Anatomy Tables - Cells & Tissues Review Items Summary

Topographical Anatomy of the Back

Structure/Space Description/Boundaries Significance
external occipital protuberance a projection on the external surface of the squamous part of the occipital bone in the midline it is the attachment site of the ligamentum nuchae and the trapezius m.; its highest point is called the inion (Latin, occiput = against head; Greek, inion = back of head)
vertebra (spina) prominens the seventh cervical vertebra it has a long, non-bifid spinous process which is prominent at the nape of the neck, hence its name (Latin, vert = to turn)

Topographical Anatomy of the Thorax

Structure/Space Description/Boundaries Significance
midaxillary line an imaginary vertical line passing through the middle of the axilla used as a surface landmark for descriptive purposes
midclavicular line an imaginary vertical line passing through the midshaft of the clavicle used as a surface landmark for descriptive purposes
deltopectoral triangle a triangle in the upper chest region that is bounded medially by the clavicle, superiorly by the deltoid m., and inferiorly by the pectoralis major m. the deltopectoral triangle is pierced by the cephalic vein on its course from the upper limb to join the axillary vein in the axilla
nipple located superficial to the 4th intercostal space in the male and prepuberal female; areola is dark ring surrounding nipple location of the left nipple may be used to help locate the apex of heart, which is approximately 8 cm from the midline in the left 5th intercostal space; a surface landmark used to place the stethoscope for auscultation of the bicuspid valve
suprasternal notch the notch located at the superior border of the manubrium of the sternum, between the sternal ends of the clavicles also known as: jugular notch

Bones of the Back Region

Bone Structure Description Notes
occipital the bone forming the posterior surface of the skull it articulates superolaterally with the parietal bones through the lambdoid suture, anteroinferiorly with the temporal bone and anteriorly with the body of the sphenoid bone (Latin, occiput = against head)
external occipital protuberance a low process on the external surface of the occipital bone in the midline it is an attachment site for the ligamentum nuchae; the superior nuchal lines of the two sides meet in the midline at the external occipital protuberance; also known as: inion (Latin, occiput = against head; Greek, inion = back of head)
mastoid process the process located posteroinferior to the external acoustic meatus it projects inferiorly from the junction of the petrous and squamous parts of the temporal bone; it contains the mastoid air cells that open into tympanic cavity through the mastoid antrum (Latin/Greek, mastoides = resembling a nipple)

 

superior nuchal line a low ridge that runs transversely on the external surface of the squamous part of the occipital bone it is an attachment site for trapezius and splenius mm. (Latin, nucha = nape)
vertebra one of a series of irregular bones that form the spine a vertebra has two parts: the vertebral body and the vertebral arch; there are 33 vertebrae total: 7 cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal; features of a typical vertebra include: body, pedicles, transverse processes, laminae, articular processes, spinous process
spinous process a posterior midline process arising from the junction of the two laminae of the vertebra it projects downward and inferiorly; it is an important site of muscle attachment; spinous processes of cervical vertebra 2-6 are bifid
vertebra prominens the seventh cervical vertebra it has a long, non-bifid spinous process which is prominent at the nape of the neck, hence its name
sacrum   a triangular bone that is the posterior skeletal element forming the pelvis it is formed by 5 fused vertebrae; the sacrum and two os coxae bones form the pelvis. (Latin, "os sacrum" meant "Holy Bone". "Holey" bone could remind you of the sacral foramina.)
posterior sacral foramina an opening in the posterior surface of the sacrum there are four pairs; each transmits the dorsal primary ramus of the respective sacral spinal nerve (Latin, foramen = an aperture)
coccyx   the most inferior portion of the vertebral column the coccyx results from the fusion of the four coccygeal vertebrae; it may be a single bone or the first coccygeal vertebra may be separated from the other three; it articulates with the fifth sacral segment; coccygeal vertebrae are reduced in complexity, having no pedicles, laminae or spines. (Latin/Greek, coccyx = cuckoo's beak)
pectoral girdle formed by the scapulae and clavicles and joined to the manubrium, it connects the upper limbs to the axial skeleton
clavicle   an "S" shaped bone located between the sternum and the scapula it articulates medially with the manubrium of the sternum and laterally with the acromion process of the scapula; it forms a strut that supports the upper limb; it is frequently fractured; it is the first bone to begin ossification during development (Latin, clavicula = little key, this term was used to refer to the catch that fastens a window as well as to keys. Curved window fasteners resemble the shape of this bone)
scapula   the bone of the shoulder the scapula floats in a sea of muscles, so it is difficult to fracture; it articulates with the axial skeleton through only one bone - the clavicle at the coracoclavicular and acromioclavicular joints
medial border the border of the scapula that runs from the superior angle to the inferior angle it is an important site of muscle attachments for the intermediate layer of back muscles, including rhomboid major and minor and serratus anterior
superior angle the angle of the scapula formed at the union of the superior and medial borders it is the attachment site for the levator scapulae m.
inferior angle the angle of the scapula formed by the union of the medial and lateral borders the inferior angle of the scapula often has a slip of origin of the latissimus dorsi attached to it
spine a heavy ridge that runs from the medial border of the scapula to the acromion process it supports the acromion process; it divides the posterior surface of the scapula into a supraspinatous fossa and an infraspinatous fossa
acromion a broad, flat process located at the lateral end of the scapular spine it articulates with the clavicle through a synovial joint (acromioclavicular joint) (Greek, akros = point)
ilium fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
iliac crest arching superior edge of the ilium that forms the rim of the "fan" attachment for abdominal wall muscles

