circle)
-ball and socket joint is large and deep
-movement of one limb affects movement of other
Clavicle
Connects upper limb to trunk
Moveable strucutre
Protects important bundles of nerves and vessels is bound to first rib via strong ligaments
Parts of cervical
-shaft
-sternal end-> medial, connects sternum at sternoclavicular joint
-acromial end-> lateral and articulates with acromion of scapula @ acromioclavicular joint
-consider tubercle -> on posteroinferior surface, fives attachment to consider ligament = medial pt of coracoclavcular lig
-trapezoid line-> attachement to trapezoid lig which is lateral part of coracoclavicular lig
-subclavian groove-> gives attachment to subclavius muscle
Spine of scapula
Thick projecting ridge of bone that divides the scapula’s posterior surface into a supraspinous fossa and a larger infraspinous fossa
Acromion
Lateral continuation of spine, forms the point of the shoulder articulates with the acromial end of the clavicle it and the spine provides attachment for the trapezius muscle
Subscapular fossa
-depression in costal surface (anterior) prickles attachment for the subscaularis muscle
Glenoid cavity
Shallow depression that receives and articulates with the head of the humerus at the glenohumeral joint
Coracoid process
-gives attachment to tendons & to the coracoclavicular lig
Deltoid tubercle
Prominence on the spine, fives attachment to the deltoid muscle
Body of scapula
Triangular basically the entire bone muns the spine, acromion, and coracoid process, has 3 borders and 3 angles (points)
Interior angle
Where the medial border meets the lateral border
Lateral angle
Where the superior border meets the lateral border
Coracoclavicular ligament
Suspends the scapula from the clavicle at the point of the suspension a balance is achieved btwn the weight of the scapula + it’s attached muscles + the muscular activity medially & the weight of the free limb laterally
Scapulothoracic joint
It is an physiological joint NOT an anatomical joint where the muscle moves the scapula on the thoracic wall
Head of humerus
-articulates with glenoid cavity
Anatomical neck
Encircles the head of the humerus
Greater tubercle of humerus
At the lateral edge of humerus provides attachment for muscles
Lesser tubercle
Projects anteriorly from front of the humerus provides attachment for muscles
Intertubercular sulcus
Groove separating the two tubercles, provides protected passage for the tendon of the long head of the biceps brachii muscle
Surgical neck
Just distal to the head and to tubercles, a common fracture site
Deltoid tuberosity
Rough area of the shaft of the humerus provides attachment for the deltoid muscle
Capitulum of humerus
Smooth surface on the lateral side of the antihero surface of the sitar humerus articulates with head of radius
Trochlea
Smooth pulley-shaped surface on the medial side of the antihero surface of the distal humerus articulates with trochlear notch of ulnar
Lateral epicondyle
Medial epicondyle
-bony projection just proximal and lateral to Capitulum gives attachement to muscles
-bony projection just proximal and medial to Trochlea, gives attachment to muscles
Radial fossa
Anterior depression just proximal to Capitulum receives the radius head during forearm flexion
Coronoid fossa
Anterior depression just proximal to Trochlea, receives Coronoid produces of ulna during forearm flexion
Olecranon fossa
Posterior depression on distal humerus, receives Olecranon of ulna during forearm extension
Olecranon
The point of the elbow severs as a short lever for extension of the elbow
Coronoid process
Projects anteriorly, gives attachement to brachialis
Trochlear notch
Formed via portions of the Olecranon & Coronoid process, resembles the jaws of a crescent wrench as grips the Trochlea of humerus
Tuberosity of ulna
Radial notch
Gives arrangement to a tendon of the brachialis muscle
Smooth rounded concavity that receives the head of radius
Head of ulna
Styloid process of ulna
-articulates with raidus, articular disc of the distal radio-ulnar joint is attached to it
- projection at distal end of the bone
Head of radius
Radial Tuberosity
Ulnar notch
Styloid process of raidus
-articulates with the Capitulum of the humerus and radial notch of ulnar
- gives attachment to one of the tendons of biceps brachii muscle
-articulates with the head of the ulna
-lateral and distal
Dorsal tubercle of radius
-a projection that produces grooves for the passage of tendons of the forearm as they travel to the carpals & digits
Interosseous border of radius & ulna
-connect thin, fibrous interosseous membrane of the forearm. The membrane helps transmit forces received via hand to radius, then to ulna and humerus
Metacarpal
1-5 lateral to medial, each metacarpal has a base, shaft, and head. The bases articulate with the Carpal bones. Head articulates with phalanges
Phalanges
-a proximal, a middle, and a distal ->except for the thumb which has only a proximal phalanx and a distal phalanx & a distal phalanx-> each has a base, shaft, & head
Intermuscular septa
-where deep and superficial fascia meet, and septa forms fascial compartments which holds individual muscles or groups