Osteology of the Vertebral Column

Bone Structure Description Notes
vertebra one of a series of irregular bones that form the spine a vertebra has two parts: the vertebral body and the vertebral arch; there are 33 vertebrae total: 7 cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal; features of a typical vertebra include: body, pedicles, transverse processes, laminae, articular processes, spinous process (Latin, vert = to turn)
vertebral body the largest part of the vertebra it is shaped like a short cylinder; adjacent vertebral bodies articulate through a symphysis
vertebral arch the ring of bone formed by the paired pedicles and paired laminae of the vertebra the transverse processes and spinous process are attached to the neural arch; the neural arch protects the spinal cord
pedicle short strong process that extends posteriorly from the posterolateral surface of the vertebral body paired; it connects the body with the transverse process; it is marked by superior & inferior vertebral notches;
transverse process a lateral process that extends from the junction of the pedicle and the lamina of the vertebra a site for muscle attachment and rib articulation
lamina a broad flat plate of bone located between the transverse process and the spinous process of the vertebra paired; it is flattened markedly in the anteroposterior direction; ligamenta flava span the interval between the laminae of adjacent vertebrae (Latin, lamina = thin plate)
articular processes processes that project inferiorly and superiorly from the junction of the lamina and pedicle of the vertebra two pairs on each vertebra (superior and inferior); the superior articular processes of one vertebra articulate with the inferior processes of the adjacent vertebra through synovial joints
intervertebral notch a notch on the superior and inferior surface of the vertebral pedicle the superior intervertebral notch of one vertebra combined with the inferior intervertebral notch of the adjacent vertebra forms the intervertebral foramen
intervertebral foramen an opening between the pedicles of adjacent vertebrae adjacent intervertebral notches form the intervertebral foramen; an opening for passage of the spinal nerve
vertebral canal the opening formed by the combination of the body and the vertebral arch it contains the spinal cord, meninges, epidural fat and the internal vertebral plexus of veins
spinous process a posterior midline process arising from the junction of the two laminae of the vertebra it projects downward and inferiorly; it is an important site of muscle attachment; spinous processes of cervical vertebra 2-6 are bifid
cervical vertebrae   the seven vertebrae of the neck cervical vertebrae have the features of the typical vertebra plus all have transverse foramina (for passage of the vertebral artery); C2-C6 have bifid spinous processes; cervical vertebrae have relatively small bodies; several cervical vertebra are named: atlas, axis, vertebra prominens
atlas (C1) the first cervical vertebra it has no vertebral body, only anterior & posterior arches; it articulates with the odontoid process of the axis (Greek, atlas refers to a titan who supported the earth on this shoulders as the atlas vertebra supports the head)
axis (C2) the second cervical vertebra the odontoid process (dens) projects superiorly from its body; it articulates with the anterior arch of the atlas (Latin, the axis provides the odontoid process which is the pivot about which the atlas vertebra rotates)
vertebra prominens the seventh cervical vertebra (more properly, the vertebral spine of C7) it has a long, non-bifid spinous process which is prominent at the nape of the neck, hence its name
thoracic vertebrae   the 12 vertebrae associated with the thoracic region thoracic vertebrae have the features of a typical vertebra plus they are characterized by long slender spines that project inferiorly; they have facets for articulation with ribs; thoracic vertebrae have bodies of intermediate size
costal articular facet on the body small smooth areas at the junction of the body and the vertebral arch most thoracic vertebrae have 2 costal facets on each side (one superior and one inferior); the superior costal facet of one vertebra and the inferior costal facet of the adjacent vertebra both articulate with the head of the same rib; also known as demifacets
costal articular facet on the transverse process a small smooth area on the transverse process of the thoracic vertebra it articulates with the articular facet on the tubercle of the rib
lumbar vertebrae   the 5 vertebrae located in the lumbar region lumbar vertebrae have the features of a typical vertebra plus they are characterized by short, blunt spines that project posteriorly; lumbar spines do not overlap making the lumbar level a good one for spinal tap; lumbar vertebrae are built strong and have the largest bodies of all vertebrae
sacrum   a triangular bone that is the posterior skeletal element forming the pelvis it is formed by 5 fused vertebrae; the sacrum and two os coxae bones form the pelvis. (Latin, os sacrum = Holy Bone. "Holey" bone could remind you of the sacral foramina.)
anterior sacral foramina an opening in the anterior surface of the sacrum there are four pairs; each transmits the ventral primary ramus of the respective sacral spinal nerve; branches of the lateral sacral aa. enter the sacral canal through these openings (Latin, foramen = an aperture)
posterior sacral foramina an opening in the posterior surface of the sacrum there are four pairs; each transmits the dorsal primary ramus of the respective sacral spinal nerve (Latin, foramen = an aperture)
sacral canal the opening in the center of the sacrum it is the continuation of the vertebral canal at sacral vertebral levels
sacral hiatus an opening in the posterior surface of the sacrum in the midline it is a normal feature that results from the failure of fusion of the laminae of the fifth sacral segment (and sometimes the fourth) during development (Latin, hiatus = to yawn)
coccyx   the most inferior portion of the vertebral column the coccyx results from the fusion of the four coccygeal vertebrae; it may be a single bone or the first coccygeal vertebra may be separated from the other three; it articulates with the fifth sacral segment; coccygeal vertebrae are reduced in complexity, having no pedicles, laminae or spines. (Latin/Greek, coccyx = cuckoo's beak)

Osteology of the Pectoral Region

Bone Structure Description Notes
clavicle   an "S" shaped bone located between the sternum and the scapula it articulates medially with the manubrium of the sternum and laterally with the acromion process of the scapula; it forms a strut that supports the upper limb; it is frequently fractured; it is the first bone to begin ossification during development (Latin, clavicula = little key, this term was used to refer to the catch that fastens a window as well as to keys. Curved window fasteners resemble the shape of this bone)
rib the bone forming the lateral thoracic wall 12 pairs; several types are described: typical or "true" ribs, "false" ribs, "floating" ribs; all three types of ribs have many features in common: head, neck, tubercle, angle, body, costal groove
sternum the broad flat bone forming the anterior thoracic wall it is formed by three parts: manubrium, body, xiphoid process (Latin, sternum = breastbone, sternere = spread out)
manubrium the superior part of the sternum (Latin, manubrium = handle)
jugular (suprasternal) notch a notch on the superior border of the manubrium it is located between the clavicular notches which articulate with the sternal ends of the clavicles (Latin, jugulum = throat)
clavicular notch a notch on the superolateral border of the manubrium it articulates with the sternal end of the clavicle
sternal angle the junction of the manubrium and body of the sternum it is an anterior projection located at the level of the costal cartilage of rib 2; an important landmark for internal thoracic anatomy
body the middle part of the sternum it articulates with the manubrium superiorly and the xiphoid process inferiorly; laterally it articulates with the costal cartilages of ribs 2-7
xiphoid process the inferior part of the sternum it is variable in size, shape & ossification; it articulates with the body of the sternum superiorly (Greek, xiphos = sword + eidos = appearance)
scapula   the bone of the shoulder the scapula floats in a sea of muscles, so it is difficult to fracture; it articulates with only one bone - the clavicle at the coracoclavicular and acromioclavicular joints
coracoid process a beak-like process that projects anteriorly from the lateral end of the superior border of the scapula it is the attachment site for the short head of the biceps brachii m., the coracobrachialis m., the pectoralis minor m. and the coracoacromial and coracoclavicular ligaments (Greek, korax = crow + eidos = appearance. The coracoid process of the scapula is shaped like a crow's beak)
humerus   the bone of the arm (brachium) the humerus articulates proximally with the scapula at the glenoid fossa; it articulates distally with the radius and ulna at the elbow joint
greater tubercle the large projection located lateral to the head of the humerus it is the attachment site of the supraspinatus, infraspinatus & teres minor mm.
intertubercular groove the groove on the anterior surface of the humerus that is located between the crest of the greater tubercle and the crest of the lesser tubercle it is occupied by the tendon of the long head of the biceps brachii m.; the transverse humeral ligament spans the intertubercular groove and holds the biceps tendon in place; it is the attachment site for the tendon of the pectoralis major (lateral lip), teres major (medial lip), and latissimus dorsi (floor) (Latin, tuber = knobby process, nodule)
crest of the greater tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the greater tubercle it forms the lateral lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the pectoralis major m.
crest of the lesser tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the lesser tubercle it forms the medial lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the teres major m.

Muscles of the Back Region - Superficial Group

Muscle Origin Insertion Action Innervation Artery Notes
latissimus dorsi vertebral spines from T7 to the sacrum, posterior third of the iliac crest, lower 3 or 4 ribs, sometimes from the inferior angle of the scapula floor of the intertubercular groove extends and rotates the arm medially, along with adduction of the arm thoracodorsal nerve (C7,8) from the posterior cord of the brachial plexus thoracodorsal a. the inserting tendon twists so that fibers originating highest insert lowest (Latin, latus = broad, dorsi = back)
levator scapulae transverse processes of C1-C4 vertebrae medial border of the scapula from the superior angle to the spine elevates the scapula dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4 dorsal scapular a. levator scapulae is named for its action (Latin, levator = to lift)
rhomboideus major spines of vertebrae T2-T5 medial border of the scapula inferior to the spine of the scapula retracts, elevates and rotates the scapula inferiorly dorsal scapular nerve (C5) dorsal scapular a. named for its shape (Greek, rhomb = oblique parallelogram)
rhomboideus minor inferior end of the ligamentum nuchae, spines of vertebrae C7 and T1 medial border of the scapula at the root of the spine of the scapula retracts, elevates and rotates the scapula inferiorly dorsal scapular nerve (C5) dorsal scapular a named for its shape (Greek, rhomb = oblique parallelogram
trapezius medial third of the superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of vertebrae C7-T12 lateral third of the clavicle, medial side of the acromion and the upper crest of the scapular spine, tubercle of the scapular spine elevates and depresses the scapula (depending on which part of the muscle contracts); rotates the scapula superiorly; retracts scapula motor: spinal accessory (XI), proprioception: C3-C4 transverse cervical a. named for its shape; trapezius is an example of a muscle that migrates during development from its level of origin (cervical) to its final position, pulling its nerve and artery along behind