Extensor & flexor retinaculum
- a transverse band of fascia extensor covers extensor muscles cause they expand, and flexor covers the flexor muscles cause they flex
Cephalic vein & basilic vein
-the dorsal venous network drains into them, cephalic vein travels on lateral (cranial) edge of the limb (anteriorly) and basilic vein travels along the caudal (medial) edge of the limb and drain into the axillary vein
Median cubital vein
Runs obliquely between cephalic and basilic veins
Perforating veins
Communicate between the superficial and deep veins
Deep veins
-will have a double
-accompany arteries & usually bear the same name as their arteries they travel with
**superficial veins dont have accompany veins
Axillary lymph nodes
-the lymph collect from the upper limb via both superficial and deep lymphatics drain into these
What two heads does pectoralis major have
Clavicular head & sternocostal head
Clavicular head
O, I, Innervation, A
-medial half of clavicle
-intertubercular sulcus of humerus
-lateral and medial pectoral nerves
-abducts & medially rotates humerus; flexes humerus when acting alon
Sternocostal head
O, I, Innervation, A
-sternum & upper costal cartilages
-intertubercular sulcus of humerus
-lateral & medial pectoral nerve
-abducts & medially rotates humerus (w/ other head) & extends humerus when acting alone
Pectoralis minor
-O,I, innervation, action
-superior ribs
-Coronoid process of scapula
-medial pectoral nerve
-stabilizes scapula
Subclavius
-O, I, innervation, A
-from rib 1
-inferior surface of clavicle
-nerve to subclavius
-anchor & depresses clavicle
Serratus anterior
-O, I, Innervation, A
-ribs 1-8
-medial border of scapula
-long thoracic nerve
-protracts, rotates, & holds scapula against thoracic wall
Trapezius
O, I, Innervation, A
-external occipital protuberance, nuchal lig, & spinous process of thoracic vertebra
-lateral clavicle & acromion and spine of scapula
-spinal accessory nerve CN XI
-elevates scapula (DESCENDING), retracts scapula (MIDDLE), depress scapula (ASCENDING), both the ascending and descending rotate glenoid cavity superiorly
Latissimus Dorsi
O,I,Innervation, A
-spinous processes of inferior thoracic vertebrae, thoracolumbar fascia, iliac crest, & inferior ribs
-intertubercular sulcus of humerus
-thoracodorsal nerve
-extends, abducts, & medially rotates humerus
Levator scapulae
O,I, innervation, A
-transverse processes of upper cervical vertebrae
-superior part of medial border of scapula
-C3,C4, & dorsal scapular nerve
-elevates scapula & rotates glenoid cavity inferiorly
Rhomboid Major
-spinous processes of upper thoracic vertebrae
-medial border of scapula
-dorsal scapular nerve
-retracts scapula & rotates glenoid cavity inferiorly
Rhomboid minor
Spinous processes of C7 & T1 vertebrae
-medial border of scapula
-dorsal scapular nerve
-retracts scapula & rotates glenoid cavity inferiorly
Deltoid
*3 parts Clavicular, middle, & spinal
-clavicle, acromion & spine of scapula
-deltoid Tuberosity of humerus
-axillary nerve
-flex & medially rotates arm (Clavicular part); abducts arm (middle); extend & laterally rotates arm (spinal)
Teres major
-inferior angle of scapula
-intertubercular sulcus of humerus
-adducts & medially rotates arm
Supraspinatus
-supraspinous fossa of scapula
-greater tubercle of humerus
-suprascapular nerve
-aids deltoid in arm abduction
What are the rotator cuff muscles
*SITS
-supraspinatus, infraspinatus, teres minor, & subscapularis
-they grasp the humoral head
Infraspinatus
-infraspinous fossa of scapula
-greater tubercle of humerus
-suprascaular nerve
-laterally rotates arm
Teres minor
-lateral border of scapula
-greater tubercle of humerus
-axillary nerve
-laterally rotates arm
Subscapularis
-subscapular fossa scapula
-lesser tubercle of humerus
-subscapular nerves
-medially rotates arm
What is the axilla
It is a fat filled compartment that is inferior to the glenohumeral joint of the arm and houses the lymph nodes and blood vessels
The axillary sheath & axillary fat
Nerves and vessels traversing the axilla in a protective wrapping that is extension of cervical fascia & is embedded in the Cushioning matrix (axillary fat) which allows for flexibility
The axillary artery
-begins at the first rib and is a continuation of the subclavian artery and ends at the inferior border of trees major which it goes and becomes the brachial artery
-supplies a ton of muscles (latissimus dorsi)
The axillary vein
-is formed via the union of the brachial vein and basilic vein , it lies slightly anterior and inferior to the axillary artery. It terminates at the 1st rib and is renamed the subclavian vein
What is the axillary lymph nodes
They are embedded in the axillary fat, they occur in 5 groups which receive the lymph in a specific order, (helps to determine treatment for breast cancer),
What is the brachial plexus
-intermingling of nerve fibers which come from the 5 anterior rami (c5, c6, c7, C8, and T1) and are the roots of the plexus-> trunks, divisions, cords, nerves
What roots form the superior trunk, middle, and inferior?