Muscles of the Back Region - Intermediate Group

Muscle Origin Insertion Action Innervation Artery Notes
serratus posterior inferior thoracolumbar fascia, spines of vertebrae T11-T12 and L1-L2 ribs 9-12, lateral to the angles pulls down lower ribs branches of the ventral primary rami of spinal nerves T9-T12 lowest posterior intercostal a., subcostal a., first two lumbar aa. a respiratory muscle, it receives ventral ramus innervation; embryonically related to the intercostal muscles, not the deep back mm. (Latin, serratus = to saw)
serratus posterior superior ligamentum nuchae, spines of vertebrae C7 and T1-T3 ribs 1-4, lateral to the angles elevates the upper ribs branches of the ventral primary rami of spinal nerves T1-T4 posterior intercostal aa. 1-4 a respiratory muscle, it receives ventral ramus innervation; embryonically related to the intercostal muscles, not the deep back mm. (Latin, serratus = to saw)

Muscles of the Back Region - Deep Group

Muscle Origin Insertion Action Innervation Artery Notes
erector spinae iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull extends and laterally bends the trunk, neck and head segmentally innervated by dorsal primary rami of spinal nerves C1-S5 supplied segmentally by: deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa. the erector spinae m. is separated into 3 columns of muscle: iliocostalis laterally, longissimus in an intermediate position and spinalis medially; each of these columns has multiple named parts

Muscles of the Pectoral Region

Muscle Origin Insertion Action Innervation Artery Notes
pectoralis major medial 1/2 of the clavicle, manubrium & body of sternum, costal cartilages of ribs 2-6, sometimes from the rectus sheath of the upper abdominal wall crest of the greater tubercle of the humerus flexes and adducts the arm, medially rotates the arm medial and lateral pectoral nerves (C5-T1) pectoral branch of the thoracoacromial trunk the deep fascia on its anterior surface should not be fused to the fascia of the mammary gland - if it is, this is an important clinical sign indicating breast disease (Latin, pectus = breast bone)
pectoralis minor ribs 3-5 coracoid process of the scapula draws the scapula forward, medialward, and downward medial pectoral nerve (C8, T1) pectoral branch of the thoracoacromial trunk branches of medial pectoral nerve usually pierce pectoralis minor to reach the pectoralis major muscle (Latin, pectus = breast bone)
serratus anterior ribs 1-8 or 9 medial border of the scapula on its costal (deep) surface it draws the scapula forward; the inferior fibers rotate the scapula superiorly long thoracic nerve (from ventral rami C5-C7) lateral thoracic a. a lesion of long thoracic nerve will cause winging of the scapula (i.e., the medial border of the scapula falls away from the posterior chest wall and looks like an angel's wing) (Latin, serratus = to saw)

Joints and Ligaments

Joint or ligament Description Notes
nuchal ligament a midline ligament that extends posteriorly from the spinous processes of cervical vertebrae and extends from the base of the skull to the 7th cervical vertebra a syndesmosis; it provides muscle attachments to the cervical spinous processes without the necessity of long spinous processes that would hinder extension of the neck (Latin, nucha = nape)

Joints and Ligaments of the Vertebral Column

Joint or ligament Description Notes
interspinous ligament a ligament that connects the spinous processes of two adjacent vertebra a syndesmosis
intervertebral disc a fibrocartilaginous disc between adjacent vertebral bodies a symphysis; it is composed of two parts: an outer anulus fibrosus and an inner nucleus pulposus; the nucleus pulposus is the remnant of the notochord; the intervertebral discs are important shock absorbers between vertebrae
ligamenta flava a ligament formed predominantly by elastic fibers which joins the laminae of adjacent vertebrae a syndesmosis; paired; the ligamentum flavum is penetrated by the needle during spinal tap (Latin, flavus = yellow, a reference to the predominance of yellow elastic fibers which gives this ligament its grossly visible color)
nuchal ligament a midline ligament that extends posteriorly from the spinous processes of cervical vertebrae and extends from the base of the skull to the 7th cervical vertebra a syndesmosis; it provides muscle attachments to the cervical spinous processes without the necessity of long spinous processes that would hinder extension of the neck; a.k.a. ligamentum nuchae (Latin, nucha = nape)
anterior longitudinal ligament a ligament that courses from superior to inferior along the anterior surfaces of all vertebral bodies it lies directly posterior to the thoracic and abdominal viscera
posterior longitudinal ligament a ligament that courses from superior to inferior along the posterior surfaces of all vertebral bodies it is broader at the intervertebral discs and narrow at the vertebral bodies which gives it a scalloped edge; it is located in the vertebral canal; it is NOT penetrated by the needle during spinal tap
supraspinous ligament a ligament that connects the tips of the spinous processes of thoracic and lumbar vertebrae a syndesmosis; the supraspinous ligament begins at the C7 vertebra and ends at the mid-sacral segmental level; it serves as a muscle attachment site
zygapophyseal joint a small joint between the articular processes of adjacent vertebrae a synovial plane joint

Blood Vessels of the Back

Artery Source Branches Supply to Notes
dorsal scapular subclavian a., 3rd part unnamed muscular branches levator scapulae m., rhomboideus major m., rhomboideus minor m. dorsal scapular a. anastomoses with the suprascapular a. and the subscapular a. to form the scapular anastomosis; dorsal scapular a is a branch of the transverse cervical a. in ~30% of cases
thoracodorsal subscapular muscular latissimus dorsi  
transverse cervical thyrocervical trunk unnamed muscular branches, possibly the dorsal scapular a. trapezius muscle and surrounding tissues transverse cervical a. gives rise to the dorsal scapular a. ~30% of the time

Arteries of the Spinal Cord & Vertebral Column

Artery Source Branches Supply to Notes
radicular, anterior they arise as multiple branches of several vessels (vertebral, posterior intercostal, lumbar, and lateral sacral aa.) they accompany the ventral rootlets to reach the spinal cord meninges; spinal cord; spinal nerve; ventral rootlets anterior radicular aa. anastomose with the anterior spinal a.
radicular, great anterior the spinal br. of the lower posterior intercostal a., subcostal a., or upper lumbar a., usually on left no named branches lower spinal cord great anterior radicular a. anastomoses with the anterior spinal a. at lower thoracic or upper lumbar spinal cord levels
radicular, posterior they arise as multiple branches of several vessels (vertebral, posterior intercostal, lumbar, and lateral sacral aa.) no named branches meninges; spinal cord; spinal nerve; dorsal rootlets posterior radicular aa. accompany the dorsal rootlets; they anastomose with the posterior spinal aa.
spinal, anterior contributions received from several arteries (vertebral, posterior intercostal, subcostal, lumbar, lateral sacral aa.) pial arterial plexus meninges; spinal cord; medulla (dorsal motor nucleus of cranial nerve X, nucleus ambiguus, spinal accessory nucleus and hypoglossal nucleus) the anterior spinal a. anastomoses with the anterior radicular brs. of the spinal rami of the vertebral, posterior intercostal, subcostal, lumbar and lateral sacral aa.
spinal, posterior contributions received from several arteries (posterior inferior cerebellar, vertebral, posterior intercostal, subcostal, lumbar, lateral sacral aa.) pial arterial plexus spinal cord, especially the dorsal columns; medulla (nucleus cuneatus and nucleus gracilis) paired; posterior spinal aa. anastomose with the posterior radicular brs. of the spinal rami of the vertebral, posterior intercostal, subcostal, lumbar and lateral sacral aa.

Arteries

Artery Source Branches Supply to Notes
thoracoacromial axillary a., 2nd part pectoral br., clavicular br., acromial br., deltoid br. pectoralis major m., pectoralis minor m., subclavius m., deltoid m., shoulder joint thoracoacromial trunk pierces the costocoracoid membrane

Veins of the Spinal Cord & Vertebral Column

Vein Tributaries Drains Into Region Drained Notes
vertebral plexus, external adjacent segmental vs. vertebral column & associated muscles connects with internal vertebral plexus
vertebral plexus, internal adjacent segmental vs. spinal cord, meninges, vertebral column connects with external vertebral plexus

Veins

Vein Tributaries Drains Into Regions Drained Notes
cephalic v. lateral side of the dorsal venous arch of the hand; superficial veins of the forearm axillary vein superficial parts of the lateral hand and lateral forearm median cubital vein usually shunts some of the blood collected by the cephalic v. to the basilic v. (Latin/Greek, kephale = head)

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
axillary nodes axilla cubital nodes; lymphatic vessels from the upper limb, thoracic wall and subscapular region efferents vessels form the subclavian trunk, some drainage to inferior deep cervical nodes upper limb, most of the mammary gland, some of the anterolateral chest wall, posterior thoracic wall and scapular region axillary nodes number from 20 to 30 and are organized in five groups based on their position within the axilla: 1) pectoral nodes, along the lateral border of the pectoralis major m.; 2) lateral nodes, located along the distal axillary v.; 3) central nodes, centrally located along axillary v.; 4) subscapular nodes, located along the subscapular v. and its tributaries; 5) apical nodes, located at the apex of axilla
parasternal nodes lateral border of sternum, along the course of the internal thoracic vessels anterior phrenic nodes, lymphatic vessels from the anterior thoracic wall larger lymphatic vessels in the root of the neck medial side of the mammary gland; medial part of the anterior chest wall and muscles parasternal nodes constitute an important drainage pattern in cases of cancer of the mammary gland; one or two parasternal nodes may be found in the anterior end of intercostal spaces 1-6; also known as: sternal nodes
pectoral nodes along the lateral border of the pectoralis major m. along the course of the lateral thoracic vessels lymphatic vessels from the mammary gland and anterolateral thoracic wall central axillary nodes anterolateral thoracic wall and muscles; most of the mammary gland an important group of nodes to examine during a breast physical exam; also known as: anterior axillary nodes