-union of c5 & c6
-continuation of C7
-union of C8 & t1
Each trunk (superior, middle, and inferior) of the brachial plexuses splits into what
Each splits into/forms the anterior and posterior divisions
What divisions form the lateral, medial, and posterior cords?
-anterior division of the superior trunk & middle trunk
-continuation of the anterior division of the inferior trunk
-union of the posterior divisions of the superior, middle, & inferior trunk
What does the musculocutateous nerve arise from
The lateral cord
What does the axillary and radial nerve arise from
The posterior cord
What does the ulnar nerve arise from
The medial cord
What does the median nerve arise from
It is formed via the union of a branch from the lateral cord and a branch from the medial cord
Most of the terminal peripheral nerves in the in the brachial plexus are what?
- they are mutlisegmental peripheral nerves in that they receive fibers from multiple spinal segments
What does the suprascapular nerve arise from?
It is a branch of the superior trunk
What does the thoracodorsal nerve arise from
It is a branch of the posterior cord
Except for the shoulder most cutaneous nerves of the upper limb are derived from
The brachial plexus
The dermatomes of the upper limbs progress
Laterally to medially (like folded diagonally) and around the periphery of the outstretched limb from C4-T2
*remember dermatomes bleed into each other
Medial cutaneous nerves are branches from the
Medial cord of the brachial plexus
Posterior cutaneous nerves are branches of
The radial nerve
The lateral cutaneous nerves arise from
Each of them arise from a separate source (axillary, radial, and musculocutaneous nerve)
The muscles of the upper limb receive motor fibers
From several spinal cord segments or nerves,most of them include components of more than one myotome except for hand muscles which only have a single mytome (T1)
The muscles of the arms are divided into what two groups and how are they separated
- the anterior or flexor compartment and the postieor or extensor compartment
-they are separated by the humerus and medial and lateral intermuscular septae
The biceps brachii which has a short and long head is innervated and does what action(s)
They are innervated via musculocutaneous nerve
And supinates when the elbow is flexed and flexes the forearm
What is the origin and insertion of the biceps brachii short head
O- coracoid process of scapula
I- radial tuberosity forearm fascia (via bicipital aponeurosis)
What is the origin and insertion of the biceps brachii long head
O- just superior to glenoid fossa
I-radial tuberosity and forearm fascia via bicipital aponeurosis
The tendon of the long head of biceps is healed by a ligament to
The intertubercular sulcus of the humerus
Insertions of biceps
It’s major insertion is the radial tuberosity via the biceps tendon from this tendon inferomedially runs bicipital aponeurosis which merges with deep fascia in the forearm; causing biceps to indirectly connect to ulna (via fascia)
What is the origin, insertion, innervation, and action of brachialis
O- anterior surface of humerus
I-coronoid process of ulna and ulnar tuberosity
Innervation- musculocutaneous nerve
Action- flexes forearm
What is the origin, insertion, innervation, and action of the Coracobrachialis
O- coracoid process of scapula
I- middle third of humerus
Innervation- musculocutaneous nerve
A-helps to flex & adduct arm, and resists shoulder dislocation
Triceps Brachii’s origin, insertion, innervation, and action
O- long head = glenoid cavity of scapula, lateral and medial head = postieor humerus
I- olecranon of ulna
Innervation - radial nerve
A- extends forearm, resist shoulder dislocation
Anconeus ‘s origin, insertion, innervation, and action is
O- lateral epicondyle of humerus
I- olecranon of ulna
innervation- radial nerve
A- assist triceps in elbow extension
What is the brachial artery
It provides the main arterial supply to the arm, is a continuation of the axillary artery beginning at the teres major and it ends at the radius where it divides into the radius and ulnar arteries
What are the major branches of the brachial artery
-profunda brachii artery
-numeral nutrient artery
-superior & inferior ulnar collateral arteries
What does the profunda brachii supply
The posterior compartment of the arm
What does the humeral nutrient artery
Supplies humerus
Superior & inferior ulnar collateral arteries supply
They supply elbow joint
The veins of the arm
Have two sets the superficial and deep they both have valves (deep more)
The brachial vein is
A deep vein that is double and accompanies the brachial artery. It begins near the elbow by the union of smaller veins and ends by merging with the basilic vein to form the axillary vein