Nerves of the Back

Nerve Source Branches Motor Sensory Notes
accessory n. cranial root: medulla - nucleus ambiguus; spinal root: spinal nucleus of the upper cervical spinal cord no named branches GSE: sternocleidomastoid and trapezius mm. none also known as: CN XI, 11th cranial nerve; spinal root enters cranial cavity by passing through the foramen magnum; exits skull by passing through the jugular foramen; accessory n. is motor only; the subtrapezial plexus of nerves receives proprioceptive fibers: for the sternocleidomastoid m. from the ventral primary rami of spinal nn. C2 and C3 - for trapezius via ventral primary rami of C3 and C4
dorsal primary ramus first branch off of the dorsal side of the spinal nerve numerous to the deep back mm.; sympathetic innervation to the skin general sense (touch, pressure, pain, heat, cold, etc.) to the skin of the back a mixed nerve containing both motor and sensory fibers (Latin, ramus = branch)
dorsal scapular n. brachial plexus (br. of C5 ventral primary ramus) no named branches rhomboideus major and minor mm.; levator scapulae m. none dorsal scapular n. passes through the scalenus medius m.
occipital n., greater dorsal primary ramus of spinal nerve C2 (medial br.) no named branches posterior neck muscles skin of the posterior surface of the scalp muscles innervated by this nerve develop from epimeres in the embryo
spinal n. formed at the point where the dorsal and ventral rootlets meet; it ends where the dorsal and ventral primary rami diverge dorsal primary ramus; ventral primary ramus to skeletal mm.; some levels carry preganglionic sympathetic axons (T1-L2) general sense (touch, pressure, pain, heat, cold, etc.) from the entire surface of the neck, trunk and extremities; visceral pain (via the white ramus communicans and the sympathetic nervous system) located at the intervertebral foramen; there are 31 pairs of spinal nerves - 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
thoracodorsal (middle subscapular) posterior cord of brachial plexus   latissimus dorsi    

Nervous Structures

Nerve Source Branches Motor Sensory Notes
dorsal primary ramus first branch off of the dorsal side of the spinal nerve numerous to the deep back mm.; sympathetic innervation to the skin general sense (touch, pressure, pain, heat, cold, etc.) to the skin of the back a mixed nerve containing both motor and sensory fibers (Latin, ramus = branch)
dorsal root multiple rootlets from the dorsal horn of the spinal cord to the spinal nerve none none general sense (touch, pressure, pain, heat, cold, etc.) dorsal root is entirely sensory in function; it is located dorsal to the denticulate ligament
dorsal root ganglion dorsal rootlets dorsal root none one dermatome a sensory ganglion located along the dorsal root within the intervertebral foramen - one per spinal nerve; location of the cell bodies of somatic afferent (sensory) neurons
spinal n. formed at the point where the dorsal and ventral rootlets meet; it ends where the dorsal and ventral primary rami diverge dorsal primary ramus; ventral primary ramus to skeletal mm.; some levels carry preganglionic sympathetic axons (T1-L2) general sense (touch, pressure, pain, heat, cold, etc.) from the entire surface of the neck, trunk and extremities; visceral pain (via the white ramus communicans and the sympathetic nervous system) located at the intervertebral foramen; there are 31 pairs of spinal nerves - 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
ventral primary ramus first branch off of the ventral side of the spinal nerve numerous to skeletal mm. of the neck, trunk and extremities; sympathetic innervation to the skin general sense (touch, pressure, pain, heat, cold, etc.) to the skin of the trunk (except the back) and extremities; visceral pain via the white rami of the sympathetic nervous system (T1-L2) a mixed nerve containing both motor and sensory fibers (Latin, ramus = branch)
ventral root multiple rootlets from the ventral horn of the spinal cord to the spinal nerve none to skeletal mm.; preganglionic sympathetic (T1-L2) none entirely motor in function; located ventral to the denticulate ligament; at all spinal core levels it contains GSE for skeletal mm.; at levels T1-L2 it contains GVE (preganglionic sympathetic) for blood vessels, sweat glands, thoracic viscera, abdominal viscera, pelvic viscera

Spinal Meninges & Spinal Cord

Structure Location/Description Notes
spinal cord lies within the dural sac in vertebral canal; continuous with medulla oblongata at foramen magnum of skull; ends inferiorly at L1/2 intervertebral disc spinal cord and brain are the central nervous system; their branches comprise the periperal nervous system
gray matter butterfly-shaped core of the spinal cord, containing neuron cell bodies ventral horns of gray mater contain motor neurons, dorsal horns contain sensory neurons, lateral horns contain autonomic nerve cell bodies
white matter surrounds the gray matter of spinal cord, contains nerve processes ascending and descending cord white color derives from fatty myelin covering of nerve processes
anterior median fissure a longitudinal midline fissure located on the ventral surface of the spinal cord the anterior spinal artery lies in this fissure ventrally
posterior median sulcus a longitudinal midline groove located on the dorsal surface of the spinal cord
cervical enlargement vertebral level C4 through T1 created by the rootlets of spinal nerves C5-T1 that form the brachial plexus
lumbrosacral enlargement vertebral level T11 through L1 created by the rootlets of spinal nerves L1-S4 that form the lumbosacral plexus
conus medullaris cone-shaped inferior end of the spinal cord; located at vertebral level L1 at birth, the conus medullaris is at the level of L2/L3 (Latin/Greek, conus = cone)
cauda equina dorsal and ventral roots of all spinal nerves inferior to L1 lies within the lumbar cistern (Latin, cauda equina = horse's tail)
arachnoid mater intermediate one of the three layers of meninges arachnoid mater is a thin membrane which is pressed against the inner surface of the dura mater by cerebrospinal fluid pressure; (Greek, arachnoids = spider ), the space deep to this layer (subarachnoid space) has a spider web-like appearance
denticulate ligament a lateral extension of pia mater from the spinal cord denticulate ligament attaches to the dura mater to anchor the spinal cord; it forms a scalloped free border; there are 2 (one on each side)
dura mater outermost of the meningeal layers covering the brain and spinal cord Latin for "tough mother"; it is the most durable of the meninges and provides support and protection for the brain and spinal cord; two types are described which differ in structure: cranial and spinal
dura mater, spinal outermost covering of the spinal cord, it forms the dural sac containing the spinal cord within vertebral canal dural sac ends at S2, coccygeal ligament (filum terminale externum) continues inferiorly to attach to coccyx (Latin, dura mater = tough mother)
epidural fat loose connective tissue within the epidural space upon the dura mater
epidural space the space external to the sac of spinal dura mater within the vertebral canal the epidural space contains epidural fat and the internal vertebral plexus of veins which is valveless (clinically relevant as potential route for hematogenous metatasis)
filum terminale internum thread-like extension of the pia mater from the conus medullaris of the spinal cord filum terminale internum is best seen between vertebral levels L2 and S2; it becomes enclosed within the filum terminale externum (Latin, filum = thread)
filum terminale externum thread-like extension of the dura mater below the end of the dural sac at S2 it attaches to the coccyx; also known as the coccygeal ligament (Latin, filum = thread)
meninges three layers of connective tissue covering the brain and spinal cord; dura mater, arachnoid mater, and pia mater meninges provide protection and nourishment of the brain, brainstem and spinal cord (Greek, menin- = membrane)
pia mater delicate membrane that lies on surface of the brain and spinal cord Latin, pia mater = delicate mother; it is the most delicate of the meninges; this layer faithfully follows all surface contours of the brain and spinal cord; pia mater has 2 specializations: denticulate ligament and filum terminale internum
subdural space the space between the dura mater and the arachnoid mater this is a potential space only; the pressure of CSF in the subarachnoid space pushes arachnoid against dura
subarachnoid space the space between the arachnoid and the pia mater subarachnoid space contains cerebrospinal fluid and spider web-like filaments (Greek, arachnoids = spider )

Nerves

Nerve Source Branches Motor Sensory Notes
intercostal n. ventral primary rami of spinal nerves T1-T11 lateral & anterior cutaneous brs. intercostal muscles; abdominal wall muscles (via T7-T11); muscles of the forearm and hand (via T1) skin of the chest and abdomen anterolaterally; skin of the medial side of the upper limb (via T1-T2) intercostal n. travels below the posterior intercostal a. in the costal groove (Latin, costa = rib)
long thoracic n. brachial plexus (ventral primary rami of spinal nerves C5-C7) no named branches serratus anterior m. no cutaneous branches located on the superficial surface of the serratus anterior m.; lesion of this nerve causes scapular winging, hence the saying "C5, 6, & 7 keep the wings from heaven"
pectoral, lateral lateral cord of the brachial plexus no named branches pectoralis major m. no cutaneous branches lateral pectoral n. communicates with the medial pectoral n. anterior to the axillary a.; it pierces the clavipectoral fascia
pectoral, medial medial cord of the brachial plexus no named branches pectoralis minor m., pectoralis major m. no cutaneous branches medial pectoral n. communicates with the lateral pectoral n. anterior to the axillary a.; it pierces the pectoralis minor m.

Viscera/Fascia

Organ/Part of Organ Location/Description
skin the membranous covering of the body, also known as the cutis
epidermis the outer epithelial portion of the skin including these layers (from superficial to deep): stratum corneum (or horny layer), stratum lucidum (or clear layer), stratum granulosum (or granular layer), stratum spinosum (or spiney layer), stratum germintivum (or germinative layer), stratum basale (or basal layer) (Greek, epi = on + derma = skin)
dermis blood, lymph vessels, nerves, sebaceous glands, and sweat glands occur in this layer of the skin, which lies between the epidermis and fatty (subcutaneous) layer
subcutaneous tissue also known as the superficial fascia, this layer lies deep to the skin and consists of loose connective tissue containing fat, cutaneous nerves, superficial veins, lymph vessles and nodes (Latin, sub = beneath + cutis = skin)
investing (deep) fascia a dense layer of connective tissue between the subcutaneous tissue and the muscles; surrounds the entire muscle group
muscular fascia a dense layer of connective tissue surrounding individual muscles
neurovascular bundle a term that describes the typical common path of a vein, artery, and nerve
thoracolumbar aponeurosis (fascia) extends laterally from the spinous processes and forms a thin covering for the deep muscles in the thoracic region and a strong, thick covering for muscles in the lumbar region.

Viscera/Fascia

Organ/Part of Organ Location/Description Notes
clavipectoral fascia deep fascia attaching to clavicle, surrounding subclavius m., thickened below as costocoracoid ligament, extending inferiorly to pectoralis minor as costocoracoid membrane (pierced by cephalic v., lateral pectoral n., thoracoacromial a.), encloses pectoralis minor, extends inferolaterally to attach to axillary fascia as suspensory ligament of axilla
mammary gland located anterior to pectoralis major m. from rib 2/3 to rib 6/7 the breast, a modified sweat gland, comprises glandular tissue arranged in up to 20 lobules, surrounded by subcutaneous connective tissue and supported by suspensory ligaments
lactiferous ducts drain the lobules of the mammary gland at the nipple beneath the nipple, the ducts form lactiferous sinuses
areola darkly pigmented skin surrounding the nipple

Clinical Terms

Term Definition
triangle of auscultation a triangular gap formed by the superior horizontal border of the latissimus dorsi, the medial border of the scapula, and the inferolateral border of the trapezius; this is a good place to examine posterior segments of the lungs with a stethoscope
lumbar triangle (Petit's triangle)/hernia bordered medially by the latissimus dorsi, laterally by the external abdominal oblique, and inferiorly by the iliac crest, this point is vulnerable to abdominal (lumbar) hernia. The definition of a hernia is the protrusion of a portion of an organ or tissue through an abnormal opening.
slipped/herniated disc herniation of the nucleus pulposis through a weakened anulus fibrosus, usually posterolaterally; it commonly puts pressure on the nerve roots or dorsal root ganglion exiting the intervertebral foramen at or below this level, leading to the symptoms of a "slipped disk;" these occur most frequently in the cervical and lumbar regions due to these segments being the most mobile. Cervical disk disease usually presents in patients older than the age of 50, and patients complain of pain (radiating down the arm), paresthesia and dysasthesia (abnormal sensations), and weakness. Lumbar disease presents with similar symptoms in the lower extremities. Both conditions are diagnosed via MRI.
radiculopathy compression or lesion of spinal nerve roots
pinched nerve refers to spinal nerves compressed by herniated discs or spondylosis; pain and sensory loss follows the dermatome; motor loss may also occur
laminectomy removal of one or more laminae of the vertebrae; this is often done to remove a herniated disc (Latin, lamina = thin plate)
nerve root avulsion tearing away of the nerve roots from the spinal cord. This does not often occur in the cervical spine as the transverse processes of vertebrae here have chutes or grooves in which the spinal nerves lie. Connective tissue attaches the nerve fibers to the chutes and any trauma will sever the nerves distal to the chutes instead of tearing them from the spinal cord. Distal injuries are easier to repair.
lumbar puncture (aka spinal tap) this procedure is used to gather CSF fluid, which is an excellent diagnostic tool; CNS infections, blood and other pathologies can affect content of this vital fluid; to perform a lumbar puncture, the patient is lying on the side with the back flexed (spreads everything out). A needle is inserted between the spinous processes of L3 and L4 or L4 and L5. A superficial landmark for finding this point is the supracristal line which runs on a line from the iliac crests and passes through L4's spinous process
meningitis infection of the meninges (either bacterial or viral). Patients typically present with the triad of fever, headache, and signs of meningeal irritation (such as neck stiffness). (Greek, menin- = membrane, -itis = inflammation)
epidural anesthesia injection of anesthetic agents into the epidural space as opposed to injection into the subarachnoid space; usually takes 10 to 20 minutes to take effect and has a direct effect on the spinal nerves; this procedure is often used in childbirth and cesarean sections
spinal anesthesia an anesthetic agent is injected directly into the subarachnoid space at the L3/L4 vertebral level, anesthetizes essentially everything inferior to the waist; the anesthesia takes effect in about a minute; this procedure can result in the patient experiencing a headache due to fluid leaking from the puncture site. Patients must be carefully monitored as sometimes (about 1 out of every 100) the anesthetic agent can travel upward and block autonomic nerves slowing the heart and depressing respirations.
caudal anesthesia this procedure is done using an in-dwelling catheter in the sacral canal; the catheter is inserted through the sacral hiatus, and the anesthetic bathes the sacral nerve roots; the position of the patient and the amount of fluid injected determines the height to which the anesthetic ascends
spina bifida a defect in the spinal column due to failure of development or fusion of the vertebral arches with varying levels of severity depending on the involvement of the spinal cord and meninges. The incidence of this has been dramatically reduced with the discovery that proper maternal intake of folic acid can prevent this in most cases.
hydrocephalus a condition that causes dilation of the cerebral ventricles due to excessive accumulation of cerebrospinal fluid. This may lead to separation of the cranial bones and enlargement of the head.(Greek, hydro = water)
myelomeningocele a congenital defect that results in the failure of the closure of the neural arches, resulting in herniation of the spinal cord and its meninges through the defect in the vertebral column. (Greek, myelos = spinal cord + menin- = membrane + cele = hernia)
anomalies/variations deviation or departure from the normal or common order, form, or rule
gynecomastia excessive development of the male mammary glands, sometimes secreting milk. This can be idiopathic, or as a result of an underlying disease process. (Greek, gyn = female + mastos = breast)
axillary tail (of Spence) part of the mammary gland may extend along the inferolateral edge of the pectoralis major toward the axilla (armpit), forming an axillary tail (of Spence). This portion of breast tissue is in the upper-outer quadrant of the breast which is important because 50% of breast cancer is located in this quadrant and in the axillary tail
supernumerary nipples (polythelia) more than the normal number of nipples, may be on the breast or other parts of the body-found along the "milk line" from axilla to groin. These accessory nipples resemble raised nevi (commonly called "moles").
supernumerary breasts (polymastia) a condition in which more than two breasts are present
carcinoma any of the various types of malignant (invasive) neoplasm derived from epithelial tissue in several sites, occuring more frequently in skin, bronchi, stomach, and prostate gland in men, and in the breast, cervix, and skin in women (Greek, carcino- = cancer + -oma = tumor)
mastectomy/lumpectomy amputation of the breast or of an affected portion (Greek, mastos = breast + -ectomy = excision)
mastitis inflammation of the mammary gland (Greek, mastos = breast + -itis = inflammation)
scintigraphy record indicating the intensity, location, and distribution of radioactivity in tissue following the use of radioactive tracer substances
mammogram special imaging examination of the breast to detect breast cancer. The American Cancer Society currently recommends that screening should begin annually at the age of 40 (and earlier in those patients with a family history of breast cancer).

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.